/// SPDX-License-Identifier: GPL-3.0-or-later
/// SPDX-FileCopyrightText: Copyright © 2022 Tony Garnock-Jones <tonyg@leastfixedpoint.com>

import { makeTemplate } from "@syndicate-lang/html";
const svg = makeTemplate('svg');

export type Pointlike =
    { x: number, y: number } | [number, number];
export type Rectlike =
    { x: number, y: number, width: number, height: number } | [number, number, number, number];

export class Point {
    readonly x: number;
    readonly y: number;

    constructor (x: number, y: number) {
        this.x = x;
        this.y = y;
    }

    static from(p: Pointlike): Point {
        if ('x' in p) {
            return new Point(p.x, p.y);
        } else {
            return new Point(p[0], p[1]);
        }
    }

    toDOM(): DOMPoint {
        return new DOMPoint(this.x, this.y);
    }

    add(p0: Pointlike): Point {
        const p = Point.from(p0);
        return new Point(this.x + p.x, this.y + p.y);
    }
    sub(p0: Pointlike): Point {
        const p = Point.from(p0);
        return new Point(this.x - p.x, this.y - p.y);
    }
    scale(n: number): Point {
        return new Point(this.x * n, this.y * n);
    }

    max(p0: Pointlike): Point {
        const p = Point.from(p0);
        return new Point(Math.max(this.x, p.x), Math.max(this.y, p.y));
    }
    min(p0: Pointlike): Point {
        const p = Point.from(p0);
        return new Point(Math.min(this.x, p.x), Math.min(this.y, p.y));
    }

    apply<N extends SVGElement>(n: N): N {
        return applyAttributes(n, { "x": this.x, "y": this.y });
    }

    withX(x: number): Point { return new Point(x, this.y); }
    withY(y: number): Point { return new Point(this.x, y); }

    static ZERO: Point = new Point(0, 0);
}

export class Rect {
    readonly x: number;
    readonly y: number;
    readonly width: number;
    readonly height: number;

    constructor (x: number, y: number, width: number, height: number) {
        this.x = x;
        this.y = y;
        this.width = width;
        this.height = height;
    }

    static from(r: Rectlike): Rect {
        if ('x' in r) {
            return new Rect(r.x, r.y, r.width, r.height);
        } else {
            return new Rect(r[0], r[1], r[2], r[3]);
        }
    }

    static originCorner(o0: Pointlike, c0: Pointlike): Rect {
        const o = Point.from(o0);
        const c = Point.from(c0);
        return new Rect(o.x, o.y, c.x - o.x, c.y - o.y);
    }

    static originExtent(o0: Pointlike, e0: Pointlike): Rect {
        const o = Point.from(o0);
        const e = Point.from(e0);
        return new Rect(o.x, o.y, e.x, e.y);
    }

    toDOM(): DOMRect {
        return new DOMRect(this.x, this.y, this.width, this.height);
    }

    get extent(): Point { return this.bottomRight.sub(this.topLeft); }

    withExtent(p0: Pointlike): Rect {
        const p = Point.from(p0);
        return new Rect(this.x, this.y, p.x, p.y);
    }

    get left(): number { return this.x; }
    get midX(): number { return this.x + this.width / 2; }
    get right(): number { return this.x + this.width; }
    get top(): number { return this.y; }
    get midY(): number { return this.y + this.height / 2; }
    get bottom(): number { return this.y + this.height; }

    withLeft(n: number): Rect { return new Rect(n, this.y, this.width, this.height); }
    withMidX(n: number): Rect { return new Rect(n - this.width / 2, this.y, this.width, this.height); }
    withRight(n: number): Rect { return new Rect(n - this.width, this.y, this.width, this.height); }
    withTop(n: number): Rect { return new Rect(this.x, n, this.width, this.height); }
    withMidY(n: number): Rect { return new Rect(this.x, n - this.height / 2, this.width, this.height); }
    withBottom(n: number): Rect { return new Rect(this.x, n - this.height, this.width, this.height); }
    withWidth(n: number): Rect { return new Rect(this.x, this.y, n, this.height); }
    withHeight(n: number): Rect { return new Rect(this.x, this.y, this.width, n); }

    get topLeft(): Point { return new Point(this.x, this.y); }
    get topMid(): Point { return this.topLeft.add(this.topRight).scale(0.5); }
    get topRight(): Point { return new Point(this.x + this.width, this.y); }
    get bottomLeft(): Point { return new Point(this.x, this.y + this.height); }
    get bottomMid(): Point { return this.bottomLeft.add(this.bottomRight).scale(0.5); }
    get bottomRight(): Point { return new Point(this.x + this.width, this.y + this.height); }
    get midLeft(): Point { return this.topLeft.add(this.bottomLeft).scale(0.5); }
    get center(): Point { return this.topLeft.add(this.bottomRight).scale(0.5); }
    get midRight(): Point { return this.topRight.add(this.bottomRight).scale(0.5); }

    withTopLeft(p0: Pointlike): Rect {
        const p = Point.from(p0);
        return new Rect(p.x, p.y, this.width, this.height);
    }
    withTopMid(p0: Pointlike): Rect {
        const p = Point.from(p0);
        return new Rect(p.x - this.width / 2, p.y, this.width, this.height);
    }
    withTopRight(p0: Pointlike): Rect {
        const p = Point.from(p0);
        return new Rect(p.x - this.width, p.y, this.width, this.height);
    }

