import type { BleDevice, BleConnectOptionsExt, BleConnectionState, BleConnectionStateChangeCallback, ScanDevicesOptions } from '../interface.uts';
import { CBCentralManager, CBPeripheral, CBService, CBCharacteristic, CBCentralManagerDelegate, CBPeripheralDelegate, CBManagerState, CBUUID } from 'CoreBluetooth';
import { NSObject, NSDictionary, NSNumber, NSError, NSUUID } from 'Foundation';
import { DispatchQueue } from 'Dispatch';
import { ServiceManager } from './service_manager.uts';

type PendingConnect = {
	resolve: () => void;
	reject: (err?: any) => void;
	timer?: number;
};

class PendingConnectImpl implements PendingConnect {
	resolve: () => void;
	reject: (err?: any) => void;
	timer?: number;
	constructor(resolve: () => void, reject: (err?: any) => void, timer?: number) {
		this.resolve = resolve;
		this.reject = reject;
		this.timer = timer;
	}
}

class CentralDelegate extends NSObject implements CBCentralManagerDelegate, CBPeripheralDelegate {
	private owner: DeviceManager;
	constructor(owner: DeviceManager) {
		super();
		this.owner = owner;
	}
	override centralManagerDidUpdateState(central: CBCentralManager): void {
		this.owner.handleCentralStateUpdate(central.state);
	}
	override centralManager(central: CBCentralManager, didDiscoverPeripheral peripheral: CBPeripheral, advertisementData: NSDictionary<any, any>, RSSI: NSNumber): void {
		this.owner.handleDiscovered(peripheral, RSSI);
	}
	override centralManager(central: CBCentralManager, didConnectPeripheral peripheral: CBPeripheral): void {
		this.owner.handleConnected(peripheral);
	}
	override centralManager(central: CBCentralManager, didFailToConnectPeripheral peripheral: CBPeripheral, error: NSError | null): void {
		this.owner.handleConnectFailed(peripheral, error);
	}
	override centralManager(central: CBCentralManager, didDisconnectPeripheral peripheral: CBPeripheral, error: NSError | null): void {
		this.owner.handleDisconnected(peripheral, error);
	}
	override peripheral(peripheral: CBPeripheral, didDiscoverServices error: NSError | null): void {
		ServiceManager.getInstance().handleServicesDiscovered(peripheral, error);
	}
	override peripheral(peripheral: CBPeripheral, didDiscoverCharacteristicsForService service: CBService, error: NSError | null): void {
		ServiceManager.getInstance().handleCharacteristicsDiscovered(peripheral, service, error);
	}
	override peripheral(peripheral: CBPeripheral, didUpdateValueForCharacteristic characteristic: CBCharacteristic, error: NSError | null): void {
		ServiceManager.getInstance().handleCharacteristicValueUpdated(peripheral, characteristic, error);
	}
	override peripheral(peripheral: CBPeripheral, didWriteValueForCharacteristic characteristic: CBCharacteristic, error: NSError | null): void {
		ServiceManager.getInstance().handleCharacteristicWrite(peripheral, characteristic, error);
	}
	override peripheral(peripheral: CBPeripheral, didUpdateNotificationStateForCharacteristic characteristic: CBCharacteristic, error: NSError | null): void {
		ServiceManager.getInstance().handleNotificationState(peripheral, characteristic, error);
	}
}

export class DeviceManager {
	private static instance: DeviceManager | null = null;
	private central: CBCentralManager | null = null;
	private delegate: CentralDelegate | null = null;
	private queue: DispatchQueue | null = null;
	private devices = new Map<string, BleDevice>();
	private peripherals = new Map<string, CBPeripheral>();
	private connectionStates = new Map<string, BleConnectionState>();
	private connectionStateChangeListeners: BleConnectionStateChangeCallback[] = [];
	private pendingConnects = new Map<string, PendingConnect>();
	private centralState: number = CBManagerState.unknown;
	private scanOptions: ScanDevicesOptions | null = null;
	private scanTimer: number | null = null;
	private isScanning: boolean = false;
	private pendingScan: boolean = false;
	private pendingScanOptions: ScanDevicesOptions | null = null;

	private constructor() {}

	static getInstance(): DeviceManager {
		if (DeviceManager.instance == null) {
			DeviceManager.instance = new DeviceManager();
		}
		return DeviceManager.instance!;
	}

