import Foundation
import ExternalAccessory
import CoreBluetooth

/// 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 turningOn = "turningOn"
    case turningOff = "turningOff"
}

/// 经典蓝牙助手类，负责iOS上的蓝牙设备管理
class ClassicBluetoothHelper: NSObject {
    private let TAG = "ClassicBluetoothHelper"
    
    // 状态监控相关
    private var isMonitoring = false
    private var stateCallback: ((BluetoothEventType, [String: Any]) -> Void)?
    
    // 用于监控蓝牙系统状态
    private var centralManager: CBCentralManager?
    
    // 通知观察者
    private var accessoryConnectionObserver: NSObjectProtocol?
    private var accessoryDisconnectionObserver: NSObjectProtocol?
    
    override init() {
        super.init()
        centralManager = CBCentralManager(delegate: nil, queue: nil, options: [CBCentralManagerOptionShowPowerAlertKey: false])
    }
    
    deinit {
        stopBluetoothStateMonitoring()
    }
    
    /// 检查蓝牙是否启用
    func isBluetoothEnabled() -> Bool {
        guard let centralManager = centralManager else { return false }
        return centralManager.state == .poweredOn
    }
    
    /// 获取已连接的蓝牙设备
    /// - Parameter completion: 完成回调
    func getConnectedDevices(completion: @escaping ([[String: String]], Error?) -> Void) {
        // 获取所有已连接的外部配件
        let accessoryManager = EAAccessoryManager.shared()
        let connectedAccessories = accessoryManager.connectedAccessories
        
        // 将配件转换为设备信息数组
        let devices = connectedAccessories.map { accessory -> [String: String] in
            return [
                "name": accessory.name,
                "address": accessory.serialNumber // iOS使用序列号作为唯一标识
            ]
        }
        
        // 返回结果
        completion(devices, nil)
    }
    
    /// 开始监听蓝牙状态变化
    /// - Parameter callback: 状态变化回调
    func startBluetoothStateMonitoring(callback: @escaping (BluetoothEventType, [String: Any]) -> Void) {
        self.stateCallback = callback
        
        if !isMonitoring {
            isMonitoring = true
            
            // 设置蓝牙中央管理器代理
            centralManager?.delegate = self
            
            // 注册蓝牙配件连接/断开通知
            let notificationCenter = NotificationCenter.default
            
            // 观察配件连接
            accessoryConnectionObserver = notificationCenter.addObserver(
                forName: NSNotification.Name.EAAccessoryDidConnect,
                object: nil,
                queue: nil
            ) { [weak self] notification in
                guard let self = self,
                      let accessory = notification.userInfo?[EAAccessoryKey] as? EAAccessory else {
                    return
                }
                
                let device: [String: String] = [
                    "name": accessory.name,
                    "address": accessory.serialNumber
                ]
                
                self.stateCallback?(.deviceConnected, ["device": device])
            }
            
            // 观察配件断开
            accessoryDisconnectionObserver = notificationCenter.addObserver(
                forName: NSNotification.Name.EAAccessoryDidDisconnect,
                object: nil,
                queue: nil
            ) { [weak self] notification in
                guard let self = self,
                      let accessory = notification.userInfo?[EAAccessoryKey] as? EAAccessory else {
                    return
                }
                
                let device: [String: String] = [
                    "name": accessory.name,
                    "address": accessory.serialNumber
                ]
                
                self.stateCallback?(.deviceDisconnected, ["device": device])
            }
            
            // 开始监视配件变化
            EAAccessoryManager.shared().registerForLocalNotifications()
        }
    }
    
    /// 停止监听蓝牙状态变化
    func stopBluetoothStateMonitoring() {
        if isMonitoring {
            isMonitoring = false
            
            // 移除蓝牙中央管理器代理
            centralManager?.delegate = nil
            
            // 注销配件通知观察者
            if let observer = accessoryConnectionObserver {
                NotificationCenter.default.removeObserver(observer)
                accessoryConnectionObserver = nil
            }
            
            if let observer = accessoryDisconnectionObserver {
                NotificationCenter.default.removeObserver(observer)
                accessoryDisconnectionObserver = nil
            }
            
            // 停止监视配件变化
            EAAccessoryManager.shared().unregisterForLocalNotifications()
        }
        
        // 清除回调
        stateCallback = nil
    }
    
    /// 报告当前蓝牙状态
    func reportCurrentBluetoothState() {
        guard let centralManager = centralManager else { return }
        
        let state: BluetoothState
        
        switch centralManager.state {
        case .poweredOn:
            state = .on
        case .poweredOff:
            state = .off
        case .resetting:
            state = .turningOff // 最接近的近似值
        case .unauthorized, .unsupported:
            state = .off // 功能上等同于关闭
        default:
            state = .unknown
        }
        
        stateCallback?(.stateChanged, ["state": state.rawValue])
    }
}

// MARK: - CBCentralManagerDelegate
extension ClassicBluetoothHelper: CBCentralManagerDelegate {
    func centralManagerDidUpdateState(_ central: CBCentralManager) {
        let state: BluetoothState
        
        switch central.state {
        case .poweredOn:
            state = .on
        case .poweredOff:
            state = .off
        case .resetting:
            state = .turningOff
        case .unauthorized, .unsupported:
            state = .off
        default:
            state = .unknown
        }
        
        stateCallback?(.stateChanged, ["state": state.rawValue])
    }
}