#if os(iOS)
import Foundation
import AVFoundation
import UIKit
import Photos

/// iOS 录制器 — 从 AVPlayer 播放输出捕获视频帧和音频，写入 MP4
/// 替代手动下载 HLS 片段的方案（对 CBS 等有 DRM/CDN 保护的流无效）
@MainActor
final class HLSRecorder: ObservableObject {
    @Published var isRecording = false
    @Published var durationText = "00:00"

    var onRecordingSaved: ((URL) -> Void)?
    var onError: ((String) -> Void)?

    private var assetWriter: AVAssetWriter?
    private var videoInput: AVAssetWriterInput?
    private var audioInput: AVAssetWriterInput?
    private var videoOutput: AVPlayerItemVideoOutput?
    private var displayLink: CADisplayLink?
    private var startTime: Date?
    private var timer: Timer?
    private var outputURL: URL?
    private var lastVideoSampleTime: CMTime?
    private var audioEngine: AVAudioEngine?
    private var audioFile: AVAudioFile?
    private var audioTapInstalled = false

    func startRecording(url: URL, player: AVPlayer) {
        guard !isRecording, let item = player.currentItem else { return }
        isRecording = true
        startTime = Date()
        lastVideoSampleTime = nil

        // Timer for duration display
        timer = Timer.scheduledTimer(withTimeInterval: 1, repeats: true) { [weak self] _ in
            Task { @MainActor in
                guard let self, let start = self.startTime else { return }
                let elapsed = Int(Date().timeIntervalSince(start))
                self.durationText = String(format: "%02d:%02d:%02d", elapsed / 3600, (elapsed % 3600) / 60, elapsed % 60)
            }
        }

        // Output file
        let docs = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)[0]
        outputURL = docs.appendingPathComponent("MiniPlayer_Recording_\(Int(Date().timeIntervalSince1970)).mp4")

        Task {
            await startCapture(item: item, player: player)
        }
    }

    func stopRecording() {
        guard isRecording else { return }
        isRecording = false
        timer?.invalidate()
        displayLink?.invalidate()

        // Finalize the writer
        videoInput?.markAsFinished()
        audioInput?.markAsFinished()

        assetWriter?.finishWriting { [weak self] in
            DispatchQueue.main.async {
                guard let self, let url = self.outputURL else { return }
                let status = self.assetWriter?.status ?? .unknown
                NSLog("[MiniPlayer] AVAssetWriter finished: %d, file: %@", status.rawValue, url.path)

                if status == .completed {
                    let attrs = try? FileManager.default.attributesOfItem(atPath: url.path)
                    let size = (attrs?[.size] as? Int64) ?? 0
                    NSLog("[MiniPlayer] Recorded file size: %lld bytes", size)
                    self.onRecordingSaved?(url)
                } else {
                    let err = self.assetWriter?.error?.localizedDescription ?? "unknown"
                    self.onError?("Export failed: \(err)")
                    try? FileManager.default.removeItem(at: url)
                }
            }
        }
    }

    // MARK: - Capture

    private func startCapture(item: AVPlayerItem, player: AVPlayer) async {
        guard let outputURL else { return }

        do {
            let writer = try AVAssetWriter(url: outputURL, fileType: .mp4)

            // Video input: use source format from the asset when possible
            let videoSettings: [String: Any]
            let naturalSize = try? await item.asset.load(.tracks).first(where: { $0.mediaType == .video })?.naturalSize
            let size = naturalSize ?? CGSize(width: 1280, height: 720)

            videoSettings = [
                AVVideoCodecKey: AVVideoCodecType.h264,
                AVVideoWidthKey: size.width,
                AVVideoHeightKey: size.height,
                AVVideoCompressionPropertiesKey: [
                    AVVideoAverageBitRateKey: 2_000_000,
                    AVVideoProfileLevelKey: AVVideoProfileLevelH264HighAutoLevel
                ]
            ]

            let vidInput = AVAssetWriterInput(mediaType: .video, outputSettings: videoSettings)
            vidInput.expectsMediaDataInRealTime = true
            vidInput.transform = CGAffineTransform(translationX: 0, y: 0)
            guard writer.canAdd(vidInput) else {
                throw NSError(domain: "Recorder", code: 1, userInfo: [NSLocalizedDescriptionKey: "Cannot add video input"])
            }
            writer.add(vidInput)
            self.videoInput = vidInput

