import Foundation

// MARK: - Connection

extension DuooomiBleSDK {

    /// 连接到指定设备。
    ///
    /// 内部会停止扫描、启动协议监听。成功后 `sdk.btState = .connected`，`sdk.connectedDevice` 写入；
    /// delegate `didConnectDevice` 回调到达。后续可调用 `getVersion` / `getDeviceInfo` / `bind` 等。
    ///
    /// - Parameters:
    ///   - deviceId: 设备 UUID（从 `discoveredDevices.id` 取，对应 `CBPeripheral.identifier.uuidString`）
    ///   - completion: 回调 `Result<DiscoveredDevice, Error>`
    ///     - 成功：连接上的 `DiscoveredDevice`
    ///     - 失败：`.connectionFailed(...)` / `.serviceNotFound` / `.characteristicNotFound`
    ///       / `.bluetoothNotPoweredOn(...)` / `.permissionDenied`
    public func connect(deviceId: String, completion: @escaping (Result<DiscoveredDevice, Error>) -> Void) {
        stopScan()
        btState = .connecting
        BleLog.i("Connecting to \(deviceId)...", "Connect")

        bleClient.connect(deviceId: deviceId) { [weak self] result in
            guard let self = self else { return }
            switch result {
            case .success(let peripheral):
                self.protocolService.startListening()

                let device = DiscoveredDevice(
                    id: peripheral.identifier.uuidString,
                    name: peripheral.name,
                    rssi: 0
                )
                self.connectedDevice = device
                self.btState = .connected
                BleLog.i("Connected: \(device.id)", "Connect")
                completion(.success(device))

            case .failure(let error):
                self.btState = .idle
                self.error = error.localizedDescription
                BleLog.e("Connect failed: \(error.localizedDescription)", "Connect")
                completion(.failure(error))
            }
        }
    }

    /// 断开当前 BLE 连接。
    ///
    /// 同步清空 `sdk.connectedDevice` / `deviceInfo` / `version` / `isActivated`，停止协议监听，
    /// 取消所有 pending RPC 回调（这些回调会收到 `.notConnected` 失败）。
    ///
    /// - Parameter completion: 回调 `Result<Void, Error>`
    ///   - 成功：已断开
    ///   - 失败：CoreBluetooth 底层错误（极少见）
    public func disconnect(completion: @escaping (Result<Void, Error>) -> Void) {
        btState = .disconnecting
        BleLog.i("Disconnect requested", "Connect")
        protocolService.stopListening()
        cancelAllPending(error: DuooomiBleError.notConnected)

        bleClient.disconnect { [weak self] result in
            guard let self = self else { return }
            if case .failure(let error) = result {
                self.error = error.localizedDescription
                BleLog.e("Disconnect error: \(error.localizedDescription)", "Connect")
            }

            self.connectedDevice = nil
            self.deviceInfo = nil
            self.version = ""
            self.isActivated = false
            self.btState = .disconnected
            BleLog.i("Disconnected", "Connect")
            completion(result)
        }
    }

    /// 返回 iOS 系统当前已连接的、和本 SDK 服务 UUID 匹配的设备列表。
    ///
    /// 用于断网后重启 App、设备仍在系统蓝牙连接列表里的快速恢复场景。
    /// 不需要先 `scan()`，对每个返回的 `DiscoveredDevice.id` 直接 `connect(deviceId:)` 即可。
    ///
    /// - Returns: 系统已连接的 `DiscoveredDevice` 数组（可能为空）
    public func getConnectedDevices() -> [DiscoveredDevice] {
        let list = bleClient.retrieveConnectedDevices()
        BleLog.d("System-connected devices: \(list.count)", "Connect")
        return list
    }
}