import * as d3 from 'd3';
import { Point } from '../types/Point';
import { Path, transformed } from './Path';

class Line extends Path {
    
    private readonly _start: Point;
    private readonly _end: Point;
    
    constructor (start: Point, end: Point) {
        
        super();
        this._start = start;
        this._end = end;
        
    }
    
    angleAlong (t: number, x: d3.ScaleLinear<number, number>, y: d3.ScaleLinear<number, number>): number {
        const s = transformed(this._start, x, y);
        const e = transformed(this._end, x, y);
        return Math.atan2(s.x - e.x, s.y - e.y);
    }
    
    apply (context: CanvasRenderingContext2D, x: d3.ScaleLinear<number, number>, y: d3.ScaleLinear<number, number>): void {
        const s = transformed(this._start, x, y);
        const e = transformed(this._end, x, y);
        context.moveTo(s.x, s.y);
        context.lineTo(e.x, e.y);
    }
    
    pointAlong (t: number, x: d3.ScaleLinear<number, number>, y: d3.ScaleLinear<number, number>): Point {
        const s = transformed(this._start, x, y);
        const e = transformed(this._end, x, y);
        return {
            x: s.x + t * (e.x - s.x),
            y: s.y + t * (e.y - s.y)
        };
    }

    points (): Point[] {
        return [this._start, this._end];
    }

}

export {
    Line
}