import init, {
    World,
    Pane,
    FullTile,
    Signal,
    available_tiles,
} from "/stackline-wasm/pkg/stackline_wasm.js";

let promises = [];
promises.push(init());

const canvas = document.getElementById("main-canvas");
const ctx = canvas.getContext("2d");

let font = new FontFace("Stackline Classic", "url(\"/font/StacklineClassic-Medium.otf\")");
promises.push(font.load());
await Promise.all(promises);

font = await font.loaded;
document.fonts.add(font);

let world = World.new();
let cx = 0;
let cy = 0;
let zoom = 1;

let pane = Pane.empty(5, 5);
world.set_pane("main", pane);

let available = available_tiles();
console.log(available);
for (let n = 0; n < available.length; n++) {
    world.set(
        n % 5,
        ~~(n / 5),
        new FullTile(available[n])
    );
}

console.log(world.toString());

resize();
window.addEventListener("resize", resize);
window.requestAnimationFrame(loop);

function draw() {
    let zoom_factor = Math.ceil(Math.pow(2, zoom));
    let tile_size = 10 * zoom_factor;
    ctx.fillStyle = "#202027";
    ctx.fillRect(0, 0, canvas.width, canvas.height);

    let panes = [];

    for (let name of world.panes()) {
        let pane = world.get_pane(name);

        ctx.strokeStyle = "rgba(128, 128, 128, 0.5)";
        ctx.lineWidth = zoom_factor;

        panes.push({
            x: pane.x,
            y: pane.y,
            width: pane.width,
            height: pane.height
        });

        ctx.strokeRect(
            Math.round(pane.x * tile_size + cx + canvas.width / 2) - zoom_factor * 1.5,
            Math.round(pane.y * tile_size + cy + canvas.height / 2) - zoom_factor * 1.5,
            Math.round(pane.width * tile_size) + zoom_factor * 3,
            Math.round(pane.height * tile_size) + zoom_factor * 3,
        );

        pane.free();
    }

    let from_y = Math.floor((-cy - canvas.height / 2) / tile_size);
    let to_y = Math.ceil((-cy + canvas.height / 2) / tile_size);
    let from_x = Math.floor((-cx - canvas.width / 2) / tile_size);
    let to_x = Math.ceil((-cx + canvas.width / 2) / tile_size);

    let width = to_x - from_x + 1;
    let height = to_y - from_y + 1;

    // TODO: memoize
    let chars = world.draw(-from_x, -from_y, width, height);
    ctx.textAlign = "left";
    ctx.textBaseline = "top";
    ctx.font = `${tile_size}px Stackline Classic`;

    for (let y = from_y; y <= to_y; y++) {
        for (let x = from_x; x <= to_x; x++) {
            let x2 = x * tile_size + cx + canvas.width / 2;
            let y2 = y * tile_size + cy + canvas.height / 2;

            let index = 3 * (width * (y - from_y) + x - from_x);

            let ch = String.fromCharCode(chars[index]);
            if (ch !== " ") {
                let fg = to_color(chars[index + 1]);
                let bg = chars[index + 2] === 0 ? null : to_color(chars[index + 2]);

                if (bg) {
                    ctx.fillStyle = `rgba(${bg.join(",")})`;
                    ctx.fillRect(
                        Math.round(x2),
                        Math.round(y2),
                        Math.round(x2 + tile_size) - Math.round(x2),
                        Math.round(y2 + tile_size) - Math.round(y2),
                    );
                }
                ctx.fillStyle = `rgba(${fg.join(",")})`;
                ctx.fillText(
                    ch,
                    Math.round(x2),
                    Math.round(y2),
                );
            } else {
                // Draw grid
                let inside = false;

                for (let pane of panes) {
                    if (x >= pane.x && x < pane.x + pane.width && y >= pane.y && y < pane.y + pane.height) {
                        inside = true;
                        break;
                    }
                }

                if (inside || width < 100 && height < 100) {
                    ctx.fillStyle = inside ? "#505050" : "#303030";

                    ctx.fillRect(
                        Math.round(x2 + tile_size / 2) - zoom_factor,
                        Math.round(y2 + tile_size / 2) - zoom_factor,
                        zoom_factor,
                        zoom_factor
                    );
                }
            }
        }
    }
}

function resize() {
    canvas.width = canvas.clientWidth;
    canvas.height = canvas.clientHeight;

    draw();
}

function loop() {
    draw();
    window.requestAnimationFrame(loop);
}

let mouse_x = 0, mouse_y = 0;
let mouse_down = false;

canvas.addEventListener("mousedown", (evt) => {
    mouse_x = evt.clientX;
    mouse_y = evt.clientY;
    mouse_down = true;
});

canvas.addEventListener("mousemove", (evt) => {
    if (mouse_down) {
        // TODO: numerically stable solution
        cx += evt.clientX - mouse_x;
        cy += evt.clientY - mouse_y;

        mouse_x = evt.clientX;
        mouse_y = evt.clientY;
    }
});

canvas.addEventListener("mouseup", (evt) => {
    mouse_down = false;
});

canvas.addEventListener("mouseleave", (evt) => {
    mouse_down = false;
});

canvas.addEventListener("wheel", (event) => {
    const ZOOM_STRENGTH = -0.005;
    zoom += event.deltaY * ZOOM_STRENGTH;
    zoom = Math.min(Math.max(zoom, 0.0), 4.0);
});

function to_color(num) {
    let alpha = (num >> 24) & 0xff;
    let red = (num >> 16) & 0xff;
    let green = (num >> 8) & 0xff;
    let blue = num & 0xff;

    return [red, green, blue, alpha];
}