const apiURL = new URL('http://localhost:8000');
const wsURL = new URL('ws://localhost:8000/ws/v1/pixels');

class ColorBar {
    #colorPicker;

    constructor() {
        this.#colorPicker = document.querySelector('#color-picker');
    }

    get hex() {
        return this.#colorPicker.value.substring(1, 7);
    };

    get decimal() {
        return parseInt(this.hex, 16);
    };
}

class BattleField {
    WIDTH$U = 64;
    HEIGHT$U = 32;
    PIXEL_SIZE$PX = 96;
    BORDER_SIZE$PX = 4;
    BACKGROUND_COLOR$HEX = '#FFFFFFFF';
    BORDER_COLOR$HEX = '#00000010';

    #colorBar;
    #main;
    #canvas;
    #context;

    constructor() {
        this.#colorBar = new ColorBar();
        this.#main = document.querySelector('#main');
        this.#canvas = document.querySelector('#battlefield');
        this.#context = this.#canvas.getContext('2d');
        this.#canvas.width = this.WIDTH$U * this.PIXEL_SIZE$PX;
        this.#canvas.height = this.HEIGHT$U * this.PIXEL_SIZE$PX;

        this.#main.onpointerdown = (event) => {
            const movement = () => Math.sqrt(Math.pow(xd$px, 2) + Math.pow(yd$px, 2)) / window.innerWidth > .005;

            let x0$pct = event.pageX * 100 / window.innerWidth;
            let y0$pct = event.pageY * 100 / window.innerHeight;
            let x0$px = event.pageX;
            let y0$px = event.pageY;
            let xd$px = 0;
            let yd$px = 0;

            this.#main.onpointermove = (event) => {
                if (movement()) document.body.classList.add('grabbing');
                this.x += event.pageX * 100 / window.innerWidth - x0$pct;
                this.y += event.pageY * 100 / window.innerHeight - y0$pct;
                x0$pct = event.pageX * 100 / window.innerWidth;
                y0$pct = event.pageY * 100 / window.innerHeight;
                xd$px += Math.abs(x0$px - event.pageX);
                yd$px += Math.abs(y0$px - event.pageY);
            };

            this.#main.onpointerup = () => {
                this.#main.onpointermove = null;
                this.#main.onpointerup = null;
                document.body.classList.remove('grabbing');
                if (movement()) return;
                const xhr = new XMLHttpRequest();
                const url = new URL(apiURL);
                url.pathname = '/api/v1/pixels';
                xhr.open('PUT', url);
                xhr.setRequestHeader('Content-Type', 'application/json; charset=UTF-8');
                xhr.send(
                    JSON.stringify({
                        x: Math.floor((event.pageX - this.#canvas.offsetLeft) / this.scale / this.PIXEL_SIZE$PX + this.WIDTH$U / 2),
                        y: Math.floor((event.pageY - this.#canvas.offsetTop) / this.scale / this.PIXEL_SIZE$PX + this.HEIGHT$U / 2),
                        color: this.#colorBar.decimal,
                    })
                );
            };
        };

        document.onwheel = (event) => {
            if (event.deltaY > 0) this.scale += .1;
            if (event.deltaY < 0) this.scale -= .1;
        };

        for (let x = 0; x < this.WIDTH$U; x++) {
            for (let y = 0; y < this.HEIGHT$U; y++) {
                this.setPixel(
                    x,
                    y,
                    this.BACKGROUND_COLOR$HEX,
                );
            }
        }
    };

    get x() {
        return Number(this.#canvas.style.left.match(/^(.*)%$/)[1]);
    };

    set x(value) {
        // const min$pct = -100 * this.scale;
        // const max$pct = 100 * this.scale + 100;
        // if (value < min$pct) {
        //     this.#canvas.style.left = `${min$pct}%`;
        //     return;
        // }
        // if (value > max$pct) {
        //     this.#canvas.style.left = `${max$pct}%`;
        //     return;
        // }
        this.#canvas.style.left = `${value}%`;
    };

    get y() {
        return Number(this.#canvas.style.top.match(/^(.*)%$/)[1]);
    };

    set y(value) {
        // const min$pct = -100 * this.scale;
        // const max$pct = 100 * this.scale + 100;
        // if (value < min$pct) {
        //     this.#canvas.style.top = `${min$pct}%`;
        //     return;
        // }
        // if (value > max$pct) {
        //     this.#canvas.style.top = `${max$pct}%`;
        //     return;
        // }
        this.#canvas.style.top = `${value}%`;
    };

    get scale() {
        return Number(this.#canvas.style.scale);
    };

    set scale(value) {
        if (value >= .2 && value <= 1) {
            this.#canvas.style.scale = String(value);

            // TODO(костыль)
            // this.x = this.x;
            // this.y = this.y;
        }
    };

    fill() {
        const xhr = new XMLHttpRequest();
        const url = new URL(apiURL);
        url.pathname = '/api/v1/pixels';
        xhr.onload = () => {
            if (xhr.status !== 200) return;
            const response = JSON.parse(xhr.response);
            for (const pixel of response.pixels) {
                this.setPixel(
                    pixel.x,
                    pixel.y,
                    decimalToHex(pixel.color),
                );
            }
        };
        xhr.open('GET', url);
        xhr.send();
    };

    setPixel(x, y, color) {
        let leftPadding = x === 0 ? this.BORDER_SIZE$PX : 0;
        let topPadding = y === 0 ? this.BORDER_SIZE$PX : 0;
        this.#context.fillStyle = this.BACKGROUND_COLOR$HEX;
        this.#context.fillRect(
            x * this.PIXEL_SIZE$PX,
            y * this.PIXEL_SIZE$PX,
            this.PIXEL_SIZE$PX,
            this.PIXEL_SIZE$PX,
        );
        this.#context.fillStyle = this.BORDER_COLOR$HEX;
        this.#context.fillRect(
            x * this.PIXEL_SIZE$PX,
            y * this.PIXEL_SIZE$PX,
            this.PIXEL_SIZE$PX,
            this.PIXEL_SIZE$PX,
        );
        this.#context.fillStyle = color;
        this.#context.fillRect(
            x * this.PIXEL_SIZE$PX + leftPadding,
            y * this.PIXEL_SIZE$PX + topPadding,
            this.PIXEL_SIZE$PX - this.BORDER_SIZE$PX - leftPadding,
            this.PIXEL_SIZE$PX - this.BORDER_SIZE$PX - topPadding,
        );
    };
}

const decimalToHex = (decimal) => `#${decimal.toString(16)}`;

window.addEventListener('DOMContentLoaded', () => {
    const battlefield = new BattleField();
    battlefield.fill();

    const wsConnect = () => {
        const ws = new WebSocket(wsURL);

        ws.onmessage = (event) => {
            const pixel = JSON.parse(event.data);
            battlefield.setPixel(
                pixel.x,
                pixel.y,
                decimalToHex(pixel.color),
            );
        };

        ws.onclose = (event) => {
            setTimeout(wsConnect, 5000);
        }

        ws.onerror = () => {
            ws.close();
        };
    };

    wsConnect();
});