feat: preserve fullscreen when autoplaying next episode

internal/playback/handler/handler.go

@@ -37,6 +37,7 @@ func (h *PlaybackHandler) Register(r *gin.Engine) {
 	r.GET("/anime/:id/watch", h.HandleWatchPage)
 	r.POST("/api/watch-progress", h.HandleSaveProgress)
 	r.POST("/api/watch-complete", h.HandleWatchComplete)
+	r.GET("/api/watch/episode/:animeId/:episode", h.HandleEpisodeData)
 	r.GET("/api/watch/thumbnails/:animeId", h.HandleEpisodeThumbnails)
 	r.GET("/watch/proxy/stream", h.HandleProxyStream)
 	r.GET("/watch/proxy/subtitle", h.HandleProxySubtitle)
@@ -78,6 +79,65 @@ func (h *PlaybackHandler) HandleWatchPage(c *gin.Context) {
 	c.HTML(http.StatusOK, "watch.gohtml", responseData)
 }
 
+// HandleEpisodeData returns the minimal payload needed to advance to the next
+// episode without a full page reload (preserves fullscreen).
+func (h *PlaybackHandler) HandleEpisodeData(c *gin.Context) {
+	animeID, err := strconv.Atoi(c.Param("animeId"))
+	if err != nil || animeID <= 0 {
+		c.Status(http.StatusBadRequest)
+		return
+	}
+
+	episode := c.Param("episode")
+	if episode == "" {
+		c.Status(http.StatusBadRequest)
+		return
+	}
+
+	mode := c.DefaultQuery("mode", "sub")
+
+	user, _ := c.Get("User")
+	userID := ""
+	if u, ok := user.(*domain.User); ok {
+		userID = u.ID
+	}
+
+	data, err := h.svc.BuildWatchData(c.Request.Context(), animeID, []string{}, episode, mode, userID)
+	if err != nil {
+		c.Status(http.StatusInternalServerError)
+		return
+	}
+
+	watchData, _ := data["WatchData"].(map[string]any)
+	if watchData == nil {
+		c.Status(http.StatusInternalServerError)
+		return
+	}
+
+	modeSources := watchData["ModeSources"]
+	availableModes, _ := watchData["AvailableModes"].([]string)
+	segments := watchData["Segments"]
+
+	// Try to resolve a title for this episode from the episode list.
+	episodeTitle := ""
+	if eps, ok := watchData["Episodes"].([]domain.EpisodeData); ok {
+		epNum, _ := strconv.Atoi(episode)
+		for _, e := range eps {
+			if e.MalID == epNum {
+				episodeTitle = e.Title
+				break
+			}
+		}
+	}
+
+	c.JSON(http.StatusOK, gin.H{
+		"mode_sources":    modeSources,
+		"available_modes": availableModes,
+		"segments":        segments,
+		"episode_title":   episodeTitle,
+	})
+}
+
 func (h *PlaybackHandler) HandleSaveProgress(c *gin.Context) {
 	user, _ := c.Get("User")
 	userID := ""

static/player/episodes/nav.ts

@@ -28,7 +28,9 @@ export const goToNextEpisode = async (): Promise<void> => {
   markEpisodeTransition(nextEp);
 
   try {
-    const res = await fetch(`/api/watch/episode/${state.malID}/${nextEp}`);
+    const res = await fetch(
+      `/api/watch/episode/${state.malID}/${nextEp}?mode=${encodeURIComponent(state.currentMode)}`
+    );
     if (!res.ok) {
       // fallback: full page navigation
       sessionStorage.setItem('mal:autoplay-next', 'true');
@@ -53,12 +55,14 @@ export const goToNextEpisode = async (): Promise<void> => {
       return;
     }
 
-    // load new video
+    // load new video (keep preferences)
-    state.video.src = `${state.streamURL}?mode=${encodeURIComponent(fallback)}&token=${encodeURIComponent(state.modeSources[fallback].token)}`;
+    const preferredQuality = localStorage.getItem('mal:preferred-quality') || 'best';
+    state.video.src = `${state.streamURL}?mode=${encodeURIComponent(fallback)}&token=${encodeURIComponent(state.modeSources[fallback].token)}${preferredQuality !== 'best' ? `&quality=${encodeURIComponent(preferredQuality)}` : ''}`;
     state.video.load();
     if (!state.video.paused) state.video.play().catch(() => {});
 
     state.currentEpisode = String(nextEp);
+    state.currentMode = fallback;
     state.pendingSeekTime = null;
     state.completionSent = false;
     state.completionAttempts = 0;