import type {
	BleDevice,
	BleConnectionState,
	BleEvent,
	BleEventCallback,
	BleEventPayload,
	BleConnectOptionsExt,
	AutoBleInterfaces,
	SendDataPayload,
	BleOptions,
	MultiProtocolDevice,
	BleProtocolType,
	ScanDevicesOptions
} from '../interface.uts';
import { ProtocolHandler } from '../protocol_handler.uts';
import { BluetoothService } from '../interface.uts';
import { DeviceManager } from './device_manager.uts';

type RawProtocolHandler = {
	protocol?: BleProtocolType;
	scanDevices?: (options?: ScanDevicesOptions) => Promise<void>;
	connect?: (device: BleDevice, options?: BleConnectOptionsExt) => Promise<void>;
	disconnect?: (device: BleDevice) => Promise<void>;
	sendData?: (device: BleDevice, payload?: SendDataPayload, options?: BleOptions) => Promise<void>;
	autoConnect?: (device: BleDevice, options?: BleConnectOptionsExt) => Promise<AutoBleInterfaces>;
}

class DeviceContext {
	device: BleDevice;
	protocol: BleProtocolType;
	state: BleConnectionState;
	handler: ProtocolHandler;
	constructor(device: BleDevice, protocol: BleProtocolType, handler: ProtocolHandler) {
		this.device = device;
		this.protocol = protocol;
		this.state = 0;
		this.handler = handler;
	}
}

const deviceMap = new Map<string, DeviceContext>();
let activeProtocol: BleProtocolType = 'standard';
let activeHandler: ProtocolHandler | null = null;
const eventListeners = new Map<BleEvent, Set<BleEventCallback>>();
let defaultBluetoothService: BluetoothService | null = null;
let connectionHooked = false;

function emit(event: BleEvent, payload: BleEventPayload) {
	const listeners = eventListeners.get(event);
	if (listeners != null) {
		listeners.forEach(cb => {
			try { cb(payload); } catch (e) { }
		});
	}
}

class ProtocolHandlerWrapper extends ProtocolHandler {
	private _raw: RawProtocolHandler | null;
	constructor(raw?: RawProtocolHandler, bluetoothService?: BluetoothService) {
		super(bluetoothService);
		this._raw = raw ?? null;
	}
	override async scanDevices(options?: ScanDevicesOptions): Promise<void> {
		const rawTyped = this._raw;
		if (rawTyped != null && typeof rawTyped.scanDevices == 'function') {
			await rawTyped.scanDevices(options);
		}
		return;
	}
	override async connect(device: BleDevice, options?: BleConnectOptionsExt): Promise<void> {
		const rawTyped = this._raw;
		if (rawTyped != null && typeof rawTyped.connect == 'function') {
			await rawTyped.connect(device, options);
		}
		return;
	}
	override async disconnect(device: BleDevice): Promise<void> {
		const rawTyped = this._raw;
		if (rawTyped != null && typeof rawTyped.disconnect == 'function') {
			await rawTyped.disconnect(device);
		}
		return;
	}
	override async sendData(device: BleDevice, payload?: SendDataPayload, options?: BleOptions): Promise<void> {
		const rawTyped = this._raw;
		if (rawTyped != null && typeof rawTyped.sendData == 'function') {
			await rawTyped.sendData(device, payload, options);
		}
		return;
	}
	override async autoConnect(device: BleDevice, options?: BleConnectOptionsExt): Promise<AutoBleInterfaces> {
		const rawTyped = this._raw;
		if (rawTyped != null && typeof rawTyped.autoConnect == 'function') {
			return await rawTyped.autoConnect(device, options);
		}
		return { serviceId: '', writeCharId: '', notifyCharId: '' };
	}
}

function isRawProtocolHandler(x: any): boolean {
	if (x == null || typeof x !== 'object') return false;
	const r = x as Record<string, unknown>;
	if (typeof r['scanDevices'] == 'function') return true;
	if (typeof r['connect'] == 'function') return true;
	if (typeof r['disconnect'] == 'function') return true;
	if (typeof r['sendData'] == 'function') return true;
	if (typeof r['autoConnect'] == 'function') return true;
	if (typeof r['protocol'] == 'string') return true;
	return false;
}

function ensureConnectionHook() {
	if (connectionHooked) return;
	connectionHooked = true;
	const dm = DeviceManager.getInstance();
	dm.onConnectionStateChange((deviceId, state) => {
		let handled = false;
		deviceMap.forEach((ctx) => {
			if (ctx.device.deviceId == deviceId) {
				ctx.state = state;
				emit('connectionStateChanged', { event: 'connectionStateChanged', device: ctx.device, protocol: ctx.protocol, state });
				handled = true;
			}
		});
		if (!handled) {
			emit('connectionStateChanged', { event: 'connectionStateChanged', device: { deviceId, name: '', rssi: 0 }, protocol: activeProtocol, state });
		}
	});
}

export const registerProtocolHandler = (handler: any) => {
	if (handler == null) return;
	let proto: BleProtocolType = 'standard';
	if (handler instanceof ProtocolHandler) {
		try { proto = (handler as ProtocolHandler).protocol as BleProtocolType; } catch (e) { }
		activeHandler = handler as ProtocolHandler;
	} else if (isRawProtocolHandler(handler)) {
		try { proto = (handler as RawProtocolHandler).protocol as BleProtocolType; } catch (e) { }
		activeHandler = new ProtocolHandlerWrapper(handler as RawProtocolHandler, defaultBluetoothService);
		(activeHandler as ProtocolHandler).protocol = proto;
	} else {
		console.warn('[AKBLE][Harmony] registerProtocolHandler unsupported handler', handler);
		return;
	}
	activeProtocol = proto;
	ensureConnectionHook();
}

