Initial Narrative / Track Explanation support

You can now press 'E' to ask pandora why it selected the currently
playing track.

Fixes #18

cmd/uitest.go

@@ -74,6 +74,8 @@ func testDataAPI() api.Client {
 	client.On("GetMoreTracks", mock.Anything).Return(func(_ string) []pandora.Track {
 		return []pandora.Track{
 			{
+				StationId:  uuid.Must(uuid.NewRandom()).String(),
+				MusicId:    uuid.Must(uuid.NewRandom()).String(),
 				TrackToken: uuid.Must(uuid.NewRandom()).String(),
 				ArtistName: "Test Artist",
 				AlbumTitle: "Test Album",
@@ -83,6 +85,17 @@ func testDataAPI() api.Client {
 	}, nil)
 	client.On("AddFeedback", mock.Anything, mock.Anything).Return(nil)
 	client.On("AddTired", mock.Anything).Return(nil)
+	client.On("GetNarrative", mock.Anything, mock.Anything).Return(pandora.Narrative{
+		Intro: "Based on what you've told us so far, we're playing this track because it features:",
+		FocusTraits: []string{
+			"vocal harmonies",
+			"mixed acoustic and electric instrumentation",
+			"minor key tonality",
+			"mild rhythmic syncopation",
+			"heavy electric rhythm guitars",
+		},
+		Paragraph: "Based on what you've told us so far, we're playing this track because it features vocal harmonies, mixed acoustic and electric instrumentation, minor key tonality, mild rhythmic syncopation and heavy electric rhythm guitars.",
+	}, nil)
 
 	return client
 }

mousiki/station_controller.go

@@ -17,6 +17,12 @@ var noStationSelected = pandora.Station{
 	Name: "No Station Selected",
 }
 
+type narrativeCache struct {
+	station   string
+	track     string
+	narrative pandora.Narrative
+}
+
 type StationController struct {
 	stationLock sync.Mutex
 	station     pandora.Station
@@ -30,9 +36,15 @@ type StationController struct {
 	notifications  chan *pandora.Track
 	stationChanged chan pandora.Station
 
+	narrativeCache narrativeCache
+
 	log logrus.FieldLogger
 }
 
+func (n narrativeCache) matches(t *pandora.Track) bool {
+	return n.station == t.StationId && n.track == t.MusicId
+}
+
 func NewStationController(c api.Client, p audio.Player) *StationController {
 	return &StationController{
 		pandora: c,
@@ -192,6 +204,25 @@ func (s *StationController) SwitchStations(station pandora.Station) {
 	s.stationChanged <- station
 }
 
+func (s *StationController) ExplainCurrentTrack() (pandora.Narrative, error) {
+	if s.narrativeCache.matches(s.playing) {
+		s.log.Debug("Returning Cached Narrative")
+		return s.narrativeCache.narrative, nil
+	}
+
+	s.log.Debug("Fetching Narrative")
+	result, err := s.pandora.GetNarrative(s.playing.StationId, s.playing.MusicId)
+	if err == nil {
+		s.narrativeCache = narrativeCache{
+			station:   s.playing.StationId,
+			track:     s.playing.MusicId,
+			narrative: result,
+		}
+	}
+
+	return result, err
+}
+
 func (s *StationController) StationChanged() <-chan pandora.Station {
 	return s.stationChanged
 }

mousiki/station_controller_test.go

@@ -2,6 +2,7 @@ package mousiki
 
 import (
 	"context"
+	"fmt"
 	"testing"
 
