import * as d3 from 'd3';
import { Link } from '../../renderables/Link';
import { LabelStyle } from '../../styles/LabelStyle';
import { Renderer } from '../Renderer';

class LinkLabelRenderer extends Renderer {

    static defaultColor = '#333333';
    static defaultFont = '14px sans-serif';

    // Nodes to render
    protected _links: Link[];

    // Styling
    protected color: string | null;
    protected font: string;

    constructor (style?: LabelStyle) {

        super();

        this._links = [];
        this.color = LinkLabelRenderer.defaultColor;
        this.font = LinkLabelRenderer.defaultFont;

        if (style) {
            if (style.color) this.color = style.color;
            if (style.font) this.font = style.font;
        }

    }

    links (): Link[];
    links (links: Link[]): this;
    links (links?: Link[]): Link[] | this {
        return arguments.length
            ? (this._links = links!, this)
            : this._links;
    }

    render (context: CanvasRenderingContext2D,
            x: d3.ScaleLinear<number, number>,
            y: d3.ScaleLinear<number, number>): void {

        if (!this._links.length) return;

        context.save();
        context.beginPath();

        if (this.color) context.fillStyle = this.color;
        context.font = this.font;
        context.textAlign = 'center';
        context.textBaseline = 'middle';

        this._links.forEach(link => {
            const path = link.path;
            if (path) {
                link.labels.forEach(label => {
                    const p = path.pointAlong(label.t, x, y);
                    context.fillText(
                        label.text,
                        p.x,
                        p.y
                    );
                });
            }
        });

    }

}

export {
    LinkLabelRenderer
}