Gracefully handle case of nothing being there to match (#222)

Closes #203

Reviewed-on: #222

src/tui/app/machine/fetch_state.rs

@@ -63,10 +63,10 @@ impl AppMachine<FetchState> {
     }
 
     pub fn app_fetch_first(inner: AppInner) -> App {
-        Self::app_fetch_new(inner, true)
+        Self::app_fetch_new(inner)
     }
 
-    fn app_fetch_new(inner: AppInner, first: bool) -> App {
+    fn app_fetch_new(inner: AppInner) -> App {
         let coll = inner.music_hoard.get_collection();
         let artist = match inner.selection.state_artist(coll) {
             Some(artist_state) => &coll[artist_state.index],
@@ -79,13 +79,7 @@ impl AppMachine<FetchState> {
         let fetch = FetchState::new(fetch_rx);
         match Self::submit_fetch_job(&*inner.musicbrainz, fetch_tx, artist) {
             Ok(()) => AppMachine::fetch_state(inner, fetch).into(),
-            Err(FetchError::NothingToFetch) => {
-                if first {
-                    AppMachine::match_state(inner, MatchState::new(None, fetch)).into()
-                } else {
-                    AppMachine::browse_state(inner).into()
-                }
-            }
+            Err(FetchError::NothingToFetch) => AppMachine::browse_state(inner).into(),
             Err(FetchError::SubmitError(daemon_err)) => {
                 AppMachine::error_state(inner, daemon_err.to_string()).into()
             }
@@ -96,8 +90,7 @@ impl AppMachine<FetchState> {
         match fetch.try_recv() {
             Ok(fetch_result) => match fetch_result {
                 Ok(next_match) => {
-                    let current = Some(next_match);
-                    AppMachine::match_state(inner, MatchState::new(current, fetch)).into()
+                    AppMachine::match_state(inner, MatchState::new(next_match, fetch)).into()
                 }
                 Err(fetch_err) => {
                     AppMachine::error_state(inner, format!("fetch failed: {fetch_err}")).into()
@@ -105,7 +98,7 @@ impl AppMachine<FetchState> {
             },
             Err(recv_err) => match recv_err {
                 TryRecvError::Empty => AppMachine::fetch_state(inner, fetch).into(),
-                TryRecvError::Disconnected => Self::app_fetch_new(inner, false),
+                TryRecvError::Disconnected => Self::app_fetch_new(inner),
             },
         }
     }
@@ -452,7 +445,7 @@ mod tests {
         let app = browse.increment_selection(Delta::Line);
 
         let app = app.unwrap_browse().fetch_musicbrainz();
-        assert!(matches!(app, AppState::Match(_)));
+        assert!(matches!(app, AppState::Browse(_)));
     }
 
     #[test]
@@ -515,7 +508,7 @@ mod tests {
             MatchOption::ManualInputMbid,
         ];
         let expected = MatchStateInfo::artist_search(artist, match_options);
-        assert_eq!(match_state.info, Some(expected).as_ref());
+        assert_eq!(match_state.info, &expected);
     }
 
     #[test]
@@ -547,7 +540,7 @@ mod tests {
         collection[0].albums.clear();
 
         let app = AppMachine::app_fetch_first(inner(music_hoard(collection)));
-        assert!(matches!(app, AppState::Match(_)));
+        assert!(matches!(app, AppState::Browse(_)));
     }
 
     #[test]

src/tui/app/machine/match_state.rs

@@ -170,19 +170,18 @@ impl MatchStateInfo {
 }
 
 pub struct MatchState {
-    current: Option<MatchStateInfo>,
+    current: MatchStateInfo,
     state: WidgetState,
     fetch: FetchState,
 }
 
