import SwiftUI
import AVKit

/// VideoPlayer widget — 视频播放器控件
/// 使用 AVKit 渲染视频，通过 SwiftBricks 接口控制
///
/// JSON Schema 示例:
/// ```json
/// {
///   "widgettype": "VideoPlayer",
///   "options": {
///     "url": "https://example.com/video.mp4",
///     "autoplay": true,
///     "controls": true
///   }
/// }
/// ```
///
/// 支持的事件:
/// - play: 播放
/// - pause: 暂停
/// - toggle: 切换播放/暂停
/// - seek: 跳转到指定时间 (参数: time)
/// - setVolume: 设置音量 (参数: volume)

struct VideoPlayerControl: View {
    let schema: ControlSchema
    @ObservedObject var engine: BricksEngine
    @State private var player: AVPlayer?
    @State private var isPlaying: Bool = false
    
    var body: some View {
        Group {
            #if os(macOS)
            macOSPlayerView
            #else
            iOSPlayerView
            #endif
        }
        .onAppear {
            setupPlayer()
            setupEventListeners()
        }
        .onDisappear {
            player?.pause()
        }
    }
    
    // MARK: - Platform-specific views
    
    #if os(macOS)
    private var macOSPlayerView: some View {
        VideoPlayerView(player: player)
            .frame(maxWidth: .infinity, maxHeight: .infinity)
    }
    
    private struct VideoPlayerView: NSViewRepresentable {
        let player: AVPlayer?
        
        func makeNSView(context: Context) -> NSView {
            let view = AVPlayerView()
            view.player = player
            view.controlsStyle = .default
            return view
        }
        
        func updateNSView(_ nsView: NSView, context: Context) {
            if let playerView = nsView as? AVPlayerView {
                playerView.player = player
            }
        }
    }
    #else
    private var iOSPlayerView: some View {
        VideoPlayer(player: player)
            .frame(maxWidth: .infinity, maxHeight: .infinity)
    }
    #endif
    
    // MARK: - Setup
    
    private func setupPlayer() {
        // 优先从 Store 获取外部注入的共享 AVPlayer（如 PlayerBridge）
        let widgetId = schema.effectiveId
        if let sharedPlayer = engine.store.getValue(id: "\(widgetId).player") as? AVPlayer {
            player = sharedPlayer
            isPlaying = sharedPlayer.rate > 0
            return
        }
        
        // Fallback: 用 schema options 中的 url 创建自己的 player
        guard let urlString = schema.options.url else { return }
        
        if let url = URL(string: urlString) {
            player = AVPlayer(url: url)
            
            if schema.options.autoplay == true {
                player?.play()
                isPlaying = true
            }
        }
    }
    
    private func setupEventListeners() {
        let widgetId = schema.effectiveId
        
        // 监听播放事件
        engine.eventBus.on("\(widgetId).play") { [weak engine] data in
            self.player?.play()
            self.isPlaying = true
            await engine?.eventBus.dispatch("\(widgetId).playing", data: EventData())
        }
        
        // 监听暂停事件
        engine.eventBus.on("\(widgetId).pause") { [weak engine] data in
            self.player?.pause()
            self.isPlaying = false
            await engine?.eventBus.dispatch("\(widgetId).paused", data: EventData())
        }
        
        // 监听切换事件
        engine.eventBus.on("\(widgetId).toggle") { [weak engine] data in
            if self.isPlaying {
                self.player?.pause()
                self.isPlaying = false
                await engine?.eventBus.dispatch("\(widgetId).paused", data: EventData())
            } else {
                self.player?.play()
                self.isPlaying = true
                await engine?.eventBus.dispatch("\(widgetId).playing", data: EventData())
            }
        }
        
        // 监听跳转事件
        engine.eventBus.on("\(widgetId).seek") { data in
            if let timeStr = data["time"] as? String, let time = Double(timeStr) {
                self.player?.seek(to: CMTime(seconds: time, preferredTimescale: 600))
            } else if let time = data["time"] as? Double {
                self.player?.seek(to: CMTime(seconds: time, preferredTimescale: 600))
            }
        }
        
        // 监听音量事件
        engine.eventBus.on("\(widgetId).setVolume") { data in
            if let volStr = data["volume"] as? String, let vol = Float(volStr) {
                self.player?.volume = vol
            } else if let vol = data["volume"] as? Float {
                self.player?.volume = vol
            }
        }
        
        // 监听设置视频源事件
        engine.eventBus.on("\(widgetId).setURL") { data in
            if let urlString = data["url"] as? String, let url = URL(string: urlString) {
                let wasPlaying = self.isPlaying
                self.player?.pause()
                self.player = AVPlayer(url: url)
                if wasPlaying {
                    self.player?.play()
                }
            }
        }
    }
    
    // MARK: - Helpers
    
    private func resolveWidth(_ opts: ControlOptions) -> CGFloat? {
        if let w = opts.width {
            if w == "100%" { return nil }
            if let px = parsePixels(w) { return px }
        }
        return nil
    }
    
    private func resolveHeight(_ opts: ControlOptions) -> CGFloat? {
        if let h = opts.height {
            if h == "100%" { return nil }
            if let px = parsePixels(h) { return px }
        }
        return nil
    }
    
    private func parsePixels(_ str: String) -> CGFloat? {
        let cleaned = str.replacingOccurrences(of: "px", with: "")
        return CGFloat(Double(cleaned) ?? 0)
    }
}