import AVFoundation
import CoreMedia
#if os(macOS)
import AppKit

// MARK: - 音频捕获上下文
class AudioCaptureContext {
    var writerInput: AVAssetWriterInput?
    nonisolated(unsafe) var isRunning: Bool = true
    nonisolated(unsafe) var appendCount: Int = 0
    nonisolated(unsafe) var formatDescription: CMAudioFormatDescription?
    nonisolated(unsafe) var firstAppendLogged: Bool = false
}

/// 全局引用，供 C 回调访问（单实例录制，线程安全由 isRunning 保护）
private nonisolated(unsafe) var gAudioContext: AudioCaptureContext?

// MARK: - MTAudioProcessingTap C 回调
private func tapPrepare(_ tap: MTAudioProcessingTap,
                        _ maxFramesPerSlice: CMItemCount,
                        _ processingFormat: UnsafePointer<AudioStreamBasicDescription>) {
    print("[Recorder] tapPrepare called, maxFrames=\(maxFramesPerSlice)")
    guard let ctx = gAudioContext else {
        print("[Recorder] tapPrepare: gAudioContext is nil!")
        return
    }
    var asbd = processingFormat.pointee
    print("[Recorder] tapPrepare: sampleRate=\(asbd.mSampleRate), channels=\(asbd.mChannelsPerFrame)")
    CMAudioFormatDescriptionCreate(allocator: kCFAllocatorDefault,
                                    asbd: &asbd,
                                    layoutSize: 0, layout: nil,
                                    magicCookieSize: 0, magicCookie: nil,
                                    extensions: nil,
                                    formatDescriptionOut: &ctx.formatDescription)
}

private func tapInit(_ tap: MTAudioProcessingTap,
                     _ clientInfo: UnsafeMutableRawPointer?,
                     _ tapStorageOut: UnsafeMutablePointer<UnsafeMutableRawPointer?>) {
    // 初始化 tap
}

private func tapUnprepare(_ tap: MTAudioProcessingTap) {
    // Nothing to clean up
}

private func tapProcess(_ tap: MTAudioProcessingTap,
                         _ numberFrames: CMItemCount,
                         _ flags: MTAudioProcessingTapFlags,
                         _ bufferListInOut: UnsafeMutablePointer<AudioBufferList>,
                         _ numberFramesOut: UnsafeMutablePointer<CMItemCount>,
                         _ flagsOut: UnsafeMutablePointer<MTAudioProcessingTapFlags>) {
    numberFramesOut.pointee = 0
    flagsOut.pointee = 0
    
    guard numberFrames > 0 else { return }
    
    // 先获取源音频数据
    var timeRange = CMTimeRange()
    var srcFlags: MTAudioProcessingTapFlags = 0
    var actualFrames: CMItemCount = 0
    
    let status = MTAudioProcessingTapGetSourceAudio(
        tap, numberFrames, bufferListInOut,
        &srcFlags, &timeRange, &actualFrames
    )
    
    numberFramesOut.pointee = actualFrames
    flagsOut.pointee = srcFlags
    
    guard status == noErr, actualFrames > 0 else { return }
    
    // 通过全局变量获取 context
    guard let ctx = gAudioContext, ctx.isRunning,
          let writerInput = ctx.writerInput,
          writerInput.isReadyForMoreMediaData else { return }
    
    let bufferList = bufferListInOut.pointee
    guard bufferList.mNumberBuffers > 0 else { return }
    
    let buf = bufferList.mBuffers
    let dataSize = Int(buf.mDataByteSize)
    guard dataSize > 0, let srcData = buf.mData else { return }
    
