// This file handles the room canvas DOM manipulation
// Functions includes:
// - initCanvas (initialize the canvas)
// - renderCanvasUpdate (render a canvas update)
// - getPlacementData (get the necessary data to place a pixel)
// - toggleTooltip (toggle the tooltip and display the pixel's information)

import $ from "jquery";
import { getPixelInfo } from ".";
import { getStudent } from "../../students";

const canvasContainer = $("#canvas-container")?.[0];
const canvas = $("#canvas")?.[0];
const canvasCtx = canvas.getContext("2d");
const selector = $("#selector")?.[0];

const positionTooltip = $("#position-tooltip")?.[0];
const tooltip = $("#tooltip")?.[0];
const colorPicker = $("#color-picker")?.[0];
const colorWheelContainer = $("#color-wheel-container")?.[0];
const colorWheel = $("#color-wheel")?.[0];

/**
 * Global variables
 */
let board, palette, selectedColorIdx;
let animation;

const zoomSpeed = 1 / 25;
let zoom = 2.5;

let x, y;
let cx = 0;
let cy = 0;
let target = { x: 0, y: 0 };
let isDrag = false;

/**
 * Returns the necessary data to place a pixel
 * @returns {{color: number, posX: number, posX: number}} the data
 */
export const getPlacementData = () => ({
    color: selectedColorIdx,
    posX: target.x,
    posY: target.y,
});

/**
 * Toggle the tooltip and display the pixel's information
 * @param {boolean} state
 */
export const toggleTooltip = async (state = false) => {
    tooltip.style.display = state ? "flex" : "none";

    if (state) {
        const pixelInfo = await getPixelInfo();
        const uid = pixelInfo.placedByUid;
        const placeDate = new Date(pixelInfo.timestamp);

        if (!pixelInfo) {
            throw new Error(
                'An error occured while hitting the "/rooms/epi-place/canvas/pixels" endpoint',
            );
        }

        const studentInfo = await getStudent(uid);

        if (!studentInfo) {
            throw new Error(
                'An error occured while hitting the "/students/:id" endpoint',
            );
        }

        document.getElementById("tooltip-time").innerHTML =
            placeDate.toLocaleTimeString();
        document.getElementById("tooltip-date").innerHTML =
            placeDate.toLocaleDateString();
        document
            .getElementById("tooltip-info-avatar")
            .setAttribute(
                "src",
                studentInfo.avatarURL ?? "/default-avatar.png",
            );
        document.getElementById("tooltip-info-quote").innerHTML =
            studentInfo.quote;
        document.getElementById("tooltip-info-login").innerHTML =
            studentInfo.login;
        // FIXME: You should implement or call a function to get the pixel's information
        // and display it. Make use of target.x and target.y to get the pixel's position.
    }
};

/**
 * Calculate the target position according to the top left corner of the canvas
 * @param {*} event
 * @returns {x: number, y: number} the target position
 */
const calculateTarget = (event) => {
    const rect = canvas.getBoundingClientRect();
    const scaleX = canvas.width / rect.width;
    const scaleY = canvas.height / rect.height;
    const canvasLeft = rect.left + window.pageXOffset;
    const canvasTop = rect.top + window.pageYOffset;

    return {
        x: Math.floor(
            ((event?.pageX ?? window.innerWidth / 2) - canvasLeft) * scaleX,
        ),
        y: Math.floor(
            ((event?.pageY ?? window.innerHeight / 2) - canvasTop) * scaleY,
        ),
    };
};

/**
 * Update the position tooltip
 * @param {*} event
 */
const positionUpdate = (event) => positionDisplay(calculateTarget(event));

/**
 * Update the position tooltip
 * @param {{x: number, y: number}} target
 */
const positionDisplay = ({ x, y }) => {
    positionTooltip.innerText = `X=${x} Y=${y}`;
    canvas.style.transform = `translate(${cx}px, ${cy}px) scale(${zoom})`;

    // We add the canvas.width * zoom to make cx and cy positive
    let selectorX = cx + canvas.width * zoom;
    let selectorY = cy + canvas.height * zoom;

    // Make odd canvas align
    if (canvas.width % 2 !== 0) {
        selectorX += zoom / 2;
        selectorY += zoom / 2;
    }