 impl MatchState {
-    pub fn new(mut current: Option<MatchStateInfo>, fetch: FetchState) -> Self {
-        let mut state = WidgetState::default();
-        if let Some(ref mut current) = current {
-            state.list.select(Some(0));
+    pub fn new(mut current: MatchStateInfo, fetch: FetchState) -> Self {
         current.push_cannot_have_mbid();
         current.push_manual_input_mbid();
-        }
+
+        let state = WidgetState::default().with_selected(Some(0));
+
         MatchState {
             current,
             state,
@@ -201,7 +200,7 @@ impl AppMachine<MatchState> {
             Ok(mbid) => mbid,
             Err(err) => return AppMachine::error_state(self.inner, err.to_string()).into(),
         };
-        match self.state.current.as_ref().unwrap() {
+        match self.state.current {
             MatchStateInfo::Artist(artist_matches) => {
                 let matching = &artist_matches.matching;
                 AppMachine::app_lookup_artist(self.inner, self.state.fetch, matching, mbid)
@@ -235,7 +234,7 @@ impl From<AppMachine<MatchState>> for App {
 impl<'a> From<&'a mut MatchState> for AppPublicState<'a> {
     fn from(state: &'a mut MatchState) -> Self {
         AppState::Match(MatchStatePublic {
-            info: state.current.as_ref().map(Into::into),
+            info: &state.current,
             state: &mut state.state,
         })
     }
@@ -254,25 +253,21 @@ impl IAppInteractMatch for AppMachine<MatchState> {
     }
 
     fn next_match(mut self) -> Self::APP {
-        if let Some(index) = self.state.state.list.selected() {
-            let result = index.saturating_add(1);
+        let index = self.state.state.list.selected().unwrap();
         let to = cmp::min(
-                result,
-                // selected() implies current exists
-                self.state.current.as_ref().unwrap().len().saturating_sub(1),
+            index.saturating_add(1),
+            self.state.current.len().saturating_sub(1),
         );
         self.state.state.list.select(Some(to));
-        }
 
         self.into()
     }
 
     fn select(mut self) -> Self::APP {
-        if let Some(index) = self.state.state.list.selected() {
-            // selected() implies current exists
+        let index = self.state.state.list.selected().unwrap();
 
         let mh = &mut self.inner.music_hoard;
-            let result = match self.state.current.as_mut().unwrap() {
+        let result = match self.state.current {
             MatchStateInfo::Artist(ref mut matches) => {
                 let info: ArtistInfo = matches.matching.info.clone();
                 match matches.list.extract_info(index, info) {
@@ -280,7 +275,7 @@ impl IAppInteractMatch for AppMachine<MatchState> {
                     InfoOption::NeedInput => return self.get_input(),
                 }
             }
-                MatchStateInfo::Album(matches) => {
+            MatchStateInfo::Album(ref mut matches) => {
                 let info: AlbumInfo = matches.matching.info.clone();
                 match matches.list.extract_info(index, info) {
                     InfoOption::Info(info) => {
@@ -294,7 +289,6 @@ impl IAppInteractMatch for AppMachine<MatchState> {
         if let Err(err) = result {
             return AppMachine::error_state(self.inner, err.to_string()).into();
         }
-        }
 
         AppMachine::app_fetch_next(self.inner, self.state.fetch)
     }
@@ -416,55 +410,35 @@ mod tests {
         FetchState::new(rx)
     }
 
-    fn match_state(match_state_info: Option<MatchStateInfo>) -> MatchState {
+    fn match_state(match_state_info: MatchStateInfo) -> MatchState {
         MatchState::new(match_state_info, fetch_state())
     }
 
     #[test]
-    fn create_empty() {
-        let matches = AppMachine::match_state(inner(music_hoard(vec![])), match_state(None));
-
-        let widget_state = WidgetState::default();
-
-        assert_eq!(matches.state.current, None);
-        assert_eq!(matches.state.state, widget_state);
-
-        let mut app: App = matches.into();
-        let public = app.get();
-        let public_matches = public.state.unwrap_match();
-
-        assert_eq!(public_matches.info, None);
-        assert_eq!(public_matches.state, &widget_state);
-    }
-
-    #[test]
-    fn create_nonempty() {
+    fn create() {
         let mut album_match = album_match();
-        let matches = AppMachine::match_state(
-            inner(music_hoard(vec![])),
-            match_state(Some(album_match.clone())),
-        );
+        let matches =
+            AppMachine::match_state(inner(music_hoard(vec![])), match_state(album_match.clone()));
         album_match.push_cannot_have_mbid();
         album_match.push_manual_input_mbid();
 
-        let mut widget_state = WidgetState::default();
-        widget_state.list.select(Some(0));
+        let widget_state = WidgetState::default().with_selected(Some(0));
 
