Channel communication between browse and matches

src/tui/app/machine/browse.rs

@@ -1,11 +1,18 @@
 use std::{sync::mpsc, thread, time};
 
-use musichoard::collection::musicbrainz::IMusicBrainzRef;
+use musichoard::collection::{
+    album::AlbumMeta,
+    artist::ArtistMeta,
+    musicbrainz::{IMusicBrainzRef, Mbid},
+};
 
-use crate::tui::app::{
+use crate::tui::{
-    machine::{App, AppInner, AppMachine},
+    app::{
-    selection::{Delta, ListSelection},
+        machine::{App, AppInner, AppMachine},
-    AppMatchesInfo, AppPublic, AppState, IAppInteractBrowse,
+        selection::{Delta, ListSelection},
+        AppMatchesInfo, AppPublic, AppState, IAppInteractBrowse,
+    },
+    lib::interface::musicbrainz::Error as MbError,
 };
 
 pub struct AppBrowse;
@@ -91,43 +98,20 @@ impl IAppInteractBrowse for AppMachine<AppBrowse> {
             }
         };
 
-        let (matches_tx, matches_rx) = mpsc::channel::<AppMatchesInfo>();
+        let (matches_tx, matches_rx) = mpsc::channel::<FetchResult>();
 
         match artist.meta.musicbrainz {
-            Some(ref mbid) => {
+            Some(ref arid) => {
-                let arid = mbid.mbid();
+                self.fetch_albums(
-
+                    matches_tx,
-                let mut album_iter = artist.albums.iter().peekable();
+                    arid.mbid().clone(),
-                while let Some(album) = album_iter.next() {
+                    artist.albums.iter().map(|a| &a.meta).cloned().collect(),
-                    if album.meta.musicbrainz.is_some() {
+                );
-                        continue;
-                    }
-
-                    match self
-                        .inner
-                        .musicbrainz
-                        .search_release_group(arid, &album.meta)
-                    {
-                        Ok(list) => matches_tx
-                            .send(AppMatchesInfo::album(album.meta.clone(), list))
-                            .expect("send fails only if receiver is disconnected"),
-                        Err(err) => return AppMachine::error(self.inner, err.to_string()).into(),
-                    }
-
-                    if album_iter.peek().is_some() {
-                        thread::sleep(time::Duration::from_secs(1));
-                    }
-                }
             }
-            None => match self.inner.musicbrainz.search_artist(&artist.meta) {
+            None => self.fetch_artist(matches_tx, artist.meta.clone()),
-                Ok(list) => matches_tx
-                    .send(AppMatchesInfo::artist(artist.meta.clone(), list))
-                    .expect("send fails only if receiver is disconnected"),
-                Err(err) => return AppMachine::error(self.inner, err.to_string()).into(),
-            },
         };
 
-        AppMachine::matches(self.inner, matches_rx).into()
+        AppMachine::app_matches(self.inner, matches_rx)
     }
 
     fn no_op(self) -> Self::APP {
@@ -135,6 +119,45 @@ impl IAppInteractBrowse for AppMachine<AppBrowse> {
     }
 }
 
+pub type FetchError = MbError;
+pub type FetchResult = Result<AppMatchesInfo, FetchError>;
+pub type FetchSender = mpsc::Sender<FetchResult>;
+pub type FetchReceiver = mpsc::Receiver<FetchResult>;
+
+trait IAppInteractBrowsePrivate {
+    fn fetch_artist(&mut self, matches_tx: FetchSender, artist: ArtistMeta);
+    fn fetch_albums(&mut self, matches_tx: FetchSender, arid: Mbid, albums: Vec<AlbumMeta>);
+}
+
+impl IAppInteractBrowsePrivate for AppMachine<AppBrowse> {
+    fn fetch_artist(&mut self, matches_tx: FetchSender, artist: ArtistMeta) {
+        let musicbrainz = &mut self.inner.musicbrainz;
+        let result = musicbrainz
+            .search_artist(&artist)
+            .map(|list| AppMatchesInfo::artist(artist, list));
+        matches_tx.send(result).expect("receiver is disconnected");
+    }
+
+    fn fetch_albums(&mut self, matches_tx: FetchSender, arid: Mbid, albums: Vec<AlbumMeta>) {
+        let mut album_iter = albums.into_iter().peekable();
+        while let Some(album) = album_iter.next() {
+            if album.musicbrainz.is_some() {
+                continue;
+            }
+
+            let musicbrainz = &mut self.inner.musicbrainz;
+            let result = musicbrainz
+                .search_release_group(&arid, &album)
+                .map(|list| AppMatchesInfo::album(album, list));
+            matches_tx.send(result).expect("receiver is disconnected");
+
+            if album_iter.peek().is_some() {
+                thread::sleep(time::Duration::from_secs(1));
+            }
+        }
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use mockall::{predicate, Sequence};

