Sort albums by month if two releases of the same artist happen in the same year (#155)

Closes #106

Reviewed-on: #155

src/bin/musichoard-edit.rs

@@ -3,7 +3,7 @@ use std::path::PathBuf;
 use structopt::{clap::AppSettings, StructOpt};
 
 use musichoard::{
-    collection::artist::ArtistId,
+    collection::{album::AlbumId, artist::ArtistId},
     database::json::{backend::JsonDatabaseFileBackend, JsonDatabase},
     MusicHoard, MusicHoardBuilder, NoLibrary,
 };
@@ -22,56 +22,54 @@ struct Opt {
     database_file_path: PathBuf,
 
     #[structopt(subcommand)]
-    category: Category,
+    command: Command,
 }
 
 #[derive(StructOpt, Debug)]
-enum Category {
-    #[structopt(about = "Edit artist information")]
-    Artist(ArtistCommand),
+enum Command {
+    #[structopt(about = "Modify artist information")]
+    Artist(ArtistOpt),
 }
 
-impl Category {
-    fn handle(self, music_hoard: &mut MH) {
-        match self {
-            Category::Artist(artist_command) => artist_command.handle(music_hoard),
-        }
-    }
+#[derive(StructOpt, Debug)]
+struct ArtistOpt {
+    // For some reason, not specyfing the artist name with the `long` name makes StructOpt failed
+    // for inexplicable reason. For example, it won't recognise `Abadde` or `Abadden` as a name and
+    // will insteady try to process it as a command.
+    #[structopt(long, help = "The name of the artist")]
+    name: String,
+
+    #[structopt(subcommand)]
+    command: ArtistCommand,
 }
 
 #[derive(StructOpt, Debug)]
 enum ArtistCommand {
     #[structopt(about = "Add a new artist to the collection")]
-    Add(ArtistValue),
+    Add,
     #[structopt(about = "Remove an artist from the collection")]
-    Remove(ArtistValue),
+    Remove,
     #[structopt(about = "Edit the artist's sort name")]
     Sort(SortCommand),
     #[structopt(name = "musicbrainz", about = "Edit the MusicBrainz URL of an artist")]
     MusicBrainz(MusicBrainzCommand),
-    #[structopt(name = "property", about = "Edit a property of an artist")]
+    #[structopt(about = "Edit a property of an artist")]
     Property(PropertyCommand),
+    #[structopt(about = "Modify the artist's album information")]
+    Album(AlbumOpt),
 }
 
 #[derive(StructOpt, Debug)]
 enum SortCommand {
     #[structopt(about = "Set the provided name as the artist's sort name")]
-    Set(ArtistSortValue),
+    Set(SortValue),
     #[structopt(about = "Clear the artist's sort name")]
-    Clear(ArtistValue),
+    Clear,
 }
 
 #[derive(StructOpt, Debug)]
-struct ArtistValue {
-    #[structopt(help = "The name of the artist")]
-    artist: String,
-}
-
-#[derive(StructOpt, Debug)]
-struct ArtistSortValue {
-    #[structopt(help = "The name of the artist")]
-    artist: String,
-    #[structopt(help = "The sort name of the artist")]
+struct SortValue {
+    #[structopt(help = "The sort name")]
     sort: String,
 }
 
@@ -80,13 +78,11 @@ enum MusicBrainzCommand {
     #[structopt(about = "Set the MusicBrainz URL overwriting any existing value")]
     Set(MusicBrainzValue),
     #[structopt(about = "Clear the MusicBrainz URL)")]
-    Clear(ArtistValue),
+    Clear,
 }
 
 #[derive(StructOpt, Debug)]
 struct MusicBrainzValue {
-    #[structopt(help = "The name of the artist")]
-    artist: String,
     #[structopt(help = "The MusicBrainz URL")]
     url: String,
 }
@@ -105,8 +101,6 @@ enum PropertyCommand {
 
 #[derive(StructOpt, Debug)]
 struct PropertyValue {
-    #[structopt(help = "The name of the artist")]
-    artist: String,
     #[structopt(help = "The name of the property")]
     property: String,
     #[structopt(help = "The list of values")]
@@ -115,101 +109,176 @@ struct PropertyValue {
 
 #[derive(StructOpt, Debug)]
 struct PropertyName {
-    #[structopt(help = "The name of the artist")]
-    artist: String,
     #[structopt(help = "The name of the property")]
     property: String,
 }
 
-impl ArtistCommand {
+#[derive(StructOpt, Debug)]
+struct AlbumOpt {
+    // Using `long` for consistency with `ArtistOpt`.
+    #[structopt(long, help = "The title of the album")]
+    title: String,
+
+    #[structopt(subcommand)]
+    command: AlbumCommand,
+}
+
+#[derive(StructOpt, Debug)]
+enum AlbumCommand {
+    #[structopt(about = "Edit the album's sequence value")]
+    Seq(AlbumSeqCommand),
+}
+
+#[derive(StructOpt, Debug)]
+enum AlbumSeqCommand {
+    #[structopt(about = "Set the sequence value overwriting any existing value")]
+    Set(AlbumSeqValue),
+    #[structopt(about = "Clear the sequence value")]
+    Clear,
+}
+
+#[derive(StructOpt, Debug)]
+struct AlbumSeqValue {
+    #[structopt(help = "The new sequence value")]
+    value: u8,
+}
+
+impl Command {
     fn handle(self, music_hoard: &mut MH) {
         match self {
-            ArtistCommand::Add(artist_value) => {
+            Command::Artist(artist_opt) => artist_opt.handle(music_hoard),
+        }
+    }
+}
+
+impl ArtistOpt {
+    fn handle(self, music_hoard: &mut MH) {
+        self.command.handle(music_hoard, &self.name)
+    }
+}
+
+impl ArtistCommand {
+    fn handle(self, music_hoard: &mut MH, artist_name: &str) {
+        match self {
+            ArtistCommand::Add => {
                 music_hoard
-                    .add_artist(ArtistId::new(artist_value.artist))
+                    .add_artist(ArtistId::new(artist_name))
                     .expect("failed to add artist");
             }
-            ArtistCommand::Remove(artist_value) => {
+            ArtistCommand::Remove => {
                 music_hoard
-                    .remove_artist(ArtistId::new(artist_value.artist))
+                    .remove_artist(ArtistId::new(artist_name))
                     .expect("failed to remove artist");
             }
             ArtistCommand::Sort(sort_command) => {
-                sort_command.handle(music_hoard);
+                sort_command.handle(music_hoard, artist_name);
             }
             ArtistCommand::MusicBrainz(musicbrainz_command) => {
-                musicbrainz_command.handle(music_hoard)
+                musicbrainz_command.handle(music_hoard, artist_name)
             }
             ArtistCommand::Property(property_command) => {
-                property_command.handle(music_hoard);
+                property_command.handle(music_hoard, artist_name);
+            }
+            ArtistCommand::Album(album_opt) => {
+                album_opt.handle(music_hoard, artist_name);
             }
         }
     }
 }
 
 impl SortCommand {
-    fn handle(self, music_hoard: &mut MH) {
+    fn handle(self, music_hoard: &mut MH, artist_name: &str) {
         match self {
             SortCommand::Set(artist_sort_value) => music_hoard
                 .set_artist_sort(
-                    ArtistId::new(artist_sort_value.artist),
+                    ArtistId::new(artist_name),
                     ArtistId::new(artist_sort_value.sort),
                 )
                 .expect("faild to set artist sort name"),
-            SortCommand::Clear(artist_value) => music_hoard
-                .clear_artist_sort(ArtistId::new(artist_value.artist))
+            SortCommand::Clear => music_hoard
+                .clear_artist_sort(ArtistId::new(artist_name))
                 .expect("failed to clear artist sort name"),
         }
     }
 }
 
 impl MusicBrainzCommand {
-    fn handle(self, music_hoard: &mut MH) {
+    fn handle(self, music_hoard: &mut MH, artist_name: &str) {
         match self {
             MusicBrainzCommand::Set(musicbrainz_value) => music_hoard
-                .set_musicbrainz_url(
-                    ArtistId::new(musicbrainz_value.artist),
-                    musicbrainz_value.url,
-                )
+                .set_artist_musicbrainz(ArtistId::new(artist_name), musicbrainz_value.url)
                 .expect("failed to set MusicBrainz URL"),
-            MusicBrainzCommand::Clear(artist_value) => music_hoard
-                .clear_musicbrainz_url(ArtistId::new(artist_value.artist))
+            MusicBrainzCommand::Clear => music_hoard
+                .clear_artist_musicbrainz(ArtistId::new(artist_name))
                 .expect("failed to clear MusicBrainz URL"),
         }
     }
 }
 
 impl PropertyCommand {
-    fn handle(self, music_hoard: &mut MH) {
+    fn handle(self, music_hoard: &mut MH, artist_name: &str) {
         match self {
             PropertyCommand::Add(property_value) => music_hoard
-                .add_to_property(
-                    ArtistId::new(property_value.artist),
+                .add_to_artist_property(
+                    ArtistId::new(artist_name),
                     property_value.property,
                     property_value.values,
                 )
                 .expect("failed to add values to property"),
             PropertyCommand::Remove(property_value) => music_hoard
-                .remove_from_property(
-                    ArtistId::new(property_value.artist),
+                .remove_from_artist_property(
+                    ArtistId::new(artist_name),
                     property_value.property,
                     property_value.values,
                 )
                 .expect("failed to remove values from property"),
             PropertyCommand::Set(property_value) => music_hoard
-                .set_property(
-                    ArtistId::new(property_value.artist),
+                .set_artist_property(
+                    ArtistId::new(artist_name),
                     property_value.property,
                     property_value.values,
                 )
                 .expect("failed to set property"),
             PropertyCommand::Clear(property_name) => music_hoard
-                .clear_property(ArtistId::new(property_name.artist), property_name.property)
+                .clear_artist_property(ArtistId::new(artist_name), property_name.property)
                 .expect("failed to clear property"),
         }
     }
 }
 
+impl AlbumOpt {
+    fn handle(self, music_hoard: &mut MH, artist_name: &str) {
+        self.command.handle(music_hoard, artist_name, &self.title)
+    }
+}
+
+impl AlbumCommand {
+    fn handle(self, music_hoard: &mut MH, artist_name: &str, album_name: &str) {
+        match self {
+            AlbumCommand::Seq(seq_command) => {
+                seq_command.handle(music_hoard, artist_name, album_name);
+            }
+        }
+    }
+}
+
+impl AlbumSeqCommand {
+    fn handle(self, music_hoard: &mut MH, artist_name: &str, album_name: &str) {
+        match self {
+            AlbumSeqCommand::Set(seq_value) => music_hoard
+                .set_album_seq(
+                    ArtistId::new(artist_name),
+                    AlbumId::new(album_name),
+                    seq_value.value,
+                )
+                .expect("failed to set sequence value"),
+            AlbumSeqCommand::Clear => music_hoard
+                .clear_album_seq(ArtistId::new(artist_name), AlbumId::new(album_name))
+                .expect("failed to clear sequence value"),
+        }
+    }
+}
+
 fn main() {
     let opt = Opt::from_args();
 
@@ -219,5 +288,5 @@ fn main() {
         .set_database(db)
         .build()
         .expect("failed to initialise MusicHoard");
-    opt.category.handle(&mut music_hoard);
+    opt.command.handle(&mut music_hoard);
 }

src/core/collection/album.rs

@@ -1,7 +1,10 @@
-use std::mem;
+use std::{
+    fmt::{self, Display},
+    mem,
+};
 
 use crate::core::collection::{
-    merge::{Merge, MergeSorted},
+    merge::{Merge, MergeSorted, WithId},
     track::Track,
 };
 
@@ -9,19 +12,106 @@ use crate::core::collection::{
 #[derive(Clone, Debug, PartialEq, Eq)]
 pub struct Album {
     pub id: AlbumId,
+    pub date: AlbumDate,
+    pub seq: AlbumSeq,
     pub tracks: Vec<Track>,
 }
 
+impl WithId for Album {
+    type Id = AlbumId;
+
+    fn id(&self) -> &Self::Id {
+        &self.id
+    }
+}
+
 /// The album identifier.
 #[derive(Clone, Debug, PartialEq, PartialOrd, Ord, Eq, Hash)]
 pub struct AlbumId {
-    pub year: u32,
     pub title: String,
 }
 
+// There are crates for handling dates, but we don't need much complexity beyond year-month-day.
+/// The album's release date.
+#[derive(Clone, Debug, Default, PartialEq, PartialOrd, Ord, Eq, Hash)]
+pub struct AlbumDate {
+    pub year: u32,
+    pub month: AlbumMonth,
+    pub day: u8,
+}
+
+impl Display for AlbumDate {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        if self.month.is_none() {
+            write!(f, "{}", self.year)
+        } else if self.day == 0 {
+            write!(f, "{}‐{:02}", self.year, self.month as u8)
+        } else {
+            write!(f, "{}‐{:02}‐{:02}", self.year, self.month as u8, self.day)
+        }
+    }
+}
+
+/// The album's sequence to determine order when two or more albums have the same release date.
+#[derive(Clone, Copy, Debug, Default, PartialEq, PartialOrd, Ord, Eq, Hash)]
+pub struct AlbumSeq(pub u8);
+
+#[repr(u8)]
+#[derive(Clone, Copy, Debug, Default, PartialEq, PartialOrd, Ord, Eq, Hash)]
+pub enum AlbumMonth {
+    #[default]
+    None = 0,
+    January = 1,
+    February = 2,
+    March = 3,
+    April = 4,
+    May = 5,
+    June = 6,
+    July = 7,
+    August = 8,
+    September = 9,
+    October = 10,
+    November = 11,
+    December = 12,
+}
+
+impl From<u8> for AlbumMonth {
+    fn from(value: u8) -> Self {
+        match value {
+            1 => AlbumMonth::January,
+            2 => AlbumMonth::February,
+            3 => AlbumMonth::March,
+            4 => AlbumMonth::April,
+            5 => AlbumMonth::May,
+            6 => AlbumMonth::June,
+            7 => AlbumMonth::July,
+            8 => AlbumMonth::August,
+            9 => AlbumMonth::September,
+            10 => AlbumMonth::October,
+            11 => AlbumMonth::November,
+            12 => AlbumMonth::December,
+            _ => AlbumMonth::None,
+        }
+    }
+}
+
+impl AlbumMonth {
+    fn is_none(&self) -> bool {
+        matches!(self, AlbumMonth::None)
+    }
+}
+
 impl Album {
-    pub fn get_sort_key(&self) -> &AlbumId {
-        &self.id
+    pub fn get_sort_key(&self) -> (&AlbumDate, &AlbumSeq, &AlbumId) {
+        (&self.date, &self.seq, &self.id)
+    }
+
+    pub fn set_seq(&mut self, seq: AlbumSeq) {
+        self.seq = seq;
+    }
+
+    pub fn clear_seq(&mut self) {
+        self.seq = AlbumSeq::default();
     }
 }
 
@@ -33,24 +123,140 @@ impl PartialOrd for Album {
 
 impl Ord for Album {
     fn cmp(&self, other: &Self) -> std::cmp::Ordering {
-        self.id.cmp(&other.id)
+        self.get_sort_key().cmp(&other.get_sort_key())
     }
 }
 
 impl Merge for Album {
     fn merge_in_place(&mut self, other: Self) {
         assert_eq!(self.id, other.id);
+        self.seq = std::cmp::max(self.seq, other.seq);
         let tracks = mem::take(&mut self.tracks);
         self.tracks = MergeSorted::new(tracks.into_iter(), other.tracks.into_iter()).collect();
     }
 }
 
+impl<S: Into<String>> From<S> for AlbumId {
+    fn from(value: S) -> Self {
+        AlbumId::new(value)
+    }
+}
+
+impl AsRef<AlbumId> for AlbumId {
+    fn as_ref(&self) -> &AlbumId {
+        self
+    }
+}
+
+impl AlbumId {
+    pub fn new<S: Into<String>>(name: S) -> AlbumId {
+        AlbumId { title: name.into() }
+    }
+}
+
+impl Display for AlbumId {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "{}", self.title)
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use crate::core::testmod::FULL_COLLECTION;
 
     use super::*;
 
