make fetching of data asynchronous; references #20

Signed-off-by: Mario Kozjak <[email protected]>

cmd/blutui.go

@@ -23,11 +23,27 @@ func main() {
 	a.Player = p
 
 	// Create Library Page
+	fc := make(chan library.FetchDone)
 	lib := library.New("http://bluesound.local:11000", a, p, sp)
-	libc, err := lib.CreateContainer()
-	if err != nil {
-		panic(err)
-	}
+	libc := lib.CreateContainer()
+
+	// Start initial fetching of data
+	go lib.FetchData(true, fc)
+
+	go func() {
+		for {
+			msg := <-fc
+			if msg.Error != nil {
+				// TODO: should probably use os.Exit(1) here
+				panic("failed fetching initial data: " + msg.Error.Error())
+			}
+
+			// Draw initial album list for the first artist in the list
+			lib.DrawArtistPane()
+			lib.DrawInitAlbums()
+			return
+		}
+	}()
 
 	a.Library = libc
 
@@ -42,13 +58,6 @@ func main() {
 
 	a.Pages.SetBackgroundColor(tcell.ColorDefault)
 
-	// Draw initial album list for the first artist in the list
-	// Disable callback afterwards
-	a.Application.SetAfterDrawFunc(func(screen tcell.Screen) {
-		lib.DrawInitAlbums()
-		a.Application.SetAfterDrawFunc(nil)
-	})
-
 	// Configure global keybindings
 	gk := keyboard.NewGlobalHandler(a, a.Player, lib, a.Pages, b)
 	a.Application.SetInputCapture(gk.Listen)

internal/keyboard/keyboard.go

@@ -64,7 +64,7 @@ func (h *GlobalHandler) Listen(event *tcell.EventKey) *tcell.EventKey {
 		}
 	case 'u':
 		// TODO: show error on bar
-		go h.library.FetchData(false)
+		go h.library.FetchData(false, nil)
 	case 'h':
 		p, _ := h.pages.GetFrontPage()
 		if p != "help" {

internal/library/artistpane.go

@@ -54,7 +54,7 @@ func (l *Library) FilterArtistPane(f []string) {
 	}
 }
 
-func (l *Library) drawArtistPane() {
+func (l *Library) DrawArtistPane() {
 	// Delete existing records, possibly after clearing the search results
 	l.artistPane.Clear()
 

internal/library/keyboard.go

@@ -43,7 +43,7 @@ func (l *Library) artistPaneKeyboardHandler(event *tcell.EventKey) *tcell.EventK
 	switch event.Key() {
 	case tcell.KeyEscape:
 		if l.artistPaneFiltered {
-			l.drawArtistPane()
+			l.DrawArtistPane()
 			l.artistPaneFiltered = false
 			return nil
 		}

internal/library/library.go

@@ -72,14 +72,18 @@ type artist struct {
 
 type Command interface {
 	Artists() []string
-	FetchData(cached bool) error
+	FetchData(cached bool, doneCh chan<- FetchDone)
 	FilterArtistPane(f []string)
 	HighlightCpArtist(name string)
 	IsFiltered() bool
 	SelectCpArtist()
 	SetCpTrackName(name string)
 }
 
+type FetchDone struct {
+	Error error
+}
+
 type Library struct {
 	container *tview.Flex
 	app       app.Command
@@ -113,14 +117,9 @@ func (l *Library) Artists() []string {
 	return l.artists
 }
 
-func (l *Library) CreateContainer() (*tview.Flex, error) {
-	err := l.FetchData(true)
-	if err != nil {
-		return nil, err
-	}
-
+func (l *Library) CreateContainer() *tview.Flex {
 	l.artistPane = l.createArtistContainer()
-	l.drawArtistPane()
+	l.DrawArtistPane()
 	l.albumPane = l.createAlbumContainer()
 
 	flex := tview.NewFlex().SetDirection(tview.FlexRow).
@@ -131,44 +130,49 @@ func (l *Library) CreateContainer() (*tview.Flex, error) {
 
 	flex.SetInputCapture(l.KeyboardHandler)
 
