import Foundation
import SpeexKit
import os.log

/// 基于杰理SpeexKit的Opus音频处理器
@available(iOS 13.0, *)
class OpusAudioProcessor: NSObject {
    
    // MARK: - 回调代理协议
    protocol AudioDataCallback: AnyObject {
        /// 接收到解码后的PCM音频数据
        func onAudioDataReceived(data: Data)
    }
    
    // MARK: - 属性
    private var isDecodingActive = false
    private weak var callback: AudioDataCallback?
    private let logger = OSLog(subsystem: "com.yunqiinnovation.ble_service", category: "OpusAudioProcessor")
    
    // MARK: - 初始化
    override init() {
        super.init()
        
        // 注册通知 - 这是SDK设计要求的
        NotificationCenter.default.addObserver(
            self,
            selector: #selector(onOpusDecodedData(_:)),
            name: NSNotification.Name(rawValue: kOPUS_DECODE_DATA),
            object: nil
        )
        
        // 启用日志
        OpusUnit.opusIsLog(true)
    }
    
    deinit {
        stopDecoding()
        NotificationCenter.default.removeObserver(self)
    }
    
    // MARK: - 通知回调
    @objc private func onOpusDecodedData(_ notification: Notification) {
        guard let pcmData = notification.object as? Data else {
            os_log("解码回调收到无效数据", log: logger, type: .error)
            return
        }
        
        // 传递给回调
        DispatchQueue.main.async { [weak self] in
            self?.callback?.onAudioDataReceived(data: pcmData)
        }
    }
    
    // MARK: - 公共接口
    
    /// 设置回调
    func setCallback(_ callback: AudioDataCallback?) {
        self.callback = callback
    }
    
    /// 开始Opus解码
    func startDecoding(sampleRate: Int32 = 16000, channels: Int32 = 1, frameSize: Int32 = 640) -> Bool {
        // 如果已经在解码，直接返回成功
        if isDecodingActive {
            os_log("Opus解码器已经在运行", log: logger, type: .debug)
            return true
        }
        
        // 设置音频参数
        OpusUnit.opusSetSampleRate(Int32(sampleRate), kbps: 16000, channels: Int32(channels))
        
        // 必须在后台线程启动解码器（SDK要求）
        DispatchQueue.global(qos: .userInitiated).async { [weak self] in
            guard let self = self else { return }
            
            // 启动解码器
            let result = OpusUnit.opusDecoderRun()
            if result == 0 {
                os_log("Opus解码器启动成功: 采样率=%d Hz", log: self.logger, type: .info, sampleRate)
                self.isDecodingActive = true
            } else {
                os_log("Opus解码器启动失败: 错误=%d", log: self.logger, type: .error, result)
            }
        }
        
        return true
    }
    
    /// 停止Opus解码
    func stopDecoding() -> Bool {
        if !isDecodingActive {
            return false
        }
        
        // 必须在后台线程停止解码器
        DispatchQueue.global(qos: .userInitiated).async { [weak self] in
            guard let self = self else { return }
            
            let result = OpusUnit.opusDecoderStop()
            os_log("Opus解码器停止: %d", log: self.logger, type: .info, result)
            self.isDecodingActive = false
        }
        
        return true
    }
    
    /// 处理Opus编码数据
    func processAudioData(_ data: Data) {
        if !isDecodingActive {
            os_log("Opus解码器未启动", log: logger, type: .error)
            return
        }
        
        // 将Opus数据送入解码器
        OpusUnit.opusWrite(data)
        // 解码结果将通过通知回调给onOpusDecodedData方法
    }
    
    /// 判断解码器是否运行中
    func isDecoding() -> Bool {
        return isDecodingActive
    }
    
    /// 清理资源
    func cleanup() {
        stopDecoding()
    }
}