+    impl AlbumDate {
+        fn new<M: Into<AlbumMonth>>(year: u32, month: M, day: u8) -> Self {
+            AlbumDate {
+                year,
+                month: month.into(),
+                day,
+            }
+        }
+    }
+
+    #[test]
+    fn album_month() {
+        assert_eq!(<u8 as Into<AlbumMonth>>::into(0), AlbumMonth::None);
+        assert_eq!(<u8 as Into<AlbumMonth>>::into(1), AlbumMonth::January);
+        assert_eq!(<u8 as Into<AlbumMonth>>::into(2), AlbumMonth::February);
+        assert_eq!(<u8 as Into<AlbumMonth>>::into(3), AlbumMonth::March);
+        assert_eq!(<u8 as Into<AlbumMonth>>::into(4), AlbumMonth::April);
+        assert_eq!(<u8 as Into<AlbumMonth>>::into(5), AlbumMonth::May);
+        assert_eq!(<u8 as Into<AlbumMonth>>::into(6), AlbumMonth::June);
+        assert_eq!(<u8 as Into<AlbumMonth>>::into(7), AlbumMonth::July);
+        assert_eq!(<u8 as Into<AlbumMonth>>::into(8), AlbumMonth::August);
+        assert_eq!(<u8 as Into<AlbumMonth>>::into(9), AlbumMonth::September);
+        assert_eq!(<u8 as Into<AlbumMonth>>::into(10), AlbumMonth::October);
+        assert_eq!(<u8 as Into<AlbumMonth>>::into(11), AlbumMonth::November);
+        assert_eq!(<u8 as Into<AlbumMonth>>::into(12), AlbumMonth::December);
+        assert_eq!(<u8 as Into<AlbumMonth>>::into(13), AlbumMonth::None);
+        assert_eq!(<u8 as Into<AlbumMonth>>::into(255), AlbumMonth::None);
+    }
+
+    #[test]
+    fn album_display() {
+        assert_eq!(AlbumDate::default().to_string(), "0");
+        assert_eq!(AlbumDate::new(1990, 0, 0).to_string(), "1990");
+        assert_eq!(AlbumDate::new(1990, 5, 0).to_string(), "1990‐05");
+        assert_eq!(AlbumDate::new(1990, 5, 6).to_string(), "1990‐05‐06");
+    }
+
+    #[test]
+    fn same_date_seq_cmp() {
+        let date = AlbumDate::new(2024, 3, 2);
+
+        let album_id_1 = AlbumId {
+            title: String::from("album z"),
+        };
+        let album_1 = Album {
+            id: album_id_1,
+            date: date.clone(),
+            seq: AlbumSeq(1),
+            tracks: vec![],
+        };
+
+        let album_id_2 = AlbumId {
+            title: String::from("album a"),
+        };
+        let album_2 = Album {
+            id: album_id_2,
+            date: date.clone(),
+            seq: AlbumSeq(2),
+            tracks: vec![],
+        };
+
+        assert_ne!(album_1, album_2);
+        assert!(album_1 < album_2);
+    }
+
+    #[test]
+    fn set_clear_seq() {
+        let mut album = Album {
+            id: "an album".into(),
+            date: AlbumDate::default(),
+            seq: AlbumSeq::default(),
+            tracks: vec![],
+        };
+
+        assert_eq!(album.seq, AlbumSeq(0));
+
+        // Setting a seq on an album.
+        album.set_seq(AlbumSeq(6));
+        assert_eq!(album.seq, AlbumSeq(6));
+
+        album.set_seq(AlbumSeq(6));
+        assert_eq!(album.seq, AlbumSeq(6));
+
+        album.set_seq(AlbumSeq(8));
+        assert_eq!(album.seq, AlbumSeq(8));
+
+        // Clearing seq.
+        album.clear_seq();
+        assert_eq!(album.seq, AlbumSeq(0));
+    }
+
     #[test]
     fn merge_album_no_overlap() {
         let left = FULL_COLLECTION[0].albums[0].to_owned();
@@ -64,9 +270,9 @@ mod tests {
         let merged = left.clone().merge(right.clone());
         assert_eq!(expected, merged);
 
-        // Non-overlapping merge should be commutative.
+        // Non-overlapping merge should be commutative in the tracks.
         let merged = right.clone().merge(left.clone());
-        assert_eq!(expected, merged);
+        assert_eq!(expected.tracks, merged.tracks);
     }
 
     #[test]

src/core/collection/artist.rs

@@ -2,6 +2,7 @@ use std::{
     collections::HashMap,
     fmt::{self, Debug, Display},
     mem,
+    str::FromStr,
 };
 
 use url::Url;
@@ -9,7 +10,7 @@ use uuid::Uuid;
 
 use crate::core::collection::{
     album::Album,
-    merge::{Merge, MergeSorted},
+    merge::{Merge, MergeCollections, WithId},
     Error,
 };
 
@@ -23,6 +24,14 @@ pub struct Artist {
     pub albums: Vec<Album>,
 }
 
+impl WithId for Artist {
+    type Id = ArtistId;
+
+    fn id(&self) -> &Self::Id {
+        &self.id
+    }
+}
+
 /// The artist identifier.
 #[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
 pub struct ArtistId {
@@ -41,8 +50,8 @@ impl Artist {
         }
     }
 
-    pub fn get_sort_key(&self) -> &ArtistId {
-        self.sort.as_ref().unwrap_or(&self.id)
+    pub fn get_sort_key(&self) -> (&ArtistId,) {
+        (self.sort.as_ref().unwrap_or(&self.id),)
     }
 
     pub fn set_sort_key<SORT: Into<ArtistId>>(&mut self, sort: SORT) {
@@ -114,18 +123,26 @@ impl PartialOrd for Artist {
 
 impl Ord for Artist {
     fn cmp(&self, other: &Self) -> std::cmp::Ordering {
-        self.get_sort_key().cmp(other.get_sort_key())
+        self.get_sort_key().cmp(&other.get_sort_key())
     }
 }
 
 impl Merge for Artist {
     fn merge_in_place(&mut self, other: Self) {
         assert_eq!(self.id, other.id);
+
         self.sort = self.sort.take().or(other.sort);
         self.musicbrainz = self.musicbrainz.take().or(other.musicbrainz);
         self.properties.merge_in_place(other.properties);
+
         let albums = mem::take(&mut self.albums);
-        self.albums = MergeSorted::new(albums.into_iter(), other.albums.into_iter()).collect();
+        self.albums = MergeCollections::merge_iter(albums, other.albums);
+    }
+}
+
+impl<S: Into<String>> From<S> for ArtistId {
+    fn from(value: S) -> Self {
+        ArtistId::new(value)
     }
 }
 
@@ -159,9 +176,13 @@ pub struct MusicBrainz(Url);
 
 impl MusicBrainz {
     /// Validate and wrap a MusicBrainz URL.
-    pub fn new<S: AsRef<str>>(url: S) -> Result<Self, Error> {
+    pub fn new_from_str<S: AsRef<str>>(url: S) -> Result<Self, Error> {
         let url = Url::parse(url.as_ref())?;
+        Self::new_from_url(url)
+    }
 
+    /// Validate and wrap a MusicBrainz URL.
+    pub fn new_from_url(url: Url) -> Result<Self, Error> {
         if !url
             .domain()
             .map(|u| u.ends_with("musicbrainz.org"))
@@ -189,11 +210,36 @@ impl AsRef<str> for MusicBrainz {
     }
 }
 
-impl TryFrom<&str> for MusicBrainz {
+impl FromStr for MusicBrainz {
+    type Err = Error;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        MusicBrainz::new_from_str(s)
+    }
+}
+
+// A blanket TryFrom would be better, but https://stackoverflow.com/a/64407892
+macro_rules! impl_try_from_for_musicbrainz {
+    ($from:ty) => {
+        impl TryFrom<$from> for MusicBrainz {
+            type Error = Error;
+
+            fn try_from(value: $from) -> Result<Self, Self::Error> {
+                MusicBrainz::new_from_str(value)
+            }
+        }
+    };
+}
+
+impl_try_from_for_musicbrainz!(&str);
+impl_try_from_for_musicbrainz!(&String);
+impl_try_from_for_musicbrainz!(String);
+
+impl TryFrom<Url> for MusicBrainz {
     type Error = Error;
 
-    fn try_from(value: &str) -> Result<Self, Self::Error> {
-        MusicBrainz::new(value)
+    fn try_from(value: Url) -> Result<Self, Self::Error> {
+        MusicBrainz::new_from_url(value)
     }
 }
 
@@ -220,34 +266,35 @@ mod tests {
     #[test]
     fn musicbrainz() {
         let uuid = "d368baa8-21ca-4759-9731-0b2753071ad8";
-        let url = format!("https://musicbrainz.org/artist/{uuid}");
-        let mb = MusicBrainz::new(&url).unwrap();
-        assert_eq!(url, mb.as_ref());
+        let url_str = format!("https://musicbrainz.org/artist/{uuid}");
+        let url: Url = url_str.as_str().try_into().unwrap();
+        let mb: MusicBrainz = url.try_into().unwrap();
+        assert_eq!(url_str, mb.as_ref());
         assert_eq!(uuid, mb.mbid());
 
         let url = "not a url at all".to_string();
         let expected_error: Error = url::ParseError::RelativeUrlWithoutBase.into();
-        let actual_error = MusicBrainz::new(url).unwrap_err();
+        let actual_error = MusicBrainz::from_str(&url).unwrap_err();
         assert_eq!(actual_error, expected_error);
         assert_eq!(actual_error.to_string(), expected_error.to_string());
 
         let url = "https://musicbrainz.org/artist/i-am-not-a-uuid".to_string();
         let expected_error: Error = Uuid::try_parse("i-am-not-a-uuid").unwrap_err().into();
-        let actual_error = MusicBrainz::new(url).unwrap_err();
+        let actual_error = MusicBrainz::from_str(&url).unwrap_err();
         assert_eq!(actual_error, expected_error);
         assert_eq!(actual_error.to_string(), expected_error.to_string());
 
         let url = "https://musicbrainz.org/artist".to_string();
         let expected_error = Error::UrlError(format!("invalid MusicBrainz URL: {url}"));
-        let actual_error = MusicBrainz::new(&url).unwrap_err();
+        let actual_error = MusicBrainz::from_str(&url).unwrap_err();
         assert_eq!(actual_error, expected_error);
         assert_eq!(actual_error.to_string(), expected_error.to_string());
     }
 
     #[test]
     fn urls() {
-        assert!(MusicBrainz::new(MUSICBRAINZ).is_ok());
-        assert!(MusicBrainz::new(MUSICBUTLER).is_err());
+        assert!(MusicBrainz::from_str(MUSICBRAINZ).is_ok());
+        assert!(MusicBrainz::from_str(MUSICBUTLER).is_err());
     }
 
     #[test]
@@ -256,11 +303,11 @@ mod tests {
         let sort_id_1 = ArtistId::new("sort id 1");
         let sort_id_2 = ArtistId::new("sort id 2");
 
-        let mut artist = Artist::new(artist_id.clone());
+        let mut artist = Artist::new(&artist_id.name);
 
         assert_eq!(artist.id, artist_id);
         assert_eq!(artist.sort, None);
-        assert_eq!(artist.get_sort_key(), &artist_id);
+        assert_eq!(artist.get_sort_key(), (&artist_id,));
         assert!(artist < Artist::new(sort_id_1.clone()));
         assert!(artist < Artist::new(sort_id_2.clone()));
 
@@ -268,7 +315,7 @@ mod tests {
 
         assert_eq!(artist.id, artist_id);
         assert_eq!(artist.sort.as_ref(), Some(&sort_id_1));
-        assert_eq!(artist.get_sort_key(), &sort_id_1);
+        assert_eq!(artist.get_sort_key(), (&sort_id_1,));
         assert!(artist > Artist::new(artist_id.clone()));
         assert!(artist < Artist::new(sort_id_2.clone()));
 
@@ -276,7 +323,7 @@ mod tests {
 
         assert_eq!(artist.id, artist_id);
         assert_eq!(artist.sort.as_ref(), Some(&sort_id_2));
-        assert_eq!(artist.get_sort_key(), &sort_id_2);
+        assert_eq!(artist.get_sort_key(), (&sort_id_2,));
         assert!(artist > Artist::new(artist_id.clone()));
         assert!(artist > Artist::new(sort_id_1.clone()));
 
@@ -284,7 +331,7 @@ mod tests {
 
         assert_eq!(artist.id, artist_id);
         assert_eq!(artist.sort, None);
-        assert_eq!(artist.get_sort_key(), &artist_id);
+        assert_eq!(artist.get_sort_key(), (&artist_id,));
         assert!(artist < Artist::new(sort_id_1.clone()));
         assert!(artist < Artist::new(sort_id_2.clone()));
     }
@@ -307,14 +354,14 @@ mod tests {
 
         // Setting a URL on an artist.
         artist.set_musicbrainz_url(MUSICBRAINZ.try_into().unwrap());
-        _ = expected.insert(MusicBrainz::new(MUSICBRAINZ).unwrap());
+        _ = expected.insert(MUSICBRAINZ.try_into().unwrap());
         assert_eq!(artist.musicbrainz, expected);
 
         artist.set_musicbrainz_url(MUSICBRAINZ.try_into().unwrap());
         assert_eq!(artist.musicbrainz, expected);
 
         artist.set_musicbrainz_url(MUSICBRAINZ_2.try_into().unwrap());
-        _ = expected.insert(MusicBrainz::new(MUSICBRAINZ_2).unwrap());
+        _ = expected.insert(MUSICBRAINZ_2.try_into().unwrap());
         assert_eq!(artist.musicbrainz, expected);
 
         // Clearing URLs.

src/core/collection/merge.rs

@@ -1,4 +1,4 @@
-use std::{cmp::Ordering, collections::HashMap, hash::Hash, iter::Peekable};
+use std::{cmp::Ordering, collections::HashMap, hash::Hash, iter::Peekable, marker::PhantomData};
 
 /// A trait for merging two objects. The merge is asymmetric with the left argument considered to be
 /// the primary whose properties are to be kept in case of collisions.
@@ -79,3 +79,45 @@ where
         }
     }
 }
+
+pub trait WithId {
+    type Id;
+
+    fn id(&self) -> &Self::Id;
+}
+
+pub struct MergeCollections<ID, T, IT> {
+    _id: PhantomData<ID>,
+    _t: PhantomData<T>,
+    _it: PhantomData<IT>,
+}
+
+impl<ID, T, IT> MergeCollections<ID, T, IT>
+where
+    ID: Eq + Hash + Clone,
+    T: WithId<Id = ID> + Merge + Ord,
+    IT: IntoIterator<Item = T>,
+{
+    pub fn merge_iter(primary: IT, secondary: IT) -> Vec<T> {
+        let primary = primary
+            .into_iter()
+            .map(|item| (item.id().clone(), item))
+            .collect();
+        Self::merge(primary, secondary)
+    }
+
+    pub fn merge(mut primary: HashMap<ID, T>, secondary: IT) -> Vec<T> {
+        for secondary_item in secondary {
+            if let Some(ref mut primary_item) = primary.get_mut(secondary_item.id()) {
+                primary_item.merge_in_place(secondary_item);
+            } else {
+                primary.insert(secondary_item.id().clone(), secondary_item);
+            }
+        }
+
+        let mut collection: Vec<T> = primary.into_values().collect();
+        collection.sort_unstable();
+
+        collection
+    }
+}

src/core/collection/mod.rs

@@ -5,7 +5,7 @@ pub mod artist;
 pub mod track;
 
 mod merge;
-pub use merge::Merge;
+pub use merge::MergeCollections;
 
 use std::fmt::{self, Display};
 

src/core/collection/track.rs

@@ -4,33 +4,37 @@ use crate::core::collection::merge::Merge;
 #[derive(Clone, Debug, PartialEq, Eq)]
 pub struct Track {
     pub id: TrackId,
+    pub number: TrackNum,
     pub artist: Vec<String>,
-    pub quality: Quality,
+    pub quality: TrackQuality,
 }
 
 /// The track identifier.
 #[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
 pub struct TrackId {
-    pub number: u32,
     pub title: String,
 }
 
+/// The track number.
+#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub struct TrackNum(pub u32);
+
 /// The track quality. Combines format and bitrate information.
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
-pub struct Quality {
-    pub format: Format,
+pub struct TrackQuality {
+    pub format: TrackFormat,
     pub bitrate: u32,
 }
 
 impl Track {
-    pub fn get_sort_key(&self) -> &TrackId {
-        &self.id
+    pub fn get_sort_key(&self) -> (&TrackNum, &TrackId) {
+        (&self.number, &self.id)
     }
 }
 
 /// The track file format.
 #[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
-pub enum Format {
+pub enum TrackFormat {
     Flac,
     Mp3,
 }
@@ -43,7 +47,7 @@ impl PartialOrd for Track {
 
 impl Ord for Track {
     fn cmp(&self, other: &Self) -> std::cmp::Ordering {
-        self.id.cmp(&other.id)
+        self.get_sort_key().cmp(&other.get_sort_key())
     }
 }
 
@@ -61,20 +65,21 @@ mod tests {
     fn merge_track() {
         let left = Track {
             id: TrackId {
-                number: 4,
                 title: String::from("a title"),
             },
+            number: TrackNum(4),
             artist: vec![String::from("left artist")],
-            quality: Quality {
-                format: Format::Flac,
+            quality: TrackQuality {
+                format: TrackFormat::Flac,
                 bitrate: 1411,
             },
         };
         let right = Track {
             id: left.id.clone(),
+            number: left.number,
             artist: vec![String::from("right artist")],
-            quality: Quality {
-                format: Format::Mp3,
+            quality: TrackQuality {
+                format: TrackFormat::Mp3,
                 bitrate: 320,
             },
         };

src/core/database/json/mod.rs

@@ -72,7 +72,7 @@ mod tests {
     use mockall::predicate;
 
     use crate::core::{
-        collection::{artist::Artist, Collection},
+        collection::{album::AlbumDate, artist::Artist, Collection},
         testmod::FULL_COLLECTION,
     };
 