	private ensureCentral(): CBCentralManager {
		if (this.central != null) return this.central!;
		if (this.queue == null) {
			this.queue = DispatchQueue.main;
		}
		this.delegate = new CentralDelegate(this);
		this.central = new CBCentralManager(delegate = this.delegate!, queue = this.queue);
		if (this.central != null) {
			this.centralState = this.central!.state;
		}
		return this.central!;
	}

	handleCentralStateUpdate(state: number) {
		this.centralState = state;
		if (state == CBManagerState.poweredOn) {
			if (this.pendingScan) {
				const opts = this.pendingScanOptions ?? {} as ScanDevicesOptions;
				this.pendingScan = false;
				this.pendingScanOptions = null;
				this.beginScan(opts);
			}
		} else if (state == CBManagerState.poweredOff) {
			this.stopScanInternal();
		}
	}

	startScan(options: ScanDevicesOptions): void {
		const central = this.ensureCentral();
		const opts = options ?? {} as ScanDevicesOptions;
		this.scanOptions = opts;
		if (this.centralState != CBManagerState.poweredOn) {
			this.pendingScan = true;
			this.pendingScanOptions = opts;
			console.warn('[AKBLE][iOS] Bluetooth not powered on yet, waiting for state update');
			return;
		}
		this.beginScan(opts, central);
	}

	private beginScan(options: ScanDevicesOptions, central?: CBCentralManager | null) {
		const mgr = central ?? this.central ?? this.ensureCentral();
		if (this.isScanning) {
			this.stopScanInternal();
		}
		const serviceIds = options.optionalServices ?? null;
		let serviceUUIDs: CBUUID[] | null = null;
		if (serviceIds != null && serviceIds.length > 0) {
			serviceUUIDs = [];
			for (let i = 0; i < serviceIds.length; i++) {
				const sid = serviceIds[i];
				try {
					const uuid = CBUUID.UUIDWithString(sid);
					if (uuid != null) serviceUUIDs.push(uuid!);
				} catch (e) {
					console.warn('[AKBLE][iOS] invalid service uuid', sid, e);
				}
			}
			if (serviceUUIDs.length == 0) serviceUUIDs = null;
		}
		try {
			mgr.scanForPeripherals(withServices = serviceUUIDs, options = null);
			this.isScanning = true;
			if (options.timeout != null && options.timeout > 0) {
				this.scanTimer = setTimeout(() => {
					this.stopScanInternal();
				}, options.timeout);
			}
		} catch (e) {
			console.error('[AKBLE][iOS] scanForPeripherals failed', e);
		}
	}

	stopScan(): void {
		this.stopScanInternal();
	}

	private stopScanInternal() {
		if (!this.isScanning) return;
		try {
			this.central?.stopScan();
		} catch (e) {
			console.warn('[AKBLE][iOS] stopScan failed', e);
		}
		this.isScanning = false;
		if (this.scanTimer != null) {
			clearTimeout(this.scanTimer);
			this.scanTimer = null;
		}
		const finished = this.scanOptions?.onScanFinished;
		this.scanOptions = null;
		if (finished != null) {
			try { finished(); } catch (e) { }
		}
	}

	handleDiscovered(peripheral: CBPeripheral, RSSI: NSNumber) {
		const deviceId = peripheral.identifier.UUIDString;
		let rssiValue = 0;
		if (RSSI != null) {
			try {
				rssiValue = RSSI.intValue;
			} catch (e) {
				rssiValue = Number(RSSI);
			}
		}
		let bleDevice = this.devices.get(deviceId);
		if (bleDevice == null) {
			bleDevice = { deviceId, name: peripheral.name ?? 'Unknown', rssi: rssiValue, lastSeen: Date.now() };
			this.devices.set(deviceId, bleDevice);
		} else {
			bleDevice.rssi = rssiValue;
			bleDevice.name = peripheral.name ?? bleDevice.name;
			bleDevice.lastSeen = Date.now();
		}
		this.peripherals.set(deviceId, peripheral);
		peripheral.delegate = this.delegate;
		const onFound = this.scanOptions?.onDeviceFound;
		if (onFound != null) {
			try { onFound(bleDevice); } catch (e) { }
		}
	}

