Add artist as top level in data structure hierarchy (#13)

Closes #12

Reviewed-on: https://git.wojciechkozlowski.eu/wojtek/musichoard/pulls/13

src/database/json.rs

@@ -77,7 +77,7 @@ impl DatabaseJsonBackend for DatabaseJsonFile {
 mod tests {
     use super::*;
 
-    use crate::{Album, AlbumId, Track};
+    use crate::{tests::test_data, Artist};
 
     struct DatabaseJsonTest {
         json: String,
@@ -94,53 +94,15 @@ mod tests {
         }
     }
 
-    fn test_data() -> Vec<Album> {
+    fn artist_to_json(artist: &Artist) -> String {
-        vec![
+        let album_artist = &artist.id.name;
-            Album {
-                id: AlbumId {
-                    artist: String::from("Artist A"),
-                    year: 1998,
-                    title: String::from("Release group A"),
-                },
-                tracks: vec![
-                    Track {
-                        number: 1,
-                        title: String::from("Track A.1"),
-                        artist: vec![String::from("Artist A.A")],
-                    },
-                    Track {
-                        number: 2,
-                        title: String::from("Track A.2"),
-                        artist: vec![String::from("Artist A.A")],
-                    },
-                    Track {
-                        number: 3,
-                        title: String::from("Track A.3"),
-                        artist: vec![String::from("Artist A.A"), String::from("Artist A.B")],
-                    },
-                ],
-            },
-            Album {
-                id: AlbumId {
-                    artist: String::from("Artist B"),
-                    year: 2008,
-                    title: String::from("Release group B"),
-                },
-                tracks: vec![Track {
-                    number: 1,
-                    title: String::from("Track B.1"),
-                    artist: vec![String::from("Artist B.A")],
-                }],
-            },
-        ]
-    }
 
-    fn album_to_json(album: &Album) -> String {
+        let mut albums: Vec<String> = vec![];
-        let album_id_artist = &album.id.artist;
+        for album in artist.albums.iter() {
-        let album_id_year = album.id.year;
+            let album_year = album.id.year;
-        let album_id_title = &album.id.title;
+            let album_title = &album.id.title;
 
-        let mut album_tracks: Vec<String> = vec![];
+            let mut tracks: Vec<String> = vec![];
             for track in album.tracks.iter() {
                 let track_number = track.number;
                 let track_title = &track.title;
@@ -151,7 +113,7 @@ mod tests {
                 }
                 let track_artist = track_artist.join(",");
 
-            album_tracks.push(format!(
+                tracks.push(format!(
                     "{{\
                      \"number\":{track_number},\
                      \"title\":\"{track_title}\",\
@@ -159,33 +121,42 @@ mod tests {
                      }}"
                 ));
             }
-        let album_tracks = album_tracks.join(",");
+            let tracks = tracks.join(",");
+
+            albums.push(format!(
+                "{{\
+                 \"id\":{{\
+                 \"year\":{album_year},\
+                 \"title\":\"{album_title}\"\
+                 }},\"tracks\":[{tracks}]\
+                 }}"
+            ));
+        }
+        let albums = albums.join(",");
 
         format!(
             "{{\
              \"id\":{{\
-             \"artist\":\"{album_id_artist}\",\
+             \"name\":\"{album_artist}\"\
-             \"year\":{album_id_year},\
+             }},\"albums\":[{albums}]\
-             \"title\":\"{album_id_title}\"\
-             }},\"tracks\":[{album_tracks}]\
              }}"
         )
     }
 
-    fn albums_to_json(albums: &Vec<Album>) -> String {
+    fn artists_to_json(artists: &Vec<Artist>) -> String {
-        let mut albums_strings: Vec<String> = vec![];
+        let mut artists_strings: Vec<String> = vec![];
-        for album in albums.iter() {
+        for artist in artists.iter() {
-            albums_strings.push(album_to_json(album));
+            artists_strings.push(artist_to_json(artist));
         }
-        let albums_json = albums_strings.join(",");
+        let artists_json = artists_strings.join(",");
-        format!("[{albums_json}]")
+        format!("[{artists_json}]")
     }
 
     #[test]
     fn write() {
         let write_data = test_data();
         let backend = DatabaseJsonTest {
-            json: albums_to_json(&write_data),
+            json: artists_to_json(&write_data),
         };
 
         DatabaseJson::new(Box::new(backend))
@@ -197,10 +168,10 @@ mod tests {
     fn read() {
         let expected = test_data();
         let backend = DatabaseJsonTest {
-            json: albums_to_json(&expected),
+            json: artists_to_json(&expected),
         };
 
