import Foundation
import CoreBluetooth
import AVFoundation
import UIKit

@objc class ClassicBluetoothHelper: NSObject, CBCentralManagerDelegate, CBPeripheralManagerDelegate {
    private let TAG = "ClassicBluetoothHelper"
    
    // AVAudioSession 用于获取已连接的蓝牙设备
    private let audioSession = AVAudioSession.sharedInstance()
    
    // 蓝牙管理器
    private var centralManager: CBCentralManager?
    private var peripheralManager: CBPeripheralManager?
    
    // 设备列表缓存
    private var bluetoothDevices: [[String: String]] = []
    
    // 设备连接和断开回调
    private var deviceEventCallback: (([String: Any]) -> Void)?
    
    // 初始化
    override init() {
        super.init()
        
        // 初始化中央管理器来检查蓝牙状态，并将自己设置为代理
        centralManager = CBCentralManager(delegate: self, queue: nil, options: [CBCentralManagerOptionShowPowerAlertKey: true])
        
        // 初始化外设管理器
        peripheralManager = CBPeripheralManager(delegate: self, queue: nil)
        
        // 请求权限
        requestBluetoothPermissions()
    }
    
    // 请求蓝牙权限
    private func requestBluetoothPermissions() {
        // 在 iOS 13 及更高版本中，需要主动请求蓝牙权限
        if #available(iOS 13.0, *) {
            // 激活音频会话将触发系统蓝牙权限请求
            do {
                try audioSession.setCategory(.playAndRecord, mode: .default, options: [.allowBluetooth, .allowBluetoothA2DP])
                try audioSession.setActive(true)
                NSLog("\(TAG): 已请求音频会话蓝牙权限")
            } catch {
                NSLog("\(TAG): 激活音频会话失败: \(error.localizedDescription)")
            }
        }
    }
    
    // CBCentralManagerDelegate 方法
    func centralManagerDidUpdateState(_ central: CBCentralManager) {
        var stateString = "unknown"
        
        switch central.state {
        case .poweredOn:
            stateString = "on"
            NSLog("\(TAG): centralManagerDidUpdateState: 蓝牙已启用")
            // 蓝牙已打开，可以开始扫描或其他操作
            // 初始化设备列表 - 主要是为了触发 iOS 的权限请求
            _ = getConnectedAudioDevices()
        case .poweredOff:
            stateString = "off"
            NSLog("\(TAG): centralManagerDidUpdateState: 蓝牙已关闭")
            // 清空设备列表
            bluetoothDevices.removeAll()
        case .resetting:
            stateString = "resetting"
            NSLog("\(TAG): centralManagerDidUpdateState: 蓝牙正在重置")
        case .unauthorized:
            stateString = "unauthorized"
            NSLog("\(TAG): centralManagerDidUpdateState: 蓝牙使用未授权")
        case .unsupported:
            stateString = "unsupported"
            NSLog("\(TAG): centralManagerDidUpdateState: 设备不支持蓝牙")
        case .unknown:
            stateString = "unknown"
            NSLog("\(TAG): centralManagerDidUpdateState: 蓝牙状态未知")
        @unknown default:
            stateString = "unknown"
            NSLog("\(TAG): centralManagerDidUpdateState: 蓝牙状态未知(default)")
        }
        
        NSLog("\(TAG): centralManagerDidUpdateState: 发送蓝牙状态变化事件: \(stateString)")
        
        // 发送蓝牙状态变化事件
        if let callback = deviceEventCallback {
            let event: [String: Any] = [
                "type": "bluetoothStateChanged",
                "state": stateString,
                "timestamp": Int(Date().timeIntervalSince1970 * 1000)
            ]
            callback(event)
        } else {
            NSLog("\(TAG): centralManagerDidUpdateState: 没有回调注册，无法发送事件")
        }
    }
    
    // CBPeripheralManagerDelegate 方法
    func peripheralManagerDidUpdateState(_ peripheral: CBPeripheralManager) {
        NSLog("\(TAG): 外设管理器状态变化: \(peripheral.state.rawValue)")
    }
    
    // 注册设备事件回调
    @objc func registerDeviceEventCallback(_ callback: @escaping ([String: Any]) -> Void) {
        deviceEventCallback = callback
    }
    
    // 检查蓝牙是否启用
    @objc func isBluetoothEnabled() -> Bool {
        guard let manager = centralManager else { return false }
        
        return manager.state == .poweredOn
    }
    
    // 获取已连接的音频设备 (A2DP 设备)
    @objc func getConnectedA2dpDevices(_ completion: @escaping ([[String: String]]?, String?) -> Void) {
        // 检查蓝牙状态和权限
        let (enabled, authorized) = checkBluetoothPermission()
        if !enabled {
            NSLog("\(TAG): 蓝牙未启用")
            completion(nil, "蓝牙未启用，请在设置中开启蓝牙")
            return
        }
        
        if !authorized {
            NSLog("\(TAG): 蓝牙权限被拒绝")
            completion(nil, "蓝牙权限被拒绝，请在设置中允许蓝牙访问")
            return
        }
        
