import {normalize} from "./normalize";

export function pts2plotter(pts: [number, number][][], width: number, height: number, px2mm = 0.1){
    let str = init(width * px2mm, height * px2mm);

    // sort paths by x(long) then by y(short)
    const sorted = pts.slice();
    sorted.sort(function (a, b) {
        const [ax,ay] = topleft(a);
        const [bx,by] = topleft(b);

        if (ax !== bx) return ax - bx;
        return ay - by;
    });

    let lead = true;
    for(const path of sorted){
        for (const cmd of poly(normalize(path), height, px2mm, lead)) {
            str += cmd;
        }
        lead = false;
    }

    str += end();

    return str;
}

function topleft(pts: [number, number][]){
    let minx = NaN;
    let miny = NaN;
    for(const pt of pts){
        if (isNaN(minx) || minx > pt[0]) minx = pt[0];
        if (isNaN(miny) || miny > pt[1]) miny = pt[1];
    }
    return [minx, miny] as [number, number];
}

function init(w: number, h: number) {
    return ` IN TB26,${plu(w)},${plu(h)} CT1 U0,0 D0,0 D40,0`;
}

function end() {
    return ' U0,0 @ @';
}

function* poly(pts: [number, number][], height: number, px2mm: number, lead = false){
    function cutpt(down: boolean, pt: [number, number]) {
        return ` ${down ? 'D' : 'U'}${plu(pt[0] * px2mm)},${plu((height - pt[1]) * px2mm)}`;
    }

    if (lead) {
        yield cutpt(false, [0, 0]);
        yield cutpt(true, [0, 1]);
    }

    yield cutpt(false, pts[0]);
    for(const pt of pts){
        yield cutpt(true, pt);
    }
}

function sqrlen(x: number, y: number) {
    return x * x + y * y;
}

function lerp(s: [number, number], e: [number, number], i: number) {
    return [s[0] + (e[0] - s[0]) * i, s[1] + (e[1] - s[1]) * i] as typeof s;
}

function plu(n: number) {
    return Math.round(n / 0.025);
}