	async connectDevice(deviceId: string, options?: BleConnectOptionsExt): Promise<void> {
		const central = this.ensureCentral();
		const timeout = options?.timeout ?? 15000;
		const peripheral = this.obtainPeripheral(deviceId, central);
		if (peripheral == null) {
			throw new Error('未找到设备');
		}
		this.connectionStates.set(deviceId, 1);
		this.emitConnectionStateChange(deviceId, 1);
		return new Promise<void>((resolve, reject) => {
			const timer = setTimeout(() => {
				this.pendingConnects.delete(deviceId);
				this.connectionStates.set(deviceId, 0);
				this.emitConnectionStateChange(deviceId, 0);
				reject(new Error('连接超时'));
			}, timeout);
			const resolveAdapter = () => {
				clearTimeout(timer);
				this.pendingConnects.delete(deviceId);
				resolve();
			};
			const rejectAdapter = (err?: any) => {
				clearTimeout(timer);
				this.pendingConnects.delete(deviceId);
				reject(err);
			};
			this.pendingConnects.set(deviceId, new PendingConnectImpl(resolveAdapter, rejectAdapter, timer));
			try {
				peripheral.delegate = this.delegate;
				central.connect(peripheral = peripheral, options = null);
			} catch (e) {
				clearTimeout(timer);
				this.pendingConnects.delete(deviceId);
				this.connectionStates.set(deviceId, 0);
				this.emitConnectionStateChange(deviceId, 0);
				reject(e);
			}
		});
	}

	async disconnectDevice(deviceId: string): Promise<void> {
		const central = this.ensureCentral();
		const peripheral = this.peripherals.get(deviceId);
		if (peripheral == null) {
			return;
		}
		try {
			central.cancelPeripheralConnection(peripheral = peripheral);
		} catch (e) {
			console.warn('[AKBLE][iOS] cancelPeripheralConnection failed', e);
		}
		this.connectionStates.set(deviceId, 0);
		this.emitConnectionStateChange(deviceId, 0);
	}

	handleConnected(peripheral: CBPeripheral) {
		const deviceId = peripheral.identifier.UUIDString;
		const pending = this.pendingConnects.get(deviceId);
		if (pending != null) {
			const timer = pending.timer;
			if (timer != null) clearTimeout(timer);
			try { pending.resolve(); } catch (e) { }
			this.pendingConnects.delete(deviceId);
		}
		this.connectionStates.set(deviceId, 2);
		this.emitConnectionStateChange(deviceId, 2);
		this.peripherals.set(deviceId, peripheral);
		peripheral.delegate = this.delegate;
		try {
			peripheral.discoverServices(serviceUUIDs = null);
		} catch (e) {
			console.warn('[AKBLE][iOS] discoverServices failed', e);
		}
	}

	handleConnectFailed(peripheral: CBPeripheral, error: NSError | null) {
		const deviceId = peripheral.identifier.UUIDString;
		const pending = this.pendingConnects.get(deviceId);
		if (pending != null) {
			const timer = pending.timer;
			if (timer != null) clearTimeout(timer);
			try { pending.reject(error ?? new Error('连接失败')); } catch (e) { }
			this.pendingConnects.delete(deviceId);
		}
		this.connectionStates.set(deviceId, 0);
		this.emitConnectionStateChange(deviceId, 0);
	}

	handleDisconnected(peripheral: CBPeripheral, _error: NSError | null) {
		const deviceId = peripheral.identifier.UUIDString;
		this.connectionStates.set(deviceId, 0);
		this.emitConnectionStateChange(deviceId, 0);
	}

	getConnectedDevices(): BleDevice[] {
		const result: BleDevice[] = [];
		this.devices.forEach((device, deviceId) => {
			if (this.connectionStates.get(deviceId) == 2) {
				result.push(device);
			}
		});
		return result;
	}

	onConnectionStateChange(listener: BleConnectionStateChangeCallback) {
		this.connectionStateChangeListeners.push(listener);
	}

	private emitConnectionStateChange(deviceId: string, state: BleConnectionState) {
		for (let i = 0; i < this.connectionStateChangeListeners.length; i++) {
			const listener = this.connectionStateChangeListeners[i];
			try { listener(deviceId, state); } catch (e) { }
		}
	}

	getPeripheral(deviceId: string): CBPeripheral | null {
		return this.peripherals.get(deviceId) ?? null;
	}

	private obtainPeripheral(deviceId: string, central: CBCentralManager): CBPeripheral | null {
		let peripheral = this.peripherals.get(deviceId) ?? null;
		if (peripheral != null) return peripheral;
		try {
			const uuid = new NSUUID(UUIDString = deviceId);
			const list = central.retrievePeripherals(withIdentifiers = [uuid]);
			if (list != null && list.length > 0) {
				peripheral = list[0];
				if (peripheral != null) {
					this.peripherals.set(deviceId, peripheral!);
					peripheral!.delegate = this.delegate;
				}
			}
		} catch (e) {
			console.warn('[AKBLE][iOS] retrievePeripherals failed', e);
		}
		return peripheral;
	}
}