        // 尝试激活音频会话以获取设备信息
        do {
            try audioSession.setCategory(.playAndRecord, mode: .default, options: [.allowBluetooth, .allowBluetoothA2DP])
            try audioSession.setActive(true)
            
            // 获取输出设备
            let devices = self.getConnectedAudioDevices()
            
            // 记录找到的设备数量
            NSLog("\(TAG): 找到 \(devices.count) 个A2DP设备")
            
            completion(devices, nil)
        } catch {
            NSLog("\(TAG): 获取A2DP设备失败: \(error.localizedDescription)")
            completion(nil, "获取A2DP设备失败: \(error.localizedDescription)")
        }
    }
    
    // 获取已连接的耳机设备
    @objc func getConnectedHeadsetDevices(_ completion: @escaping ([[String: String]]?, String?) -> Void) {
        // 检查蓝牙状态和权限
        let (enabled, authorized) = checkBluetoothPermission()
        if !enabled {
            NSLog("\(TAG): 蓝牙未启用")
            completion(nil, "蓝牙未启用，请在设置中开启蓝牙")
            return
        }
        
        if !authorized {
            NSLog("\(TAG): 蓝牙权限被拒绝")
            completion(nil, "蓝牙权限被拒绝，请在设置中允许蓝牙访问")
            return
        }
        
        // 尝试激活音频会话以获取设备信息
        do {
            try audioSession.setCategory(.playAndRecord, mode: .default, options: [.allowBluetooth])
            try audioSession.setActive(true)
            
            // 获取输出设备
            let devices = self.getConnectedAudioDevices()
            
            // 记录找到的设备数量
            NSLog("\(TAG): 找到 \(devices.count) 个耳机设备")
            
            completion(devices, nil)
        } catch {
            NSLog("\(TAG): 获取耳机设备失败: \(error.localizedDescription)")
            completion(nil, "获取耳机设备失败: \(error.localizedDescription)")
        }
    }
    
    // 使用原生方式检查蓝牙权限
    private func checkBluetoothPermission() -> (enabled: Bool, authorized: Bool) {
        // 检查蓝牙是否启用
        let isEnabled = centralManager?.state == .poweredOn
        
        // 检查蓝牙权限
        var isAuthorized = true
        var authDescription = "unknown"
        
        if #available(iOS 13.0, *) {
            let authStatus = centralManager?.authorization
            
            switch authStatus {
            case .allowedAlways:
                authDescription = "allowedAlways"
                isAuthorized = true
            case .denied:
                authDescription = "denied"
                isAuthorized = false
            case .restricted:
                authDescription = "restricted"
                isAuthorized = false
            case .notDetermined:
                authDescription = "notDetermined"
                // 未决定状态仍然当作授权, 因为系统会在实际使用时弹出请求
                isAuthorized = true
            default:
                authDescription = "unknown"
                isAuthorized = true
            }
            
            NSLog("\(TAG): 原生蓝牙权限状态: \(authDescription)")
        } else {
            // iOS 13 以下版本没有细粒度的权限控制
            authDescription = "legacy_version"
            NSLog("\(TAG): iOS版本低于13，使用旧版权限模型")
        }
        
        NSLog("\(TAG): 蓝牙状态: 启用=\(isEnabled), 已授权=\(isAuthorized), 权限描述=\(authDescription)")
        return (isEnabled, isAuthorized)
    }
    
    // 原生方式检查蓝牙权限并返回给 Flutter
    @objc func checkAndRequestNativePermission(_ completion: @escaping ([String: Any]) -> Void) {
        // 确保 centralManager 已初始化
        if centralManager == nil {
            centralManager = CBCentralManager(delegate: self, queue: nil)
            NSLog("\(self.TAG): 创建新的蓝牙管理器用于权限检查")
        }
        
        // 延迟执行检查，确保 centralManager 状态已更新
        DispatchQueue.main.asyncAfter(deadline: .now() + 0.5) {
            // 再次检查蓝牙权限，以获取最新状态
            let (enabled, authorized) = self.checkBluetoothPermission()
            
