import AVFoundation
#if os(macOS)
import AppKit

/// 屏幕录制器：录制屏幕 + 麦克风音频，保存到 ~/Movies/MiniPlayer/
@MainActor
final class ScreenRecorder: NSObject, AVCaptureFileOutputRecordingDelegate {
    
    private var session: AVCaptureSession?
    private var fileOutput: AVCaptureMovieFileOutput?
    private var isConfigured = false
    private var timer: Timer?
    private var startDate: Date?
    
    @Published var isRecording = false
    @Published var durationText = "00:00"
    
    var onRecordingSaved: ((URL) -> Void)?
    var onError: ((String) -> Void)?
    
    /// 保存目录
    private var saveDirectory: URL {
        let movies = FileManager.default.urls(for: .moviesDirectory, in: .userDomainMask).first!
        let dir = movies.appendingPathComponent("MiniPlayer", isDirectory: true)
        try? FileManager.default.createDirectory(at: dir, withIntermediateDirectories: true)
        return dir
    }
    
    /// 开始录制
    func startRecording() {
        guard !isRecording else { return }
        
        // 首次配置 session（避免每次重建）
        if !isConfigured {
            guard configureSession() else { return }
            isConfigured = true
        }
        
        guard let fileOutput = fileOutput else {
            onError?("Recording not ready")
            return
        }
        
        // 生成文件名：录制_2026-06-24_15-30-45.mp4
        let formatter = DateFormatter()
        formatter.dateFormat = "yyyy-MM-dd_HH-mm-ss"
        let filename = "Recording_\(formatter.string(from: Date())).mp4"
        let outputURL = saveDirectory.appendingPathComponent(filename)
        
        // 启动 session 并开始录制
        if let session = session, !session.isRunning {
            session.startRunning()
        }
        
        fileOutput.startRecording(to: outputURL, recordingDelegate: self)
    }
    
    /// 停止录制 → 弹出保存对话框
    func stopRecording() {
        guard isRecording, let fileOutput = fileOutput else { return }
        fileOutput.stopRecording()
    }
    
    private func startTimer() {
        startDate = Date()
        durationText = "00:00"
        timer = Timer.scheduledTimer(withTimeInterval: 1.0, repeats: true) { [weak self] _ in
            Task { @MainActor in
                guard let self = self, let start = self.startDate else { return }
                let elapsed = Int(Date().timeIntervalSince(start))
                let m = elapsed / 60
                let s = elapsed % 60
                let h = m / 60
                if h > 0 {
                    self.durationText = String(format: "%d:%02d:%02d", h, m % 60, s)
                } else {
                    self.durationText = String(format: "%02d:%02d", m, s)
                }
            }
        }
    }
    
    private func stopTimer() {
        timer?.invalidate()
        timer = nil
        startDate = nil
        durationText = "00:00"
    }
    
    /// 弹出保存对话框
    private func showSaveDialog(tempURL: URL) {
        let panel = NSSavePanel()
        panel.nameFieldStringValue = tempURL.lastPathComponent
        panel.allowedContentTypes = [.mpeg4Movie]
        panel.directoryURL = saveDirectory
        panel.title = "Save Recording"
        
        panel.begin { [weak self] response in
            guard let self = self else { return }
            if response == .OK, let destURL = panel.url {
                do {
                    // 如果目标已存在先删除
                    if FileManager.default.fileExists(atPath: destURL.path) {
                        try FileManager.default.removeItem(at: destURL)
                    }
                    try FileManager.default.moveItem(at: tempURL, to: destURL)
                    self.onRecordingSaved?(destURL)
                } catch {
                    self.onError?("Save failed: \(error.localizedDescription)")
                }
            } else {
                // 用户取消 → 删除临时文件
                try? FileManager.default.removeItem(at: tempURL)
            }
        }
    }
    
    private func configureSession() -> Bool {
        let session = AVCaptureSession()
        session.sessionPreset = .hd1920x1080
        
        // 屏幕输入（主显示器）
        guard let displayID = NSScreen.main?.deviceDescription[NSDeviceDescriptionKey("NSScreenNumber")] as? CGDirectDisplayID else {
            onError?("No display found")
            return false
        }
        
        let screenInput = AVCaptureScreenInput(displayID: displayID)
        guard let screenInput = screenInput else {
            onError?("Cannot create screen input")
            return false
        }
        screenInput.capturesMouseClicks = false
        screenInput.capturesCursor = true
        
        if session.canAddInput(screenInput) {
            session.addInput(screenInput)
        } else {
            onError?("Cannot add screen input")
            return false
        }
        
        // 麦克风输入
        if let audioDevice = AVCaptureDevice.default(for: .audio),
           let audioInput = try? AVCaptureDeviceInput(device: audioDevice) {
            if session.canAddInput(audioInput) {
                session.addInput(audioInput)
            }
        }
        
        // 文件输出
        let output = AVCaptureMovieFileOutput()
        if session.canAddOutput(output) {
            session.addOutput(output)
        } else {
            onError?("Cannot add file output")
            return false
        }
        
        self.session = session
        self.fileOutput = output
        
        // 请求屏幕录制权限
        #if canImport(ScreenCaptureKit)
        if !CGPreflightScreenCaptureAccess() {
            CGRequestScreenCaptureAccess()
        }
        #endif
        
        return true
    }
    
    // MARK: - AVCaptureFileOutputRecordingDelegate
    nonisolated func fileOutputRecordingDidStart(_ output: AVCaptureFileOutput) {
        Task { @MainActor in
            self.isRecording = true
            self.startTimer()
        }
    }
    
    nonisolated func fileOutput(_ output: AVCaptureFileOutput, didFinishRecordingTo outputFileURL: URL, from connections: [AVCaptureConnection], error: Error?) {
        Task { @MainActor in
            self.isRecording = false
            self.stopTimer()
            if let error = error {
                self.onError?("Recording failed: \(error.localizedDescription)")
            } else {
                self.showSaveDialog(tempURL: outputFileURL)
            }
            self.session?.stopRunning()
        }
    }
    
    deinit {
        session?.stopRunning()
    }
}

#endif