    // 创建 CMBlockBuffer
    var blockBuffer: CMBlockBuffer?
    let blockStatus = CMBlockBufferCreateWithMemoryBlock(
        allocator: kCFAllocatorDefault, memoryBlock: nil,
        blockLength: dataSize, blockAllocator: kCFAllocatorDefault,
        customBlockSource: nil, offsetToData: 0,
        dataLength: dataSize,
        flags: kCMBlockBufferAssureMemoryNowFlag,
        blockBufferOut: &blockBuffer
    )
    guard blockStatus == kCMBlockBufferNoErr, let bb = blockBuffer else { return }
    
    let replaceStatus = CMBlockBufferReplaceDataBytes(
        with: srcData, blockBuffer: bb,
        offsetIntoDestination: 0, dataLength: dataSize
    )
    guard replaceStatus == kCMBlockBufferNoErr else { return }
    
    // 获取 format description
    guard let fd = ctx.formatDescription else { return }
    
    // 用累积帧数计算 PTS
    let sampleRate = Double(timeRange.duration.timescale) > 0
        ? Double(timeRange.duration.timescale) : 44100.0
    let ptsValue = Double(ctx.appendCount) / sampleRate
    let pts = CMTime(seconds: ptsValue, preferredTimescale: Int32(sampleRate))
    
    var sampleBuffer: CMSampleBuffer?
    let createStatus = CMAudioSampleBufferCreateReadyWithPacketDescriptions(
        allocator: kCFAllocatorDefault,
        dataBuffer: bb,
        formatDescription: fd,
        sampleCount: actualFrames,
        presentationTimeStamp: pts,
        packetDescriptions: nil,
        sampleBufferOut: &sampleBuffer
    )
    guard createStatus == noErr, let sb = sampleBuffer else { return }
    
    if writerInput.append(sb) {
        ctx.appendCount += actualFrames
        if !ctx.firstAppendLogged {
            ctx.firstAppendLogged = true
            print("[Recorder] ✓ First audio frame appended! pts=\(pts.seconds)s, frames=\(actualFrames)")
        }
    }
}

// 空的 init/finalize 回调
private func tapInit(_ tap: MTAudioProcessingTap) {}
private func tapFinalize(_ tap: MTAudioProcessingTap) {}

/// 视频源录制器：从 AVPlayerItemVideoOutput 抓帧 + MTAudioProcessingTap 捕获音频，写入 mp4
@MainActor
final class PlayerRecorder: NSObject {
    
    private var writer: AVAssetWriter?
    private var videoInput: AVAssetWriterInput?
    private var audioInput: AVAssetWriterInput?
    private var timer: Timer?
    private var startDate: Date?
    private var weakOutput: AVPlayerItemVideoOutput?
    nonisolated(unsafe) private var isRunning = false
    
    // 视频：缓存上一帧，确保静态场景也能持续写入
    private var lastPixelBuffer: CVPixelBuffer?
    private var captureFrameCount: Int = 0
    
    // 音频 (MTAudioProcessingTap)
    private var audioTap: MTAudioProcessingTap?
    private var audioContext: AudioCaptureContext?
    private weak var currentPlayerItem: AVPlayerItem?
    
    nonisolated(unsafe) private var recordStartTime: CMTime = .zero
    
    @Published var isRecording = false
    @Published var durationText = "00:00"
    
    var onRecordingSaved: ((URL) -> Void)?
    var onError: ((String) -> Void)?
    
    private var tempURL: URL?
    
    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
    }
    
    // MARK: - 开始录制
    func startRecording(from output: AVPlayerItemVideoOutput, playerItem: AVPlayerItem, startTime: CMTime) {
        guard !isRecording else { return }
        
        weakOutput = output
        currentPlayerItem = playerItem
        lastPixelBuffer = nil
        captureFrameCount = 0
        isRunning = false
        recordStartTime = startTime
        