-	return flex, nil
+	return flex
 }
 
-func (l *Library) FetchData(cached bool) error {
+func (l *Library) FetchData(cached bool, doneCh chan<- FetchDone) {
 	go l.spinner.Start()
 
 	c, err := cache.LoadCache()
 	if err != nil {
 		log.Println("Error loading local cache:", err)
-		return err
+		doneCh <- FetchDone{Error: err}
+		return
 	}
 
 	body, err := cache.FetchAndCache(l.API+"/Browse?key=LocalMusic%3AbySection%2F%252FAlbums%253Fservice%253DLocalMusic", c, cached)
 	if err != nil {
 		log.Println("Error fetching/caching data:", err)
-		return err
+		doneCh <- FetchDone{Error: err}
+		return
 	}
 
 	var sections browse
 	err = xml.Unmarshal(body, &sections)
 	if err != nil {
 		log.Println("Error parsing the sections XML:", err)
-		return err
+		doneCh <- FetchDone{Error: err}
+		return
 	}
 
 	// parse album sections (alphabetical order) from xml
 	for _, item := range sections.Items {
 		body, err = cache.FetchAndCache(l.API+"/Browse?key="+url.QueryEscape(item.BrowseKey), c, cached)
 		if err != nil {
 			log.Println("Error fetching album sections:", err)
-			return err
+			doneCh <- FetchDone{Error: err}
+			return
 		}
 
 		var albums browse
 		err = xml.Unmarshal(body, &albums)
 		if err != nil {
 			log.Println("Error parsing the albums XML:", err)
-			return err
+			doneCh <- FetchDone{Error: err}
+			return
 		}
 
 		// iterate albums and fill m.albumArtists
@@ -179,14 +183,16 @@ func (l *Library) FetchData(cached bool) error {
 			body, err = cache.FetchAndCache(l.API+"/Browse?key="+url.QueryEscape(al.BrowseKey), c, cached)
 			if err != nil {
 				log.Println("Error fetching album tracks:", err)
-				return err
+				doneCh <- FetchDone{Error: err}
+				return
 			}
 
 			var tracks browse
 			err = xml.Unmarshal(body, &tracks)
 			if err != nil {
 				log.Println("Error parsing the album tracks XML:", err)
-				return err
+				doneCh <- FetchDone{Error: err}
+				return
 			}
 
 			var albumTracks []track
@@ -217,15 +223,17 @@ func (l *Library) FetchData(cached bool) error {
 				c, cached)
 			if err != nil {
 				log.Println("Error fetching album date:", err)
-				return err
+				doneCh <- FetchDone{Error: err}
+				return
 			}
 
 			var s songs
 			var year int
 			err = xml.Unmarshal(body, &s)
 			if err != nil {
 				log.Println("Error parsing the album songs XML:", err)
-				return err
+				doneCh <- FetchDone{Error: err}
+				return
 			}
 
 			if len(s.Album) > 0 {
@@ -282,7 +290,7 @@ func (l *Library) FetchData(cached bool) error {
 	}
 
 	l.spinner.Stop()
-	return nil
+	doneCh <- FetchDone{Error: nil}
 }
 
 func (l *Library) IsFiltered() bool {

spinner/spinner.go

@@ -7,7 +7,6 @@ import (
 	"time"
 
 	"github.com/gdamore/tcell/v2"
-	"github.com/mkozjak/blutui/internal"
 	"github.com/mkozjak/blutui/internal/app"
 	"github.com/mkozjak/tview"
 )
@@ -18,7 +17,6 @@ type Command interface {
 	Stop()
 }
 
-
 // Spinner represents a spinner widget.
 type Spinner struct {
 	*tview.Box
@@ -85,8 +83,6 @@ func (s *Spinner) GetContainer() tview.Primitive {
 
 // Draw draws this primitive onto the screen.
 func (s *Spinner) Draw(screen tcell.Screen) {
-	internal.Log("check:", s.active)
-
 	if s.active {
 		s.Box.DrawForSubclass(screen, s)
 		x, y, width, _ := s.Box.GetInnerRect()