 	"github.com/google/uuid"
@@ -68,3 +69,87 @@ func TestStationController_Play(t *testing.T) {
 	require.Len(t, played, 3)
 	require.Equal(t, []string{"1", "2", "3"}, played)
 }
+
+func stationControllerTestFunc(f func(t *testing.T, c *mocks.Client, sut *StationController)) func(t *testing.T) {
+	return func(t *testing.T) {
+		c := &mocks.Client{}
+		p := &mocks.Player{}
+		sut := NewStationController(c, p)
+		sut.log = testutil.NopLogger()
+		sut.playing = &pandora.Track{
+			MusicId:   uuid.Must(uuid.NewRandom()).String(),
+			StationId: uuid.Must(uuid.NewRandom()).String(),
+		}
+
+		f(t, c, sut)
+	}
+}
+
+func TestStationController_ExplainCurrentTrack(t *testing.T) {
+	t.Run("Valid", stationControllerTestFunc(func(t *testing.T, c *mocks.Client, sut *StationController) {
+		expected := pandora.Narrative{
+			Intro:       uuid.Must(uuid.NewRandom()).String(),
+			FocusTraits: []string{uuid.Must(uuid.NewRandom()).String()},
+			Paragraph:   uuid.Must(uuid.NewRandom()).String(),
+		}
+
+		c.On("GetNarrative", mock.Anything, mock.Anything).Return(expected, nil)
+
+		result, err := sut.ExplainCurrentTrack()
+		c.AssertCalled(t, "GetNarrative", sut.playing.StationId, sut.playing.MusicId)
+		require.NoError(t, err)
+		require.Equal(t, expected, result)
+	}))
+
+	t.Run("Pandora Error", stationControllerTestFunc(func(t *testing.T, c *mocks.Client, sut *StationController) {
+		c.On("GetNarrative", mock.Anything, mock.Anything).
+			Return(pandora.Narrative{}, fmt.Errorf("dummy"))
+
+		_, err := sut.ExplainCurrentTrack()
+		require.EqualError(t, err, "dummy")
+	}))
+
+	t.Run("Caches Track", stationControllerTestFunc(func(t *testing.T, c *mocks.Client, sut *StationController) {
+		expected := pandora.Narrative{
+			Intro:       uuid.Must(uuid.NewRandom()).String(),
+			FocusTraits: []string{uuid.Must(uuid.NewRandom()).String()},
+			Paragraph:   uuid.Must(uuid.NewRandom()).String(),
+		}
+
+		c.On("GetNarrative", mock.Anything, mock.Anything).Return(expected, nil)
+
+		_, _ = sut.ExplainCurrentTrack()
+		result, err := sut.ExplainCurrentTrack()
+		c.AssertCalled(t, "GetNarrative", sut.playing.StationId, sut.playing.MusicId)
+		c.AssertNumberOfCalls(t, "GetNarrative", 1)
+		require.NoError(t, err)
+		require.Equal(t, expected, result)
+	}))
+
+	t.Run("Expires Cache When Track Changes", stationControllerTestFunc(func(t *testing.T, c *mocks.Client, sut *StationController) {
+		expected := pandora.Narrative{
+			Intro:       uuid.Must(uuid.NewRandom()).String(),
+			FocusTraits: []string{uuid.Must(uuid.NewRandom()).String()},
+			Paragraph:   uuid.Must(uuid.NewRandom()).String(),
+		}
+
+		c.On("GetNarrative", mock.Anything, mock.Anything).Return(expected, nil)
+
+		result, err := sut.ExplainCurrentTrack()
+		c.AssertCalled(t, "GetNarrative", sut.playing.StationId, sut.playing.MusicId)
+		require.NoError(t, err)
+		require.Equal(t, expected, result)
+
+		sut.playing = &pandora.Track{
+			MusicId:   uuid.Must(uuid.NewRandom()).String(),
+			StationId: uuid.Must(uuid.NewRandom()).String(),
+		}
+
+		result, err = sut.ExplainCurrentTrack()
+		c.AssertCalled(t, "GetNarrative", sut.playing.StationId, sut.playing.MusicId)
+		require.NoError(t, err)
+		require.Equal(t, expected, result)
+
+		c.AssertNumberOfCalls(t, "GetNarrative", 2)
+	}))
+}

mousiki/ui/main.go

@@ -22,7 +22,8 @@ const pageMain = "main"
 type mainWindow struct {
 	*cview.Pages
 