    // Find the translate
    selectorX %= zoom;
    selectorY %= zoom;

    // Center selector on the pixel
    selectorX -= zoom / 2;
    selectorY -= zoom / 2;

    selector.style.transform = `translate(${selectorX}px, ${selectorY}px) scale(${zoom})`;
};

// Toggle the color wheel on click on the color picker
colorPicker.addEventListener("click", () => {
    const state = colorWheelContainer.style.display;

    colorWheelContainer.style.display =
        !state || state === "none" ? "block" : "none";
});

/**
 * Transform #RRGGBB to 0xBBGGRRAA
 * @param {string} hex
 * @returns {number} the 32 bits color
 */
const transformHexTo32Bits = (hex) => {
    const reverse = hex.substring(1).match(/.{2}/g).reverse().join("");

    return parseInt(`0xFF${reverse}`, 16);
};

/**
 * Render the canvas
 * @param {number[]} pixels
 * @param {string[]} colors
 */
const renderCanvas = (pixels, colors) => {
    const img = new ImageData(canvas.width, canvas.height);
    const data = new Uint32Array(img.data.buffer);

    board = pixels;
    palette = colors;
    for (let i = 0; i < pixels.length; i++) {
        data[i] = transformHexTo32Bits(colors[pixels[i]]);
    }

    canvasCtx.putImageData(img, 0, 0);
    canvasCtx.imageSmoothingEnabled = false;
    canvas.style.imageRendering = "pixelated";

    // Remove all the colors from the color wheel
    while (colorWheel.firstChild) {
        colorWheel.removeChild(colorWheel.firstChild);
    }

    // Add the colors to the color wheel
    for (let i = 0; i < colors.length; i++) {
        const btn = document.createElement("button");

        colorWheel.appendChild(btn);

        btn.addEventListener("click", () => {
            selectedColorIdx = i;
            colorPicker.style.color = colors[i];
            colorPicker.style.border = `${colors[i]} 0.1rem solid`;
        });

        btn.style.backgroundColor = colors[i];
    }
};

/**
 * Initialize the canvas
 * @param {*} roomConfig
 * @param {number[]} pixels
 */
export const initCanvas = (roomConfig, pixels) => {
    const canvasDimensions = roomConfig.metadata.canvasDimensions;

    canvas.width = canvasDimensions;
    canvas.height = canvasDimensions;

    positionDisplay({ x: canvasDimensions / 2, y: canvasDimensions / 2 });
    selectedColorIdx = 0;

    const roomColors = roomConfig.settings.roomColors.split(",");

    colorPicker.style.color = roomColors[0];
    colorPicker.style.border = `${roomColors[0]} 0.1rem solid`;

    renderCanvas(pixels, roomColors);
};

/**
 * Update the canvas
 * @param {string} color
 * @param {number} x
 * @param {number} y
 */
export const renderCanvasUpdate = (color, x, y) => {
    const img = new ImageData(canvas.width, canvas.height);
    const data = new Uint32Array(img.data.buffer);

    board[y * canvas.width + x] = color;
    for (let i = 0; i < board.length; i++) {
        data[i] = transformHexTo32Bits(palette[board[i]]);
    }

    canvasCtx.putImageData(img, 0, 0);
};

/**
 * Reset the canvas values
 */
export const resetValues = () => {
    zoom = 2.5;
    x = 0;
    y = 0;
    cx = 0;
    cy = 0;
    isDrag = false;

    positionDisplay({ x, y });
    colorWheelContainer.style.display = "none";
    toggleTooltip(false);
};

// Handle scroll on canvas
document.addEventListener("wheel", (e) => {
    // Make sure we're scrolling on the canvas or the body and not the UI
    if (e.target !== canvas && e.target !== canvasContainer) {
        return;
    }

    clearInterval(animation);
    toggleTooltip(false);

    const delta = Math.sign(e.deltaY) * zoomSpeed;
    const zoomFactor = 1 + delta;
    const oldZoom = zoom;
    const newZoom = Math.max(2.5, Math.min(40, oldZoom * zoomFactor));

    // Get the position of the mouse relative to the canvas
    const mouseX = e.clientX - window.innerWidth / 2;
    const mouseY = e.clientY - window.innerHeight / 2;

