/**
 * statsviewcontroller.js stores the JavaScript functions to update the stats page
 * when the websocket updates.
 */

const BUSY_SERVER_BOUND = 2;
const VERY_BUSY_SERVER_BOUND = 3;

const MEDIUM_USE_BOUND = 100; // operations per 10 seconds
const HIGH_USE_BOUND = 300;

const serverTrafficMessages = {
    0: 'Not Busy',
    1: 'Busy',
    2: 'Very Busy',
};

/**
 * userDataComparator sorts the users based on the rate
 *
 * @param {*} user1 the first user to compare
 * @param {*} user2 the second user to comapre
 * @returns an integer indiciating which user should come first
 */
function userDataComparator(user1, user2) {
    if (user1.rate < user2.rate) {
        return 1;
    }
    if (user1.rate > user2.rate) {
        return -1;
    }
    return 0;
}

/**
 * calculateServerTraffic() returns an integer corresponding
 * to the current traffic that can be used to get the message
 * from "serverTrafficMessages"
 *
 * @param {*} data the incoming data from the backend
 * @returns an integer where 0 is not busy, 1 is busy, and 2 is very busy.
 */
function calculateServerTraffic(data) {
    const currentTraffic = data.connectedUsers.length;

    let serverTraffic = 0;
    if (currentTraffic < BUSY_SERVER_BOUND) {
        serverTraffic = 0;
    } else if (currentTraffic >= BUSY_SERVER_BOUND && currentTraffic < VERY_BUSY_SERVER_BOUND) {
        serverTraffic = 1;
    } else {
        serverTraffic = 2;
    }

    return serverTraffic;
}

/**
 * getUserRateColor determines what color the user's rate should
 * be on the front end
 * @param {*} rate the operations per time interval for a specific user
 * @returns a string representing the color to make the user rate
 */
function getUserRateColor(rate) {
    if (rate < MEDIUM_USE_BOUND) {
        return 'black';
    }
    if (rate >= MEDIUM_USE_BOUND && rate < HIGH_USE_BOUND) {
        return 'orange';
    }
    if (rate >= HIGH_USE_BOUND) {
        return 'red';
    }
    return 'black';
}

/**
 * handleStatsUpdats() is called when new data is received from the backend
 * from a websocket event. The method updates the HTML site to reflect the
 * updated data
 *
 * @param {*} data the data coming from the backend.
 */
function handleStatsUpdate(data) {
    let userListInnerHTML = '';
    data.connectedUsers.sort(userDataComparator);
    data.connectedUsers.forEach(userData => {
        const userRateColor = getUserRateColor(userData.rate);
        const userEntry = `<p>${userData.time}</p>
            <p>${userData.username}</p>
            <p>Operations: ${userData.operations}</p>
            <p style="color:${userRateColor}">Rate: ${userData.rate} operations per last 10 seconds</p>
            `; // user data comes as last 10 seconds but it can be adjusted in DastStats.ts and websocket.ts
        userListInnerHTML += '<li class="none">' + userEntry + '</li>';
    });

    document.getElementById('connection-count').innerHTML = `Current Connections: ${data.connectedUsers.length}`;
    document.getElementById('connected-user-list').innerHTML = userListInnerHTML;

    const serverTraffic = calculateServerTraffic(data);
    let serverTrafficMessage = 'Not Busy';
    switch (serverTraffic) {
        case 0:
            serverTrafficMessage = 'Not Busy';
            break;
        case 1:
            serverTrafficMessage = 'Busy';
            break;
        case 2:
            serverTrafficMessage = 'Very Busy';
            break;
        default:
    }
    document.getElementById('stats-traffic-message').className = 'stats-server-status-item stats-server-status-' + serverTraffic;
    document.getElementById('stats-traffic-message').innerHTML = `<p>${serverTrafficMessage}</p>`;
}