@@ -82,7 +82,10 @@ mod tests {
     fn expected() -> Collection {
         let mut expected = FULL_COLLECTION.to_owned();
         for artist in expected.iter_mut() {
-            artist.albums.clear();
+            for album in artist.albums.iter_mut() {
+                album.date = AlbumDate::default();
+                album.tracks.clear();
+            }
         }
         expected
     }

src/core/database/json/testmod.rs

@@ -1,5 +1,5 @@
 pub static DATABASE_JSON: &str = "{\
-    \"V20240210\":\
+    \"V20240302\":\
     [\
     {\
     \"name\":\"Album_Artist ‘A’\",\
@@ -8,7 +8,11 @@ pub static DATABASE_JSON: &str = "{\
     \"properties\":{\
     \"MusicButler\":[\"https://www.musicbutler.io/artist-page/000000000\"],\
     \"Qobuz\":[\"https://www.qobuz.com/nl-nl/interpreter/artist-a/download-streaming-albums\"]\
-    }\
+    },\
+    \"albums\":[\
+    {\"title\":\"album_title a.a\",\"seq\":1},\
+    {\"title\":\"album_title a.b\",\"seq\":1}\
+    ]\
     },\
     {\
     \"name\":\"Album_Artist ‘B’\",\
@@ -21,19 +25,33 @@ pub static DATABASE_JSON: &str = "{\
     \"https://www.musicbutler.io/artist-page/111111112\"\
     ],\
     \"Qobuz\":[\"https://www.qobuz.com/nl-nl/interpreter/artist-b/download-streaming-albums\"]\
-    }\
+    },\
+    \"albums\":[\
+    {\"title\":\"album_title b.a\",\"seq\":1},\
+    {\"title\":\"album_title b.b\",\"seq\":3},\
+    {\"title\":\"album_title b.c\",\"seq\":2},\
+    {\"title\":\"album_title b.d\",\"seq\":4}\
+    ]\
     },\
     {\
     \"name\":\"The Album_Artist ‘C’\",\
     \"sort\":\"Album_Artist ‘C’, The\",\
     \"musicbrainz\":\"https://musicbrainz.org/artist/11111111-1111-1111-1111-111111111111\",\
-    \"properties\":{}\
+    \"properties\":{},\
+    \"albums\":[\
+    {\"title\":\"album_title c.a\",\"seq\":0},\
+    {\"title\":\"album_title c.b\",\"seq\":0}\
+    ]\
     },\
     {\
     \"name\":\"Album_Artist ‘D’\",\
     \"sort\":null,\
     \"musicbrainz\":null,\
-    \"properties\":{}\
+    \"properties\":{},\
+    \"albums\":[\
+    {\"title\":\"album_title d.a\",\"seq\":0},\
+    {\"title\":\"album_title d.b\",\"seq\":0}\
+    ]\
     }\
     ]\
     }";

src/core/database/serde/deserialize.rs

@@ -2,15 +2,19 @@ use std::collections::HashMap;
 
 use serde::Deserialize;
 
-use crate::{
-    collection::artist::{ArtistId, MusicBrainz},
-    core::{
-        collection::{artist::Artist, Collection},
-        database::{serde::Database, LoadError},
+use crate::core::{
+    collection::{
+        album::{Album, AlbumDate, AlbumId, AlbumSeq},
+        artist::{Artist, ArtistId},
+        Collection,
     },
+    database::LoadError,
 };
 
-pub type DeserializeDatabase = Database<DeserializeArtist>;
+#[derive(Debug, Deserialize)]
+pub enum DeserializeDatabase {
+    V20240302(Vec<DeserializeArtist>),
+}
 
 #[derive(Debug, Deserialize)]
 pub struct DeserializeArtist {
@@ -18,6 +22,13 @@ pub struct DeserializeArtist {
     sort: Option<String>,
     musicbrainz: Option<String>,
     properties: HashMap<String, Vec<String>>,
+    albums: Vec<DeserializeAlbum>,
+}
+
+#[derive(Debug, Deserialize)]
+pub struct DeserializeAlbum {
+    title: String,
+    seq: u8,
 }
 
 impl TryFrom<DeserializeDatabase> for Collection {
@@ -25,7 +36,7 @@ impl TryFrom<DeserializeDatabase> for Collection {
 
     fn try_from(database: DeserializeDatabase) -> Result<Self, Self::Error> {
         match database {
-            Database::V20240210(collection) => collection
+            DeserializeDatabase::V20240302(collection) => collection
                 .into_iter()
                 .map(|artist| artist.try_into())
                 .collect(),
@@ -40,9 +51,20 @@ impl TryFrom<DeserializeArtist> for Artist {
         Ok(Artist {
             id: ArtistId::new(artist.name),
             sort: artist.sort.map(ArtistId::new),
-            musicbrainz: artist.musicbrainz.map(MusicBrainz::new).transpose()?,
+            musicbrainz: artist.musicbrainz.map(TryInto::try_into).transpose()?,
             properties: artist.properties,
-            albums: vec![],
+            albums: artist.albums.into_iter().map(Into::into).collect(),
         })
     }
 }
+
+impl From<DeserializeAlbum> for Album {
+    fn from(album: DeserializeAlbum) -> Self {
+        Album {
+            id: AlbumId { title: album.title },
+            date: AlbumDate::default(),
+            seq: AlbumSeq(album.seq),
+            tracks: vec![],
+        }
+    }
+}

src/core/database/serde/mod.rs

@@ -2,10 +2,3 @@
 
 pub mod deserialize;
 pub mod serialize;
-
-use serde::{Deserialize, Serialize};
-
-#[derive(Debug, Serialize, Deserialize)]
-pub enum Database<ARTIST> {
-    V20240210(Vec<ARTIST>),
-}

src/core/database/serde/serialize.rs

@@ -2,12 +2,12 @@ use std::collections::BTreeMap;
 
 use serde::Serialize;
 
-use crate::core::{
-    collection::{artist::Artist, Collection},
-    database::serde::Database,
-};
+use crate::core::collection::{album::Album, artist::Artist, Collection};
 
-pub type SerializeDatabase<'a> = Database<SerializeArtist<'a>>;
+#[derive(Debug, Serialize)]
+pub enum SerializeDatabase<'a> {
+    V20240302(Vec<SerializeArtist<'a>>),
+}
 
 #[derive(Debug, Serialize)]
 pub struct SerializeArtist<'a> {
@@ -15,11 +15,18 @@ pub struct SerializeArtist<'a> {
     sort: Option<&'a str>,
     musicbrainz: Option<&'a str>,
     properties: BTreeMap<&'a str, &'a Vec<String>>,
+    albums: Vec<SerializeAlbum<'a>>,
+}
+
+#[derive(Debug, Serialize)]
+pub struct SerializeAlbum<'a> {
+    title: &'a str,
+    seq: u8,
 }
 
 impl<'a> From<&'a Collection> for SerializeDatabase<'a> {
     fn from(collection: &'a Collection) -> Self {
-        Database::V20240210(collection.iter().map(|artist| artist.into()).collect())
+        SerializeDatabase::V20240302(collection.iter().map(Into::into).collect())
     }
 }
 
@@ -34,6 +41,16 @@ impl<'a> From<&'a Artist> for SerializeArtist<'a> {
                 .iter()
                 .map(|(k, v)| (k.as_ref(), v))
                 .collect(),
+            albums: artist.albums.iter().map(Into::into).collect(),
+        }
+    }
+}
+
+impl<'a> From<&'a Album> for SerializeAlbum<'a> {
+    fn from(album: &'a Album) -> Self {
+        SerializeAlbum {
+            title: &album.id.title,
+            seq: album.seq.0,
         }
     }
 }

src/core/library/beets/mod.rs

@@ -7,7 +7,7 @@ pub mod executor;
 use mockall::automock;
 
 use crate::core::{
-    collection::track::Format,
+    collection::track::TrackFormat,
     library::{Error, Field, ILibrary, Item, Query},
 };
 
@@ -27,6 +27,10 @@ const LIST_FORMAT_ARG: &str = concat!(
     list_format_separator!(),
     "$year",
     list_format_separator!(),
+    "$month",
+    list_format_separator!(),
+    "$day",
+    list_format_separator!(),
     "$album",
     list_format_separator!(),
     "$track",
@@ -42,6 +46,21 @@ const LIST_FORMAT_ARG: &str = concat!(
 const TRACK_FORMAT_FLAC: &str = "FLAC";
 const TRACK_FORMAT_MP3: &str = "MP3";
 
+fn format_to_str(format: &TrackFormat) -> &'static str {
+    match format {
+        TrackFormat::Flac => TRACK_FORMAT_FLAC,
+        TrackFormat::Mp3 => TRACK_FORMAT_MP3,
+    }
+}
+
+fn str_to_format(format: &str) -> Option<TrackFormat> {
+    match format {
+        TRACK_FORMAT_FLAC => Some(TrackFormat::Flac),
+        TRACK_FORMAT_MP3 => Some(TrackFormat::Mp3),
+        _ => None,
+    }
+}
+
 trait ToBeetsArg {
     fn to_arg(&self, include: bool) -> String;
 }
@@ -57,10 +76,13 @@ impl ToBeetsArg for Field {
             Field::AlbumArtist(ref s) => format!("{negate}albumartist:{s}"),
             Field::AlbumArtistSort(ref s) => format!("{negate}albumartist_sort:{s}"),
             Field::AlbumYear(ref u) => format!("{negate}year:{u}"),
+            Field::AlbumMonth(ref e) => format!("{negate}month:{}", *e as u8),
+            Field::AlbumDay(ref u) => format!("{negate}day:{u}"),
             Field::AlbumTitle(ref s) => format!("{negate}album:{s}"),
             Field::TrackNumber(ref u) => format!("{negate}track:{u}"),
             Field::TrackTitle(ref s) => format!("{negate}title:{s}"),
             Field::TrackArtist(ref v) => format!("{negate}artist:{}", v.join("; ")),
+            Field::TrackFormat(ref f) => format!("{negate}format:{}", format_to_str(f)),
             Field::All(ref s) => format!("{negate}{s}"),
         }
     }
@@ -127,36 +149,38 @@ impl<BLE: IBeetsLibraryExecutor> ILibraryPrivate for BeetsLibrary<BLE> {
             }
 
             let split: Vec<&str> = line.split(LIST_FORMAT_SEPARATOR).collect();
-            if split.len() != 9 {
+            if split.len() != 11 {
                 return Err(Error::Invalid(line.to_string()));
             }
 
             let album_artist = split[0].to_string();
-            let album_artist_sort = if !split[1].is_empty() {
-                Some(split[1].to_string())
-            } else {
-                None
+            let album_artist_sort = match !split[1].is_empty() {
+                true => Some(split[1].to_string()),
+                false => None,
             };
             let album_year = split[2].parse::<u32>()?;
-            let album_title = split[3].to_string();
-            let track_number = split[4].parse::<u32>()?;
-            let track_title = split[5].to_string();
-            let track_artist = split[6]
+            let album_month = split[3].parse::<u8>()?.into();
+            let album_day = split[4].parse::<u8>()?;
+            let album_title = split[5].to_string();
+            let track_number = split[6].parse::<u32>()?;
+            let track_title = split[7].to_string();
+            let track_artist = split[8]
                 .to_string()
                 .split("; ")
                 .map(|s| s.to_owned())
                 .collect();
-            let track_format = match split[7].to_string().as_str() {
-                TRACK_FORMAT_FLAC => Format::Flac,
-                TRACK_FORMAT_MP3 => Format::Mp3,
-                _ => return Err(Error::Invalid(line.to_string())),
+            let track_format = match str_to_format(split[9].to_string().as_str()) {
+                Some(format) => format,
+                None => return Err(Error::Invalid(line.to_string())),
             };
-            let track_bitrate = split[8].trim_end_matches("kbps").parse::<u32>()?;
+            let track_bitrate = split[10].trim_end_matches("kbps").parse::<u32>()?;
 
             items.push(Item {
                 album_artist,
                 album_artist_sort,
                 album_year,
+                album_month,
+                album_day,
                 album_title,
                 track_number,
                 track_title,
@@ -177,7 +201,7 @@ mod testmod;
 mod tests {
     use mockall::predicate;
 
-    use crate::core::library::testmod::LIBRARY_ITEMS;
+    use crate::{collection::album::AlbumMonth, core::library::testmod::LIBRARY_ITEMS};
 
     use super::*;
     use testmod::LIBRARY_BEETS;
@@ -191,6 +215,7 @@ mod tests {
                 String::from("some.artist.1"),
                 String::from("some.artist.2"),
             ]))
+            .exclude(Field::TrackFormat(TrackFormat::Mp3))
             .exclude(Field::All(String::from("some.all")))
             .to_args();
         query.sort();
@@ -199,6 +224,7 @@ mod tests {
             query,
             vec![
                 String::from("^album:some.album"),
+                String::from("^format:MP3"),
                 String::from("^some.all"),
                 String::from("artist:some.artist.1; some.artist.2"),
                 String::from("track:5"),
@@ -209,7 +235,10 @@ mod tests {
             .exclude(Field::AlbumArtist(String::from("some.albumartist")))
             .exclude(Field::AlbumArtistSort(String::from("some.albumartist")))
             .include(Field::AlbumYear(3030))
+            .include(Field::AlbumMonth(AlbumMonth::April))
+            .include(Field::AlbumDay(6))
             .include(Field::TrackTitle(String::from("some.track")))
+            .include(Field::TrackFormat(TrackFormat::Flac))
             .exclude(Field::TrackArtist(vec![
                 String::from("some.artist.1"),
                 String::from("some.artist.2"),
@@ -223,6 +252,9 @@ mod tests {
                 String::from("^albumartist:some.albumartist"),
                 String::from("^albumartist_sort:some.albumartist"),
                 String::from("^artist:some.artist.1; some.artist.2"),
+                String::from("day:6"),
+                String::from("format:FLAC"),
+                String::from("month:4"),
                 String::from("title:some.track"),
                 String::from("year:3030"),
             ]
@@ -335,8 +367,8 @@ mod tests {
             .split(LIST_FORMAT_SEPARATOR)
             .map(|s| s.to_owned())
             .collect::<Vec<String>>();
-        invalid_string[7].clear();
-        invalid_string[7].push_str("invalid format");
+        invalid_string[9].clear();
+        invalid_string[9].push_str("invalid format");
         let invalid_string = invalid_string.join(LIST_FORMAT_SEPARATOR);
         output[2] = invalid_string.clone();
         let result = Ok(output);

src/core/library/beets/testmod.rs

@@ -2,27 +2,115 @@ use once_cell::sync::Lazy;
 
