import type { BleService, BleCharacteristic, BleDataReceivedCallback, BleCharacteristicProperties, WriteCharacteristicOptions, AutoDiscoverAllResult } from '../interface.uts';
import { CBPeripheral, CBService, CBCharacteristic, CBCharacteristicWriteType } from 'CoreBluetooth';
import { Data, NSError } from 'Foundation';
import { DeviceManager } from './device_manager.uts';

function toUint8Array(value: Uint8Array | ArrayBuffer): Uint8Array {
	if (value instanceof Uint8Array) return value;
	return new Uint8Array(value);
}

function dataToUint8Array(data: Data | null): Uint8Array {
	if (data == null) return new Uint8Array(0);
	const base64 = data.base64EncodedString(options = 0);
	if (base64 == null) return new Uint8Array(0);
	const raw = atob(base64);
	const out = new Uint8Array(raw.length);
	for (let i = 0; i < raw.length; i++) {
		out[i] = raw.charCodeAt(i) & 0xff;
	}
	return out;
}

function uint8ArrayToData(bytes: Uint8Array): Data {
	if (bytes.length == 0) {
		return new Data();
	}
	let binary = '';
	for (let i = 0; i < bytes.length; i++) {
		binary += String.fromCharCode(bytes[i]);
	}
	const base64 = btoa(binary);
	const data = new Data(base64Encoded = base64);
	return data != null ? data! : new Data();
}

function iterateNSArray<T>(collection: any, handler: (item: T | null) => void) {
	if (collection == null) return;
	if (Array.isArray(collection)) {
		for (let i = 0; i < collection.length; i++) {
			handler(collection[i] as T);
		}
		return;
	}
	try {
		const count = collection.count as number;
		if (typeof count === 'number') {
			for (let i = 0; i < count; i++) {
				const item = collection.objectAtIndex(i);
				handler(item as T);
			}
			return;
		}
	} catch (e) { }
	try {
		const len = collection.length as number;
		if (typeof len === 'number') {
			for (let i = 0; i < len; i++) {
				handler(collection[i] as T);
			}
		}
	} catch (e2) { }
}

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

function makeCharProperties(flags: number): BleCharacteristicProperties {
	const read = (flags & 0x02) != 0;
	const write = (flags & 0x08) != 0;
	const notify = (flags & 0x10) != 0;
	const indicate = (flags & 0x20) != 0;
	const writeNoRsp = (flags & 0x04) != 0;
	return {
		read,
		write,
		notify,
		indicate,
		writeWithoutResponse: writeNoRsp,
		canRead: read,
		canWrite: write || writeNoRsp,
		canNotify: notify || indicate
	};
}

function getCharPropertiesValue(characteristic: CBCharacteristic): number {
	try {
		const anyProps = characteristic.properties as any;
		if (anyProps != null && anyProps.rawValue != null) {
			return Number(anyProps.rawValue);
		}
	} catch (e) { }
	try {
		return Number((characteristic as any).properties);
	} catch (e2) { }
	return 0;
}

export class ServiceManager {
	private static instance: ServiceManager | null = null;
	private services = new Map<string, BleService[]>();
	private characteristics = new Map<string, Map<string, BleCharacteristic[]>>();
	private serviceWaiters = new Map<string, ((list: BleService[] | null, error?: Error) => void)[]>();
	private characteristicWaiters = new Map<string, ((list: BleCharacteristic[] | null, error?: Error) => void)[]>();
	private pendingReads = new Map<string, PendingCallback>();
	private pendingWrites = new Map<string, PendingCallback>();
	private notifyCallbacks = new Map<string, BleDataReceivedCallback>();
	private deviceManager = DeviceManager.getInstance();

	private constructor() {}

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

	resetDiscoveryState(deviceId: string) {
		this.services.delete(deviceId);
		this.characteristics.forEach((_value, key) => {
			if (key.startsWith(deviceId + '|')) {
				this.characteristics.delete(key);
			}
		});
	}

	handleServicesDiscovered(peripheral: CBPeripheral, error: NSError | null) {
		const deviceId = peripheral.identifier.UUIDString;
		if (error != null) {
			const err = new Error('服务发现失败: ' + error.localizedDescription);
			this.resolveServiceWaiters(deviceId, null, err);
			return;
		}
		const list: BleService[] = [];
		const native = peripheral.services;
		iterateNSArray<CBService>(native, (svc) => {
			if (svc == null) return;
			const uuid = svc.UUID.UUIDString;
			list.push({ uuid, isPrimary: svc.isPrimary });
		});
		this.services.set(deviceId, list);
		this.resolveServiceWaiters(deviceId, list, null);
	}