-        let mut read_data: Vec<Album> = vec![];
+        let mut read_data: Vec<Artist> = vec![];
         DatabaseJson::new(Box::new(backend))
             .read(&mut read_data)
             .unwrap();
@@ -212,12 +183,12 @@ mod tests {
     fn reverse() {
         let expected = test_data();
         let backend = DatabaseJsonTest {
-            json: albums_to_json(&expected),
+            json: artists_to_json(&expected),
         };
         let mut database = DatabaseJson::new(Box::new(backend));
 
         let write_data = test_data();
-        let mut read_data: Vec<Album> = vec![];
+        let mut read_data: Vec<Artist> = vec![];
         database.write(&write_data).unwrap();
         database.read(&mut read_data).unwrap();
 

src/lib.rs

@@ -20,7 +20,6 @@ pub struct Track {
 /// The album identifier.
 #[derive(Debug, Deserialize, Serialize, PartialEq, Eq, Clone, Hash)]
 pub struct AlbumId {
-    pub artist: String,
     pub year: u32,
     pub title: String,
 }
@@ -31,3 +30,103 @@ pub struct Album {
     pub id: AlbumId,
     pub tracks: Vec<Track>,
 }
+
+/// The artist identifier.
+#[derive(Debug, Deserialize, Serialize, PartialEq, Eq, Clone, Hash)]
+pub struct ArtistId {
+    pub name: String,
+}
+
+/// An artist.
+#[derive(Debug, Deserialize, Serialize, PartialEq, Eq)]
+pub struct Artist {
+    pub id: ArtistId,
+    pub albums: Vec<Album>,
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    pub fn test_data() -> Vec<Artist> {
+        vec![
+            Artist {
+                id: ArtistId {
+                    name: "album_artist a".to_string(),
+                },
+                albums: vec![
+                    Album {
+                        id: AlbumId {
+                            year: 1998,
+                            title: "album_title a.a".to_string(),
+                        },
+                        tracks: vec![
+                            Track {
+                                number: 1,
+                                title: "track a.a.1".to_string(),
+                                artist: vec!["artist a.a.1".to_string()],
+                            },
+                            Track {
+                                number: 2,
+                                title: "track a.a.2".to_string(),
+                                artist: vec![
+                                    "artist a.a.2.1".to_string(),
+                                    "artist a.a.2.2".to_string(),
+                                ],
+                            },
+                            Track {
+                                number: 3,
+                                title: "track a.a.3".to_string(),
+                                artist: vec!["artist a.a.3".to_string()],
+                            },
+                        ],
+                    },
+                    Album {
+                        id: AlbumId {
+                            year: 2015,
+                            title: "album_title a.b".to_string(),
+                        },
+                        tracks: vec![
+                            Track {
+                                number: 1,
+                                title: "track a.b.1".to_string(),
+                                artist: vec!["artist a.b.1".to_string()],
+                            },
+                            Track {
+                                number: 2,
+                                title: "track a.b.2".to_string(),
+                                artist: vec!["artist a.b.2".to_string()],
+                            },
+                        ],
+                    },
+                ],
+            },
+            Artist {
+                id: ArtistId {
+                    name: "album_artist b.a".to_string(),
+                },
+                albums: vec![Album {
+                    id: AlbumId {
+                        year: 2003,
+                        title: "album_title b.a".to_string(),
+                    },
+                    tracks: vec![
+                        Track {
+                            number: 1,
+                            title: "track b.a.1".to_string(),
+                            artist: vec!["artist b.a.1".to_string()],
+                        },
+                        Track {
+                            number: 2,
+                            title: "track b.a.2".to_string(),
+                            artist: vec![
+                                "artist b.a.2.1".to_string(),
+                                "artist b.a.2.2".to_string(),
+                            ],
+                        },
+                    ],
+                }],
+            },
+        ]
+    }
+}

src/library/beets.rs

@@ -1,9 +1,13 @@
 //! Module for interacting with the music library via
 //! [beets](https://beets.readthedocs.io/en/stable/).
 
-use std::{collections::HashSet, fmt::Display, process::Command};
+use std::{
+    collections::{HashMap, HashSet},
+    fmt::Display,
+    process::Command,
+};
 
-use crate::{Album, AlbumId, Track};
+use crate::{Album, AlbumId, Artist, ArtistId, Track};
 
 use super::{Error, Library, Query, QueryOption};
 
