content.js

/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

const TIMER_SIZES = ["10px", "12px", "14px", "16px"];

const TIMER_LOCATIONS = [
    ["0px", "auto", "0px", "auto"],
    ["0px", "auto", "auto", "0px"],
    ["auto", "0px", "auto", "0px"],
    ["auto", "0px", "0px", "auto"]
];

var gTimer;
var gAlert;

// Update timer
//
function updateTimer(text, size, location) {
    if (!text) {
        if (gTimer) {
            // Hide timer
            gTimer.hidden = true;
        }
    } else {
        if (!gTimer) {
            // Create timer
            gTimer = document.createElement("div");
            gTimer.setAttribute("class", "leechblock-timer");
            gTimer.addEventListener("dblclick", function (e) { this.style.display = "none"; });
        }

        if (!document.body.contains(gTimer)) {
            // Insert timer at end of document body
            document.body.appendChild(gTimer);
        }

        // Set text
        gTimer.innerText = text;

        // Set size
        if (size >= 0 && size < TIMER_SIZES.length) {
            gTimer.style.fontSize = TIMER_SIZES[size];
        }

        // Set location
        if (location >= 0 && location < TIMER_LOCATIONS.length) {
            gTimer.style.top = TIMER_LOCATIONS[location][0];
            gTimer.style.bottom = TIMER_LOCATIONS[location][1];
            gTimer.style.left = TIMER_LOCATIONS[location][2];
            gTimer.style.right = TIMER_LOCATIONS[location][3];
        }

        // Show timer
        gTimer.hidden = false;
    }
}

// Show alert message
//
function showAlert(text) {
    let alertBox, alertIcon, alertText;

    if (!gAlert) {
        // Create container
        gAlert = document.createElement("div");
        gAlert.setAttribute("class", "leechblock-alert-container");
        document.body.appendChild(gAlert);

        // Create message box
        alertBox = document.createElement("div");
        alertBox.setAttribute("class", "leechblock-alert-box");
        alertBox.addEventListener("click", hideAlert);
        alertIcon = document.createElement("div");
        alertIcon.setAttribute("class", "leechblock-alert-icon");
        alertBox.appendChild(alertIcon);
        alertText = document.createElement("div");
        alertText.setAttribute("class", "leechblock-alert-text");
        alertBox.appendChild(alertText);
        gAlert.appendChild(alertBox);
    }

    // Set text
    alertText.innerText = text;

    // Show timer
    gAlert.style.display = "flex";
}

// Hide alert message
//
function hideAlert() {
    if (gAlert) {
        gAlert.style.display = "none";
    }
}

// Check page for keyword(s)
//
function checkKeyword(keywordRE) {
    // Get all text nodes in document
    let textNodes = document.evaluate(
        "//text()", document, null, XPathResult.ORDERED_NODE_SNAPSHOT_TYPE, null);

    //console.log("Checking " + textNodes.snapshotLength + " text node(s) for keyword(s)...");

    for (let i = 0; i < textNodes.snapshotLength; i++) {
        if (keywordRE && keywordRE.test(textNodes.snapshotItem(i).data)) {
            return true; // keyword(s) found
        }
    }

    return false; // keyword(s) not found
}

// Apply filter
//
function applyFilter(name) {
    document.body.style.filter = `${name}(100%)`;
}

/*** EVENT HANDLERS BEGIN HERE ***/

function handleMessage(message, sender, sendResponse) {
    if (message.type == "timer") {
        updateTimer(message.text, message.size, message.location);
    } else if (message.type == "alert") {
        showAlert(message.text);
    } else if (message.type == "keyword") {
        let keyword = checkKeyword(message.keywordRE);
        sendResponse(keyword);
    } else if (message.type == "filter") {
        applyFilter(message.name);
    }
}

browser.runtime.onMessage.addListener(handleMessage);