-	stationPicker *stationPicker
+	stationPicker  *stationPicker
+	narrativePopup *narrativePopup
 
 	nowPlaying        *pandora.Track
 	nowPlayingSong    *cview.TextView
@@ -84,6 +85,7 @@ func MainWindow(cancelFunc func(), player audio.Player, controller *mousiki.Stat
 
 	root.AddPage(pageMain, grid, true, true)
 	root.stationPicker = NewStationPickerForPager(cancelFunc, root.Pages, controller)
+	root.narrativePopup = NewNarrativePopupForPager(cancelFunc, root.Pages, controller)
 
 	root.history.ScrollToEnd().
 		SetDrawFunc(func(_ tcell.Screen, x, y, w, h int) (rx int, ry int, rw int, rh int) {
@@ -149,20 +151,25 @@ func (w *mainWindow) updateShortcuts() {
 		w.shortcuts.AddItem(cview.NewTextView().SetTextAlign(cview.AlignCenter).SetWrap(false).SetText("[Q] Quit"), 0, 0, 1, 1, 0, 0, false).
 			AddItem(cview.NewTextView().SetTextAlign(cview.AlignCenter).SetWrap(false).SetText("[ESC] Stations"), 0, 1, 1, 1, 0, 0, false).
 			AddItem(cview.NewTextView().SetTextAlign(cview.AlignCenter).SetWrap(false).SetText("[Space] Play / Pause"), 0, 2, 1, 1, 0, 0, false).
-			AddItem(cview.NewTextView().SetTextAlign(cview.AlignCenter).SetWrap(false).SetText("[N] Next"), 0, 3, 1, 1, 0, 0, false).
-			AddItem(cview.NewTextView().SetTextAlign(cview.AlignCenter).SetWrap(false).SetText("[-] Ban Song"), 0, 4, 1, 1, 0, 0, false).
-			AddItem(cview.NewTextView().SetTextAlign(cview.AlignCenter).SetWrap(false).SetText("[T] Tired Of Song"), 0, 5, 1, 1, 0, 0, false).
-			AddItem(cview.NewTextView().SetTextAlign(cview.AlignCenter).SetWrap(false).SetText("[+] Love Song"), 0, 6, 1, 1, 0, 0, false)
+			AddItem(cview.NewTextView().SetTextAlign(cview.AlignCenter).SetWrap(false).SetText("[E] Explain"), 0, 3, 1, 1, 0, 0, false).
+			AddItem(cview.NewTextView().SetTextAlign(cview.AlignCenter).SetWrap(false).SetText("[N] Next"), 0, 4, 1, 1, 0, 0, false).
+			AddItem(cview.NewTextView().SetTextAlign(cview.AlignCenter).SetWrap(false).SetText("[-] Ban Song"), 0, 5, 1, 1, 0, 0, false).
+			AddItem(cview.NewTextView().SetTextAlign(cview.AlignCenter).SetWrap(false).SetText("[T] Tired Of Song"), 0, 6, 1, 1, 0, 0, false).
+			AddItem(cview.NewTextView().SetTextAlign(cview.AlignCenter).SetWrap(false).SetText("[+] Love Song"), 0, 7, 1, 1, 0, 0, false)
 	} else if page == stationPickerPageName {
 		w.shortcuts.AddItem(cview.NewTextView().SetTextAlign(cview.AlignCenter).SetWrap(false).SetText("[Q/ESC] Quit"), 0, 0, 1, 2, 0, 0, false).
 			AddItem(cview.NewTextView().SetTextAlign(cview.AlignCenter).SetWrap(false).SetText("[Space/Enter] Change Station"), 0, 2, 1, 2, 0, 0, false)
+	} else if page == narrativePopupPageName {
+		w.shortcuts.AddItem(cview.NewTextView().SetTextAlign(cview.AlignCenter).SetWrap(false).SetText("[ESC/E] Close"), 0, 2, 1, 1, 0, 0, false)
 	}
 }
 
 func (w *mainWindow) HandleKey(app *cview.Application) func(ev *tcell.EventKey) *tcell.EventKey {
 	return func(ev *tcell.EventKey) *tcell.EventKey {
 		if page, _ := w.GetFrontPage(); page == stationPickerPageName {
 			return w.stationPicker.HandleKey(ev)
+		} else if page == narrativePopupPageName {
+			return w.narrativePopup.HandleKey(ev)
 		}
 