@@ -94,7 +98,7 @@ trait LibraryPrivate {
     const LIST_FORMAT_ARG: &'static str;
 
     fn list_cmd_and_args(query: &Query) -> Vec<String>;
-    fn list_to_albums(list_output: Vec<String>) -> Result<Vec<Album>, Error>;
+    fn list_to_artists(list_output: Vec<String>) -> Result<Vec<Artist>, Error>;
 }
 
 impl Beets {
@@ -104,10 +108,10 @@ impl Beets {
 }
 
 impl Library for Beets {
-    fn list(&mut self, query: &Query) -> Result<Vec<Album>, Error> {
+    fn list(&mut self, query: &Query) -> Result<Vec<Artist>, Error> {
         let cmd = Self::list_cmd_and_args(query);
         let output = self.executor.exec(&cmd)?;
-        Self::list_to_albums(output)
+        Self::list_to_artists(output)
     }
 }
 
@@ -142,9 +146,9 @@ impl LibraryPrivate for Beets {
         cmd
     }
 
-    fn list_to_albums(list_output: Vec<String>) -> Result<Vec<Album>, Error> {
+    fn list_to_artists(list_output: Vec<String>) -> Result<Vec<Artist>, Error> {
-        let mut albums: Vec<Album> = vec![];
+        let mut artists: Vec<Artist> = vec![];
-        let mut album_ids = HashSet::<AlbumId>::new();
+        let mut album_ids = HashMap::<ArtistId, HashSet<AlbumId>>::new();
 
         for line in list_output.iter() {
             let split: Vec<&str> = line.split(Self::LIST_FORMAT_SEPARATOR).collect();
@@ -160,8 +164,9 @@ impl LibraryPrivate for Beets {
             let track_title = split[4].to_string();
             let track_artist = split[5].to_string();
 
-            let aid = AlbumId {
+            let artist_id = ArtistId { name: album_artist };
-                artist: album_artist,
+
+            let album_id = AlbumId {
                 year: album_year,
                 title: album_title,
             };
@@ -172,20 +177,44 @@ impl LibraryPrivate for Beets {
                 artist: track_artist.split("; ").map(|s| s.to_owned()).collect(),
             };
 
-            if album_ids.contains(&aid) {
+            let artist = if album_ids.contains_key(&artist_id) {
                 // Beets returns results in order so we look from the back.
-                let album = albums.iter_mut().rev().find(|a| a.id == aid).unwrap();
+                artists
+                    .iter_mut()
+                    .rev()
+                    .find(|a| a.id == artist_id)
+                    .unwrap()
+            } else {
+                album_ids.insert(artist_id.clone(), HashSet::<AlbumId>::new());
+                artists.push(Artist {
+                    id: artist_id.clone(),
+                    albums: vec![],
+                });
+                artists.last_mut().unwrap()
+            };
+
+            if album_ids[&artist_id].contains(&album_id) {
+                // Beets returns results in order so we look from the back.
+                let album = artist
+                    .albums
+                    .iter_mut()
+                    .rev()
+                    .find(|a| a.id == album_id)
+                    .unwrap();
                 album.tracks.push(track);
             } else {
-                album_ids.insert(aid.clone());
+                album_ids
-                albums.push(Album {
+                    .get_mut(&artist_id)
-                    id: aid,
+                    .unwrap()
+                    .insert(album_id.clone());
+                artist.albums.push(Album {
+                    id: album_id,
                     tracks: vec![track],
                 });
             }
         }
 
-        Ok(albums)
+        Ok(artists)
     }
 }
 
@@ -220,6 +249,8 @@ impl BeetsExecutor for SystemExecutor {
 mod tests {
     use super::*;
 
+    use crate::tests::test_data;
+
     struct TestExecutor {
         arguments: Option<Vec<String>>,
         output: Option<Result<Vec<String>, Error>>,
@@ -232,60 +263,15 @@ mod tests {
         }
     }
 
-    fn test_data() -> Vec<Album> {
+    fn artist_to_beets_string(artist: &Artist) -> Vec<String> {
-        vec![
+        let mut strings = vec![];
-            Album {
-                id: AlbumId {
-                    artist: "album_artist.a".to_string(),
-                    year: 1998,
-                    title: "album_title.a".to_string(),
-                },
-                tracks: vec![
-                    Track {
-                        number: 1,
-                        title: "track.a.1".to_string(),
-                        artist: vec!["artist.a.1".to_string()],
-                    },
-                    Track {
-                        number: 2,
-                        title: "track.a.2".to_string(),
-                        artist: vec!["artist.a.2.1".to_string(), "artist.a.2.2".to_string()],
-                    },
-                    Track {
-                        number: 3,
-                        title: "track.a.3".to_string(),
-                        artist: vec!["artist.a.3".to_string()],
-                    },
-                ],
-            },
-            Album {
-                id: AlbumId {
-                    artist: "album_artist.b".to_string(),
-                    year: 2003,
-                    title: "album_title.b".to_string(),
-                },
-                tracks: vec![
-                    Track {
-                        number: 1,
-                        title: "track.b.1".to_string(),
-                        artist: vec!["artist.b.1".to_string()],
-                    },
-                    Track {
-                        number: 2,
-                        title: "track.b.2".to_string(),
-                        artist: vec!["artist.b.2.1".to_string(), "artist.b.2.2".to_string()],
-                    },
-                ],
-            },
-        ]
-    }
 