-        assert_eq!(matches.state.current.as_ref(), Some(&album_match));
+        assert_eq!(matches.state.current, album_match);
         assert_eq!(matches.state.state, widget_state);
 
         let mut app: App = matches.into();
         let public = app.get();
         let public_matches = public.state.unwrap_match();
 
-        assert_eq!(public_matches.info, Some(&album_match));
+        assert_eq!(public_matches.info, &album_match);
         assert_eq!(public_matches.state, &widget_state);
     }
 
     fn match_state_flow(mut matches_info: MatchStateInfo, len: usize) {
         // tx must exist for rx to return Empty rather than Disconnected.
         let (_tx, rx) = mpsc::channel();
-        let app_matches = MatchState::new(Some(matches_info.clone()), FetchState::new(rx));
+        let app_matches = MatchState::new(matches_info.clone(), FetchState::new(rx));
 
         let mut music_hoard = music_hoard(vec![]);
         let artist_id = ArtistId::new("Artist");
@@ -494,40 +468,39 @@ mod tests {
         matches_info.push_cannot_have_mbid();
         matches_info.push_manual_input_mbid();
 
-        let mut widget_state = WidgetState::default();
-        widget_state.list.select(Some(0));
+        let widget_state = WidgetState::default().with_selected(Some(0));
 
-        assert_eq!(matches.state.current.as_ref(), Some(&matches_info));
+        assert_eq!(matches.state.current, matches_info);
         assert_eq!(matches.state.state, widget_state);
 
         let matches = matches.prev_match().unwrap_match();
 
-        assert_eq!(matches.state.current.as_ref(), Some(&matches_info));
+        assert_eq!(matches.state.current, matches_info);
         assert_eq!(matches.state.state.list.selected(), Some(0));
 
         let mut matches = matches;
         for ii in 1..len {
             matches = matches.next_match().unwrap_match();
 
-            assert_eq!(matches.state.current.as_ref(), Some(&matches_info));
+            assert_eq!(matches.state.current, matches_info);
             assert_eq!(matches.state.state.list.selected(), Some(ii));
         }
 
         // Next is CannotHaveMBID
         let matches = matches.next_match().unwrap_match();
 
-        assert_eq!(matches.state.current.as_ref(), Some(&matches_info));
+        assert_eq!(matches.state.current, matches_info);
         assert_eq!(matches.state.state.list.selected(), Some(len));
 
         // Next is ManualInputMbid
         let matches = matches.next_match().unwrap_match();
 
-        assert_eq!(matches.state.current.as_ref(), Some(&matches_info));
+        assert_eq!(matches.state.current, matches_info);
         assert_eq!(matches.state.state.list.selected(), Some(len + 1));
 
         let matches = matches.next_match().unwrap_match();
 
-        assert_eq!(matches.state.current.as_ref(), Some(&matches_info));
+        assert_eq!(matches.state.current, matches_info);
         assert_eq!(matches.state.state.list.selected(), Some(len + 1));
 
         // Go prev_match first as selecting on manual input does not go back to fetch.
@@ -560,7 +533,7 @@ mod tests {
         let matches_info = artist_match();
 
         let (_tx, rx) = mpsc::channel();
-        let app_matches = MatchState::new(Some(matches_info.clone()), FetchState::new(rx));
+        let app_matches = MatchState::new(matches_info.clone(), FetchState::new(rx));
 
         let mut music_hoard = music_hoard(vec![]);
         match matches_info {
@@ -584,7 +557,7 @@ mod tests {
         let matches_info = album_match();
 
         let (_tx, rx) = mpsc::channel();
-        let app_matches = MatchState::new(Some(matches_info.clone()), FetchState::new(rx));
+        let app_matches = MatchState::new(matches_info.clone(), FetchState::new(rx));
 
         let mut music_hoard = music_hoard(vec![]);
         match matches_info {
@@ -608,7 +581,7 @@ mod tests {
         let matches_info = artist_match();
 
         let (_tx, rx) = mpsc::channel();
-        let app_matches = MatchState::new(Some(matches_info.clone()), FetchState::new(rx));
+        let app_matches = MatchState::new(matches_info.clone(), FetchState::new(rx));
 
         let mut music_hoard = music_hoard(vec![]);
         match matches_info {
@@ -627,35 +600,23 @@ mod tests {
     #[test]
     fn abort() {
         let mut album_match = album_match();
-        let matches = AppMachine::match_state(
-            inner(music_hoard(vec![])),
-            match_state(Some(album_match.clone())),
-        );
+        let matches =
+            AppMachine::match_state(inner(music_hoard(vec![])), match_state(album_match.clone()));
         album_match.push_cannot_have_mbid();
         album_match.push_manual_input_mbid();
 