        // 临时文件
        let formatter = DateFormatter()
        formatter.dateFormat = "yyyy-MM-dd_HH-mm-ss"
        let filename = "Recording_\(formatter.string(from: Date())).mp4"
        let url = saveDirectory.appendingPathComponent(filename)
        tempURL = url
        
        do {
            writer = try AVAssetWriter(outputURL: url, fileType: .mp4)
        } catch {
            onError?("Cannot create writer: \(error.localizedDescription)")
            return
        }
        
        guard let writer = writer else { return }
        
        // 视频输入
        let videoSettings: [String: Any] = [
            AVVideoCodecKey: AVVideoCodecType.h264,
            AVVideoWidthKey: 1920,
            AVVideoHeightKey: 1080
        ]
        let vInput = AVAssetWriterInput(mediaType: .video, outputSettings: videoSettings)
        vInput.expectsMediaDataInRealTime = true
        if writer.canAdd(vInput) {
            writer.add(vInput)
            videoInput = vInput
        }
        
        // 音频输入
        let audioSettings: [String: Any] = [
            AVFormatIDKey: kAudioFormatMPEG4AAC,
            AVSampleRateKey: 44100,
            AVNumberOfChannelsKey: 2,
            AVEncoderBitRateKey: 128000
        ]
        let aInput = AVAssetWriterInput(mediaType: .audio, outputSettings: audioSettings)
        aInput.expectsMediaDataInRealTime = true
        if writer.canAdd(aInput) {
            writer.add(aInput)
            audioInput = aInput
        }
        
        let success = writer.startWriting()
        if !success {
            print("[Recorder] startWriting failed: \(writer.error?.localizedDescription ?? "unknown")")
            onError?("Cannot start writer: \(writer.error?.localizedDescription ?? "unknown")")
            return
        }
        
        writer.startSession(atSourceTime: .zero)
        print("[Recorder] Writer started, session at .zero")
        
        // 启动视频抓帧
        isRecording = true
        isRunning = true
        startTimer()
        startCaptureLoop()
        
        // 启动音频捕获（MTAudioProcessingTap）
        setupAudioTap(playerItem: playerItem, audioWriterInput: aInput)
    }
    
    // MARK: - 停止录制
    func stopRecording() {
        guard isRecording else { return }
        isRecording = false
        isRunning = false
        captureTimer?.invalidate()
        captureTimer = nil
        stopTimer()
        
        // 停止音频 tap
        audioContext?.isRunning = false
        
        // 移除 audioMix（移除 tap）
        currentPlayerItem?.audioMix = nil
        currentPlayerItem = nil
        
        // 释放 tap 和 context
        audioTap = nil
        audioContext = nil
        gAudioContext = nil
        
        videoInput?.markAsFinished()
        audioInput?.markAsFinished()
        
        writer?.finishWriting { [weak self] in
            Task { @MainActor in
                guard let self = self, let w = self.writer else { return }
                let count = self.captureFrameCount
                print("[Recorder] finishWriting status: \(w.status.rawValue), error: \(w.error?.localizedDescription ?? "none"), video frames: \(count)")
                if w.status == .completed, let url = self.tempURL {
                    self.showSaveDialog(tempURL: url)
                } else {
                    self.onError?("Recording failed: \(w.error?.localizedDescription ?? "unknown (status=\(w.status.rawValue))")")
                    if let url = self.tempURL {
                        try? FileManager.default.removeItem(at: url)
                    }
                }
            }
        }
        
        lastPixelBuffer = nil
    }
    
    // MARK: - 音频 Tap 设置
    private func setupAudioTap(playerItem: AVPlayerItem, audioWriterInput: AVAssetWriterInput) {
        let asset = playerItem.asset
        
        Task {
            do {
                let audioTracks = try await asset.loadTracks(withMediaType: .audio)
                guard let audioTrack = audioTracks.first else {
                    print("[Recorder] ❌ No audio track for tap")
                    return
                }
                guard self.isRunning else {
                    print("[Recorder] ❌ isRunning=false, aborting audio tap setup")
                    return
                }
                
                print("[Recorder] Audio track found: \(audioTrack.trackID), setting up tap...")
                