 		if ev.Key() == tcell.KeyRune && ev.Rune() == ' ' {
@@ -202,6 +209,8 @@ func (w *mainWindow) HandleKey(app *cview.Application) func(ev *tcell.EventKey)
 			if err := w.controller.ProvideFeedback(pandora.TrackRatingBan); err != nil {
 				w.log.WithError(err).Error("Failed to add feedback")
 			}
+		} else if ev.Key() == tcell.KeyRune && ev.Rune() == 'e' {
+			w.ShowNarrativePopup()
 		} else {
 			return ev
 		}
@@ -210,14 +219,33 @@ func (w *mainWindow) HandleKey(app *cview.Application) func(ev *tcell.EventKey)
 	}
 }
 
+func intClamp(n, low, high int) int {
+	if n < low {
+		return low
+	}
+
+	if n > high {
+		return high
+	}
+
+	return n
+}
+
 func (w *mainWindow) OnResize(width, height int) {
 	w.stationPicker.Resize(width/2, height/2)
+
+	// TODO: Can we grow this automatically based on explanation length?
+	w.narrativePopup.Resize(intClamp(width/2, 40, 120), intClamp(height/4, 10, 16))
 }
 
 func (w *mainWindow) ShowStationPicker() {
 	w.stationPicker.Open()
 }
 
+func (w *mainWindow) ShowNarrativePopup() {
+	w.narrativePopup.Open()
+}
+
 func (w *mainWindow) SyncData(ctx context.Context, app *cview.Application) {
 	progress := w.player.ProgressChan()
 	next := w.controller.NotificationChan()

mousiki/ui/narrative_popup.go

@@ -0,0 +1,82 @@
+package ui
+
+import (
+	"github.com/gdamore/tcell"
+	"github.com/nlowe/mousiki/mousiki"
+	"github.com/sirupsen/logrus"
+	"gitlab.com/tslocum/cview"
+)
+
+const narrativePopupPageName = "narrativePopup"
+
+type narrativePopup struct {
+	*CenteredModal
+	root *cview.TextView
+
+	cancelFunc func()
+
+	controller *mousiki.StationController
+	pager      *cview.Pages
+
+	log logrus.FieldLogger
+}
+
+func NewNarrativePopupForPager(cancelFunc func(), pager *cview.Pages, controller *mousiki.StationController) *narrativePopup {
+	result := &narrativePopup{
+		root:       cview.NewTextView(),
+		cancelFunc: cancelFunc,
+		controller: controller,
+		pager:      pager,
+		log:        logrus.WithField("prefix", narrativePopupPageName),
+	}
+
+	result.root.SetWrap(true).
+		SetWordWrap(true).
+		SetTitle("Explanation").
+		SetBorder(true).
+		SetBorderPadding(1, 1, 1, 1)
+
+	result.CenteredModal = NewCenteredModal(result.root)
+
+	pager.AddPage(narrativePopupPageName, result, true, false)
+	return result
+}
+
+func (n *narrativePopup) Open() {
+	if page, _ := n.pager.GetFrontPage(); page == narrativePopupPageName {
+		return
+	}
+
+	if n.controller.NowPlaying() == nil {
+		n.log.Debug("No Track is playing")
+		return
+	}
+
+	n.log.Info("Fetching Track Narrative")
+	narrative, err := n.controller.ExplainCurrentTrack()
+	if err != nil {
+		n.log.WithError(err).Errorf("Failed to explain current track")
+		return
+	}
+
+	n.root.SetText(narrative.Paragraph)
+	n.pager.ShowPage(narrativePopupPageName)
+}
+
+func (n *narrativePopup) Close() {
+	if page, _ := n.pager.GetFrontPage(); page != narrativePopupPageName {
+		return
+	}
+
+	n.pager.HidePage(narrativePopupPageName)
+}
+
+func (n *narrativePopup) HandleKey(ev *tcell.EventKey) *tcell.EventKey {
+	if ev.Key() == tcell.KeyEscape || (ev.Key() == tcell.KeyRune && ev.Rune() == 'e') {
+		n.Close()
+
+		return nil
+	}
+
+	return ev
+}