 pub static LIBRARY_BEETS: Lazy<Vec<String>> = Lazy::new(|| -> Vec<String> {
     vec![
-        String::from("Album_Artist ‘A’ -*^-  -*^- 1998 -*^- album_title a.a -*^- 1 -*^- track a.a.1 -*^- artist a.a.1 -*^- FLAC -*^- 992"),
-        String::from("Album_Artist ‘A’ -*^-  -*^- 1998 -*^- album_title a.a -*^- 2 -*^- track a.a.2 -*^- artist a.a.2.1; artist a.a.2.2 -*^- MP3 -*^- 320"),
-        String::from("Album_Artist ‘A’ -*^-  -*^- 1998 -*^- album_title a.a -*^- 3 -*^- track a.a.3 -*^- artist a.a.3 -*^- FLAC -*^- 1061"),
-        String::from("Album_Artist ‘A’ -*^-  -*^- 1998 -*^- album_title a.a -*^- 4 -*^- track a.a.4 -*^- artist a.a.4 -*^- FLAC -*^- 1042"),
-        String::from("Album_Artist ‘A’ -*^-  -*^- 2015 -*^- album_title a.b -*^- 1 -*^- track a.b.1 -*^- artist a.b.1 -*^- FLAC -*^- 1004"),
-        String::from("Album_Artist ‘A’ -*^-  -*^- 2015 -*^- album_title a.b -*^- 2 -*^- track a.b.2 -*^- artist a.b.2 -*^- FLAC -*^- 1077"),
-        String::from("Album_Artist ‘B’ -*^-  -*^- 2003 -*^- album_title b.a -*^- 1 -*^- track b.a.1 -*^- artist b.a.1 -*^- MP3 -*^- 190"),
-        String::from("Album_Artist ‘B’ -*^-  -*^- 2003 -*^- album_title b.a -*^- 2 -*^- track b.a.2 -*^- artist b.a.2.1; artist b.a.2.2 -*^- MP3 -*^- 120"),
-        String::from("Album_Artist ‘B’ -*^-  -*^- 2008 -*^- album_title b.b -*^- 1 -*^- track b.b.1 -*^- artist b.b.1 -*^- FLAC -*^- 1077"),
-        String::from("Album_Artist ‘B’ -*^-  -*^- 2008 -*^- album_title b.b -*^- 2 -*^- track b.b.2 -*^- artist b.b.2.1; artist b.b.2.2 -*^- MP3 -*^- 320"),
-        String::from("Album_Artist ‘B’ -*^-  -*^- 2009 -*^- album_title b.c -*^- 1 -*^- track b.c.1 -*^- artist b.c.1 -*^- MP3 -*^- 190"),
-        String::from("Album_Artist ‘B’ -*^-  -*^- 2009 -*^- album_title b.c -*^- 2 -*^- track b.c.2 -*^- artist b.c.2.1; artist b.c.2.2 -*^- MP3 -*^- 120"),
-        String::from("Album_Artist ‘B’ -*^-  -*^- 2015 -*^- album_title b.d -*^- 1 -*^- track b.d.1 -*^- artist b.d.1 -*^- MP3 -*^- 190"),
-        String::from("Album_Artist ‘B’ -*^-  -*^- 2015 -*^- album_title b.d -*^- 2 -*^- track b.d.2 -*^- artist b.d.2.1; artist b.d.2.2 -*^- MP3 -*^- 120"),
-        String::from("The Album_Artist ‘C’ -*^- Album_Artist ‘C’, The -*^- 1985 -*^- album_title c.a -*^- 1 -*^- track c.a.1 -*^- artist c.a.1 -*^- MP3 -*^- 320"),
-        String::from("The Album_Artist ‘C’ -*^- Album_Artist ‘C’, The -*^- 1985 -*^- album_title c.a -*^- 2 -*^- track c.a.2 -*^- artist c.a.2.1; artist c.a.2.2 -*^- MP3 -*^- 120"),
-        String::from("The Album_Artist ‘C’ -*^- Album_Artist ‘C’, The -*^- 2018 -*^- album_title c.b -*^- 1 -*^- track c.b.1 -*^- artist c.b.1 -*^- FLAC -*^- 1041"),
-        String::from("The Album_Artist ‘C’ -*^- Album_Artist ‘C’, The -*^- 2018 -*^- album_title c.b -*^- 2 -*^- track c.b.2 -*^- artist c.b.2.1; artist c.b.2.2 -*^- FLAC -*^- 756"),
-        String::from("Album_Artist ‘D’ -*^-  -*^- 1995 -*^- album_title d.a -*^- 1 -*^- track d.a.1 -*^- artist d.a.1 -*^- MP3 -*^- 120"),
-        String::from("Album_Artist ‘D’ -*^-  -*^- 1995 -*^- album_title d.a -*^- 2 -*^- track d.a.2 -*^- artist d.a.2.1; artist d.a.2.2 -*^- MP3 -*^- 120"),
-        String::from("Album_Artist ‘D’ -*^-  -*^- 2028 -*^- album_title d.b -*^- 1 -*^- track d.b.1 -*^- artist d.b.1 -*^- FLAC -*^- 841"),
-        String::from("Album_Artist ‘D’ -*^-  -*^- 2028 -*^- album_title d.b -*^- 2 -*^- track d.b.2 -*^- artist d.b.2.1; artist d.b.2.2 -*^- FLAC -*^- 756")
+        String::from(
+            "Album_Artist ‘A’ -*^-  -*^- \
+             1998 -*^- 00 -*^- 00 -*^- album_title a.a -*^- \
+             1 -*^- track a.a.1 -*^- artist a.a.1 -*^- FLAC -*^- 992",
+        ),
+        String::from(
+            "Album_Artist ‘A’ -*^-  -*^- \
+             1998 -*^- 00 -*^- 00 -*^- album_title a.a -*^- \
+             2 -*^- track a.a.2 -*^- artist a.a.2.1; artist a.a.2.2 -*^- MP3 -*^- 320",
+        ),
+        String::from(
+            "Album_Artist ‘A’ -*^-  -*^- \
+             1998 -*^- 00 -*^- 00 -*^- album_title a.a -*^- \
+             3 -*^- track a.a.3 -*^- artist a.a.3 -*^- FLAC -*^- 1061",
+        ),
+        String::from(
+            "Album_Artist ‘A’ -*^-  -*^- \
+             1998 -*^- 00 -*^- 00 -*^- album_title a.a -*^- \
+             4 -*^- track a.a.4 -*^- artist a.a.4 -*^- FLAC -*^- 1042",
+        ),
+        String::from(
+            "Album_Artist ‘A’ -*^-  -*^- \
+             2015 -*^- 04 -*^- 00 -*^- album_title a.b -*^- \
+             1 -*^- track a.b.1 -*^- artist a.b.1 -*^- FLAC -*^- 1004",
+        ),
+        String::from(
+            "Album_Artist ‘A’ -*^-  -*^- \
+             2015 -*^- 04 -*^- 00 -*^- album_title a.b -*^- \
+             2 -*^- track a.b.2 -*^- artist a.b.2 -*^- FLAC -*^- 1077",
+        ),
+        String::from(
+            "Album_Artist ‘B’ -*^-  -*^- \
+             2003 -*^- 06 -*^- 06 -*^- album_title b.a -*^- \
+             1 -*^- track b.a.1 -*^- artist b.a.1 -*^- MP3 -*^- 190",
+        ),
+        String::from(
+            "Album_Artist ‘B’ -*^-  -*^- \
+             2003 -*^- 06 -*^- 06 -*^- album_title b.a -*^- \
+             2 -*^- track b.a.2 -*^- artist b.a.2.1; artist b.a.2.2 -*^- MP3 -*^- 120",
+        ),
+        String::from(
+            "Album_Artist ‘B’ -*^-  -*^- \
+             2008 -*^- 00 -*^- 00 -*^- album_title b.b -*^- \
+             1 -*^- track b.b.1 -*^- artist b.b.1 -*^- FLAC -*^- 1077",
+        ),
+        String::from(
+            "Album_Artist ‘B’ -*^-  -*^- \
+             2008 -*^- 00 -*^- 00 -*^- album_title b.b -*^- \
+             2 -*^- track b.b.2 -*^- artist b.b.2.1; artist b.b.2.2 -*^- MP3 -*^- 320",
+        ),
+        String::from(
+            "Album_Artist ‘B’ -*^-  -*^- \
+             2009 -*^- 00 -*^- 00 -*^- album_title b.c -*^- \
+             1 -*^- track b.c.1 -*^- artist b.c.1 -*^- MP3 -*^- 190",
+        ),
+        String::from(
+            "Album_Artist ‘B’ -*^-  -*^- \
+             2009 -*^- 00 -*^- 00 -*^- album_title b.c -*^- \
+             2 -*^- track b.c.2 -*^- artist b.c.2.1; artist b.c.2.2 -*^- MP3 -*^- 120",
+        ),
+        String::from(
+            "Album_Artist ‘B’ -*^-  -*^- \
+             2015 -*^- 00 -*^- 00 -*^- album_title b.d -*^- \
+             1 -*^- track b.d.1 -*^- artist b.d.1 -*^- MP3 -*^- 190",
+        ),
+        String::from(
+            "Album_Artist ‘B’ -*^-  -*^- \
+             2015 -*^- 00 -*^- 00 -*^- album_title b.d -*^- \
+             2 -*^- track b.d.2 -*^- artist b.d.2.1; artist b.d.2.2 -*^- MP3 -*^- 120",
+        ),
+        String::from(
+            "The Album_Artist ‘C’ -*^- Album_Artist ‘C’, The -*^- \
+             1985 -*^- 00 -*^- 00 -*^- album_title c.a -*^- \
+             1 -*^- track c.a.1 -*^- artist c.a.1 -*^- MP3 -*^- 320",
+        ),
+        String::from(
+            "The Album_Artist ‘C’ -*^- Album_Artist ‘C’, The -*^- \
+             1985 -*^- 00 -*^- 00 -*^- album_title c.a -*^- \
+             2 -*^- track c.a.2 -*^- artist c.a.2.1; artist c.a.2.2 -*^- MP3 -*^- 120",
+        ),
+        String::from(
+            "The Album_Artist ‘C’ -*^- Album_Artist ‘C’, The -*^- \
+             2018 -*^- 00 -*^- 00 -*^- album_title c.b -*^- \
+             1 -*^- track c.b.1 -*^- artist c.b.1 -*^- FLAC -*^- 1041",
+        ),
+        String::from(
+            "The Album_Artist ‘C’ -*^- Album_Artist ‘C’, The -*^- \
+             2018 -*^- 00 -*^- 00 -*^- album_title c.b -*^- \
+             2 -*^- track c.b.2 -*^- artist c.b.2.1; artist c.b.2.2 -*^- FLAC -*^- 756",
+        ),
+        String::from(
+            "Album_Artist ‘D’ -*^-  -*^- \
+             1995 -*^- 00 -*^- 00 -*^- album_title d.a -*^- \
+             1 -*^- track d.a.1 -*^- artist d.a.1 -*^- MP3 -*^- 120",
+        ),
+        String::from(
+            "Album_Artist ‘D’ -*^-  -*^- \
+             1995 -*^- 00 -*^- 00 -*^- album_title d.a -*^- \
+             2 -*^- track d.a.2 -*^- artist d.a.2.1; artist d.a.2.2 -*^- MP3 -*^- 120",
+        ),
+        String::from(
+            "Album_Artist ‘D’ -*^-  -*^- \
+             2028 -*^- 00 -*^- 00 -*^- album_title d.b -*^- \
+             1 -*^- track d.b.1 -*^- artist d.b.1 -*^- FLAC -*^- 841",
+        ),
+        String::from(
+            "Album_Artist ‘D’ -*^-  -*^- \
+             2028 -*^- 00 -*^- 00 -*^- album_title d.b -*^- \
+             2 -*^- track d.b.2 -*^- artist d.b.2.1; artist d.b.2.2 -*^- FLAC -*^- 756",
+        ),
     ]
 });

src/core/library/mod.rs

@@ -8,7 +8,7 @@ use std::{collections::HashSet, fmt, num::ParseIntError, str::Utf8Error};
 #[cfg(test)]
 use mockall::automock;
 
-use crate::core::collection::track::Format;
+use crate::core::collection::{album::AlbumMonth, track::TrackFormat};
 
 /// Trait for interacting with the music library.
 #[cfg_attr(test, automock)]
@@ -32,11 +32,13 @@ pub struct Item {
     pub album_artist: String,
     pub album_artist_sort: Option<String>,
     pub album_year: u32,
+    pub album_month: AlbumMonth,
+    pub album_day: u8,
     pub album_title: String,
     pub track_number: u32,
     pub track_title: String,
     pub track_artist: Vec<String>,
-    pub track_format: Format,
+    pub track_format: TrackFormat,
     pub track_bitrate: u32,
 }
 
@@ -46,10 +48,13 @@ pub enum Field {
     AlbumArtist(String),
     AlbumArtistSort(String),
     AlbumYear(u32),
+    AlbumMonth(AlbumMonth),
+    AlbumDay(u8),
     AlbumTitle(String),
     TrackNumber(u32),
     TrackTitle(String),
     TrackArtist(Vec<String>),
+    TrackFormat(TrackFormat),
     All(String),
 }
 

src/core/library/testmod.rs

@@ -1,6 +1,9 @@
 use once_cell::sync::Lazy;
 
-use crate::core::{collection::track::Format, library::Item};
+use crate::core::{
+    collection::{album::AlbumMonth, track::TrackFormat},
+    library::Item,
+};
 