export const scanDevices = async (options?: ScanDevicesOptions): Promise<void> => {
	ensureDefaultProtocolHandler();
	if (activeHandler == null) {
		console.log('[AKBLE][Harmony] no active scan handler');
		return;
	}
	const handler = activeHandler as ProtocolHandler;
	const original = options ?? null;
	const scanOptions: ScanDevicesOptions = {} as ScanDevicesOptions;
	if (original != null) {
		if (original.protocols != null) scanOptions.protocols = original.protocols;
		if (original.optionalServices != null) scanOptions.optionalServices = original.optionalServices;
		if (original.timeout != null) scanOptions.timeout = original.timeout;
	}
	const userFound = original?.onDeviceFound ?? null;
	scanOptions.onDeviceFound = (device: BleDevice) => {
		emit('deviceFound', { event: 'deviceFound', device });
		if (userFound != null) {
			try { userFound(device); } catch (err) { }
		}
	};
	const userFinished = original?.onScanFinished ?? null;
	scanOptions.onScanFinished = () => {
		emit('scanFinished', { event: 'scanFinished' });
		if (userFinished != null) {
			try { userFinished(); } catch (err) { }
		}
	};
	try {
		await handler.scanDevices(scanOptions);
	} catch (e) {
		console.warn('[AKBLE][Harmony] scan handler error', e);
	}
}

export const connectDevice = async (deviceId: string, protocol: BleProtocolType, options?: BleConnectOptionsExt): Promise<void> => {
	const handler = activeHandler;
	if (handler == null) throw new Error('No protocol handler');
	const device: BleDevice = { deviceId, name: '', rssi: 0 };
	await handler.connect(device, options);
	const ctx = new DeviceContext(device, protocol, handler);
	ctx.state = 2;
	deviceMap.set(getDeviceKey(deviceId, protocol), ctx);
	emit('connectionStateChanged', { event: 'connectionStateChanged', device, protocol, state: 2 });
}

export const disconnectDevice = async (deviceId: string, protocol: BleProtocolType): Promise<void> => {
	const ctx = deviceMap.get(getDeviceKey(deviceId, protocol));
	if (ctx == null || ctx.handler == null) return;
	await ctx.handler.disconnect(ctx.device);
	ctx.state = 0;
	emit('connectionStateChanged', { event: 'connectionStateChanged', device: ctx.device, protocol, state: 0 });
	deviceMap.delete(getDeviceKey(deviceId, protocol));
}

export const sendData = async (payload: SendDataPayload, options?: BleOptions): Promise<void> => {
	const ctx = deviceMap.get(getDeviceKey(payload.deviceId, payload.protocol));
	if (ctx == null) throw new Error('Device not connected');
	if (ctx.handler == null) throw new Error('sendData not supported for this protocol');
	await ctx.handler.sendData(ctx.device, payload, options);
	emit('dataSent', { event: 'dataSent', device: ctx.device, protocol: payload.protocol, data: payload.data });
}

export const getConnectedDevices = (): MultiProtocolDevice[] => {
	const result: MultiProtocolDevice[] = [];
	deviceMap.forEach((ctx: DeviceContext) => {
		result.push({
			deviceId: ctx.device.deviceId,
			name: ctx.device.name,
			rssi: ctx.device.rssi,
			protocol: ctx.protocol
		});
	});
	return result;
}

export const getConnectionState = (deviceId: string, protocol: BleProtocolType): BleConnectionState => {
	const ctx = deviceMap.get(getDeviceKey(deviceId, protocol));
	if (ctx == null) return 0;
	return ctx.state;
}

export const on = (event: BleEvent, callback: BleEventCallback) => {
	if (!eventListeners.has(event)) eventListeners.set(event, new Set());
	eventListeners.get(event)!.add(callback);
}

export const off = (event: BleEvent, callback?: BleEventCallback) => {
	if (callback == null) {
		eventListeners.delete(event);
	} else {
		eventListeners.get(event)?.delete(callback as BleEventCallback);
	}
}

function getDeviceKey(deviceId: string, protocol: BleProtocolType): string {
	return `${deviceId}|${protocol}`;
}

export const autoConnect = async (deviceId: string, protocol: BleProtocolType, options?: BleConnectOptionsExt): Promise<AutoBleInterfaces> => {
	const handler = activeHandler;
	if (handler == null) throw new Error('autoConnect not supported for this protocol');
	const device: BleDevice = { deviceId, name: '', rssi: 0 };
	return await handler.autoConnect(device, options) as AutoBleInterfaces;
}

function ensureDefaultProtocolHandler(): void {
	if (activeHandler != null) return;
	const service = defaultBluetoothService;
	if (service == null) return;
	try {
		const dm = DeviceManager.getInstance();
		const raw: RawProtocolHandler = {
			protocol: 'standard',
			scanDevices: (options?: ScanDevicesOptions) => dm.startScan(options ?? {} as ScanDevicesOptions),
			connect: (device, options?: BleConnectOptionsExt) => dm.connectDevice(device.deviceId, options),
			disconnect: (device) => dm.disconnectDevice(device.deviceId),
			autoConnect: () => Promise.resolve({ serviceId: '', writeCharId: '', notifyCharId: '' })
		};
		const wrapper = new ProtocolHandlerWrapper(raw, service);
		activeHandler = wrapper;
		activeProtocol = raw.protocol as BleProtocolType;
		ensureConnectionHook();
		console.log('[AKBLE][Harmony] default protocol handler registered', activeProtocol);
	} catch (e) {
		console.warn('[AKBLE][Harmony] register default protocol handler failed', e);
	}
}

export const setDefaultBluetoothService = (service: BluetoothService) => {
	defaultBluetoothService = service;
	ensureDefaultProtocolHandler();
};