import Foundation
import AVFoundation

/// 蓝牙事件类型
enum BluetoothEventType {
    case stateChanged
    case deviceConnected
    case deviceDisconnected
}

/// 蓝牙状态枚举
enum BluetoothState: String {
    case unknown = "unknown"
    case off = "off"
    case on = "on"
    case unauthorized = "unauthorized"
    case unsupported = "unsupported"
}

/// 简化的蓝牙助手类，专注于iOS上的蓝牙耳机检测
class ClassicBluetoothHelper: NSObject {
    // 状态监控相关
    private var isMonitoring = false
    private var stateCallback: ((BluetoothEventType, [String: Any]) -> Void)?
    
    // 音频路由变化观察者
    private var routeChangeObserver: NSObjectProtocol?
    
    deinit {
        stopBluetoothStateMonitoring()
    }
    
    /// 检查蓝牙是否启用（通过检查是否有连接的蓝牙音频设备）
    func isBluetoothEnabled() -> Bool {
        // 检查是否有连接的蓝牙音频设备
        let hasBtDevices = !getConnectedAudioDevices().isEmpty
        
        // 如果有连接的蓝牙设备，则认为蓝牙是开启状态
        if hasBtDevices {
            print("蓝牙状态检查: 已检测到蓝牙设备，蓝牙已开启")
            return true
        }
        
        // 如果没有连接设备，返回false (无法100%确定蓝牙是否打开，只能知道没有连接设备)
        print("蓝牙状态检查: 未检测到蓝牙设备")
        return false
    }
    
    /// 获取已连接的蓝牙耳机
    func getConnectedDevices(completion: @escaping ([[String: String]], Error?) -> Void) {
        // 获取音频设备（主要是蓝牙耳机）
        let audioDevices = getConnectedAudioDevices()
        
        // 日志输出
        if !audioDevices.isEmpty {
            print("已找到\(audioDevices.count)个蓝牙音频设备:")
            for device in audioDevices {
                print("- \(device["name"] ?? "未知") (\(device["address"] ?? "未知地址"))")
            }
        } else {
            print("未找到蓝牙音频设备")
        }
        
        completion(audioDevices, nil)
    }
    
    // 获取连接的蓝牙音频设备
    private func getConnectedAudioDevices() -> [[String: String]] {
        var result: [[String: String]] = []
        
        // 获取当前音频路由
        let outputs = AVAudioSession.sharedInstance().currentRoute.outputs
        
        // 过滤蓝牙相关设备
        for output in outputs where isBluetoothOutput(output.portType) {
            let device: [String: String] = [
                "name": output.portName,
                "address": cleanDeviceAddress(output.uid)
            ]
            result.append(device)
        }
        
        return result
    }
    
    // 检查是否为蓝牙输出
    private func isBluetoothOutput(_ portType: AVAudioSession.Port) -> Bool {
        return portType == .bluetoothA2DP || portType == .bluetoothHFP || portType == .bluetoothLE
    }
    
    // 清理设备地址
    private func cleanDeviceAddress(_ address: String) -> String {
        // 移除类似 "-tacl" 的后缀
        if let range = address.range(of: "-", options: .backwards) {
            return String(address[..<range.lowerBound])
        }
        return address
    }
    
    /// 开始监听蓝牙状态变化
    func startBluetoothStateMonitoring(callback: @escaping (BluetoothEventType, [String: Any]) -> Void) {
        self.stateCallback = callback
        
        if !isMonitoring {
            isMonitoring = true
            
            // 观察音频路由变化
            let notificationCenter = NotificationCenter.default
            routeChangeObserver = notificationCenter.addObserver(
                forName: AVAudioSession.routeChangeNotification,
                object: nil,
                queue: nil
            ) { [weak self] notification in
                self?.handleAudioRouteChange(notification)
            }
            
            // 激活音频会话
            activateAudioSession()
            
            // 报告当前状态
            reportCurrentBluetoothState()
        }
    }
    
    // 处理音频路由变化
    private func handleAudioRouteChange(_ notification: Notification) {
        guard let userInfo = notification.userInfo,
              let reasonValue = userInfo[AVAudioSessionRouteChangeReasonKey] as? UInt,
              let reason = AVAudioSession.RouteChangeReason(rawValue: reasonValue) else {
            return
        }
        
        switch reason {
        case .newDeviceAvailable:
            // 新音频设备已连接
            let audioDevices = getConnectedAudioDevices()
            for device in audioDevices {
                stateCallback?(.deviceConnected, ["device": device])
            }
            
            // 如果有蓝牙设备连接，报告蓝牙状态为开启
            if !audioDevices.isEmpty {
                reportBluetoothState(.on)
            }
            
        case .oldDeviceUnavailable:
            // 获取断开之前的路由
            if let previousRoute = userInfo[AVAudioSessionRouteChangePreviousRouteKey] as? AVAudioSessionRouteDescription {
                for output in previousRoute.outputs where isBluetoothOutput(output.portType) {
                    let device: [String: String] = [
                        "name": output.portName,
                        "address": cleanDeviceAddress(output.uid)
                    ]
                    stateCallback?(.deviceDisconnected, ["device": device])
                }
                
                // 检查当前是否还有蓝牙设备
                let currentDevices = getConnectedAudioDevices()
                if currentDevices.isEmpty {
                    // 如果没有任何蓝牙设备连接，可以认为蓝牙状态变为未知
                    reportBluetoothState(.unknown)
                }
            }
            
        default:
            break
        }
    }
    
    // 激活音频会话
    private func activateAudioSession() {
        do {
            let audioSession = AVAudioSession.sharedInstance()
            try audioSession.setCategory(.playback, mode: .default)
            try audioSession.setActive(true)
        } catch {
            print("设置音频会话失败: \(error.localizedDescription)")
        }
    }
    
    /// 停止监听蓝牙状态变化
    func stopBluetoothStateMonitoring() {
        if isMonitoring {
            isMonitoring = false
            
            // 移除音频路由观察者
            if let observer = routeChangeObserver {
                NotificationCenter.default.removeObserver(observer)
                routeChangeObserver = nil
            }
            
            // 关闭音频会话
            deactivateAudioSession()
        }
        
        // 清除回调
        stateCallback = nil
    }
    
    // 关闭音频会话
    private func deactivateAudioSession() {
        do {
            try AVAudioSession.sharedInstance().setActive(false)
        } catch {
            print("关闭音频会话失败: \(error.localizedDescription)")
        }
    }
    
    /// 报告当前蓝牙状态
    func reportCurrentBluetoothState() {
        // 检查当前是否有蓝牙设备连接
        let devices = getConnectedAudioDevices()
        
        if !devices.isEmpty {
            print("蓝牙状态: 已检测到蓝牙设备，报告状态为开启")
            reportBluetoothState(.on)
        } else {
            print("蓝牙状态: 未检测到蓝牙设备，报告状态为未知")
            reportBluetoothState(.unknown)
        }
    }
    
    // 报告蓝牙状态变化
    private func reportBluetoothState(_ state: BluetoothState) {
        print("向Flutter端报告的蓝牙状态: \(state.rawValue)")
        stateCallback?(.stateChanged, ["state": state.rawValue])
    }
}