-        let mut widget_state = WidgetState::default();
-        widget_state.list.select(Some(0));
+        let widget_state = WidgetState::default().with_selected(Some(0));
 
-        assert_eq!(matches.state.current.as_ref(), Some(&album_match));
+        assert_eq!(matches.state.current, album_match);
         assert_eq!(matches.state.state, widget_state);
 
         matches.abort().unwrap_browse();
     }
 
-    #[test]
-    fn select_empty() {
-        // This test will become obsolete with #203 so it just needs to work well enough for
-        // coverage. We expect the error state, because after selecting, fetch will be invoked, but
-        // with an empty collection, an error will be raised.
-        let matches = AppMachine::match_state(inner(music_hoard(vec![])), match_state(None));
-        matches.select().unwrap_error();
-    }
-
     #[test]
     fn select_manual_input_empty() {
         let matches =
-            AppMachine::match_state(inner(music_hoard(vec![])), match_state(Some(album_match())));
+            AppMachine::match_state(inner(music_hoard(vec![])), match_state(album_match()));
 
         // album_match has two matches which means that the fourth option should be manual input.
         let matches = matches.next_match().unwrap_match();
@@ -692,7 +653,7 @@ mod tests {
         let artist_match = MatchStateInfo::artist_search(artist.clone(), matches_vec);
         let matches = AppMachine::match_state(
             inner_with_mb(music_hoard(vec![]), mb_job_sender),
-            match_state(Some(artist_match)),
+            match_state(artist_match),
         );
 
         // There are no matches which means that the second option should be manual input.
@@ -726,7 +687,7 @@ mod tests {
             MatchStateInfo::album_search(artist_id.clone(), album.clone(), matches_vec);
         let matches = AppMachine::match_state(
             inner_with_mb(music_hoard(vec![]), mb_job_sender),
-            match_state(Some(album_match)),
+            match_state(album_match),
         );
 
         // There are no matches which means that the second option should be manual input.

src/tui/app/machine/mod.rs

@@ -219,11 +219,17 @@ where
 mod tests {
     use std::sync::mpsc;
 
-    use musichoard::collection::Collection;
+    use musichoard::collection::{
+        artist::{ArtistId, ArtistMeta},
+        Collection,
+    };
 
     use crate::tui::{
-        app::{AppState, IApp, IAppInput, IAppInteractBrowse, InputEvent},
-        lib::{interface::musicbrainz::daemon::MockIMbJobSender, MockIMusicHoard},
+        app::{AppState, IApp, IAppInput, IAppInteractBrowse, InputEvent, MatchStateInfo},
+        lib::{
+            interface::musicbrainz::{api::Lookup, daemon::MockIMbJobSender},
+            MockIMusicHoard,
+        },
     };
 
     use super::*;
@@ -513,8 +519,10 @@ mod tests {
 
         let (_, rx) = mpsc::channel();
         let fetch = FetchState::new(rx);
+        let artist = ArtistMeta::new(ArtistId::new("Artist"));
+        let info = MatchStateInfo::artist_lookup(artist.clone(), Lookup::new(artist.clone()));
         app =
-            AppMachine::match_state(app.unwrap_browse().inner, MatchState::new(None, fetch)).into();
+            AppMachine::match_state(app.unwrap_browse().inner, MatchState::new(info, fetch)).into();
 
         let state = app.state();
         assert!(matches!(state, AppState::Match(_)));

src/tui/app/mod.rs

@@ -263,7 +263,7 @@ impl MatchStateInfo {
 }
 
 pub struct MatchStatePublic<'app> {
-    pub info: Option<&'app MatchStateInfo>,
+    pub info: &'app MatchStateInfo,
     pub state: &'app mut WidgetState,
 }
 

