Add downloading message to home screen.

Download files in the background and keep track of progress.

internal/application/application.go

@@ -154,7 +154,8 @@ func Run() {
 
 	app.initializeManagers()
 	app.initializeAudio()
-	downloadProgressChan := make(chan download.DownloadStatus)
+	// Create a buffered channel so log writes don't slow down downloads.
+	downloadProgressChan := make(chan download.DownloadStatus, 1000)
 
 	app.PageRouter = page.NewRouter(page.PageCtx{
 		CfgPtr:         app.Config.Load(),

internal/download/Download.go

@@ -30,6 +30,7 @@ func DownloadAudioFiles(progressChan chan<- DownloadStatus, filenames []string,
 	// First, calculate the total size of files that need to be downloaded
 	totalSize := int64(0)
 	filesToDownload := []string{}
+	totalDownloaded := int64(0)
 
 	for _, filename := range filenames {
 		destPath := filepath.Join(destDir, filename)
@@ -62,13 +63,15 @@ func DownloadAudioFiles(progressChan chan<- DownloadStatus, filenames []string,
 
 			// Append it to the list to download
 			filesToDownload = append(filesToDownload, filename)
-			// And increase the total bytes to download
-			totalSize += resp.ContentLength
 		} else if err != nil {
 			logger.Error("unknown error: %v", err)
 		} else {
 			logger.Error("File %s exists, skipping...", filename)
+			totalDownloaded += fileStat.Size()
 		}
+		// Calculate the total of ALL files to give the illusion of
+		// "picking up where you left off" to the user
+		totalSize += resp.ContentLength
 		resp.Body.Close()
 	}
 
@@ -79,8 +82,6 @@ func DownloadAudioFiles(progressChan chan<- DownloadStatus, filenames []string,
 		Msg: "Starting download...",
 	}
 
-	totalDownloaded := int64(0)
-
 	// Download each file that doesn't exist
 	for _, filename := range filesToDownload {
 		url := urlBase + filename

internal/page/home.go

@@ -153,47 +153,81 @@ func (p *Home) HandleEvent(event *sdl.Event) error {
 	return nil
 }
 
-// Update updates animations and changing textures and other changes using `dt` which represents a time delta in float32.
 func (p *Home) Update(dt float32) error {
-	select {
-	case progressUpdate, ok := <-p.Context.MessageChannel:
-		if !ok {
-			// Channel is closed, set message to READY
-			newMsg, err := NewStringItem("Status: READY", p.font, colors.Green)
-			if err != nil {
-				return err
+	var (
+		progressUpdate download.DownloadStatus
+		ok             bool
+		gotUpdate      bool
+	)
+
+	// Drain the channel, keeping only the newest update.
+	for {
+		select {
+		case progressUpdate, ok = <-p.Context.MessageChannel:
+			gotUpdate = true
+
+			if !ok {
+				// Channel was closed while draining.
+				newMsg, err := NewStringItem("Status: READY", p.font, colors.Green)
+				if err != nil {
+					return err
+				}
+				messageScale := float32(28) / float32(p.baseFontSize)
+				newMsg.W = int32(float32(newMsg.W) * messageScale)
+				newMsg.H = int32(float32(newMsg.H) * messageScale)
+				p.message = newMsg
+				p.isDownloadComplete = true
+
+				return nil
 			}
-			messageScale := float32(28) / float32(p.baseFontSize)
-			newMsg.W = int32(float32(newMsg.W) * messageScale)
-			newMsg.H = int32(float32(newMsg.H) * messageScale)
-			p.message = newMsg
-			p.isDownloadComplete = true
-		} else if progressUpdate.Err != nil {
-			// Handle error
-			newMsg, err := NewStringItem(fmt.Sprintf("Status: %s", progressUpdate.Err.Error), p.font, colors.Red)
-			if err != nil {
-				return err
-			}
-			messageScale := float32(28) / float32(p.baseFontSize)
-			newMsg.W = int32(float32(newMsg.W) * messageScale)
-			newMsg.H = int32(float32(newMsg.H) * messageScale)
-			p.message = newMsg
-		} else {
-			// Update progress message
-			percentComplete := float64(progressUpdate.Cur) / float64(progressUpdate.Max) * 100
-			msg := fmt.Sprintf("Status: Downloading assets %.1f%% Complete", percentComplete)
-			newMsg, err := NewStringItem(msg, p.font, colors.White)
-			if err != nil {
-				return err
-			}
-			messageScale := float32(28) / float32(p.baseFontSize)
-			newMsg.W = int32(float32(newMsg.W) * messageScale)
-			newMsg.H = int32(float32(newMsg.H) * messageScale)
-			p.message = newMsg
+
+		default:
+			goto drained
 		}
-	default:
-		// No update, do nothing
 	}
+
+drained:
+
+	if !gotUpdate {
+		return nil
+	}
+
+	if progressUpdate.Err != nil {
+		// Handle error
+		newMsg, err := NewStringItem(
+			fmt.Sprintf("Status: %s", progressUpdate.Err.Error()),
+			p.font,
+			colors.Red,
+		)
+		if err != nil {
+			return err
+		}
+
+		messageScale := float32(28) / float32(p.baseFontSize)
+		newMsg.W = int32(float32(newMsg.W) * messageScale)
+		newMsg.H = int32(float32(newMsg.H) * messageScale)
+		p.message = newMsg
+
+	} else {
+		// Update progress message using ONLY the latest update.
+		percentComplete := float64(progressUpdate.Cur) / float64(progressUpdate.Max) * 100
+
+		msg := fmt.Sprintf(
+			"Status: Downloading assets %.1f%% Complete",
+			percentComplete,
+		)
+
+		newMsg, err := NewStringItem(msg, p.font, colors.White)
+		if err != nil {
+			return err
+		}
+
+		messageScale := float32(28) / float32(p.baseFontSize)
+		newMsg.W = int32(float32(newMsg.W) * messageScale)
+		newMsg.H = int32(float32(newMsg.H) * messageScale)
+		p.message = newMsg
+	}
+
 	return nil
 }