'use strict';
const electron = require('electron');
const app = electron.app; 
const log = require('./log.js');
const logLevels = require('./enums/logLevels.js');
const { getMainWindow, setIsAutoReload, getIsOnline } = require('./windowMgr');
const { getConfigField } = require('./config');

const memoryRefreshThreshold = 60 * 60 * 1000;
const maxIdleTime = 4 * 60 * 60 * 1000;
const memoryRefreshInterval = 60 * 60 * 1000;
const cpuUsageThreshold = 5;

let isInMeeting = false;
let canReload = true;
let preloadMemory;
let preloadWindow;

// once a minute
setInterval(gatherMemory, 1000 * 60);

/**
 * Gathers system memory and logs it to the remote system
 */
function gatherMemory() {
    let appMetrics = app.getAppMetrics();
    log.send(logLevels.INFO, `Current App Metrics -> ${JSON.stringify(appMetrics)}`);
}

/**
 * Method that checks memory usage every minute
 * and verify if the user in inactive if so it reloads the
 * application to free up some memory consumption
 */
function optimizeMemory() {

    if (!preloadMemory.cpuUsage) {
        log.send(logLevels.INFO, `cpu usage not available`);
        return;
    }

    const cpuUsagePercentage = preloadMemory.cpuUsage.percentCPUUsage;
    const activeNetworkRequest = preloadMemory.activeRequests === 0;

    electron.powerMonitor.querySystemIdleTime((time) => {
        const idleTime = time * 1000;
        if (cpuUsagePercentage <= cpuUsageThreshold
            && !isInMeeting
            && getIsOnline()
            && canReload
            && idleTime > maxIdleTime
            && activeNetworkRequest
        ) {
            getConfigField('memoryRefresh')
                .then((enabled) => {
                    if (enabled) {
                        const mainWindow = getMainWindow();
    
                        if (mainWindow && !mainWindow.isDestroyed()) {
                            setIsAutoReload(true);
                            log.send(logLevels.INFO, `Reloading the app to optimize memory usage as 
                            memory consumption is no longer detectable 
                            CPU usage percentage was ${preloadMemory.cpuUsage.percentCPUUsage} 
                            user was in a meeting? ${isInMeeting}
                            pending network request on the client was ${preloadMemory.activeRequests}
                            is network online? ${getIsOnline()}`);
                            mainWindow.reload();
    
                            // do not refresh for another 1hrs
                            canReload = false;
                            setTimeout(() => {
                                canReload = true;
                            }, memoryRefreshThreshold);
                        }
                    } else {
                        log.send(logLevels.INFO, `Memory refresh not enabled by the user so Not Reloading the app`);
                    }
                });
        } else {
            log.send(logLevels.INFO, `Not Reloading the app as
                            application was refreshed less than a hour ago? ${canReload ? 'no' : 'yes'}
                            memory consumption is no longer detectable
                            CPU usage percentage was ${preloadMemory.cpuUsage.percentCPUUsage} 
                            user was in a meeting? ${isInMeeting}
                            pending network request on the client was ${preloadMemory.activeRequests}
                            is network online? ${getIsOnline()}`);
        }
    });  
}

/**
 * Sets the current user meeting status
 * @param meetingStatus - Whether user is in an active meeting
 */
function setIsInMeeting(meetingStatus) {
    isInMeeting = meetingStatus;
}

/**
 * Sets preload memory info and calls optimize memory func
 *
 * @param activeRequests - pending active network requests on the client
 */
function setPreloadMemoryInfo(activeRequests) {
    log.send(logLevels.INFO, 'Memory info received from preload process now running optimize memory logic');
    const cpuUsage = process.getCPUUsage();
    preloadMemory = { cpuUsage, activeRequests };
    optimizeMemory();
}

/**
 * Sets the preload window
 *
 * @param win - preload window
 */
function setPreloadWindow(win) {
    log.send(logLevels.INFO, 'Preload window registered');
    preloadWindow = win;
}

/**
 * Request memory info from the registered preload window
 * which invokes the optimize memory func
 */
function requestMemoryInfo() {
    if (preloadWindow) {
        log.send(logLevels.INFO, 'Requesting memory information from the preload script');
        preloadWindow.send('memory-info-request');
    }
}

/**
 * Requests memory info from the renderer every 4 hrs
 */
setInterval(() => {
    requestMemoryInfo();
}, memoryRefreshInterval);

module.exports = {
    setIsInMeeting,
    setPreloadMemoryInfo,
    setPreloadWindow,
};