    // Calculate the new center point based on the mouse position
    const newCx = mouseX - (mouseX - cx) * (newZoom / oldZoom);
    const newCy = mouseY - (mouseY - cy) * (newZoom / oldZoom);

    if (newZoom !== oldZoom) {
        zoom = newZoom;
        cx = newCx;
        cy = newCy;
        positionUpdate();
    }
});

// Handle click and drag on canvas
document.addEventListener("mousedown", (e) => {
    // Make sure we're clicking on the canvas or the body and not the UI
    if (e.target !== canvas && e.target !== canvasContainer) {
        return;
    }

    e.preventDefault();

    // Ignore if right click
    if (e.button === 2) {
        return;
    }

    clearInterval(animation);

    isDrag = false;
    x = e.clientX;
    y = e.clientY;

    document.addEventListener("mousemove", mouseMove);
});

// Smooth animation
function easeOutQuart(t, b, c, d) {
    t /= d;
    t--;
    return -c * (t * t * t * t - 1) + b;
}

// Handle when the user releases the mouse
document.addEventListener("mouseup", (e) => {
    document.removeEventListener("mousemove", mouseMove);

    // Make sure we're clicking on the canvas or the body and not the UI
    if (e.target !== canvas && e.target !== canvasContainer) {
        return;
    }

    e.preventDefault();

    // Get the tile position
    target = calculateTarget(e);

    // Make sure we're clicking on the canvas
    if (
        target.x >= 0 &&
        target.x < canvas.width &&
        target.y >= 0 &&
        target.y < canvas.height
    ) {
        // We want to differentiate between a click and a drag
        // If it is a click, we want to move the camera to the clicked tile

        // We wait to see if the position changed
        // If it did not, we consider it a click
        if (!isDrag) {
            const duration = 1000;
            const startZoom = zoom;
            const endZoom = Math.max(15, Math.min(40, zoom));

            // Get the position of the click in relation to the center of the screen
            const clickX = e.clientX - window.innerWidth / 2;
            const clickY = e.clientY - window.innerHeight / 2;
            const canvaswidthzoom = canvas.width * startZoom;
            const canvasheightzoom = canvas.height * startZoom;
            const startx = (cx + canvaswidthzoom / 2) / startZoom;
            const starty = (cy + canvasheightzoom / 2) / startZoom;
            const endx = startx - clickX / startZoom;
            const endy = starty - clickY / startZoom;
            const endCx = endx * endZoom - (canvas.width / 2) * endZoom;
            const endCy = endy * endZoom - (canvas.height / 2) * endZoom;
            const startCx = cx;
            const startCy = cy;
            const startTime = Date.now();

            // If the distance is small enough, we just warp to it
            if (
                Math.abs(endCx - startCx) < 10 &&
                Math.abs(endCy - startCy) < 10
            ) {
                cx = endCx;
                cy = endCy;
                zoom = endZoom;
                canvas.style.transform = `translate(${cx}px, ${cy}px) scale(${zoom})`;
            } else {
                clearInterval(animation);

                animation = setInterval(() => {
                    const elapsed = Date.now() - startTime;

                    if (elapsed >= duration) {
                        clearInterval(animation);
                        return;
                    }

                    const t = elapsed / duration;

                    zoom = easeOutQuart(t, startZoom, endZoom - startZoom, 1);
                    cx = easeOutQuart(t, startCx, endCx - startCx, 1);
                    cy = easeOutQuart(t, startCy, endCy - startCy, 1);

                    positionUpdate();
                }, 10);
            }
        }

        // Toggle the tooltip if it is a click
        toggleTooltip(!isDrag);

        // Update the position of the tooltip
        positionDisplay(target);
    }
});

// Handle mouse move
const mouseMove = (e) => {
    e.preventDefault();

    toggleTooltip(false);
    positionUpdate();

    const dx = e.clientX - x;
    const dy = e.clientY - y;

    // For a big enough delta, we consider it a drag
    if (Math.abs(dx) > 0.5 || Math.abs(dy) > 0.5) {
        isDrag = true;
    }

    x = e.clientX;
    y = e.clientY;
    cx += dx;
    cy += dy;

    canvas.style.transform = `translate(${cx}px, ${cy}px) scale(${zoom})`;
};