 pub static LIBRARY_ITEMS: Lazy<Vec<Item>> = Lazy::new(|| -> Vec<Item> {
     vec![
@@ -8,17 +11,21 @@ pub static LIBRARY_ITEMS: Lazy<Vec<Item>> = Lazy::new(|| -> Vec<Item> {
             album_artist: String::from("Album_Artist ‘A’"),
             album_artist_sort: None,
             album_year: 1998,
+            album_month: AlbumMonth::None,
+            album_day: 0,
             album_title: String::from("album_title a.a"),
             track_number: 1,
             track_title: String::from("track a.a.1"),
             track_artist: vec![String::from("artist a.a.1")],
-            track_format: Format::Flac,
+            track_format: TrackFormat::Flac,
             track_bitrate: 992,
         },
         Item {
             album_artist: String::from("Album_Artist ‘A’"),
             album_artist_sort: None,
             album_year: 1998,
+            album_month: AlbumMonth::None,
+            album_day: 0,
             album_title: String::from("album_title a.a"),
             track_number: 2,
             track_title: String::from("track a.a.2"),
@@ -26,68 +33,80 @@ pub static LIBRARY_ITEMS: Lazy<Vec<Item>> = Lazy::new(|| -> Vec<Item> {
                 String::from("artist a.a.2.1"),
                 String::from("artist a.a.2.2"),
             ],
-            track_format: Format::Mp3,
+            track_format: TrackFormat::Mp3,
             track_bitrate: 320,
         },
         Item {
             album_artist: String::from("Album_Artist ‘A’"),
             album_artist_sort: None,
             album_year: 1998,
+            album_month: AlbumMonth::None,
+            album_day: 0,
             album_title: String::from("album_title a.a"),
             track_number: 3,
             track_title: String::from("track a.a.3"),
             track_artist: vec![String::from("artist a.a.3")],
-            track_format: Format::Flac,
+            track_format: TrackFormat::Flac,
             track_bitrate: 1061,
         },
         Item {
             album_artist: String::from("Album_Artist ‘A’"),
             album_artist_sort: None,
             album_year: 1998,
+            album_month: AlbumMonth::None,
+            album_day: 0,
             album_title: String::from("album_title a.a"),
             track_number: 4,
             track_title: String::from("track a.a.4"),
             track_artist: vec![String::from("artist a.a.4")],
-            track_format: Format::Flac,
+            track_format: TrackFormat::Flac,
             track_bitrate: 1042,
         },
         Item {
             album_artist: String::from("Album_Artist ‘A’"),
             album_artist_sort: None,
             album_year: 2015,
+            album_month: AlbumMonth::April,
+            album_day: 0,
             album_title: String::from("album_title a.b"),
             track_number: 1,
             track_title: String::from("track a.b.1"),
             track_artist: vec![String::from("artist a.b.1")],
-            track_format: Format::Flac,
+            track_format: TrackFormat::Flac,
             track_bitrate: 1004,
         },
         Item {
             album_artist: String::from("Album_Artist ‘A’"),
             album_artist_sort: None,
             album_year: 2015,
+            album_month: AlbumMonth::April,
+            album_day: 0,
             album_title: String::from("album_title a.b"),
             track_number: 2,
             track_title: String::from("track a.b.2"),
             track_artist: vec![String::from("artist a.b.2")],
-            track_format: Format::Flac,
+            track_format: TrackFormat::Flac,
             track_bitrate: 1077,
         },
         Item {
             album_artist: String::from("Album_Artist ‘B’"),
             album_artist_sort: None,
             album_year: 2003,
+            album_month: AlbumMonth::June,
+            album_day: 6,
             album_title: String::from("album_title b.a"),
             track_number: 1,
             track_title: String::from("track b.a.1"),
             track_artist: vec![String::from("artist b.a.1")],
-            track_format: Format::Mp3,
+            track_format: TrackFormat::Mp3,
             track_bitrate: 190,
         },
         Item {
             album_artist: String::from("Album_Artist ‘B’"),
             album_artist_sort: None,
             album_year: 2003,
+            album_month: AlbumMonth::June,
+            album_day: 6,
             album_title: String::from("album_title b.a"),
             track_number: 2,
             track_title: String::from("track b.a.2"),
@@ -95,24 +114,28 @@ pub static LIBRARY_ITEMS: Lazy<Vec<Item>> = Lazy::new(|| -> Vec<Item> {
                 String::from("artist b.a.2.1"),
                 String::from("artist b.a.2.2"),
             ],
-            track_format: Format::Mp3,
+            track_format: TrackFormat::Mp3,
             track_bitrate: 120,
         },
         Item {
             album_artist: String::from("Album_Artist ‘B’"),
             album_artist_sort: None,
             album_year: 2008,
+            album_month: AlbumMonth::None,
+            album_day: 0,
             album_title: String::from("album_title b.b"),
             track_number: 1,
             track_title: String::from("track b.b.1"),
             track_artist: vec![String::from("artist b.b.1")],
-            track_format: Format::Flac,
+            track_format: TrackFormat::Flac,
             track_bitrate: 1077,
         },
         Item {
             album_artist: String::from("Album_Artist ‘B’"),
             album_artist_sort: None,
             album_year: 2008,
+            album_month: AlbumMonth::None,
+            album_day: 0,
             album_title: String::from("album_title b.b"),
             track_number: 2,
             track_title: String::from("track b.b.2"),
@@ -120,24 +143,28 @@ pub static LIBRARY_ITEMS: Lazy<Vec<Item>> = Lazy::new(|| -> Vec<Item> {
                 String::from("artist b.b.2.1"),
                 String::from("artist b.b.2.2"),
             ],
-            track_format: Format::Mp3,
+            track_format: TrackFormat::Mp3,
             track_bitrate: 320,
         },
         Item {
             album_artist: String::from("Album_Artist ‘B’"),
             album_artist_sort: None,
             album_year: 2009,
+            album_month: AlbumMonth::None,
+            album_day: 0,
             album_title: String::from("album_title b.c"),
             track_number: 1,
             track_title: String::from("track b.c.1"),
             track_artist: vec![String::from("artist b.c.1")],
-            track_format: Format::Mp3,
+            track_format: TrackFormat::Mp3,
             track_bitrate: 190,
         },
         Item {
             album_artist: String::from("Album_Artist ‘B’"),
             album_artist_sort: None,
             album_year: 2009,
+            album_month: AlbumMonth::None,
+            album_day: 0,
             album_title: String::from("album_title b.c"),
             track_number: 2,
             track_title: String::from("track b.c.2"),
@@ -145,24 +172,28 @@ pub static LIBRARY_ITEMS: Lazy<Vec<Item>> = Lazy::new(|| -> Vec<Item> {
                 String::from("artist b.c.2.1"),
                 String::from("artist b.c.2.2"),
             ],
-            track_format: Format::Mp3,
+            track_format: TrackFormat::Mp3,
             track_bitrate: 120,
         },
         Item {
             album_artist: String::from("Album_Artist ‘B’"),
             album_artist_sort: None,
             album_year: 2015,
+            album_month: AlbumMonth::None,
+            album_day: 0,
             album_title: String::from("album_title b.d"),
             track_number: 1,
             track_title: String::from("track b.d.1"),
             track_artist: vec![String::from("artist b.d.1")],
-            track_format: Format::Mp3,
+            track_format: TrackFormat::Mp3,
             track_bitrate: 190,
         },
         Item {
             album_artist: String::from("Album_Artist ‘B’"),
             album_artist_sort: None,
             album_year: 2015,
+            album_month: AlbumMonth::None,
+            album_day: 0,
             album_title: String::from("album_title b.d"),
             track_number: 2,
             track_title: String::from("track b.d.2"),
@@ -170,24 +201,28 @@ pub static LIBRARY_ITEMS: Lazy<Vec<Item>> = Lazy::new(|| -> Vec<Item> {
                 String::from("artist b.d.2.1"),
                 String::from("artist b.d.2.2"),
             ],
-            track_format: Format::Mp3,
+            track_format: TrackFormat::Mp3,
             track_bitrate: 120,
         },
         Item {
             album_artist: String::from("The Album_Artist ‘C’"),
             album_artist_sort: Some(String::from("Album_Artist ‘C’, The")),
             album_year: 1985,
+            album_month: AlbumMonth::None,
+            album_day: 0,
             album_title: String::from("album_title c.a"),
             track_number: 1,
             track_title: String::from("track c.a.1"),
             track_artist: vec![String::from("artist c.a.1")],
-            track_format: Format::Mp3,
+            track_format: TrackFormat::Mp3,
             track_bitrate: 320,
         },
         Item {
             album_artist: String::from("The Album_Artist ‘C’"),
             album_artist_sort: Some(String::from("Album_Artist ‘C’, The")),
             album_year: 1985,
+            album_month: AlbumMonth::None,
+            album_day: 0,
             album_title: String::from("album_title c.a"),
             track_number: 2,
             track_title: String::from("track c.a.2"),
@@ -195,24 +230,28 @@ pub static LIBRARY_ITEMS: Lazy<Vec<Item>> = Lazy::new(|| -> Vec<Item> {
                 String::from("artist c.a.2.1"),
                 String::from("artist c.a.2.2"),
             ],
-            track_format: Format::Mp3,
+            track_format: TrackFormat::Mp3,
             track_bitrate: 120,
         },
         Item {
             album_artist: String::from("The Album_Artist ‘C’"),
             album_artist_sort: Some(String::from("Album_Artist ‘C’, The")),
             album_year: 2018,
+            album_month: AlbumMonth::None,
+            album_day: 0,
             album_title: String::from("album_title c.b"),
             track_number: 1,
             track_title: String::from("track c.b.1"),
             track_artist: vec![String::from("artist c.b.1")],
-            track_format: Format::Flac,
+            track_format: TrackFormat::Flac,
             track_bitrate: 1041,
         },
         Item {
             album_artist: String::from("The Album_Artist ‘C’"),
             album_artist_sort: Some(String::from("Album_Artist ‘C’, The")),
             album_year: 2018,
+            album_month: AlbumMonth::None,
+            album_day: 0,
             album_title: String::from("album_title c.b"),
             track_number: 2,
             track_title: String::from("track c.b.2"),
@@ -220,24 +259,28 @@ pub static LIBRARY_ITEMS: Lazy<Vec<Item>> = Lazy::new(|| -> Vec<Item> {
                 String::from("artist c.b.2.1"),
                 String::from("artist c.b.2.2"),
             ],
-            track_format: Format::Flac,
+            track_format: TrackFormat::Flac,
             track_bitrate: 756,
         },
         Item {
             album_artist: String::from("Album_Artist ‘D’"),
             album_artist_sort: None,
             album_year: 1995,
+            album_month: AlbumMonth::None,
+            album_day: 0,
             album_title: String::from("album_title d.a"),
             track_number: 1,
             track_title: String::from("track d.a.1"),
             track_artist: vec![String::from("artist d.a.1")],
-            track_format: Format::Mp3,
+            track_format: TrackFormat::Mp3,
             track_bitrate: 120,
         },
         Item {
             album_artist: String::from("Album_Artist ‘D’"),
             album_artist_sort: None,
             album_year: 1995,
+            album_month: AlbumMonth::None,
+            album_day: 0,
             album_title: String::from("album_title d.a"),
             track_number: 2,
             track_title: String::from("track d.a.2"),
@@ -245,24 +288,28 @@ pub static LIBRARY_ITEMS: Lazy<Vec<Item>> = Lazy::new(|| -> Vec<Item> {
                 String::from("artist d.a.2.1"),
                 String::from("artist d.a.2.2"),
             ],
-            track_format: Format::Mp3,
+            track_format: TrackFormat::Mp3,
             track_bitrate: 120,
         },
         Item {
             album_artist: String::from("Album_Artist ‘D’"),
             album_artist_sort: None,
             album_year: 2028,
+            album_month: AlbumMonth::None,
+            album_day: 0,
             album_title: String::from("album_title d.b"),
             track_number: 1,
             track_title: String::from("track d.b.1"),
             track_artist: vec![String::from("artist d.b.1")],
-            track_format: Format::Flac,
+            track_format: TrackFormat::Flac,
             track_bitrate: 841,
         },
         Item {
             album_artist: String::from("Album_Artist ‘D’"),
             album_artist_sort: None,
             album_year: 2028,
+            album_month: AlbumMonth::None,
+            album_day: 0,
             album_title: String::from("album_title d.b"),
             track_number: 2,
             track_title: String::from("track d.b.2"),
@@ -270,7 +317,7 @@ pub static LIBRARY_ITEMS: Lazy<Vec<Item>> = Lazy::new(|| -> Vec<Item> {
                 String::from("artist d.b.2.1"),
                 String::from("artist d.b.2.2"),
             ],
-            track_format: Format::Flac,
+            track_format: TrackFormat::Flac,
             track_bitrate: 756,
         },
     ]

src/core/musichoard/musichoard.rs

@@ -2,10 +2,10 @@ use std::collections::HashMap;
 
 use crate::core::{
     collection::{
-        album::{Album, AlbumId},
-        artist::{Artist, ArtistId},
-        track::{Quality, Track, TrackId},
-        Collection, Merge,
+        album::{Album, AlbumDate, AlbumId, AlbumSeq},
+        artist::{Artist, ArtistId, MusicBrainz},
+        track::{Track, TrackId, TrackNum, TrackQuality},
+        Collection, MergeCollections,
     },
     database::IDatabase,
     library::{ILibrary, Item, Query},
@@ -73,19 +73,7 @@ impl<LIB, DB> MusicHoard<LIB, DB> {
     }
 
     fn merge_collections(&self) -> Collection {
-        let mut primary = self.library_cache.clone();
-        for secondary_artist in self.database_cache.iter().cloned() {
-            if let Some(ref mut primary_artist) = primary.get_mut(&secondary_artist.id) {
-                primary_artist.merge_in_place(secondary_artist);
-            } else {
-                primary.insert(secondary_artist.id.clone(), secondary_artist);
-            }
-        }
-
-        let mut collection: Collection = primary.into_values().collect();
-        Self::sort_artists(&mut collection);
-
-        collection
+        MergeCollections::merge(self.library_cache.clone(), self.database_cache.clone())
     }
 
     fn items_to_artists(items: Vec<Item>) -> Result<HashMap<ArtistId, Artist>, Error> {
@@ -99,17 +87,22 @@ impl<LIB, DB> MusicHoard<LIB, DB> {
             let artist_sort = item.album_artist_sort.map(|s| ArtistId { name: s });
 
             let album_id = AlbumId {
-                year: item.album_year,
                 title: item.album_title,
             };
 
+            let album_date = AlbumDate {
+                year: item.album_year,
+                month: item.album_month,
+                day: item.album_day,
+            };
+
             let track = Track {
                 id: TrackId {
-                    number: item.track_number,
                     title: item.track_title,
                 },
+                number: TrackNum(item.track_number),
                 artist: item.track_artist,
-                quality: Quality {
+                quality: TrackQuality {
                     format: item.track_format,
                     bitrate: item.track_bitrate,
                 },
@@ -149,6 +142,8 @@ impl<LIB, DB> MusicHoard<LIB, DB> {
                 Some(album) => album.tracks.push(track),
                 None => artist.albums.push(Album {
                     id: album_id,
+                    date: album_date,
+                    seq: AlbumSeq(0),
                     tracks: vec![track],
                 }),
             }
@@ -176,6 +171,22 @@ impl<LIB, DB> MusicHoard<LIB, DB> {
             Error::CollectionError(format!("artist '{}' is not in the collection", artist_id))
         })
     }
+
+    fn get_album_mut<'a>(artist: &'a mut Artist, album_id: &AlbumId) -> Option<&'a mut Album> {
+        artist.albums.iter_mut().find(|a| &a.id == album_id)
+    }
+
+    fn get_album_mut_or_err<'a>(
+        artist: &'a mut Artist,
+        album_id: &AlbumId,
+    ) -> Result<&'a mut Album, Error> {
+        Self::get_album_mut(artist, album_id).ok_or_else(|| {
+            Error::CollectionError(format!(
+                "album '{}' does not belong to the artist",
+                album_id
+            ))
+        })
+    }
 }
 
 impl<LIB: ILibrary> MusicHoard<LIB, NoDatabase> {
@@ -248,39 +259,61 @@ impl<LIB, DB: IDatabase> MusicHoard<LIB, DB> {
         Ok(())
     }
 
-    fn update_collection<F>(&mut self, func: F) -> Result<(), Error>
+    fn update_collection<FnColl>(&mut self, fn_coll: FnColl) -> Result<(), Error>
     where
-        F: FnOnce(&mut Collection),
+        FnColl: FnOnce(&mut Collection),
     {
-        func(&mut self.pre_commit);
+        fn_coll(&mut self.pre_commit);
         self.commit()
     }
 
-    fn update_artist_and<ID: AsRef<ArtistId>, F1, F2>(
+    fn update_artist_and<FnArtist, FnColl>(
         &mut self,
-        artist_id: ID,
-        f1: F1,
-        f2: F2,
+        artist_id: &ArtistId,
+        fn_artist: FnArtist,
+        fn_coll: FnColl,
     ) -> Result<(), Error>
     where
-        F1: FnOnce(&mut Artist),
-        F2: FnOnce(&mut Collection),
+        FnArtist: FnOnce(&mut Artist),
+        FnColl: FnOnce(&mut Collection),
     {
-        f1(Self::get_artist_mut_or_err(
-            &mut self.pre_commit,
-            artist_id.as_ref(),
-        )?);
-        self.update_collection(f2)
+        let artist = Self::get_artist_mut_or_err(&mut self.pre_commit, artist_id)?;
+        fn_artist(artist);
+        self.update_collection(fn_coll)
     }
 
-    fn update_artist<ID: AsRef<ArtistId>, F>(&mut self, artist_id: ID, func: F) -> Result<(), Error>
+    fn update_artist<FnArtist>(
+        &mut self,
+        artist_id: &ArtistId,
+        fn_artist: FnArtist,
+    ) -> Result<(), Error>
     where
-        F: FnOnce(&mut Artist),
+        FnArtist: FnOnce(&mut Artist),
     {
-        self.update_artist_and(artist_id, func, |_| {})
+        self.update_artist_and(artist_id, fn_artist, |_| {})
     }
 
-    pub fn add_artist<ID: Into<ArtistId>>(&mut self, artist_id: ID) -> Result<(), Error> {
+    fn update_album_and<FnAlbum, FnArtist, FnColl>(
+        &mut self,
+        artist_id: &ArtistId,
+        album_id: &AlbumId,
+        fn_album: FnAlbum,
+        fn_artist: FnArtist,
+        fn_coll: FnColl,
+    ) -> Result<(), Error>
+    where
+        FnAlbum: FnOnce(&mut Album),
+        FnArtist: FnOnce(&mut Artist),
+        FnColl: FnOnce(&mut Collection),
+    {
+        let artist = Self::get_artist_mut_or_err(&mut self.pre_commit, artist_id)?;
+        let album = Self::get_album_mut_or_err(artist, album_id)?;
+        fn_album(album);
+        fn_artist(artist);
+        self.update_collection(fn_coll)
+    }
+
+    pub fn add_artist<IntoId: Into<ArtistId>>(&mut self, artist_id: IntoId) -> Result<(), Error> {
         let artist_id: ArtistId = artist_id.into();
 
         self.update_collection(|collection| {
@@ -291,7 +324,7 @@ impl<LIB, DB: IDatabase> MusicHoard<LIB, DB> {
         })
     }
 
-    pub fn remove_artist<ID: AsRef<ArtistId>>(&mut self, artist_id: ID) -> Result<(), Error> {
+    pub fn remove_artist<Id: AsRef<ArtistId>>(&mut self, artist_id: Id) -> Result<(), Error> {
         self.update_collection(|collection| {
             let index_opt = collection.iter().position(|a| &a.id == artist_id.as_ref());
             if let Some(index) = index_opt {
@@ -300,77 +333,113 @@ impl<LIB, DB: IDatabase> MusicHoard<LIB, DB> {
         })
     }
 
-    pub fn set_artist_sort<ID: AsRef<ArtistId>, SORT: Into<ArtistId>>(
+    pub fn set_artist_sort<Id: AsRef<ArtistId>, IntoId: Into<ArtistId>>(
         &mut self,
-        artist_id: ID,
-        artist_sort: SORT,
+        artist_id: Id,
+        artist_sort: IntoId,
     ) -> Result<(), Error> {
         self.update_artist_and(
-            artist_id,
+            artist_id.as_ref(),
             |artist| artist.set_sort_key(artist_sort),
             |collection| Self::sort_artists(collection),
         )
     }
 
-    pub fn clear_artist_sort<ID: AsRef<ArtistId>>(&mut self, artist_id: ID) -> Result<(), Error> {
+    pub fn clear_artist_sort<Id: AsRef<ArtistId>>(&mut self, artist_id: Id) -> Result<(), Error> {
         self.update_artist_and(
-            artist_id,
+            artist_id.as_ref(),
             |artist| artist.clear_sort_key(),
             |collection| Self::sort_artists(collection),
         )
     }
 
-    pub fn set_musicbrainz_url<ID: AsRef<ArtistId>, S: AsRef<str>>(
+    pub fn set_artist_musicbrainz<Id: AsRef<ArtistId>, Mb: TryInto<MusicBrainz, Error = E>, E>(
         &mut self,
-        artist_id: ID,
-        url: S,
-    ) -> Result<(), Error> {
-        let url = url.as_ref().try_into()?;
-        self.update_artist(artist_id, |artist| artist.set_musicbrainz_url(url))
+        artist_id: Id,
+        url: Mb,
+    ) -> Result<(), Error>
+    where
+        Error: From<E>,
+    {
+        let mb = url.try_into()?;
+        self.update_artist(artist_id.as_ref(), |artist| artist.set_musicbrainz_url(mb))
     }
 
-    pub fn clear_musicbrainz_url<ID: AsRef<ArtistId>>(
+    pub fn clear_artist_musicbrainz<Id: AsRef<ArtistId>>(
         &mut self,
-        artist_id: ID,
+        artist_id: Id,
     ) -> Result<(), Error> {
-        self.update_artist(artist_id, |artist| artist.clear_musicbrainz_url())
+        self.update_artist(artist_id.as_ref(), |artist| artist.clear_musicbrainz_url())
     }
 