src/tui/app/machine/matches.rs

@@ -1,4 +1,4 @@
-use std::{cmp, sync::mpsc};
+use std::cmp;
 
 use crate::tui::app::{
     machine::{App, AppInner, AppMachine},
@@ -6,6 +6,8 @@ use crate::tui::app::{
     IAppInteractMatches, MatchOption, WidgetState,
 };
 
+use super::browse::{FetchError, FetchReceiver};
+
 impl AppArtistMatches {
     fn len(&self) -> usize {
         self.list.len()
@@ -43,21 +45,32 @@ impl AppMatchesInfo {
 }
 
 pub struct AppMatches {
-    matches_rx: mpsc::Receiver<AppMatchesInfo>,
+    matches_rx: FetchReceiver,
     current: Option<AppMatchesInfo>,
     state: WidgetState,
 }
 
-impl AppMachine<AppMatches> {
+impl AppMatches {
-    pub fn matches(inner: AppInner, matches_rx: mpsc::Receiver<AppMatchesInfo>) -> Self {
+    fn new(matches_rx: FetchReceiver) -> Self {
-        let mut state = AppMatches {
+        AppMatches {
             matches_rx,
             current: None,
             state: WidgetState::default(),
-        };
+        }
-        state.next_matches_info();
+    }
+}
+
+impl AppMachine<AppMatches> {
+    fn matches(inner: AppInner, state: AppMatches) -> Self {
         AppMachine { inner, state }
     }
+
+    pub fn app_matches(inner: AppInner, matches_rx: FetchReceiver) -> App {
+        match AppMatches::new(matches_rx).next_matches_info() {
+            Ok(state) => AppMachine::matches(inner, state).into(),
+            Err(err) => AppMachine::error(inner, format!("fetch failed: {err}")).into(),
+        }
+    }
 }
 
 impl From<AppMachine<AppMatches>> for App {
@@ -105,10 +118,15 @@ impl IAppInteractMatches for AppMachine<AppMatches> {
     }
 
     fn select(mut self) -> Self::APP {
-        self.state.next_matches_info();
+        match self.state.next_matches_info() {
-        match self.state.current {
+            Ok(state) => {
-            Some(_) => self.into(),
+                self.state = state;
-            None => AppMachine::browse(self.inner).into(),
+                match self.state.current {
+                    Some(_) => self.into(),
+                    None => AppMachine::browse(self.inner).into(),
+                }
+            }
+            Err(err) => AppMachine::error(self.inner, format!("fetch failed: {err}")).into(),
         }
     }
 
@@ -121,28 +139,34 @@ impl IAppInteractMatches for AppMachine<AppMatches> {
     }
 }
 
-trait IAppInteractMatchesPrivate {
+trait IAppInteractMatchesPrivate
-    fn next_matches_info(&mut self);
+where
+    Self: Sized,
+{
+    fn next_matches_info(self) -> Result<Self, FetchError>;
 }
 
 impl IAppInteractMatchesPrivate for AppMatches {
-    fn next_matches_info(&mut self) {
+    fn next_matches_info(mut self) -> Result<Self, FetchError> {
-        // FIXME: try_recv might not be appropriate for asynchronous version.
+        (self.current, self.state) = match self.matches_rx.recv() {
-        (self.current, self.state) = match self.matches_rx.try_recv() {
+            Ok(fetch_result) => {
-            Ok(mut next_match) => {
+                let mut next_match = fetch_result?;
                 next_match.push_cannot_have_mbid();
                 let mut state = WidgetState::default();
                 state.list.select(Some(0));
                 (Some(next_match), state)
             }
             Err(_) => (None, WidgetState::default()),
-        }
+        };
+
+        Ok(self)
     }
 }
 