	handleCharacteristicsDiscovered(peripheral: CBPeripheral, service: CBService, error: NSError | null) {
		const deviceId = peripheral.identifier.UUIDString;
		const serviceId = service.UUID.UUIDString;
		const key = this.characteristicKey(deviceId, serviceId);
		if (error != null) {
			const err = new Error('特征发现失败: ' + error.localizedDescription);
			this.resolveCharacteristicWaiters(key, null, err);
			return;
		}
		const list: BleCharacteristic[] = [];
		const chars = service.characteristics;
		iterateNSArray<CBCharacteristic>(chars, (ch) => {
			if (ch == null) return;
			const propsValue = getCharPropertiesValue(ch);
			const props = makeCharProperties(propsValue);
			list.push({
				uuid: ch.UUID.UUIDString,
				service: { uuid: serviceId, isPrimary: service.isPrimary },
				properties: props
			});
		});
		let map = this.characteristics.get(deviceId);
		if (map == null) {
			map = new Map<string, BleCharacteristic[]>();
			this.characteristics.set(deviceId, map);
		}
		map.set(serviceId, list);
		this.resolveCharacteristicWaiters(key, list, null);
	}

	handleCharacteristicValueUpdated(peripheral: CBPeripheral, characteristic: CBCharacteristic, error: NSError | null) {
		const deviceId = peripheral.identifier.UUIDString;
		const serviceId = characteristic.service.UUID.UUIDString;
		const charId = characteristic.UUID.UUIDString;
		const notifyKey = this.notifyKey(deviceId, serviceId, charId);
		const readKey = this.operationKey(deviceId, serviceId, charId, 'read');
		if (error != null) {
			const pending = this.pendingReads.get(readKey);
			if (pending != null) {
				this.pendingReads.delete(readKey);
				try { pending.reject(error); } catch (e) { }
			}
			return;
		}
		const bytes = dataToUint8Array(characteristic.value);
		const pending = this.pendingReads.get(readKey);
		if (pending != null) {
			this.pendingReads.delete(readKey);
			if (pending.timer != null) clearTimeout(pending.timer);
			try { pending.resolve(bytes.buffer as ArrayBuffer); } catch (e) { }
		}
		const cb = this.notifyCallbacks.get(notifyKey);
		if (cb != null) {
			try { cb(bytes); } catch (e) { }
		}
	}

	handleCharacteristicWrite(peripheral: CBPeripheral, characteristic: CBCharacteristic, error: NSError | null) {
		const deviceId = peripheral.identifier.UUIDString;
		const serviceId = characteristic.service.UUID.UUIDString;
		const charId = characteristic.UUID.UUIDString;
		const writeKey = this.operationKey(deviceId, serviceId, charId, 'write');
		const pending = this.pendingWrites.get(writeKey);
		if (pending == null) return;
		this.pendingWrites.delete(writeKey);
		if (pending.timer != null) clearTimeout(pending.timer);
		if (error != null) {
			try { pending.reject(error); } catch (e) { }
		} else {
			try { pending.resolve(true); } catch (e) { }
		}
	}

	handleNotificationState(peripheral: CBPeripheral, characteristic: CBCharacteristic, error: NSError | null) {
		if (error != null) {
			console.warn('[AKBLE][iOS] notify state change error', error.localizedDescription);
		}
	}

	getServices(deviceId: string, callback?: (services: BleService[] | null, error?: Error) => void): Promise<BleService[]> {
		const cached = this.services.get(deviceId);
		if (cached != null && cached.length > 0) {
			if (callback != null) callback(cached, null);
			return Promise.resolve(cached);
		}
		return new Promise((resolve, reject) => {
			this.enqueueServiceWaiter(deviceId, (list, err) => {
				if (err != null || list == null) {
					if (callback != null) callback(null, err ?? new Error('服务获取失败'));
					reject(err ?? new Error('服务获取失败'));
				} else {
					if (callback != null) callback(list, null);
					resolve(list);
				}
			});
			const peripheral = this.deviceManager.getPeripheral(deviceId);
			if (peripheral == null) {
				const err = new Error('设备未连接');
				this.resolveServiceWaiters(deviceId, null, err);
				return;
			}
			try {
				peripheral.discoverServices(serviceUUIDs = null);
			} catch (e) {
				const err = e instanceof Error ? e : new Error('服务发现失败');
				this.resolveServiceWaiters(deviceId, null, err);
			}
		});
	}