-    pub fn add_to_property<ID: AsRef<ArtistId>, S: AsRef<str> + Into<String>>(
+    pub fn add_to_artist_property<Id: AsRef<ArtistId>, S: AsRef<str> + Into<String>>(
         &mut self,
-        artist_id: ID,
+        artist_id: Id,
         property: S,
         values: Vec<S>,
     ) -> Result<(), Error> {
-        self.update_artist(artist_id, |artist| artist.add_to_property(property, values))
+        self.update_artist(artist_id.as_ref(), |artist| {
+            artist.add_to_property(property, values)
+        })
     }
 
-    pub fn remove_from_property<ID: AsRef<ArtistId>, S: AsRef<str>>(
+    pub fn remove_from_artist_property<Id: AsRef<ArtistId>, S: AsRef<str>>(
         &mut self,
-        artist_id: ID,
+        artist_id: Id,
         property: S,
         values: Vec<S>,
     ) -> Result<(), Error> {
-        self.update_artist(artist_id, |artist| {
+        self.update_artist(artist_id.as_ref(), |artist| {
             artist.remove_from_property(property, values)
         })
     }
 
-    pub fn set_property<ID: AsRef<ArtistId>, S: AsRef<str> + Into<String>>(
+    pub fn set_artist_property<Id: AsRef<ArtistId>, S: AsRef<str> + Into<String>>(
         &mut self,
-        artist_id: ID,
+        artist_id: Id,
         property: S,
         values: Vec<S>,
     ) -> Result<(), Error> {
-        self.update_artist(artist_id, |artist| artist.set_property(property, values))
+        self.update_artist(artist_id.as_ref(), |artist| {
+            artist.set_property(property, values)
+        })
     }
 
-    pub fn clear_property<ID: AsRef<ArtistId>, S: AsRef<str>>(
+    pub fn clear_artist_property<Id: AsRef<ArtistId>, S: AsRef<str>>(
         &mut self,
-        artist_id: ID,
+        artist_id: Id,
         property: S,
     ) -> Result<(), Error> {
-        self.update_artist(artist_id, |artist| artist.clear_property(property))
+        self.update_artist(artist_id.as_ref(), |artist| artist.clear_property(property))
+    }
+
+    pub fn set_album_seq<ArtistIdRef: AsRef<ArtistId>, AlbumIdRef: AsRef<AlbumId>>(
+        &mut self,
+        artist_id: ArtistIdRef,
+        album_id: AlbumIdRef,
+        seq: u8,
+    ) -> Result<(), Error> {
+        self.update_album_and(
+            artist_id.as_ref(),
+            album_id.as_ref(),
+            |album| album.set_seq(AlbumSeq(seq)),
+            |artist| artist.albums.sort_unstable(),
+            |_| {},
+        )
+    }
+
+    pub fn clear_album_seq<ArtistIdRef: AsRef<ArtistId>, AlbumIdRef: AsRef<AlbumId>>(
+        &mut self,
+        artist_id: ArtistIdRef,
+        album_id: AlbumIdRef,
+    ) -> Result<(), Error> {
+        self.update_album_and(
+            artist_id.as_ref(),
+            album_id.as_ref(),
+            |album| album.clear_seq(),
+            |artist| artist.albums.sort_unstable(),
+            |_| {},
+        )
     }
 }
 
@@ -523,7 +592,7 @@ mod tests {
         assert!(music_hoard.add_artist(artist_id.clone()).is_ok());
 
         let actual_err = music_hoard
-            .set_musicbrainz_url(&artist_id, MUSICBUTLER)
+            .set_artist_musicbrainz(&artist_id, MUSICBUTLER)
             .unwrap_err();
         let expected_err = Error::CollectionError(format!(
             "an error occurred when processing a URL: invalid MusicBrainz URL: {MUSICBUTLER}"
@@ -549,23 +618,23 @@ mod tests {
 
         // Setting a URL on an artist not in the collection is an error.
         assert!(music_hoard
-            .set_musicbrainz_url(&artist_id_2, MUSICBRAINZ)
+            .set_artist_musicbrainz(&artist_id_2, MUSICBRAINZ)
             .is_err());
         assert_eq!(music_hoard.collection[0].musicbrainz, expected);
 
         // Setting a URL on an artist.
         assert!(music_hoard
-            .set_musicbrainz_url(&artist_id, MUSICBRAINZ)
+            .set_artist_musicbrainz(&artist_id, MUSICBRAINZ)
             .is_ok());
-        _ = expected.insert(MusicBrainz::new(MUSICBRAINZ).unwrap());
+        _ = expected.insert(MUSICBRAINZ.try_into().unwrap());
         assert_eq!(music_hoard.collection[0].musicbrainz, expected);
 
         // Clearing URLs on an artist that does not exist is an error.
-        assert!(music_hoard.clear_musicbrainz_url(&artist_id_2).is_err());
+        assert!(music_hoard.clear_artist_musicbrainz(&artist_id_2).is_err());
         assert_eq!(music_hoard.collection[0].musicbrainz, expected);
 
         // Clearing URLs.
-        assert!(music_hoard.clear_musicbrainz_url(&artist_id).is_ok());
+        assert!(music_hoard.clear_artist_musicbrainz(&artist_id).is_ok());
         _ = expected.take();
         assert_eq!(music_hoard.collection[0].musicbrainz, expected);
     }
@@ -587,13 +656,13 @@ mod tests {
 
         // Adding URLs to an artist not in the collection is an error.
         assert!(music_hoard
-            .add_to_property(&artist_id_2, "MusicButler", vec![MUSICBUTLER])
+            .add_to_artist_property(&artist_id_2, "MusicButler", vec![MUSICBUTLER])
             .is_err());
         assert!(music_hoard.collection[0].properties.is_empty());
 
         // Adding mutliple URLs without clashes.
         assert!(music_hoard
-            .add_to_property(&artist_id, "MusicButler", vec![MUSICBUTLER, MUSICBUTLER_2])
+            .add_to_artist_property(&artist_id, "MusicButler", vec![MUSICBUTLER, MUSICBUTLER_2])
             .is_ok());
         expected.push(MUSICBUTLER.to_owned());
         expected.push(MUSICBUTLER_2.to_owned());
@@ -604,7 +673,7 @@ mod tests {
 
         // Removing URLs from an artist not in the collection is an error.
         assert!(music_hoard
-            .remove_from_property(&artist_id_2, "MusicButler", vec![MUSICBUTLER])
+            .remove_from_artist_property(&artist_id_2, "MusicButler", vec![MUSICBUTLER])
             .is_err());
         assert_eq!(
             music_hoard.collection[0].properties.get("MusicButler"),
@@ -613,7 +682,11 @@ mod tests {
 
         // Removing multiple URLs without clashes.
         assert!(music_hoard
-            .remove_from_property(&artist_id, "MusicButler", vec![MUSICBUTLER, MUSICBUTLER_2])
+            .remove_from_artist_property(
+                &artist_id,
+                "MusicButler",
+                vec![MUSICBUTLER, MUSICBUTLER_2]
+            )
             .is_ok());
         expected.clear();
         assert!(music_hoard.collection[0].properties.is_empty());
@@ -636,13 +709,13 @@ mod tests {
 
         // Seting URL on an artist not in the collection is an error.
         assert!(music_hoard
-            .set_property(&artist_id_2, "MusicButler", vec![MUSICBUTLER])
+            .set_artist_property(&artist_id_2, "MusicButler", vec![MUSICBUTLER])
             .is_err());
         assert!(music_hoard.collection[0].properties.is_empty());
 
         // Set URLs.
         assert!(music_hoard
-            .set_property(&artist_id, "MusicButler", vec![MUSICBUTLER, MUSICBUTLER_2])
+            .set_artist_property(&artist_id, "MusicButler", vec![MUSICBUTLER, MUSICBUTLER_2])
             .is_ok());
         expected.clear();
         expected.push(MUSICBUTLER.to_owned());
@@ -654,17 +727,62 @@ mod tests {
 
         // Clearing URLs on an artist that does not exist is an error.
         assert!(music_hoard
-            .clear_property(&artist_id_2, "MusicButler")
+            .clear_artist_property(&artist_id_2, "MusicButler")
             .is_err());
 
         // Clear URLs.
         assert!(music_hoard
-            .clear_property(&artist_id, "MusicButler")
+            .clear_artist_property(&artist_id, "MusicButler")
             .is_ok());
         expected.clear();
         assert!(music_hoard.collection[0].properties.is_empty());
     }
 
+    #[test]
+    fn set_clear_album_seq() {
+        let mut database = MockIDatabase::new();
+
+        let artist_id = ArtistId::new("an artist");
+        let album_id = AlbumId::new("an album");
+        let album_id_2 = AlbumId::new("another album");
+
+        let mut database_result = vec![Artist::new(artist_id.clone())];
+        database_result[0].albums.push(Album {
+            id: album_id.clone(),
+            date: AlbumDate::default(),
+            seq: AlbumSeq::default(),
+            tracks: vec![],
+        });
+
+        database
+            .expect_load()
+            .times(1)
+            .return_once(|| Ok(database_result));
+        database.expect_save().times(2).returning(|_| Ok(()));
+
+        let mut music_hoard = MusicHoard::database(database).unwrap();
+        assert_eq!(music_hoard.collection[0].albums[0].seq, AlbumSeq(0));
+
+        // Seting seq on an album not belonging to the artist is an error.
+        assert!(music_hoard
+            .set_album_seq(&artist_id, &album_id_2, 6)
+            .is_err());
+        assert_eq!(music_hoard.collection[0].albums[0].seq, AlbumSeq(0));
+
+        // Set seq.
+        assert!(music_hoard.set_album_seq(&artist_id, &album_id, 6).is_ok());
+        assert_eq!(music_hoard.collection[0].albums[0].seq, AlbumSeq(6));
+
+        // Clearing seq on an album that does not exist is an error.
+        assert!(music_hoard
+            .clear_album_seq(&artist_id, &album_id_2)
+            .is_err());
+
+        // Clear seq.
+        assert!(music_hoard.clear_album_seq(&artist_id, &album_id).is_ok());
+        assert_eq!(music_hoard.collection[0].albums[0].seq, AlbumSeq(0));
+    }
+
     #[test]
     fn merge_collection_no_overlap() {
         let half: usize = FULL_COLLECTION.len() / 2;
@@ -887,7 +1005,7 @@ mod tests {
     }
 
     #[test]
-    fn rescan_library_album_title_year_clash() {
+    fn rescan_library_album_id_clash() {
         let mut library = MockILibrary::new();
 
         let mut expected = LIBRARY_COLLECTION.to_owned();
@@ -895,10 +1013,10 @@ mod tests {
         let clashed_album_id = &expected[1].albums[0].id;
 
         let mut items = LIBRARY_ITEMS.to_owned();
-        for item in items.iter_mut().filter(|it| {
-            (it.album_year == removed_album_id.year) && (it.album_title == removed_album_id.title)
-        }) {
-            item.album_year = clashed_album_id.year;
+        for item in items
+            .iter_mut()
+            .filter(|it| it.album_title == removed_album_id.title)
+        {
             item.album_title = clashed_album_id.title.clone();
         }
 
@@ -916,6 +1034,7 @@ mod tests {
         let mut music_hoard = MusicHoard::library(library);
 
         music_hoard.rescan_library().unwrap();
+        assert_eq!(music_hoard.get_collection()[0], expected[0]);
         assert_eq!(music_hoard.get_collection(), &expected);
     }
 

src/core/testmod.rs

@@ -1,10 +1,10 @@
 use once_cell::sync::Lazy;
-use std::collections::HashMap;
+use std::{collections::HashMap, str::FromStr};
 
 use crate::core::collection::{
-    album::{Album, AlbumId},
+    album::{Album, AlbumDate, AlbumId, AlbumMonth, AlbumSeq},
     artist::{Artist, ArtistId, MusicBrainz},
-    track::{Format, Quality, Track, TrackId},
+    track::{Track, TrackFormat, TrackId, TrackNum, TrackQuality},
 };
 use crate::tests::*;
 