            // 尝试主动请求蓝牙权限（如果尚未决定）
            if #available(iOS 13.0, *) {
                if self.centralManager?.authorization == .notDetermined {
                    NSLog("\(self.TAG): 蓝牙权限状态为未决定，尝试主动请求权限")
                    // 启动扫描会触发系统权限请求
                    self.centralManager?.scanForPeripherals(withServices: nil, options: nil)
                    // 立即停止扫描
                    self.centralManager?.stopScan()
                }
            }
            
            let result: [String: Any] = [
                "enabled": enabled,
                "authorized": authorized,
                "status": self.getPermissionStatusText(enabled: enabled, authorized: authorized)
            ]
            
            NSLog("\(self.TAG): 返回权限检查结果: \(result)")
            completion(result)
        }
    }
    
    // 获取权限状态文本
    private func getPermissionStatusText(enabled: Bool, authorized: Bool) -> String {
        if !enabled {
            return "disabled"  // 蓝牙已禁用
        }
        
        if !authorized {
            return "denied"    // 权限被拒绝
        }
        
        return "granted"       // 已授权
    }
    
    // 获取当前连接的音频设备
    private func getConnectedAudioDevices() -> [[String: String]] {
        var result: [[String: String]] = []
        
        // 尝试初始化设备列表
        if bluetoothDevices.isEmpty {
            // 只在第一次使用时初始化
            NSLog("\(TAG): 第一次获取蓝牙设备，初始化设备列表")
        }
        
        // 获取可用的音频输出设备
        guard let outputs = audioSession.currentRoute.outputs as? [AVAudioSessionPortDescription] else {
            NSLog("\(TAG): 无法获取当前音频输出设备")
            return result
        }
        
        NSLog("\(TAG): 当前音频路由包含 \(outputs.count) 个输出设备")
        
        // 过滤蓝牙相关设备
        for output in outputs {
            NSLog("\(TAG): 检查音频输出设备: \(output.portName), 类型: \(output.portType.rawValue)")
            
            if output.portType == .bluetoothA2DP || output.portType == .bluetoothHFP || output.portType == .bluetoothLE {
                let device: [String: String] = [
                    "name": output.portName,
                    "address": output.uid // iOS 使用 UID 作为设备标识符
                ]
                result.append(device)
                NSLog("\(TAG): 添加蓝牙设备: \(output.portName)")
            }
        }
        
        return result
    }
    
    // 监听蓝牙设备连接/断开
    @objc func startBluetoothDeviceMonitoring() {
        // 注册音频会话通知
        NotificationCenter.default.addObserver(
            self, 
            selector: #selector(handleRouteChange(_:)),
            name: AVAudioSession.routeChangeNotification,
            object: nil
        )
        
        // 注册蓝牙状态变化通知
        NotificationCenter.default.addObserver(
            self,
            selector: #selector(handleBluetoothStateChange(_:)),
            name: NSNotification.Name(rawValue: "CBCentralManagerDidUpdateStateNotification"),
            object: nil
        )
    }
    
    // 处理音频路由变化
    @objc private func handleRouteChange(_ notification: Notification) {
        guard let userInfo = notification.userInfo,
              let reasonValue = userInfo[AVAudioSessionRouteChangeReasonKey] as? UInt,
              let reason = AVAudioSession.RouteChangeReason(rawValue: reasonValue) else {
            return
        }
        
        // 获取当前设备
        let currentDevices = getConnectedAudioDevices()
        
        // 检查原因
        switch reason {
        case .newDeviceAvailable:
            // 新设备已连接 - 查找新增的设备
            for device in currentDevices {
                if !deviceExistsInCache(device: device) {
                    // 找到新设备
                    NSLog("\(TAG): 新的音频设备已连接: \(device["name"] ?? "未知设备")")
                    
                    // 添加到缓存
                    bluetoothDevices.append(device)
                    
                    // 发送设备连接事件
                    sendDeviceConnectedEvent(device: device)
                }
            }
            
        case .oldDeviceUnavailable:
            // 设备已断开 - 查找从缓存中移除的设备
            var devicesToRemove: [[String: String]] = []
            
            for cachedDevice in bluetoothDevices {
                if !deviceExistsInList(device: cachedDevice, list: currentDevices) {
                    // 设备已断开
                    NSLog("\(TAG): 音频设备已断开: \(cachedDevice["name"] ?? "未知设备")")
                    devicesToRemove.append(cachedDevice)
                    
                    // 发送设备断开事件
                    sendDeviceDisconnectedEvent(device: cachedDevice)
                }
            }
            
