import { BatteryStatus, IBatteryInstrumentation } from '@lenovo-software/lsa-clients-common';
import { Logger } from '../common/logger';

export class BatteryInstrumentation implements IBatteryInstrumentation {
    private logger = Logger.getInstance();
    private batteryStatus: BatteryStatus = new BatteryStatus();

    constructor() {
        // Start battery instrumentation
        this.startBatteryInstrumentation();
    }
    public async getCurrentBatteryStatus(): Promise<BatteryStatus> {
        this.logger.logMessage(`Current battery status.: ${JSON.stringify(this.batteryStatus)}`);
        return Promise.resolve(this.batteryStatus);
    }

    /**
     * Starts battery instrumentation and bind battery listeners
     */
    private async startBatteryInstrumentation(): Promise<void> {
        if ('getBattery' in navigator) {
            // @ts-ignore
            const battery = await navigator.getBattery(); //returns BatteryManager
            this.monitorBattery(battery);

            this.logger.logMessage(`Battery instrumentation started.`);
        } else {
            // Battery not supported or battery no present
            this.logger.logMessage(`Battery not supported or battery no present`);
        }
    }

    /**
     * Updates battery status values
     *
     * @param battery
     */
    private updateBatteryStatus(battery: any): void {
        this.batteryStatus.charging = battery.charging;
        this.batteryStatus.level = battery.level * 100;
        this.batteryStatus.dischargingTime = battery.dischargingTime;
    }

    /**
     * Function to monitor battery events and update the states of battery
     *
     * @param battery Battery Information
     *
     */
    private monitorBattery(battery: any): void {
        this.updateBatteryStatus(battery);
        // Monitor for futher updates.
        battery.addEventListener('levelchange', () => this.updateBatteryStatus(battery));
        battery.addEventListener('chargingchange', () => this.updateBatteryStatus(battery));
        battery.addEventListener('dischargingtimechange', () => this.updateBatteryStatus(battery));
    }
}