src/tests.rs

@@ -11,54 +11,59 @@ macro_rules! library_collection {
                 albums: vec![
                     Album {
                         id: AlbumId {
-                            year: 1998,
                             title: "album_title a.a".to_string(),
                         },
+                        date: AlbumDate {
+                            year: 1998,
+                            month: AlbumMonth::None,
+                            day: 0,
+                        },
+                        seq: AlbumSeq(0),
                         tracks: vec![
                             Track {
                                 id: TrackId {
-                                    number: 1,
                                     title: "track a.a.1".to_string(),
                                 },
+                                number: TrackNum(1),
                                 artist: vec!["artist a.a.1".to_string()],
-                                quality: Quality {
-                                    format: Format::Flac,
+                                quality: TrackQuality {
+                                    format: TrackFormat::Flac,
                                     bitrate: 992,
                                 },
                             },
                             Track {
                                 id: TrackId {
-                                    number: 2,
                                     title: "track a.a.2".to_string(),
                                 },
+                                number: TrackNum(2),
                                 artist: vec![
                                     "artist a.a.2.1".to_string(),
                                     "artist a.a.2.2".to_string(),
                                 ],
-                                quality: Quality {
-                                    format: Format::Mp3,
+                                quality: TrackQuality {
+                                    format: TrackFormat::Mp3,
                                     bitrate: 320,
                                 },
                             },
                             Track {
                                 id: TrackId {
-                                    number: 3,
                                     title: "track a.a.3".to_string(),
                                 },
+                                number: TrackNum(3),
                                 artist: vec!["artist a.a.3".to_string()],
-                                quality: Quality {
-                                    format: Format::Flac,
+                                quality: TrackQuality {
+                                    format: TrackFormat::Flac,
                                     bitrate: 1061,
                                 },
                             },
                             Track {
                                 id: TrackId {
-                                    number: 4,
                                     title: "track a.a.4".to_string(),
                                 },
+                                number: TrackNum(4),
                                 artist: vec!["artist a.a.4".to_string()],
-                                quality: Quality {
-                                    format: Format::Flac,
+                                quality: TrackQuality {
+                                    format: TrackFormat::Flac,
                                     bitrate: 1042,
                                 },
                             },
@@ -66,29 +71,34 @@ macro_rules! library_collection {
                     },
                     Album {
                         id: AlbumId {
-                            year: 2015,
                             title: "album_title a.b".to_string(),
                         },
+                        date: AlbumDate {
+                            year: 2015,
+                            month: AlbumMonth::April,
+                            day: 0,
+                        },
+                        seq: AlbumSeq(0),
                         tracks: vec![
                             Track {
                                 id: TrackId {
-                                    number: 1,
                                     title: "track a.b.1".to_string(),
                                 },
+                                number: TrackNum(1),
                                 artist: vec!["artist a.b.1".to_string()],
-                                quality: Quality {
-                                    format: Format::Flac,
+                                quality: TrackQuality {
+                                    format: TrackFormat::Flac,
                                     bitrate: 1004,
                                 },
                             },
                             Track {
                                 id: TrackId {
-                                    number: 2,
                                     title: "track a.b.2".to_string(),
                                 },
+                                number: TrackNum(2),
                                 artist: vec!["artist a.b.2".to_string()],
-                                quality: Quality {
-                                    format: Format::Flac,
+                                quality: TrackQuality {
+                                    format: TrackFormat::Flac,
                                     bitrate: 1077,
                                 },
                             },
@@ -106,32 +116,37 @@ macro_rules! library_collection {
                 albums: vec![
                     Album {
                         id: AlbumId {
-                            year: 2003,
                             title: "album_title b.a".to_string(),
                         },
+                        date: AlbumDate {
+                            year: 2003,
+                            month: AlbumMonth::June,
+                            day: 6,
+                        },
+                        seq: AlbumSeq(0),
                         tracks: vec![
                             Track {
                                 id: TrackId {
-                                    number: 1,
                                     title: "track b.a.1".to_string(),
                                 },
+                                number: TrackNum(1),
                                 artist: vec!["artist b.a.1".to_string()],
-                                quality: Quality {
-                                    format: Format::Mp3,
+                                quality: TrackQuality {
+                                    format: TrackFormat::Mp3,
                                     bitrate: 190,
                                 },
                             },
                             Track {
                                 id: TrackId {
-                                    number: 2,
                                     title: "track b.a.2".to_string(),
                                 },
+                                number: TrackNum(2),
                                 artist: vec![
                                     "artist b.a.2.1".to_string(),
                                     "artist b.a.2.2".to_string(),
                                 ],
-                                quality: Quality {
-                                    format: Format::Mp3,
+                                quality: TrackQuality {
+                                    format: TrackFormat::Mp3,
                                     bitrate: 120,
                                 },
                             },
@@ -139,32 +154,37 @@ macro_rules! library_collection {
                     },
                     Album {
                         id: AlbumId {
-                            year: 2008,
                             title: "album_title b.b".to_string(),
                         },
+                        date: AlbumDate {
+                            year: 2008,
+                            month: AlbumMonth::None,
+                            day: 0,
+                        },
+                        seq: AlbumSeq(0),
                         tracks: vec![
                             Track {
                                 id: TrackId {
-                                    number: 1,
                                     title: "track b.b.1".to_string(),
                                 },
+                                number: TrackNum(1),
                                 artist: vec!["artist b.b.1".to_string()],
-                                quality: Quality {
-                                    format: Format::Flac,
+                                quality: TrackQuality {
+                                    format: TrackFormat::Flac,
                                     bitrate: 1077,
                                 },
                             },
                             Track {
                                 id: TrackId {
-                                    number: 2,
                                     title: "track b.b.2".to_string(),
                                 },
+                                number: TrackNum(2),
                                 artist: vec![
                                     "artist b.b.2.1".to_string(),
                                     "artist b.b.2.2".to_string(),
                                 ],
-                                quality: Quality {
-                                    format: Format::Mp3,
+                                quality: TrackQuality {
+                                    format: TrackFormat::Mp3,
                                     bitrate: 320,
                                 },
                             },
@@ -172,32 +192,37 @@ macro_rules! library_collection {
                     },
                     Album {
                         id: AlbumId {
-                            year: 2009,
                             title: "album_title b.c".to_string(),
                         },
+                        date: AlbumDate {
+                            year: 2009,
+                            month: AlbumMonth::None,
+                            day: 0,
+                        },
+                        seq: AlbumSeq(0),
                         tracks: vec![
                             Track {
                                 id: TrackId {
-                                    number: 1,
                                     title: "track b.c.1".to_string(),
                                 },
+                                number: TrackNum(1),
                                 artist: vec!["artist b.c.1".to_string()],
-                                quality: Quality {
-                                    format: Format::Mp3,
+                                quality: TrackQuality {
+                                    format: TrackFormat::Mp3,
                                     bitrate: 190,
                                 },
                             },
                             Track {
                                 id: TrackId {
-                                    number: 2,
                                     title: "track b.c.2".to_string(),
                                 },
+                                number: TrackNum(2),
                                 artist: vec![
                                     "artist b.c.2.1".to_string(),
                                     "artist b.c.2.2".to_string(),
                                 ],
-                                quality: Quality {
-                                    format: Format::Mp3,
+                                quality: TrackQuality {
+                                    format: TrackFormat::Mp3,
                                     bitrate: 120,
                                 },
                             },
@@ -205,32 +230,37 @@ macro_rules! library_collection {
                     },
                     Album {
                         id: AlbumId {
-                            year: 2015,
                             title: "album_title b.d".to_string(),
                         },
+                        date: AlbumDate {
+                            year: 2015,
+                            month: AlbumMonth::None,
+                            day: 0,
+                        },
+                        seq: AlbumSeq(0),
                         tracks: vec![
                             Track {
                                 id: TrackId {
-                                    number: 1,
                                     title: "track b.d.1".to_string(),
                                 },
+                                number: TrackNum(1),
                                 artist: vec!["artist b.d.1".to_string()],
-                                quality: Quality {
-                                    format: Format::Mp3,
+                                quality: TrackQuality {
+                                    format: TrackFormat::Mp3,
                                     bitrate: 190,
                                 },
                             },
                             Track {
                                 id: TrackId {
-                                    number: 2,
                                     title: "track b.d.2".to_string(),
                                 },
+                                number: TrackNum(2),
                                 artist: vec![
                                     "artist b.d.2.1".to_string(),
                                     "artist b.d.2.2".to_string(),
                                 ],
-                                quality: Quality {
-                                    format: Format::Mp3,
+                                quality: TrackQuality {
+                                    format: TrackFormat::Mp3,
                                     bitrate: 120,
                                 },
                             },
@@ -250,32 +280,37 @@ macro_rules! library_collection {
                 albums: vec![
                     Album {
                         id: AlbumId {
-                            year: 1985,
                             title: "album_title c.a".to_string(),
                         },
+                        date: AlbumDate {
+                            year: 1985,
+                            month: AlbumMonth::None,
+                            day: 0,
+                        },
+                        seq: AlbumSeq(0),
                         tracks: vec![
                             Track {
                                 id: TrackId {
-                                    number: 1,
                                     title: "track c.a.1".to_string(),
                                 },
+                                number: TrackNum(1),
                                 artist: vec!["artist c.a.1".to_string()],
-                                quality: Quality {
-                                    format: Format::Mp3,
+                                quality: TrackQuality {
+                                    format: TrackFormat::Mp3,
                                     bitrate: 320,
                                 },
                             },
                             Track {
                                 id: TrackId {
-                                    number: 2,
                                     title: "track c.a.2".to_string(),
                                 },
+                                number: TrackNum(2),
                                 artist: vec![
                                     "artist c.a.2.1".to_string(),
                                     "artist c.a.2.2".to_string(),
                                 ],
-                                quality: Quality {
-                                    format: Format::Mp3,
+                                quality: TrackQuality {
+                                    format: TrackFormat::Mp3,
                                     bitrate: 120,
                                 },
                             },
@@ -283,32 +318,37 @@ macro_rules! library_collection {
                     },
                     Album {
                         id: AlbumId {
-                            year: 2018,
                             title: "album_title c.b".to_string(),
                         },
+                        date: AlbumDate {
+                            year: 2018,
+                            month: AlbumMonth::None,
+                            day: 0,
+                        },
+                        seq: AlbumSeq(0),
                         tracks: vec![
                             Track {
                                 id: TrackId {
-                                    number: 1,
                                     title: "track c.b.1".to_string(),
                                 },
+                                number: TrackNum(1),
                                 artist: vec!["artist c.b.1".to_string()],
-                                quality: Quality {
-                                    format: Format::Flac,
+                                quality: TrackQuality {
+                                    format: TrackFormat::Flac,
                                     bitrate: 1041,
                                 },
                             },
                             Track {
                                 id: TrackId {
-                                    number: 2,
                                     title: "track c.b.2".to_string(),
                                 },
+                                number: TrackNum(2),
                                 artist: vec![
                                     "artist c.b.2.1".to_string(),
                                     "artist c.b.2.2".to_string(),
                                 ],
-                                quality: Quality {
-                                    format: Format::Flac,
+                                quality: TrackQuality {
+                                    format: TrackFormat::Flac,
                                     bitrate: 756,
                                 },
                             },
@@ -326,32 +366,37 @@ macro_rules! library_collection {
                 albums: vec![
                     Album {
                         id: AlbumId {
-                            year: 1995,
                             title: "album_title d.a".to_string(),
                         },
+                        date: AlbumDate {
+                            year: 1995,
+                            month: AlbumMonth::None,
+                            day: 0,
+                        },
+                        seq: AlbumSeq(0),
                         tracks: vec![
                             Track {
                                 id: TrackId {
-                                    number: 1,
                                     title: "track d.a.1".to_string(),
                                 },
+                                number: TrackNum(1),
                                 artist: vec!["artist d.a.1".to_string()],
-                                quality: Quality {
-                                    format: Format::Mp3,
+                                quality: TrackQuality {
+                                    format: TrackFormat::Mp3,
                                     bitrate: 120,
                                 },
                             },
                             Track {
                                 id: TrackId {
-                                    number: 2,
                                     title: "track d.a.2".to_string(),
                                 },
+                                number: TrackNum(2),
                                 artist: vec![
                                     "artist d.a.2.1".to_string(),
                                     "artist d.a.2.2".to_string(),
                                 ],
-                                quality: Quality {
-                                    format: Format::Mp3,
+                                quality: TrackQuality {
+                                    format: TrackFormat::Mp3,
                                     bitrate: 120,
                                 },
                             },
@@ -359,32 +404,37 @@ macro_rules! library_collection {
                     },
                     Album {
                         id: AlbumId {
-                            year: 2028,
                             title: "album_title d.b".to_string(),
                         },
+                        date: AlbumDate {
+                            year: 2028,
+                            month: AlbumMonth::None,
+                            day: 0,
+                        },
+                        seq: AlbumSeq(0),
                         tracks: vec![
                             Track {
                                 id: TrackId {
-                                    number: 1,
                                     title: "track d.b.1".to_string(),
                                 },
+                                number: TrackNum(1),
                                 artist: vec!["artist d.b.1".to_string()],
-                                quality: Quality {
-                                    format: Format::Flac,
+                                quality: TrackQuality {
+                                    format: TrackFormat::Flac,
                                     bitrate: 841,
                                 },
                             },
                             Track {
                                 id: TrackId {
-                                    number: 2,
                                     title: "track d.b.2".to_string(),
                                 },
+                                number: TrackNum(2),
                                 artist: vec![
                                     "artist d.b.2.1".to_string(),
                                     "artist d.b.2.2".to_string(),
                                 ],
-                                quality: Quality {
-                                    format: Format::Flac,
+                                quality: TrackQuality {
+                                    format: TrackFormat::Flac,
                                     bitrate: 756,
                                 },
                             },
@@ -404,12 +454,9 @@ macro_rules! full_collection {
         let artist_a = iter.next().unwrap();
         assert_eq!(artist_a.id.name, "Album_Artist ‘A’");
 
-        artist_a.musicbrainz = Some(
-            MusicBrainz::new(
-                "https://musicbrainz.org/artist/00000000-0000-0000-0000-000000000000",
-            )
-                .unwrap(),
-        );
+        artist_a.musicbrainz = Some(MusicBrainz::from_str(
+            "https://musicbrainz.org/artist/00000000-0000-0000-0000-000000000000",
+        ).unwrap());
 
         artist_a.properties = HashMap::from([
             (String::from("MusicButler"), vec![
@@ -422,14 +469,15 @@ macro_rules! full_collection {
             ]),
         ]);
 
+        artist_a.albums[0].seq = AlbumSeq(1);
+        artist_a.albums[1].seq = AlbumSeq(1);
+
         let artist_b = iter.next().unwrap();
         assert_eq!(artist_b.id.name, "Album_Artist ‘B’");
 
-        artist_b.musicbrainz = Some(
-            MusicBrainz::new(
-                "https://musicbrainz.org/artist/11111111-1111-1111-1111-111111111111",
-            ).unwrap(),
-        );
+        artist_b.musicbrainz = Some(MusicBrainz::from_str(
+            "https://musicbrainz.org/artist/11111111-1111-1111-1111-111111111111",
+        ).unwrap());
 
         artist_b.properties = HashMap::from([
             (String::from("MusicButler"), vec![
@@ -444,14 +492,17 @@ macro_rules! full_collection {
             ]),
         ]);
 
+        artist_b.albums[0].seq = AlbumSeq(1);
+        artist_b.albums[1].seq = AlbumSeq(3);
+        artist_b.albums[2].seq = AlbumSeq(2);
+        artist_b.albums[3].seq = AlbumSeq(4);
+
         let artist_c = iter.next().unwrap();
         assert_eq!(artist_c.id.name, "The Album_Artist ‘C’");
 
-        artist_c.musicbrainz = Some(
-            MusicBrainz::new(
-                "https://musicbrainz.org/artist/11111111-1111-1111-1111-111111111111",
-            ).unwrap(),
-        );
+        artist_c.musicbrainz = Some(MusicBrainz::from_str(
+            "https://musicbrainz.org/artist/11111111-1111-1111-1111-111111111111",
+        ).unwrap());
 
         // Nothing for artist_d
 

src/tui/app/machine/reload.rs

@@ -1,7 +1,7 @@
 use crate::tui::{
     app::{
         machine::{App, AppInner, AppMachine},
-        selection::IdSelection,
+        selection::KeySelection,
         AppPublic, AppState, IAppInteractReload,
     },
     lib::IMusicHoard,
@@ -36,7 +36,7 @@ impl<MH: IMusicHoard> IAppInteractReload for AppMachine<MH, AppReload> {
     type APP = App<MH>;
 
     fn reload_library(mut self) -> Self::APP {
-        let previous = IdSelection::get(
+        let previous = KeySelection::get(
             self.inner.music_hoard.get_collection(),
             &self.inner.selection,
         );
@@ -45,7 +45,7 @@ impl<MH: IMusicHoard> IAppInteractReload for AppMachine<MH, AppReload> {
     }
 
     fn reload_database(mut self) -> Self::APP {
-        let previous = IdSelection::get(
+        let previous = KeySelection::get(
             self.inner.music_hoard.get_collection(),
             &self.inner.selection,
         );
@@ -63,11 +63,11 @@ impl<MH: IMusicHoard> IAppInteractReload for AppMachine<MH, AppReload> {
 }
 
 trait IAppInteractReloadPrivate<MH: IMusicHoard> {
-    fn refresh(self, previous: IdSelection, result: Result<(), musichoard::Error>) -> App<MH>;
+    fn refresh(self, previous: KeySelection, result: Result<(), musichoard::Error>) -> App<MH>;
 }
 
 impl<MH: IMusicHoard> IAppInteractReloadPrivate<MH> for AppMachine<MH, AppReload> {
-    fn refresh(mut self, previous: IdSelection, result: Result<(), musichoard::Error>) -> App<MH> {
+    fn refresh(mut self, previous: KeySelection, result: Result<(), musichoard::Error>) -> App<MH> {
         match result {
             Ok(()) => {
                 self.inner

src/tui/app/selection/album.rs

@@ -1,12 +1,12 @@
 use std::cmp;
 
 use musichoard::collection::{
-    album::{Album, AlbumId},
+    album::{Album, AlbumDate, AlbumId, AlbumSeq},
     track::Track,
 };
 
 use crate::tui::app::selection::{
-    track::{IdSelectTrack, TrackSelection},
+    track::{KeySelectTrack, TrackSelection},
     Delta, SelectionState, WidgetState,
 };
 
@@ -26,9 +26,9 @@ impl AlbumSelection {
         selection
     }
 
-    pub fn reinitialise(&mut self, albums: &[Album], album: Option<IdSelectAlbum>) {
+    pub fn reinitialise(&mut self, albums: &[Album], album: Option<KeySelectAlbum>) {
         if let Some(album) = album {
-            let result = albums.binary_search_by(|a| a.get_sort_key().cmp(&album.album_id));
+            let result = albums.binary_search_by(|a| a.get_sort_key().cmp(&album.get_sort_key()));
             match result {
                 Ok(index) => self.reinitialise_with_index(albums, index, album.track),
                 Err(index) => self.reinitialise_with_index(albums, index, None),
@@ -42,7 +42,7 @@ impl AlbumSelection {
         &mut self,
         albums: &[Album],
         index: usize,
-        active_track: Option<IdSelectTrack>,
+        active_track: Option<KeySelectTrack>,
     ) {
         if albums.is_empty() {
             self.state.list.select(None);
@@ -160,21 +160,26 @@ impl AlbumSelection {
     }
 }
 
-pub struct IdSelectAlbum {
-    album_id: AlbumId,
-    track: Option<IdSelectTrack>,
+pub struct KeySelectAlbum {
+    key: (AlbumDate, AlbumSeq, AlbumId),
+    track: Option<KeySelectTrack>,
 }
 
-impl IdSelectAlbum {
+impl KeySelectAlbum {
     pub fn get(albums: &[Album], selection: &AlbumSelection) -> Option<Self> {
         selection.state.list.selected().map(|index| {
             let album = &albums[index];
-            IdSelectAlbum {
-                album_id: album.get_sort_key().clone(),
-                track: IdSelectTrack::get(&album.tracks, &selection.track),
+            let key = album.get_sort_key();
+            KeySelectAlbum {
+                key: (key.0.to_owned(), key.1.to_owned(), key.2.to_owned()),
+                track: KeySelectTrack::get(&album.tracks, &selection.track),
             }
         })
     }
+
+    pub fn get_sort_key(&self) -> (&AlbumDate, &AlbumSeq, &AlbumId) {
+        (&self.key.0, &self.key.1, &self.key.2)
+    }
 }
 
 #[cfg(test)]
@@ -330,20 +335,20 @@ mod tests {
 
         // Re-initialise.
         let expected = sel.clone();
-        let active_album = IdSelectAlbum::get(albums, &sel);
+        let active_album = KeySelectAlbum::get(albums, &sel);
         sel.reinitialise(albums, active_album);
         assert_eq!(sel, expected);
 
         // Re-initialise out-of-bounds.
         let mut expected = sel.clone();
         expected.decrement(albums, Delta::Line);
-        let active_album = IdSelectAlbum::get(albums, &sel);
+        let active_album = KeySelectAlbum::get(albums, &sel);
         sel.reinitialise(&albums[..(albums.len() - 1)], active_album);
         assert_eq!(sel, expected);
 
         // Re-initialise empty.
         let expected = AlbumSelection::initialise(&[]);
-        let active_album = IdSelectAlbum::get(albums, &sel);
+        let active_album = KeySelectAlbum::get(albums, &sel);
         sel.reinitialise(&[], active_album);
         assert_eq!(sel, expected);
     }

src/tui/app/selection/artist.rs

@@ -7,7 +7,7 @@ use musichoard::collection::{
 };
 
 use crate::tui::app::selection::{
-    album::{AlbumSelection, IdSelectAlbum},
+    album::{AlbumSelection, KeySelectAlbum},
     Delta, SelectionState, WidgetState,
 };
 