src/tui/app/selection/mod.rs

@@ -36,6 +36,14 @@ impl PartialEq for WidgetState {
     }
 }
 
+impl WidgetState {
+    #[must_use]
+    pub const fn with_selected(mut self, selected: Option<usize>) -> Self {
+        self.list = self.list.with_selected(selected);
+        self
+    }
+}
+
 pub enum Delta {
     Line,
     Page,

src/tui/ui/display.rs

@@ -122,17 +122,10 @@ impl UiDisplay {
         )
     }
 
-    pub fn display_nothing_matching() -> &'static str {
-        "Matching nothing"
-    }
-
-    pub fn display_matching_info(info: Option<&MatchStateInfo>) -> String {
-        match info.as_ref() {
-            Some(kind) => match kind {
+    pub fn display_matching_info(info: &MatchStateInfo) -> String {
+        match info {
             MatchStateInfo::Artist(m) => UiDisplay::display_artist_matching(&m.matching),
             MatchStateInfo::Album(m) => UiDisplay::display_album_matching(&m.matching),
-            },
-            None => UiDisplay::display_nothing_matching().to_string(),
         }
     }
 

src/tui/ui/match_state.rs

@@ -13,21 +13,10 @@ pub struct MatchOverlay<'a, 'b> {
 }
 
 impl<'a, 'b> MatchOverlay<'a, 'b> {
-    pub fn new(info: Option<&'a MatchStateInfo>, state: &'b mut WidgetState) -> Self {
+    pub fn new(info: &'a MatchStateInfo, state: &'b mut WidgetState) -> Self {
         match info {
-            Some(info) => match info {
             MatchStateInfo::Artist(m) => Self::artists(&m.matching, &m.list, state),
             MatchStateInfo::Album(m) => Self::albums(&m.matching, &m.list, state),
-            },
-            None => Self::empty(state),
-        }
-    }
-
-    fn empty(state: &'b mut WidgetState) -> Self {
-        MatchOverlay {
-            matching: UiDisplay::display_nothing_matching().to_string(),
-            list: List::default(),
-            state,
         }
     }
 

src/tui/ui/mod.rs

@@ -140,11 +140,7 @@ impl Ui {
         UiWidget::render_overlay_widget("Fetching", fetch_text, area, false, frame)
     }
 
-    fn render_match_overlay(
-        info: Option<&MatchStateInfo>,
-        state: &mut WidgetState,
-        frame: &mut Frame,
-    ) {
+    fn render_match_overlay(info: &MatchStateInfo, state: &mut WidgetState, frame: &mut Frame) {
         let area = OverlayBuilder::default().build(frame.area());
         let st = MatchOverlay::new(info, state);
         UiWidget::render_overlay_list_widget(&st.matching, st.list, st.state, true, area, frame)
@@ -329,26 +325,6 @@ mod tests {
         draw_test_suite(artists, &mut selection);
     }
 
-    #[test]
-    fn draw_empty_matches() {
-        let collection = &COLLECTION;
-        let mut selection = Selection::new(collection);
-
-        let mut terminal = terminal();
-
-        let mut widget_state = WidgetState::default();
-
-        let mut app = AppPublic {
-            inner: public_inner(collection, &mut selection),
-            state: AppState::Match(MatchStatePublic {
-                info: None,
-                state: &mut widget_state,
-            }),
-            input: None,
-        };
-        terminal.draw(|frame| Ui::render(&mut app, frame)).unwrap();
-    }
-
     fn artist_meta() -> ArtistMeta {
         ArtistMeta::new(ArtistId::new("an artist"))
     }
@@ -428,13 +404,12 @@ mod tests {
         ];
 
         for info in match_state_infos.iter() {
-            let mut widget_state = WidgetState::default();
-            widget_state.list.select(Some(0));
+            let mut widget_state = WidgetState::default().with_selected(Some(0));
 
             let mut app = AppPublic {
                 inner: public_inner(collection, &mut selection),
                 state: AppState::Match(MatchStatePublic {
-                    info: Some(info),
+                    info,
                     state: &mut widget_state,
                 }),
                 input: None,