                // 创建音频捕获上下文
                let context = AudioCaptureContext()
                context.writerInput = audioWriterInput
                context.isRunning = true
                self.audioContext = context
                
                // ★ 设置全局引用，供 C 回调访问
                gAudioContext = context
                
                // 创建 MTAudioProcessingTap
                var callbacks = MTAudioProcessingTapCallbacks(
                    version: kMTAudioProcessingTapCallbacksVersion_0,
                    clientInfo: nil,
                    init: tapInit,
                    finalize: tapFinalize,
                    prepare: tapPrepare,
                    unprepare: tapUnprepare,
                    process: tapProcess
                )
                
                var tap: MTAudioProcessingTap?
                let status = MTAudioProcessingTapCreate(
                    kCFAllocatorDefault,
                    &callbacks,
                    kMTAudioProcessingTapCreationFlag_PostEffects,
                    &tap
                )
                
                guard status == noErr, let audioTap = tap else {
                    print("[Recorder] ❌ MTAudioProcessingTapCreate failed: \(status)")
                    gAudioContext = nil
                    return
                }
                
                self.audioTap = audioTap
                
                // 创建 audioMix 并挂上 tap
                let params = AVMutableAudioMixInputParameters(track: audioTrack)
                params.audioTapProcessor = audioTap
                let audioMix = AVMutableAudioMix()
                audioMix.inputParameters = [params]
                
                playerItem.audioMix = audioMix
                print("[Recorder] ✓ Audio tap installed on player item")
            } catch {
                print("[Recorder] ❌ Audio tap setup failed: \(error)")
            }
        }
    }
    
    // MARK: - 视频抓帧 (30fps Timer)
    private var captureTimer: Timer?
    
    private func startCaptureLoop() {
        captureTimer = Timer.scheduledTimer(withTimeInterval: 1.0 / 30.0, repeats: true) { [weak self] _ in
            Task { @MainActor in
                self?.captureVideoFrame()
            }
        }
    }
    
    private func captureVideoFrame() {
        guard isRunning, let output = weakOutput, let input = videoInput,
              input.isReadyForMoreMediaData else { return }
        
        let hostTime = CACurrentMediaTime()
        let itemTime = output.itemTime(forHostTime: hostTime)
        
        // 尝试获取新帧，否则复用上一帧
        if let pb = output.copyPixelBuffer(forItemTime: itemTime, itemTimeForDisplay: nil) {
            lastPixelBuffer = pb
        }
        
        guard let pb = lastPixelBuffer else { return }
        
        // 相对时间戳
        let relativeTime = CMTimeSubtract(itemTime, recordStartTime)
        guard relativeTime.seconds >= 0 else { return }
        
        let sampleBuffer = Self.createSampleBuffer(from: pb, time: relativeTime)
        if let sb = sampleBuffer {
            if input.append(sb) {
                captureFrameCount += 1
            }
        }
    }
    
    private static func createSampleBuffer(from pixelBuffer: CVPixelBuffer, time: CMTime) -> CMSampleBuffer? {
        var info = CMSampleTimingInfo()
        info.presentationTimeStamp = time
        info.duration = CMTime(value: 1, timescale: 30)
        info.decodeTimeStamp = .invalid
        
        var formatDescription: CMFormatDescription?
        CMVideoFormatDescriptionCreateForImageBuffer(allocator: kCFAllocatorDefault, imageBuffer: pixelBuffer, formatDescriptionOut: &formatDescription)
        
        guard let fd = formatDescription else { return nil }
        
        var sampleBuffer: CMSampleBuffer?
        CMSampleBufferCreateReadyWithImageBuffer(allocator: kCFAllocatorDefault, imageBuffer: pixelBuffer, formatDescription: fd, sampleTiming: &info, sampleBufferOut: &sampleBuffer)
        return sampleBuffer
    }
    
    // MARK: - Timer (显示录制时长)
    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"
    }
    
    // MARK: - 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 {
                    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 {
                try? FileManager.default.removeItem(at: tempURL)
            }
        }
    }
}

#endif