@@ -27,9 +27,9 @@ impl ArtistSelection {
         selection
     }
 
-    pub fn reinitialise(&mut self, artists: &[Artist], active: Option<IdSelectArtist>) {
+    pub fn reinitialise(&mut self, artists: &[Artist], active: Option<KeySelectArtist>) {
         if let Some(active) = active {
-            let result = artists.binary_search_by(|a| a.get_sort_key().cmp(&active.artist_id));
+            let result = artists.binary_search_by(|a| a.get_sort_key().cmp(&active.get_sort_key()));
             match result {
                 Ok(index) => self.reinitialise_with_index(artists, index, active.album),
                 Err(index) => self.reinitialise_with_index(artists, index, None),
@@ -43,7 +43,7 @@ impl ArtistSelection {
         &mut self,
         artists: &[Artist],
         index: usize,
-        active_album: Option<IdSelectAlbum>,
+        active_album: Option<KeySelectAlbum>,
     ) {
         if artists.is_empty() {
             self.state.list.select(None);
@@ -193,21 +193,26 @@ impl ArtistSelection {
     }
 }
 
-pub struct IdSelectArtist {
-    artist_id: ArtistId,
-    album: Option<IdSelectAlbum>,
+pub struct KeySelectArtist {
+    key: (ArtistId,),
+    album: Option<KeySelectAlbum>,
 }
 
-impl IdSelectArtist {
+impl KeySelectArtist {
     pub fn get(artists: &[Artist], selection: &ArtistSelection) -> Option<Self> {
         selection.state.list.selected().map(|index| {
             let artist = &artists[index];
-            IdSelectArtist {
-                artist_id: artist.get_sort_key().clone(),
-                album: IdSelectAlbum::get(&artist.albums, &selection.album),
+            let key = artist.get_sort_key();
+            KeySelectArtist {
+                key: (key.0.to_owned(),),
+                album: KeySelectAlbum::get(&artist.albums, &selection.album),
             }
         })
     }
+
+    pub fn get_sort_key(&self) -> (&ArtistId,) {
+        (&self.key.0,)
+    }
 }
 
 #[cfg(test)]
@@ -385,20 +390,20 @@ mod tests {
 
         // Re-initialise.
         let expected = sel.clone();
-        let active_artist = IdSelectArtist::get(artists, &sel);
+        let active_artist = KeySelectArtist::get(artists, &sel);
         sel.reinitialise(artists, active_artist);
         assert_eq!(sel, expected);
 
         // Re-initialise out-of-bounds.
         let mut expected = sel.clone();
         expected.decrement(artists, Delta::Line);
-        let active_artist = IdSelectArtist::get(artists, &sel);
+        let active_artist = KeySelectArtist::get(artists, &sel);
         sel.reinitialise(&artists[..(artists.len() - 1)], active_artist);
         assert_eq!(sel, expected);
 
         // Re-initialise empty.
         let expected = ArtistSelection::initialise(&[]);
-        let active_artist = IdSelectArtist::get(artists, &sel);
+        let active_artist = KeySelectArtist::get(artists, &sel);
         sel.reinitialise(&[], active_artist);
         assert_eq!(sel, expected);
     }

src/tui/app/selection/mod.rs

@@ -5,7 +5,7 @@ mod track;
 use musichoard::collection::{album::Album, artist::Artist, track::Track, Collection};
 use ratatui::widgets::ListState;
 
-use artist::{ArtistSelection, IdSelectArtist};
+use artist::{ArtistSelection, KeySelectArtist};
 
 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
 pub enum Category {
@@ -64,7 +64,7 @@ impl Selection {
         self.artist.album.track.state.list = selected.track;
     }
 
-    pub fn select_by_id(&mut self, artists: &[Artist], selected: IdSelection) {
+    pub fn select_by_id(&mut self, artists: &[Artist], selected: KeySelection) {
         self.artist.reinitialise(artists, selected.artist);
     }
 
@@ -229,14 +229,14 @@ impl ListSelection {
     }
 }
 
-pub struct IdSelection {
-    artist: Option<IdSelectArtist>,
+pub struct KeySelection {
+    artist: Option<KeySelectArtist>,
 }
 
-impl IdSelection {
+impl KeySelection {
     pub fn get(collection: &Collection, selection: &Selection) -> Self {
-        IdSelection {
-            artist: IdSelectArtist::get(collection, &selection.artist),
+        KeySelection {
+            artist: KeySelectArtist::get(collection, &selection.artist),
         }
     }
 }

src/tui/app/selection/track.rs

@@ -1,6 +1,6 @@
 use std::cmp;
 
-use musichoard::collection::track::{Track, TrackId};
+use musichoard::collection::track::{Track, TrackId, TrackNum};
 
 use crate::tui::app::selection::{Delta, SelectionState, WidgetState};
 
@@ -18,9 +18,9 @@ impl TrackSelection {
         selection
     }
 
-    pub fn reinitialise(&mut self, tracks: &[Track], track: Option<IdSelectTrack>) {
+    pub fn reinitialise(&mut self, tracks: &[Track], track: Option<KeySelectTrack>) {
         if let Some(track) = track {
-            let result = tracks.binary_search_by(|t| t.get_sort_key().cmp(&track.track_id));
+            let result = tracks.binary_search_by(|t| t.get_sort_key().cmp(&track.get_sort_key()));
             match result {
                 Ok(index) | Err(index) => self.reinitialise_with_index(tracks, index),
             }
@@ -100,19 +100,24 @@ impl TrackSelection {
     }
 }
 
-pub struct IdSelectTrack {
-    track_id: TrackId,
+pub struct KeySelectTrack {
+    key: (TrackNum, TrackId),
 }
 
-impl IdSelectTrack {
+impl KeySelectTrack {
     pub fn get(tracks: &[Track], selection: &TrackSelection) -> Option<Self> {
         selection.state.list.selected().map(|index| {
             let track = &tracks[index];
-            IdSelectTrack {
-                track_id: track.get_sort_key().clone(),
+            let key = track.get_sort_key();
+            KeySelectTrack {
+                key: (key.0.to_owned(), key.1.to_owned()),
             }
         })
     }
+
+    pub fn get_sort_key(&self) -> (&TrackNum, &TrackId) {
+        (&self.key.0, &self.key.1)
+    }
 }
 
 #[cfg(test)]
@@ -210,20 +215,20 @@ mod tests {
 
         // Re-initialise.
         let expected = sel.clone();
-        let active_track = IdSelectTrack::get(tracks, &sel);
+        let active_track = KeySelectTrack::get(tracks, &sel);
         sel.reinitialise(tracks, active_track);
         assert_eq!(sel, expected);
 
         // Re-initialise out-of-bounds.
         let mut expected = sel.clone();
         expected.decrement(tracks, Delta::Line);
-        let active_track = IdSelectTrack::get(tracks, &sel);
+        let active_track = KeySelectTrack::get(tracks, &sel);
         sel.reinitialise(&tracks[..(tracks.len() - 1)], active_track);
         assert_eq!(sel, expected);
 
         // Re-initialise empty.
         let expected = TrackSelection::initialise(&[]);
-        let active_track = IdSelectTrack::get(tracks, &sel);
+        let active_track = KeySelectTrack::get(tracks, &sel);
         sel.reinitialise(&[], active_track);
         assert_eq!(sel, expected);
     }

src/tui/mod.rs

@@ -11,12 +11,12 @@ pub use handler::EventHandler;
 pub use listener::EventListener;
 pub use ui::Ui;
 
-use crossterm::event::{DisableMouseCapture, EnableMouseCapture};
-use crossterm::terminal::{self, EnterAlternateScreen, LeaveAlternateScreen};
-use ratatui::backend::Backend;
-use ratatui::Terminal;
-use std::io;
-use std::marker::PhantomData;
+use crossterm::{
+    event::{DisableMouseCapture, EnableMouseCapture},
+    terminal::{self, EnterAlternateScreen, LeaveAlternateScreen},
+};
+use ratatui::{backend::Backend, Terminal};
+use std::{io, marker::PhantomData};
 
 use crate::tui::{
     app::{IAppAccess, IAppInteract},
@@ -26,7 +26,7 @@ use crate::tui::{
     ui::IUi,
 };
 
-#[derive(Debug, PartialEq, Eq)]
+#[derive(Debug, Eq, PartialEq)]
 pub enum Error {
     Io(String),
     Event(String),
@@ -112,8 +112,8 @@ impl<B: Backend, UI: IUi, APP: IAppInteract + IAppAccess> Tui<B, UI, APP> {
                     match listener_handle.join() {
                         Ok(err) => return Err(err.into()),
                         // Calling std::panic::resume_unwind(err) as recommended by the Rust docs
-                        // will not produce an error message. The panic error message is printed at
-                        // the location of the panic which at the time is hidden by the TUI.
+                        // will not produce an error message. This may be due to the panic simply
+                        // causing the process to abort in which case there is nothing to unwind.
                         Err(_) => return Err(Error::ListenerPanic),
                     }
                 }
@@ -251,10 +251,9 @@ mod tests {
 
         let result = Tui::main(terminal, app, ui, handler, listener);
         assert!(result.is_err());
-        assert_eq!(
-            result.unwrap_err(),
-            Error::Event(EventError::Recv.to_string())
-        );
+
+        let error = EventError::Recv;
+        assert_eq!(result.unwrap_err(), Error::Event(error.to_string()));
     }
 
     #[test]

src/tui/testmod.rs

@@ -1,10 +1,11 @@
+use std::{collections::HashMap, str::FromStr};
+
 use musichoard::collection::{
-    album::{Album, AlbumId},
+    album::{Album, AlbumDate, AlbumId, AlbumMonth, AlbumSeq},
     artist::{Artist, ArtistId, MusicBrainz},
-    track::{Format, Quality, Track, TrackId},
+    track::{Track, TrackFormat, TrackId, TrackNum, TrackQuality},
 };
 use once_cell::sync::Lazy;
-use std::collections::HashMap;
 
 use crate::tests::*;
 

src/tui/ui.rs

@@ -3,7 +3,7 @@ use std::collections::HashMap;
 use musichoard::collection::{
     album::Album,
     artist::Artist,
-    track::{Format, Track},
+    track::{Track, TrackFormat},
     Collection,
 };
 use ratatui::{
@@ -287,9 +287,13 @@ impl<'a, 'b> AlbumState<'a, 'b> {
         let album = state.list.selected().map(|i| &albums[i]);
         let info = Paragraph::new(format!(
             "Title: {}\n\
-             Year: {}",
+             Date: {}{}",
             album.map(|a| a.id.title.as_str()).unwrap_or(""),
-            album.map(|a| a.id.year.to_string()).unwrap_or_default(),
+            album.map(|a| a.date.to_string()).unwrap_or_default(),
+            album
+                .filter(|a| a.seq.0 > 0)
+                .map(|a| format!(" ({})", a.seq.0))
+                .unwrap_or_default()
         ));
 
         AlbumState {
@@ -323,13 +327,13 @@ impl<'a, 'b> TrackState<'a, 'b> {
              Title: {}\n\
              Artist: {}\n\
              Quality: {}",
-            track.map(|t| t.id.number.to_string()).unwrap_or_default(),
+            track.map(|t| t.number.0.to_string()).unwrap_or_default(),
             track.map(|t| t.id.title.as_str()).unwrap_or(""),
             track.map(|t| t.artist.join("; ")).unwrap_or_default(),
             track
                 .map(|t| match t.quality.format {
-                    Format::Flac => "FLAC".to_string(),
-                    Format::Mp3 => format!("MP3 {}kbps", t.quality.bitrate),
+                    TrackFormat::Flac => "FLAC".to_string(),
+                    TrackFormat::Mp3 => format!("MP3 {}kbps", t.quality.bitrate),
                 })
                 .unwrap_or_default(),
         ));

tests/database/json.rs

@@ -4,7 +4,7 @@ use once_cell::sync::Lazy;
 use tempfile::NamedTempFile;
 
 use musichoard::{
-    collection::{artist::Artist, Collection},
+    collection::{album::AlbumDate, artist::Artist, Collection},
     database::{
         json::{backend::JsonDatabaseFileBackend, JsonDatabase},
         IDatabase,
@@ -19,7 +19,10 @@ pub static DATABASE_TEST_FILE: Lazy<PathBuf> =
 fn expected() -> Collection {
     let mut expected = COLLECTION.to_owned();
     for artist in expected.iter_mut() {
-        artist.albums.clear();
+        for album in artist.albums.iter_mut() {
+            album.date = AlbumDate::default();
+            album.tracks.clear();
+        }
     }
     expected
 }

tests/files/database/database.json

@@ -1 +1 @@
-{"V20240210":[{"name":"Аркона","sort":"Arkona","musicbrainz":"https://musicbrainz.org/artist/baad262d-55ef-427a-83c7-f7530964f212","properties":{"Bandcamp":["https://arkonamoscow.bandcamp.com/"],"MusicButler":["https://www.musicbutler.io/artist-page/283448581"],"Qobuz":["https://www.qobuz.com/nl-nl/interpreter/arkona/download-streaming-albums"]}},{"name":"Eluveitie","sort":null,"musicbrainz":"https://musicbrainz.org/artist/8000598a-5edb-401c-8e6d-36b167feaf38","properties":{"MusicButler":["https://www.musicbutler.io/artist-page/269358403"],"Qobuz":["https://www.qobuz.com/nl-nl/interpreter/eluveitie/download-streaming-albums"]}},{"name":"Frontside","sort":null,"musicbrainz":"https://musicbrainz.org/artist/3a901353-fccd-4afd-ad01-9c03f451b490","properties":{"MusicButler":["https://www.musicbutler.io/artist-page/826588800"],"Qobuz":["https://www.qobuz.com/nl-nl/interpreter/frontside/download-streaming-albums"]}},{"name":"Heaven’s Basement","sort":"Heaven’s Basement","musicbrainz":"https://musicbrainz.org/artist/c2c4d56a-d599-4a18-bd2f-ae644e2198cc","properties":{"MusicButler":["https://www.musicbutler.io/artist-page/291158685"],"Qobuz":["https://www.qobuz.com/nl-nl/interpreter/heaven-s-basement/download-streaming-albums"]}},{"name":"Metallica","sort":null,"musicbrainz":"https://musicbrainz.org/artist/65f4f0c5-ef9e-490c-aee3-909e7ae6b2ab","properties":{"MusicButler":["https://www.musicbutler.io/artist-page/3996865"],"Qobuz":["https://www.qobuz.com/nl-nl/interpreter/metallica/download-streaming-albums"]}}]}
+{"V20240302":[{"name":"Аркона","sort":"Arkona","musicbrainz":"https://musicbrainz.org/artist/baad262d-55ef-427a-83c7-f7530964f212","properties":{"Bandcamp":["https://arkonamoscow.bandcamp.com/"],"MusicButler":["https://www.musicbutler.io/artist-page/283448581"],"Qobuz":["https://www.qobuz.com/nl-nl/interpreter/arkona/download-streaming-albums"]},"albums":[{"title":"Slovo","seq":0}]},{"name":"Eluveitie","sort":null,"musicbrainz":"https://musicbrainz.org/artist/8000598a-5edb-401c-8e6d-36b167feaf38","properties":{"MusicButler":["https://www.musicbutler.io/artist-page/269358403"],"Qobuz":["https://www.qobuz.com/nl-nl/interpreter/eluveitie/download-streaming-albums"]},"albums":[{"title":"Vên [re‐recorded]","seq":0},{"title":"Slania","seq":0}]},{"name":"Frontside","sort":null,"musicbrainz":"https://musicbrainz.org/artist/3a901353-fccd-4afd-ad01-9c03f451b490","properties":{"MusicButler":["https://www.musicbutler.io/artist-page/826588800"],"Qobuz":["https://www.qobuz.com/nl-nl/interpreter/frontside/download-streaming-albums"]},"albums":[{"title":"…nasze jest królestwo, potęga i chwała na wieki…","seq":0}]},{"name":"Heaven’s Basement","sort":"Heaven’s Basement","musicbrainz":"https://musicbrainz.org/artist/c2c4d56a-d599-4a18-bd2f-ae644e2198cc","properties":{"MusicButler":["https://www.musicbutler.io/artist-page/291158685"],"Qobuz":["https://www.qobuz.com/nl-nl/interpreter/heaven-s-basement/download-streaming-albums"]},"albums":[{"title":"Paper Plague","seq":0},{"title":"Unbreakable","seq":0}]},{"name":"Metallica","sort":null,"musicbrainz":"https://musicbrainz.org/artist/65f4f0c5-ef9e-490c-aee3-909e7ae6b2ab","properties":{"MusicButler":["https://www.musicbutler.io/artist-page/3996865"],"Qobuz":["https://www.qobuz.com/nl-nl/interpreter/metallica/download-streaming-albums"]},"albums":[{"title":"Ride the Lightning","seq":0},{"title":"S&M","seq":0}]}]}