    withBottomLeft(p0: Pointlike): Rect {
        const p = Point.from(p0);
        return new Rect(p.x, p.y - this.height, this.width, this.height);
    }
    withBottomMid(p0: Pointlike): Rect {
        const p = Point.from(p0);
        return new Rect(p.x - this.width / 2, p.y - this.height, this.width, this.height);
    }
    withBottomRight(p0: Pointlike): Rect {
        const p = Point.from(p0);
        return new Rect(p.x - this.width, p.y - this.height, this.width, this.height);
    }

    withMidLeft(p0: Pointlike): Rect {
        const p = Point.from(p0);
        return new Rect(p.x, p.y - this.height / 2, this.width, this.height);
    }
    withCenter(p0: Pointlike): Rect {
        const p = Point.from(p0);
        return new Rect(p.x - this.width / 2, p.y - this.height / 2, this.width, this.height);
    }
    withMidRight(p0: Pointlike): Rect {
        const p = Point.from(p0);
        return new Rect(p.x - this.width, p.y - this.height / 2, this.width, this.height);
    }

    apply<N extends SVGElement>(n: N): N {
        return applyAttributes(n, {
            "x": this.x,
            "y": this.y,
            "width": this.width,
            "height": this.height,
        });
    }
}

export type Prop<V, T, TLike> = (v: V) => {
    get: () => T,
    set: (t: TLike) => V,
};

export type Anchor = Prop<Rect, Point, Pointlike>;

function anchor<V, T, TLike>(g: keyof V, s: keyof V): Prop<V, T, TLike> {
    return (v: V) => ({
        get: (): T => { return (v as any)[g]; },
        set: (t: TLike): V => { return (v as any)[s](t); },
    });
}

export const TOP_LEFT = anchor<Rect, Point, Pointlike>('topLeft', 'withTopLeft');
export const TOP_MID = anchor<Rect, Point, Pointlike>('topMid', 'withTopMid');
export const TOP_RIGHT = anchor<Rect, Point, Pointlike>('topRight', 'withTopRight');
export const BOTTOM_LEFT = anchor<Rect, Point, Pointlike>('bottomLeft', 'withBottomLeft');
export const BOTTOM_MID = anchor<Rect, Point, Pointlike>('bottomMid', 'withBottomMid');
export const BOTTOM_RIGHT = anchor<Rect, Point, Pointlike>('bottomRight', 'withBottomRight');
export const MID_LEFT = anchor<Rect, Point, Pointlike>('midLeft', 'withMidLeft');
export const CENTER = anchor<Rect, Point, Pointlike>('center', 'withCenter');
export const MID_RIGHT = anchor<Rect, Point, Pointlike>('midRight', 'withMidRight');

export type Attributes = { [key: string]: string | number | undefined | null };

let playground: SVGSVGElement = null as any;

export function init() {
    playground = document.getElementById('playground')! as any;
}

export function temporarilyInDom<R>(e: SVGElement, f: () => R, parent = playground): R {
    parent.appendChild(e);
    const result = f();
    parent.removeChild(e);
    return result;
}

export function clientRect(e: SVGElement, parent = playground) {
    return temporarilyInDom(e, () => Rect.from(e.getBoundingClientRect()), parent);
}

export function bbox(e: SVGGraphicsElement, parent = playground) {
    return temporarilyInDom(e, () => Rect.from(e.getBBox()), parent);
}

export function textLength(e: SVGTextContentElement, parent = playground) {
    return temporarilyInDom(e, () => e.getComputedTextLength(), parent);
}

export function applyAttributes<N extends Element>(n: N, attributes?: Attributes): N {
    if (attributes !== void 0) {
        for (const key in attributes) {
            const val = attributes[key];
            if (val !== void 0 && val !== null) {
                n.setAttribute(key, '' + val);
            }
        }
    }
    return n;
}

export function text(text: string, attributes?: Attributes): SVGTextElement {
    return applyAttributes(svg.tag(SVGTextElement)`<text>${text}</text>`, attributes);
}

export function rect(extent0: Pointlike = Point.ZERO, attributes?: Attributes): SVGRectElement {
    const extent = Point.from(extent0);
    return applyAttributes(
        svg.tag(SVGRectElement)`<rect width="${extent.x}" height="${extent.y}"/>`,
        attributes);
}

export function circle(radius: number, attributes?: Attributes): SVGCircleElement {
    return applyAttributes(svg.tag(SVGCircleElement)`<circle r="${radius}"/>`, attributes);
}

export function alignTo(a: SVGGraphicsElement, n: Anchor, b: SVGGraphicsElement) {
    n(bbox(a)).set(n(bbox(b)).get()).apply(a);
}

export function placard(n: SVGGraphicsElement, attributes?: Attributes): SVGSVGElement {
    const padding = new Point(12, 6);
    const base = rect(bbox(n).extent.add(padding.scale(2)), attributes);
    return svg.tag(SVGSVGElement)`
        <svg class="placard">
            ${base}
            <g transform="translate(${padding.x} ${padding.y})">${n}</g>
        </svg>`;
}