	getCharacteristics(deviceId: string, serviceId: string, callback?: (list: BleCharacteristic[] | null, error?: Error) => void): Promise<BleCharacteristic[]> {
		const cached = this.characteristics.get(deviceId)?.get(serviceId) ?? null;
		if (cached != null && cached.length > 0) {
			if (callback != null) callback(cached, null);
			return Promise.resolve(cached);
		}
		return new Promise((resolve, reject) => {
			const key = this.characteristicKey(deviceId, serviceId);
			this.enqueueCharacteristicWaiter(key, (list, err) => {
				if (err != null || list == null) {
					if (callback != null) callback(null, err ?? new Error('特征获取失败'));
					reject(err ?? new Error('特征获取失败'));
				} else {
					if (callback != null) callback(list, null);
					resolve(list);
				}
			});
			const peripheral = this.deviceManager.getPeripheral(deviceId);
			if (peripheral == null) {
				const err = new Error('设备未连接');
				this.resolveCharacteristicWaiters(key, null, err);
				return;
			}
			const service = this.findNativeService(peripheral, serviceId);
			if (service == null) {
				const err = new Error('未找到服务');
				this.resolveCharacteristicWaiters(key, null, err);
				return;
			}
			try {
				peripheral.discoverCharacteristics(characteristicUUIDs = null, forService = service);
			} catch (e) {
				const err = e instanceof Error ? e : new Error('特征发现失败');
				this.resolveCharacteristicWaiters(key, null, err);
			}
		});
	}

	async readCharacteristic(deviceId: string, serviceId: string, characteristicId: string): Promise<ArrayBuffer> {
		const peripheral = this.deviceManager.getPeripheral(deviceId);
		if (peripheral == null) throw new Error('设备未连接');
		const characteristic = this.findNativeCharacteristic(peripheral, serviceId, characteristicId);
		if (characteristic == null) throw new Error('未找到特征值');
		return new Promise<ArrayBuffer>((resolve, reject) => {
			const key = this.operationKey(deviceId, serviceId, characteristicId, 'read');
			const timer = setTimeout(() => {
				this.pendingReads.delete(key);
				reject(new Error('读取超时'));
			}, 10000);
			this.pendingReads.set(key, { resolve, reject, timer });
			try {
				peripheral.readValueForCharacteristic(characteristic);
			} catch (e) {
				clearTimeout(timer);
				this.pendingReads.delete(key);
				reject(e);
			}
		});
	}

	async writeCharacteristic(deviceId: string, serviceId: string, characteristicId: string, value: Uint8Array | ArrayBuffer, options?: WriteCharacteristicOptions): Promise<boolean> {
		const peripheral = this.deviceManager.getPeripheral(deviceId);
		if (peripheral == null) throw new Error('设备未连接');
		const characteristic = this.findNativeCharacteristic(peripheral, serviceId, characteristicId);
		if (characteristic == null) throw new Error('未找到特征值');
		const payload = uint8ArrayToData(toUint8Array(value));
		const waitForResponse = options?.waitForResponse ?? true;
		const key = this.operationKey(deviceId, serviceId, characteristicId, 'write');
		if (!waitForResponse) {
			try {
				peripheral.writeValue(payload, forCharacteristic = characteristic, type = CBCharacteristicWriteType.withoutResponse);
				return true;
			} catch (e) {
				throw e;
			}
		}
		return new Promise<boolean>((resolve, reject) => {
			const timer = setTimeout(() => {
				this.pendingWrites.delete(key);
				reject(new Error('写入超时'));
			}, options?.giveupTimeoutMs ?? 10000);
			this.pendingWrites.set(key, { resolve, reject, timer });
			try {
				peripheral.writeValue(payload, forCharacteristic = characteristic, type = CBCharacteristicWriteType.withResponse);
			} catch (e) {
				clearTimeout(timer);
				this.pendingWrites.delete(key);
				reject(e);
			}
		});
	}

	async subscribeCharacteristic(deviceId: string, serviceId: string, characteristicId: string, callback: BleDataReceivedCallback): Promise<void> {
		const peripheral = this.deviceManager.getPeripheral(deviceId);
		if (peripheral == null) throw new Error('设备未连接');
		const characteristic = this.findNativeCharacteristic(peripheral, serviceId, characteristicId);
		if (characteristic == null) throw new Error('未找到特征值');
		const key = this.notifyKey(deviceId, serviceId, characteristicId);
		this.notifyCallbacks.set(key, callback);
		try {
			peripheral.setNotifyValue(true, forCharacteristic = characteristic);
		} catch (e) {
			this.notifyCallbacks.delete(key);
			throw e;
		}
	}

