diff --git a/Sources/PlayerBridge.swift b/Sources/PlayerBridge.swift
index 94cd570..88c20dd 100644
--- a/Sources/PlayerBridge.swift
+++ b/Sources/PlayerBridge.swift
@@ -122,6 +122,28 @@ final class PlayerBridge: ObservableObject {
     #if os(iOS)
     let hlsRecorder = HLSRecorder()
     let pipController = PiPController()
+    
+    // 诊断日志
+    private var diagLogURL: URL?
+    private var diagLogHandle: FileHandle?
+    
+    private func startDiagnosticLog() {
+        let docs = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)[0]
+        diagLogURL = docs.appendingPathComponent("miniplayer_diag.log")
+        // 清空旧日志
+        try? "".write(to: diagLogURL!, atomically: true, encoding: .utf8)
+        diagLogHandle = try? FileHandle(forWritingTo: diagLogURL!)
+        diagLogHandle?.seekToEndOfFile()
+        diagLog("=== MiniPlayer diagnostic log started ===")
+    }
+    
+    func diagLog(_ msg: String) {
+        let line = "\(Date()): \(msg)\n"
+        print("[MiniPlayer] \(msg)")
+        if let data = line.data(using: .utf8) {
+            try? diagLogHandle?.write(contentsOf: data)
+        }
+    }
     #endif
     
     // MARK: - 初始化
@@ -132,6 +154,8 @@ final class PlayerBridge: ObservableObject {
         #elseif os(iOS)
         // iOS: 配置音频会话（支持后台播放 + PiP）
         configureAudioSession()
+        // 开启诊断日志文件
+        startDiagnosticLog()
         #endif
         
         player.volume = volume
@@ -242,7 +266,7 @@ final class PlayerBridge: ObservableObject {
         
         currentIndex = index
         let item = queue[index]
-        print("[MiniPlayer] playIndex(\(index)): \(item.url.absoluteString)")
+        diagLog("playIndex(\(index)): \(item.url.lastPathComponent)")
         
         // 本地文件诊断：检查文件是否存在和可读
         if item.url.isFileURL {
@@ -250,7 +274,7 @@ final class PlayerBridge: ObservableObject {
             let exists = FileManager.default.fileExists(atPath: path)
             let readable = FileManager.default.isReadableFile(atPath: path)
             let fileSize = (try? FileManager.default.attributesOfItem(atPath: path)[.size] as? Int) ?? 0
-            print("[MiniPlayer] Local file check: exists=\(exists), readable=\(readable), size=\(fileSize), path=\(path)")
+            diagLog("Local file check: exists=\(exists) readable=\(readable) size=\(fileSize)")
         }
         
         // 先清除旧的 KVO，避免野指针
@@ -271,7 +295,7 @@ final class PlayerBridge: ObservableObject {
         player.replaceCurrentItem(with: playerItem)
         player.play()
         isPlaying = true
-        print("[MiniPlayer] player.play() called, rate=\(player.rate), timeControlStatus=\(player.timeControlStatus.rawValue)")
+        diagLog("play() called, rate=\(player.rate) timeControlStatus=\(player.timeControlStatus.rawValue)")
         
         cachedDuration = 0
         progressRatio = 0
@@ -304,7 +328,7 @@ final class PlayerBridge: ObservableObject {
         
         // KVO 可能从非主线程回调，用 DispatchQueue.main.async
         itemStatusObserver = playerItem.observe(\.status, options: [.new]) { [weak self] pi, _ in
-            print("[MiniPlayer] KVO status changed: \(pi.status.rawValue), error=\(pi.error?.localizedDescription ?? "none")")
+            self?.diagLog("KVO status: \(pi.status.rawValue)")
             DispatchQueue.main.async {
                 switch pi.status {
                 case .readyToPlay:
@@ -326,9 +350,7 @@ final class PlayerBridge: ObservableObject {
                     let errMsg = err?.localizedDescription ?? "Unknown error"
                     let errCode = (err as NSError?)?.code ?? 0
                     let isLocalFile = item.url.isFileURL
-                    NSLog("[MiniPlayer] ❌ AVPlayerItem failed: error=%@, code=%d, domain=%@, localFile=%d, url=%@",
-                          errMsg, errCode, (err as NSError?)?.domain ?? "none", isLocalFile ? 1 : 0,
-                          item.url.absoluteString)
+                    self?.diagLog("AVPlayerItem FAILED: \(errMsg) code=\(errCode) localFile=\(isLocalFile)")
                     self?.playerStatus = .error(errMsg)
                     self?.loadingTimer?.invalidate()
                     self?.loadingTimer = nil
@@ -574,8 +596,10 @@ final class PlayerBridge: ObservableObject {
     
     func addItem(url: URL, name: String, type: String) {
         let urlString = url.absoluteString
+        print("[MiniPlayer] addItem: name=\(name), type=\(type), scheme=\(url.scheme ?? "nil")")
         // 检查队列是否已有相同URL
         if queue.contains(where: { $0.url.absoluteString == urlString }) {
+            print("[MiniPlayer] addItem: already in queue, skipping")
             showToast("⚠️ \(name) already in queue")
             return
         }
@@ -583,7 +607,11 @@ final class PlayerBridge: ObservableObject {
         let libItem = library.addItem(url: urlString, name: name, type: type)
         queue.append(MediaItem(id: UUID().uuidString, url: url, name: name,
                                 mediaType: type, libraryID: libItem.id))
-        if queue.count == 1 { playIndex(0) }
+        print("[MiniPlayer] addItem: added to queue, count=\(queue.count)")
+        if queue.count == 1 { 
+            print("[MiniPlayer] addItem: first item, calling playIndex(0)")
+            playIndex(0) 
+        }
     }
     
     func removeItem(at index: Int) {
@@ -729,8 +757,11 @@ final class PlayerBridge: ObservableObject {
     
     /// 处理 iOS 文件选择器结果
     func handleFileImport(_ urls: [URL]) {
+        diagLog("handleFileImport: \(urls.count) URLs")
         for url in urls {
+            diagLog("processing: \(url.lastPathComponent)")
             let didStartAccessing = url.startAccessingSecurityScopedResource()
+            diagLog("startAccessingSecurityScopedResource: \(didStartAccessing)")
             defer {
                 if didStartAccessing { url.stopAccessingSecurityScopedResource() }
             }
@@ -747,13 +778,15 @@ final class PlayerBridge: ObservableObject {
                     let ext = url.pathExtension
                     let newURL = docsDir.appendingPathComponent("\(nameWithoutExt)_\(ts).\(ext)")
                     try FileManager.default.copyItem(at: url, to: newURL)
+                    diagLog("copied to: \(newURL.lastPathComponent)")
                     addItem(url: newURL, name: url.lastPathComponent, type: "file")
                 } else {
                     try FileManager.default.copyItem(at: url, to: localURL)
+                    diagLog("copied to: \(localURL.lastPathComponent)")
                     addItem(url: localURL, name: url.lastPathComponent, type: "file")
                 }
             } catch {
-                // 复制失败则直接用原始 URL（可能是 iCloud 文件等）
+                diagLog("copy failed: \(error.localizedDescription)")
                 addItem(url: url, name: url.lastPathComponent, type: "file")
             }
         }