expo-ble-app-demo/ble/services/DeviceInfoService.ts

import {BleProtocolService} from './BleProtocolService';
import {COMMAND_TYPES, RESPONSE_TYPES} from '../protocol/Constants';
import {DeviceInfo, ActivationStatus} from '../protocol/types';
import {Buffer} from 'buffer';

export class DeviceInfoService {
    private protocol = BleProtocolService.getInstance();
    private static instance: DeviceInfoService;
    private listeners: Map<string, Set<Function>> = new Map();

    private constructor() {
        this.protocol.addListener(RESPONSE_TYPES.DEVICE_INFO_REPORT, this.onDeviceInfo);
        this.protocol.addListener(RESPONSE_TYPES.ACTIVATION_STATUS, this.onActivationStatus);
    }

    public static getInstance(): DeviceInfoService {
        if (!DeviceInfoService.instance) {
            DeviceInfoService.instance = new DeviceInfoService();
        }
        return DeviceInfoService.instance;
    }

    private onDeviceInfo = (data: ArrayBuffer, deviceId: string) => {
        try {
            const str = Buffer.from(data).toString('utf-8');
            // Remove null characters if any
            const cleanStr = str.replace(/\0/g, '');
            const json = JSON.parse(cleanStr) as DeviceInfo;
            this.emit('deviceInfo', json);
        } catch (e) {
            console.error("Failed to parse device info", e);
        }
    }

    private onActivationStatus = (data: ArrayBuffer, deviceId: string) => {
        try {
            const str = Buffer.from(data).toString('utf-8');
            const cleanStr = str.replace(/\0/g, '');
            const json = JSON.parse(cleanStr) as ActivationStatus;
            this.emit('activationStatus', json);
        } catch (e) {
            console.error("Failed to parse activation status", e);
        }
    }

    public addListener(event: string, cb: Function) {
        if (!this.listeners.has(event)) this.listeners.set(event, new Set());
        this.listeners.get(event)!.add(cb);
    }

    public removeListener(event: string, cb: Function) {
        if (this.listeners.has(event)) {
            this.listeners.get(event)!.delete(cb);
        }
    }

    private emit(event: string, data: any) {
        this.listeners.get(event)?.forEach(cb => cb(data));
    }

    public async queryDeviceInfo(deviceId: string) {
        await this.protocol.send(deviceId, COMMAND_TYPES.DEVICE_INFO_SETTINGS, {
            type: COMMAND_TYPES.DEVICE_INFO_SETTINGS
        });
    }

    public async queryActivationStatus(deviceId: string) {
        await this.protocol.send(deviceId, COMMAND_TYPES.ACTIVATION_QUERY, {
            type: COMMAND_TYPES.ACTIVATION_QUERY
        });
    }

    public async queryDeviceVersion(deviceId: string) {
        await this.protocol.send(deviceId, COMMAND_TYPES.VERSION_QUERY, {type: COMMAND_TYPES.VERSION_QUERY})
    }
}