-    fn album_to_beets_string(album: &Album) -> Vec<String> {
+        let album_artist = &artist.id.name;
-        let album_artist = &album.id.artist;
+
+        for album in artist.albums.iter() {
             let album_year = &album.id.year;
             let album_title = &album.id.title;
 
-        let mut strings = vec![];
             for track in album.tracks.iter() {
                 let track_number = &track.number;
                 let track_title = &track.title;
@@ -297,14 +283,15 @@ mod tests {
                     Beets::LIST_FORMAT_SEPARATOR,
                 ));
             }
+        }
 
         strings
     }
 
-    fn albums_to_beets_string(albums: &Vec<Album>) -> Vec<String> {
+    fn artists_to_beets_string(artists: &Vec<Artist>) -> Vec<String> {
         let mut strings = vec![];
-        for album in albums.iter() {
+        for artist in artists.iter() {
-            strings.append(&mut album_to_beets_string(album));
+            strings.append(&mut artist_to_beets_string(artist));
         }
         strings
     }
@@ -340,14 +327,14 @@ mod tests {
         let mut beets = Beets::new(Box::new(executor));
         let output = beets.list(&Query::default()).unwrap();
 
-        let expected: Vec<Album> = vec![];
+        let expected: Vec<Artist> = vec![];
         assert_eq!(output, expected);
     }
 
     #[test]
     fn test_list_ordered() {
         let expected = test_data();
-        let output = albums_to_beets_string(&expected);
+        let output = artists_to_beets_string(&expected);
 
         let executor = TestExecutor {
             arguments: Some(vec!["ls".to_string(), Beets::LIST_FORMAT_ARG.to_string()]),
@@ -362,18 +349,21 @@ mod tests {
     #[test]
     fn test_list_unordered() {
         let mut expected = test_data();
-        let mut output = albums_to_beets_string(&expected);
+        let mut output = artists_to_beets_string(&expected);
         let last = output.len() - 1;
         output.swap(0, last);
 
-        // Putting the last track first will make its entire album come first in the output.
+        // Putting the last track first will make the entire artist come first in the output.
         expected.rotate_right(1);
 
+        // Same applies to that artists' albums, but here the artist has only one album.
+        assert_eq!(expected[0].albums.len(), 1);
+
         // Same applies to that album's tracks.
-        expected[0].tracks.rotate_right(1);
+        expected[0].albums[0].tracks.rotate_right(1);
 
         // And the (now) second album's tracks first track comes last.
-        expected[1].tracks.rotate_left(1);
+        expected[1].albums[0].tracks.rotate_left(1);
 
         let executor = TestExecutor {
             arguments: Some(vec!["ls".to_string(), Beets::LIST_FORMAT_ARG.to_string()]),
@@ -388,10 +378,10 @@ mod tests {
     #[test]
     fn test_list_album_title_year_clash() {
         let mut expected = test_data();
-        expected[1].id.year = expected[0].id.year;
+        expected[0].albums[0].id.year = expected[1].albums[0].id.year;
-        expected[1].id.title = expected[0].id.title.clone();
+        expected[0].albums[0].id.title = expected[1].albums[0].id.title.clone();
 
-        let output = albums_to_beets_string(&expected);
+        let output = artists_to_beets_string(&expected);
 
         let executor = TestExecutor {
             arguments: Some(vec!["ls".to_string(), Beets::LIST_FORMAT_ARG.to_string()]),
@@ -423,7 +413,7 @@ mod tests {
         let mut beets = Beets::new(Box::new(executor));
         let output = beets.list(&query).unwrap();
 
-        let expected: Vec<Album> = vec![];
+        let expected: Vec<Artist> = vec![];
         assert_eq!(output, expected);
     }
 }

src/library/mod.rs

@@ -2,7 +2,7 @@
 
 use std::{num::ParseIntError, str::Utf8Error};
 
-use crate::Album;
+use crate::Artist;
 
 pub mod beets;
 
@@ -129,5 +129,5 @@ impl From<Utf8Error> for Error {
 /// Trait for interacting with the music library.
 pub trait Library {
     /// List lirbary items that match the a specific query.
-    fn list(&mut self, query: &Query) -> Result<Vec<Album>, Error>;
+    fn list(&mut self, query: &Query) -> Result<Vec<Artist>, Error>;
 }