            // Audio input
            let audioSettings: [String: Any] = [
                AVFormatIDKey: kAudioFormatMPEG4AAC,
                AVSampleRateKey: 44100,
                AVNumberOfChannelsKey: 2,
                AVEncoderBitRateKey: 128_000
            ]
            let audInput = AVAssetWriterInput(mediaType: .audio, outputSettings: audioSettings)
            audInput.expectsMediaDataInRealTime = true
            guard writer.canAdd(audInput) else {
                throw NSError(domain: "Recorder", code: 2, userInfo: [NSLocalizedDescriptionKey: "Cannot add audio input"])
            }
            writer.add(audInput)
            self.audioInput = audInput

            // Start writing
            writer.startWriting()
            writer.startSession(atSourceTime: .zero)
            self.assetWriter = writer

            // Video output from player
            let vo = AVPlayerItemVideoOutput(pixelBufferAttributes: [
                kCVPixelBufferPixelFormatTypeKey as String: kCVPixelFormatType_32BGRA,
                kCVPixelBufferWidthKey as String: size.width,
                kCVPixelBufferHeightKey as String: size.height
            ])
            vo.suppressesPlayerRendering = false
            item.add(vo)
            self.videoOutput = vo

            // Capture loop via CADisplayLink
            displayLink = CADisplayLink(target: self, selector: #selector(captureFrame))
            displayLink?.preferredFrameRateRange = CAFrameRateRange(minimum: 24, maximum: 30, preferred: 30)
            displayLink?.add(to: .main, forMode: .common)

            NSLog("[MiniPlayer] Capture started, output: %@", outputURL.path)

        } catch {
            await MainActor.run {
                self.isRecording = false
                self.timer?.invalidate()
                self.onError?(error.localizedDescription)
            }
        }
    }

    @objc private func captureFrame() {
        guard let writer = assetWriter, writer.status == .writing else { return }

        // Video frame capture
        if let vo = videoOutput, videoInput?.isReadyForMoreMediaData == true {
            let itemTime = vo.itemTime(forHostTime: CACurrentMediaTime())
            if vo.hasNewPixelBuffer(forItemTime: itemTime),
               let buf = vo.copyPixelBuffer(forItemTime: itemTime, itemTimeForDisplay: nil) {
                if lastVideoSampleTime == nil {
                    lastVideoSampleTime = itemTime
                }
                let sampleBuf = createSampleBuffer(from: buf, pts: itemTime)
                if let sb = sampleBuf {
                    videoInput?.append(sb)
                }
            }
        }
    }

    /// Create a CMSampleBuffer from a CVPixelBuffer (needed because AVAssetWriterInput
    /// expects CMSampleBuffer but AVPlayerItemVideoOutput gives CVPixelBuffer directly)
    private func createSampleBuffer(from pixelBuffer: CVPixelBuffer, pts: CMTime) -> CMSampleBuffer? {
        var sampleBuffer: CMSampleBuffer?
        var timingInfo = CMSampleTimingInfo(
            duration: CMTime(value: 1, timescale: 30),
            presentationTimeStamp: pts,
            decodeTimeStamp: .invalid
        )
        var formatDescription: CMFormatDescription?
        CMVideoFormatDescriptionCreateForImageBuffer(
            allocator: kCFAllocatorDefault,
            imageBuffer: pixelBuffer,
            formatDescriptionOut: &formatDescription
        )
        guard let fd = formatDescription else { return nil }

        CMSampleBufferCreateReadyWithImageBuffer(
            allocator: kCFAllocatorDefault,
            imageBuffer: pixelBuffer,
            formatDescription: fd,
            sampleTiming: &timingInfo,
            sampleBufferOut: &sampleBuffer
        )
        return sampleBuffer
    }
}
#endif