window.addEventListener("load", () => main());

const main = () => {
    // Video folder
    const videoFolder = "./videos";

    // TODO: Use JSON instead of hardcoded objects

    // Video list, as a list of ["filename", "extension"]
    const videos = {
        1: ["nameOfFirstVideo", "mp4"],
        2: ["nameOfSecondVideo", "mp4"],
        3: ["nameOfThirdVideo", "mp4"],
        4: ["nameOfFourthVideo", "mp4"],
    };

    /* Add option for each videos
     * For example:
     * {
     *   1: [2],
     *   2: [3, 4]
     * };
     *
     * The video 1 offer the option to redirect to the video 2
     * The video 2 offer the option to redirect to the video 3 and 4 */
    const tree = {
        1: [2],
        2: [3, 4],
    };

    // Main Element who will receive the videos
    const mainElement = document.getElementsByTagName("main").item(0);

    // Current video showed to the user
    let currentVideo;

    // Add property to the player
    currentVideo = document.createElement("video");
    currentVideo.controls = true;
    currentVideo.width = window.innerWidth - window.innerWidth / 4;
    currentVideo.style = "\
        display: block; \
        margin: auto;";

    // Init the page with the first video
    const firstVideo = 1;
    const source = document.createElement("source");
    source.type = `video/${videos[firstVideo][1]}`;

    currentVideo.appendChild(source);
    mainElement.appendChild(currentVideo);

    updateVideo(videoFolder, videos, tree, source, firstVideo);

    // TODO: Remove the current video and the buttons

    // TODO: Add function who go to the next video (used by the button's listener)
};

/**
 * Remove all buttons from an HTMLElement
 * @param {HTMLElement } parentButtons Parent element of the buttons
 */
const removeButtons = (parentButtons) => {
    const buttons = parentButtons.getElementsByTagName("button");
    for (let index = 0; index < buttons.length; index++) {
        parentButtons.removeChild(buttons[index]);
    }
};

/**
 * Update the video and the buttons
 * @param {string} videoFolder Directory's name who contains videos
 * @param {{number: string[]}} videosList List of videos filenames
 * @param {{int: int[]}} tree List of all the videos from videosList with the next possibles choices from the video
 * @param {HTMLSourceElement} source Current video
 * @param {number} newVideoId Video ID to add to the main element
 */
const updateVideo = (videoFolder, videosList, tree, source, newVideoId) => {
    const mainElement = source.parentElement.parentElement;
    source.src = `${videoFolder}/${videosList[newVideoId][0]}.${videosList[newVideoId][1]}`;

    if (tree[newVideoId]) {
        tree[newVideoId].forEach((nextVideoId, counter) => {
            const button = document.createElement("button");

            // TODO: Add custom label for the button redirection
            const textButton = "Choix n°";

            button.textContent = textButton + counter;

            button.addEventListener("click", () => {
                // Remove older buttons
                removeButtons(mainElement);

                // Update with the new video
                updateVideo(videoFolder, videosList, tree, source, nextVideoId);
            });

            mainElement.appendChild(button);
        });
    } else {
        removeButtons(mainElement);
        const endText = document.createElement("h2");
        endText.innerText = "Merci d'avoir regardé !";
        mainElement.appendChild(endText);
    }
};