	async unsubscribeCharacteristic(deviceId: string, serviceId: string, characteristicId: string): Promise<void> {
		const peripheral = this.deviceManager.getPeripheral(deviceId);
		if (peripheral == null) return;
		const characteristic = this.findNativeCharacteristic(peripheral, serviceId, characteristicId);
		if (characteristic == null) return;
		const key = this.notifyKey(deviceId, serviceId, characteristicId);
		this.notifyCallbacks.delete(key);
		try {
			peripheral.setNotifyValue(false, forCharacteristic = characteristic);
		} catch (e) {
			console.warn('[AKBLE][iOS] unsubscribe failed', e);
		}
	}

	async autoDiscoverAll(deviceId: string): Promise<AutoDiscoverAllResult> {
		const services = await this.getServices(deviceId);
		const allCharacteristics: BleCharacteristic[] = [];
		for (let i = 0; i < services.length; i++) {
			const svc = services[i];
			const chars = await this.getCharacteristics(deviceId, svc.uuid);
			for (let j = 0; j < chars.length; j++) {
				allCharacteristics.push(chars[j]);
			}
		}
		return { services, characteristics: allCharacteristics };
	}

	async subscribeAllNotifications(deviceId: string, callback: BleDataReceivedCallback): Promise<void> {
		const services = await this.getServices(deviceId);
		for (let i = 0; i < services.length; i++) {
			const svc = services[i];
			const chars = await this.getCharacteristics(deviceId, svc.uuid);
			for (let j = 0; j < chars.length; j++) {
				const charDef = chars[j];
				if (charDef.properties != null && (charDef.properties.notify || charDef.properties.indicate)) {
					try {
						await this.subscribeCharacteristic(deviceId, svc.uuid, charDef.uuid, callback);
					} catch (e) {
						console.warn('[AKBLE][iOS] subscribeAllNotifications failed', svc.uuid, charDef.uuid, e);
					}
				}
			}
		}
	}

	private enqueueServiceWaiter(deviceId: string, waiter: (list: BleService[] | null, error?: Error) => void) {
		let queue = this.serviceWaiters.get(deviceId);
		if (queue == null) {
			queue = [];
			this.serviceWaiters.set(deviceId, queue);
		}
		queue.push(waiter);
	}

	private enqueueCharacteristicWaiter(key: string, waiter: (list: BleCharacteristic[] | null, error?: Error) => void) {
		let queue = this.characteristicWaiters.get(key);
		if (queue == null) {
			queue = [];
			this.characteristicWaiters.set(key, queue);
		}
		queue.push(waiter);
	}

	private resolveServiceWaiters(deviceId: string, list: BleService[] | null, error: Error | null) {
		const queue = this.serviceWaiters.get(deviceId);
		if (queue == null) return;
		this.serviceWaiters.delete(deviceId);
		for (let i = 0; i < queue.length; i++) {
			const waiter = queue[i];
			try { waiter(list, error ?? undefined); } catch (e) { }
		}
	}

	private resolveCharacteristicWaiters(key: string, list: BleCharacteristic[] | null, error: Error | null) {
		const queue = this.characteristicWaiters.get(key);
		if (queue == null) return;
		this.characteristicWaiters.delete(key);
		for (let i = 0; i < queue.length; i++) {
			const waiter = queue[i];
			try { waiter(list, error ?? undefined); } catch (e) { }
		}
	}

	private findNativeService(peripheral: CBPeripheral, serviceId: string): CBService | null {
		const services = peripheral.services;
		let found: CBService | null = null;
		iterateNSArray<CBService>(services, (svc) => {
			if (found != null) return;
			if (svc != null && svc.UUID.UUIDString == serviceId) found = svc;
		});
		if (found != null) return found;
		return null;
	}

	private findNativeCharacteristic(peripheral: CBPeripheral, serviceId: string, characteristicId: string): CBCharacteristic | null {
		const service = this.findNativeService(peripheral, serviceId);
		if (service == null) return null;
		const chars = service.characteristics;
		let found: CBCharacteristic | null = null;
		iterateNSArray<CBCharacteristic>(chars, (ch) => {
			if (found != null) return;
			if (ch != null && ch.UUID.UUIDString == characteristicId) found = ch;
		});
		if (found != null) return found;
		return null;
	}

	private notifyKey(deviceId: string, serviceId: string, charId: string): string {
		return `${deviceId}|${serviceId}|${charId}|notify`;
	}

	private operationKey(deviceId: string, serviceId: string, charId: string, op: string): string {
		return `${deviceId}|${serviceId}|${charId}|${op}`;
	}

	private characteristicKey(deviceId: string, serviceId: string): string {
		return `${deviceId}|${serviceId}`;
	}
}