Add download preview flow and search fallback

backend/handlers/api.go

@@ -64,12 +64,23 @@ func (h *Hub) Remove(conn *websocket.Conn) {
 	_ = conn.Close()
 }
 
+type PreviewResponse struct {
+	Title           string            `json:"title"`
+	Thumbnail       string            `json:"thumbnail"`
+	Duration        string            `json:"duration"`
+	DurationSeconds int               `json:"durationSeconds"`
+	StartDefault    string            `json:"startDefault"`
+	EndDefault      string            `json:"endDefault"`
+	Qualities       []map[string]any  `json:"qualities"`
+}
+
 func RegisterRoutes(router *gin.Engine, app *App) {
 	router.GET("/healthz", func(c *gin.Context) {
 		c.JSON(http.StatusOK, gin.H{"status": "ok"})
 	})
 	router.GET("/ws", app.handleWS)
 	router.GET("/api/history/check", app.checkDuplicate)
+	router.POST("/api/download/preview", app.previewDownload)
 	router.POST("/api/upload", app.uploadFile)
 	router.POST("/api/download", app.startDownload)
 	router.POST("/api/search", app.searchMedia)
@@ -132,6 +143,7 @@ func (a *App) startDownload(c *gin.Context) {
 		URL   string `json:"url"`
 		Start string `json:"start"`
 		End   string `json:"end"`
+		Quality string `json:"quality"`
 		Force bool   `json:"force"`
 	}
 	if err := c.ShouldBindJSON(&req); err != nil {
@@ -157,13 +169,46 @@ func (a *App) startDownload(c *gin.Context) {
 		return
 	}
 
-	go a.runDownload(recordID, req.URL, req.Start, req.End, outputPath)
+	quality := strings.TrimSpace(req.Quality)
+	if quality == "" {
+		quality = "best"
+	}
+
+	go a.runDownload(recordID, req.URL, req.Start, req.End, quality, outputPath)
 	c.JSON(http.StatusAccepted, gin.H{"message": "download started", "recordId": recordID})
 }
 
-func (a *App) runDownload(recordID int64, url, start, end, outputPath string) {
+func (a *App) previewDownload(c *gin.Context) {
+	var req struct {
+		URL string `json:"url"`
+	}
+	if err := c.ShouldBindJSON(&req); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		return
+	}
+	if strings.TrimSpace(req.URL) == "" {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "url is required"})
+		return
+	}
+
+	cmd := exec.Command("python3", a.WorkerScript, "--mode", "probe", "--url", req.URL, "--output", filepath.Join(a.DownloadsDir, "probe.tmp"))
+	output, err := cmd.CombinedOutput()
+	if err != nil {
+		c.JSON(http.StatusBadGateway, gin.H{"error": strings.TrimSpace(string(output))})
+		return
+	}
+
+	var preview PreviewResponse
+	if err := json.Unmarshal(output, &preview); err != nil {
+		c.JSON(http.StatusBadGateway, gin.H{"error": "invalid probe response"})
+		return
+	}
+	c.JSON(http.StatusOK, preview)
+}
+
+func (a *App) runDownload(recordID int64, url, start, end, quality, outputPath string) {
 	a.Hub.Broadcast("progress", gin.H{"type": "download", "status": "queued", "progress": 0, "url": url})
-	cmd := exec.Command("python3", a.WorkerScript, "--url", url, "--start", start, "--end", end, "--output", outputPath)
+	cmd := exec.Command("python3", a.WorkerScript, "--url", url, "--start", start, "--end", end, "--quality", quality, "--output", outputPath)
 	stdout, err := cmd.StdoutPipe()
 	if err != nil {
 		a.Hub.Broadcast("progress", gin.H{"type": "download", "status": "error", "progress": 0, "message": err.Error()})
@@ -187,6 +232,9 @@ func (a *App) runDownload(recordID int64, url, start, end, outputPath string) {
 			a.Hub.Broadcast("progress", msg)
 		}
 	}
+	if err := scanner.Err(); err != nil {
+		a.Hub.Broadcast("progress", gin.H{"type": "download", "status": "error", "progress": 100, "message": err.Error()})
+	}
 
 	status := "completed"
 	if err := cmd.Wait(); err != nil {