 #[cfg(test)]
 mod tests {
-    use mpsc::Receiver;
+    use std::sync::mpsc;
+
     use musichoard::collection::{
         album::{AlbumDate, AlbumId, AlbumMeta, AlbumPrimaryType, AlbumSecondaryType},
         artist::{ArtistId, ArtistMeta},
@@ -227,10 +251,10 @@ mod tests {
         vec![matches_info_1, matches_info_2]
     }
 
-    fn receiver(matches_info_vec: Vec<AppMatchesInfo>) -> Receiver<AppMatchesInfo> {
+    fn receiver(matches_info_vec: Vec<AppMatchesInfo>) -> FetchReceiver {
         let (tx, rx) = mpsc::channel();
         for matches_info in matches_info_vec.into_iter() {
-            tx.send(matches_info).unwrap();
+            tx.send(Ok(matches_info)).unwrap();
         }
         rx
     }
@@ -243,7 +267,8 @@ mod tests {
 
     #[test]
     fn create_empty() {
-        let matches = AppMachine::matches(inner(music_hoard(vec![])), receiver(vec![]));
+        let matches =
+            AppMachine::app_matches(inner(music_hoard(vec![])), receiver(vec![])).unwrap_matches();
 
         let widget_state = WidgetState::default();
 
@@ -261,10 +286,11 @@ mod tests {
     #[test]
     fn create_nonempty() {
         let mut matches_info_vec = album_matches_info_vec();
-        let matches = AppMachine::matches(
+        let matches = AppMachine::app_matches(
             inner(music_hoard(vec![])),
             receiver(matches_info_vec.clone()),
-        );
+        )
+        .unwrap_matches();
         push_cannot_have_mbid(&mut matches_info_vec);
 
         let mut widget_state = WidgetState::default();
@@ -282,10 +308,11 @@ mod tests {
     }
 
     fn matches_flow(mut matches_info_vec: Vec<AppMatchesInfo>) {
-        let matches = AppMachine::matches(
+        let matches = AppMachine::app_matches(
             inner(music_hoard(vec![])),
             receiver(matches_info_vec.clone()),
-        );
+        )
+        .unwrap_matches();
         push_cannot_have_mbid(&mut matches_info_vec);
 
         let mut widget_state = WidgetState::default();
@@ -337,10 +364,11 @@ mod tests {
     #[test]
     fn matches_abort() {
         let mut matches_info_vec = album_matches_info_vec();
-        let matches = AppMachine::matches(
+        let matches = AppMachine::app_matches(
             inner(music_hoard(vec![])),
             receiver(matches_info_vec.clone()),
-        );
+        )
+        .unwrap_matches();
         push_cannot_have_mbid(&mut matches_info_vec);
 
         let mut widget_state = WidgetState::default();
@@ -354,7 +382,8 @@ mod tests {
 
     #[test]
     fn matches_select_empty() {
-        let matches = AppMachine::matches(inner(music_hoard(vec![])), receiver(vec![]));
+        let matches =
+            AppMachine::app_matches(inner(music_hoard(vec![])), receiver(vec![])).unwrap_matches();
 
         assert_eq!(matches.state.current, None);
 
@@ -363,7 +392,8 @@ mod tests {
 
     #[test]
     fn no_op() {
-        let matches = AppMachine::matches(inner(music_hoard(vec![])), receiver(vec![]));
+        let matches =
+            AppMachine::app_matches(inner(music_hoard(vec![])), receiver(vec![])).unwrap_matches();
         let app = matches.no_op();
         app.unwrap_matches();
     }

src/tui/app/machine/mod.rs

@@ -314,7 +314,7 @@ mod tests {
         assert!(app.is_running());
 
         let (_, rx) = mpsc::channel();
-        app = AppMachine::matches(app.unwrap_browse().inner, rx).into();
+        app = AppMachine::app_matches(app.unwrap_browse().inner, rx);
 
         let state = app.state();
         assert!(matches!(state, AppState::Matches(_)));