新增下载任务数设置

src/contexts/DownloadContext.tsx

@@ -21,28 +21,85 @@ interface DownloadContextType {
 const DownloadContext = createContext<DownloadContextType | undefined>(undefined);
 
 export function DownloadProvider({ children }: { children: React.ReactNode }) {
+  const [tasks, setTasks] = useState<M3U8DownloadTask[]>([]);
+  const [showDownloadPanel, setShowDownloadPanel] = useState(false);
+  const [startingTaskIds, setStartingTaskIds] = useState<Set<string>>(new Set());
+
+  // 自动启动下一个等待的任务
+  const startNextPendingTask = useCallback((currentDownloader: M3U8Downloader) => {
+    // 从localStorage读取最大同时下载限制，默认6个
+    const maxConcurrentDownloads = typeof window !== 'undefined'
+      ? Number(localStorage.getItem('maxConcurrentDownloads') || 6)
+      : 6;
+
+    const allTasks = currentDownloader.getAllTasks();
+    const downloadingCount = allTasks.filter(t => t.status === 'downloading').length;
+
+    // 如果当前下载数量小于限制，启动下一个ready任务
+    if (downloadingCount < maxConcurrentDownloads) {
+      const readyTask = allTasks.find(t => t.status === 'ready');
+      if (readyTask) {
+        currentDownloader.startTask(readyTask.id);
+        setTasks(currentDownloader.getAllTasks());
+      }
+    }
+  }, []);
+
   const [downloader] = useState(() => new M3U8Downloader({
     onProgress: (task) => {
       setTasks(downloader.getAllTasks());
     },
     onComplete: (task) => {
       setTasks(downloader.getAllTasks());
+      // 任务完成后，尝试启动下一个等待的任务
+      startNextPendingTask(downloader);
     },
     onError: (task, error) => {
       console.error('下载错误:', error);
       setTasks(downloader.getAllTasks());
+      // 任务出错后，尝试启动下一个等待的任务
+      startNextPendingTask(downloader);
     },
   }));
 
-  const [tasks, setTasks] = useState<M3U8DownloadTask[]>([]);
-  const [showDownloadPanel, setShowDownloadPanel] = useState(false);
-
   const addDownloadTask = useCallback(async (url: string, title: string, type: 'TS' | 'MP4' = 'TS') => {
     try {
       const taskId = await downloader.createTask(url, title, type);
       setTasks(downloader.getAllTasks());
-      await downloader.startTask(taskId);
-      setTasks(downloader.getAllTasks());
+
+      // 从localStorage读取最大同时下载限制，默认6个
+      const maxConcurrentDownloads = typeof window !== 'undefined'
+        ? Number(localStorage.getItem('maxConcurrentDownloads') || 6)
+        : 6;
+
+      // 检查当前正在下载的任务数量（包括正在启动的）
+      setStartingTaskIds(prev => {
+        const allTasks = downloader.getAllTasks();
+        const currentDownloadingCount = allTasks.filter(t => t.status === 'downloading').length;
+        const totalActiveCount = currentDownloadingCount + prev.size;
+
+        // 如果未超过限制，标记为正在启动并启动任务
+        if (totalActiveCount < maxConcurrentDownloads) {
+          const newSet = new Set(prev);
+          newSet.add(taskId);
+
+          // 异步启动任务
+          downloader.startTask(taskId).then(() => {
+            setTasks(downloader.getAllTasks());
+            // 启动完成后，从正在启动列表中移除
+            setStartingTaskIds(current => {
+              const updated = new Set(current);
+              updated.delete(taskId);
+              return updated;
+            });
+          });
+
+          return newSet;
+        }
+
+        // 否则任务保持ready状态，等待其他任务完成后自动启动
+        return prev;
+      });
     } catch (error) {
       console.error('添加下载任务失败:', error);
       throw error;
@@ -50,19 +107,33 @@ export function DownloadProvider({ children }: { children: React.ReactNode }) {
   }, [downloader]);
 
   const startTask = useCallback((taskId: string) => {
-    downloader.startTask(taskId);
-    setTasks(downloader.getAllTasks());
+    // 从localStorage读取最大同时下载限制，默认6个
+    const maxConcurrentDownloads = typeof window !== 'undefined'
+      ? Number(localStorage.getItem('maxConcurrentDownloads') || 6)
+      : 6;
+
+    const currentDownloadingCount = downloader.getAllTasks().filter(t => t.status === 'downloading').length;
+
+    // 如果未超过限制，启动任务
+    if (currentDownloadingCount < maxConcurrentDownloads) {
+      downloader.startTask(taskId);
+      setTasks(downloader.getAllTasks());
+    }
   }, [downloader]);
 
   const pauseTask = useCallback((taskId: string) => {
     downloader.pauseTask(taskId);
     setTasks(downloader.getAllTasks());
-  }, [downloader]);
+    // 暂停任务后，尝试启动下一个等待的任务
+    startNextPendingTask(downloader);
+  }, [downloader, startNextPendingTask]);
 
   const cancelTask = useCallback((taskId: string) => {
     downloader.cancelTask(taskId);
     setTasks(downloader.getAllTasks());
-  }, [downloader]);
+    // 取消任务后，尝试启动下一个等待的任务
+    startNextPendingTask(downloader);
+  }, [downloader, startNextPendingTask]);
 
   const retryFailedSegments = useCallback((taskId: string) => {
     downloader.retryFailedSegments(taskId);