            // 从缓存中移除断开的设备
            for device in devicesToRemove {
                if let index = bluetoothDevices.firstIndex(where: { $0["address"] == device["address"] }) {
                    bluetoothDevices.remove(at: index)
                }
            }
            
        default:
            break
        }
    }
    
    // 处理蓝牙状态变化
    @objc private func handleBluetoothStateChange(_ notification: Notification) {
        guard let manager = centralManager else { return }
        
        var stateString = "unknown"
        
        switch manager.state {
        case .poweredOn:
            stateString = "on"
            NSLog("\(TAG): 蓝牙状态变化: 已启用")
        case .poweredOff:
            stateString = "off"
            NSLog("\(TAG): 蓝牙状态变化: 已关闭")
            // 清空设备列表
            bluetoothDevices.removeAll()
        case .resetting:
            stateString = "resetting"
            NSLog("\(TAG): 蓝牙状态变化: 正在重置")
        case .unauthorized:
            stateString = "unauthorized"
            NSLog("\(TAG): 蓝牙状态变化: 未授权")
        case .unsupported:
            stateString = "unsupported"
            NSLog("\(TAG): 蓝牙状态变化: 不支持")
        case .unknown:
            stateString = "unknown"
            NSLog("\(TAG): 蓝牙状态变化: 未知")
        @unknown default:
            stateString = "unknown"
            NSLog("\(TAG): 蓝牙状态变化: 未知(default)")
        }
        
        NSLog("\(TAG): 发送蓝牙状态变化事件: \(stateString)")
        
        // 发送蓝牙状态变化事件
        if let callback = deviceEventCallback {
            let event: [String: Any] = [
                "type": "bluetoothStateChanged",
                "state": stateString,
                "timestamp": Int(Date().timeIntervalSince1970 * 1000)
            ]
            callback(event)
        }
    }
    
    // 发送设备连接事件
    private func sendDeviceConnectedEvent(device: [String: String]) {
        if let callback = deviceEventCallback, 
           let name = device["name"], 
           let address = device["address"] {
            
            let deviceMap: [String: Any] = [
                "name": name,
                "address": address,
                "type": "a2dp" // iOS 默认认为是 A2DP 设备
            ]
            
            let event: [String: Any] = [
                "type": "deviceConnected",
                "device": deviceMap,
                "timestamp": Int(Date().timeIntervalSince1970 * 1000)
            ]
            
            callback(event)
        }
    }
    
    // 发送设备断开事件
    private func sendDeviceDisconnectedEvent(device: [String: String]) {
        if let callback = deviceEventCallback, 
           let name = device["name"], 
           let address = device["address"] {
            
            let deviceMap: [String: Any] = [
                "name": name,
                "address": address,
                "type": "a2dp" // iOS 默认认为是 A2DP 设备
            ]
            
            let event: [String: Any] = [
                "type": "deviceDisconnected",
                "device": deviceMap,
                "timestamp": Int(Date().timeIntervalSince1970 * 1000)
            ]
            
            callback(event)
        }
    }
    
    // 检查设备是否存在于缓存中
    private func deviceExistsInCache(device: [String: String]) -> Bool {
        return deviceExistsInList(device: device, list: bluetoothDevices)
    }
    
    // 检查设备是否存在于列表中
    private func deviceExistsInList(device: [String: String], list: [[String: String]]) -> Bool {
        guard let address = device["address"] else { return false }
        return list.contains { $0["address"] == address }
    }
    
    // 停止监听
    @objc func stopBluetoothDeviceMonitoring() {
        NotificationCenter.default.removeObserver(self, name: AVAudioSession.routeChangeNotification, object: nil)
        NotificationCenter.default.removeObserver(self, name: NSNotification.Name(rawValue: "CBCentralManagerDidUpdateStateNotification"), object: nil)
    }
    
    // 释放资源
    @objc func dispose() {
        stopBluetoothDeviceMonitoring()
        deviceEventCallback = nil
    }
    
    // 打开系统设置
    @objc func openSettings() -> Bool {
        NSLog("\(TAG): 尝试打开应用设置")
        if let url = URL(string: UIApplication.openSettingsURLString) {
            if UIApplication.shared.canOpenURL(url) {
                UIApplication.shared.open(url, options: [:], completionHandler: nil)
                return true
            }
        }
        return false
    }
    
    // 打开蓝牙设置（iOS 只能打开系统设置，无法直接跳转到蓝牙设置）
    @objc func openBluetoothSettings() -> Bool {
        // 在 iOS 10+ 上直接跳转到蓝牙设置页面
        if #available(iOS 10.0, *) {
            NSLog("\(TAG): 尝试使用 URL Scheme 打开蓝牙设置")
            if let url = URL(string: "App-prefs:root=Bluetooth") {
                if UIApplication.shared.canOpenURL(url) {
                    UIApplication.shared.open(url, options: [:], completionHandler: nil)
                    return true
                }
            }
        }
        
        // 如果无法直接跳转到蓝牙设置，则打开一般设置
        return openSettings()
    }
}