import { DrawCommand } from "regl";
import { Vector2 } from "../common";
import { CoordinateSystem, Kind } from "./coordinate-system";
import { LinearScale } from "../scales/linear";
import { LogScale } from "../scales/log";
import { CandyGraph } from "../candygraph";

interface Props {
  xdomain: Vector2;
  ydomain: Vector2;
  xrange: Vector2;
  yrange: Vector2;
}

export class CartesianCoordinateSystem extends CoordinateSystem {
  /** @internal */
  public readonly glsl: string;

  /** @internal */
  public readonly kind = Kind.Cartesian;

  /** @internal */
  public readonly scope: DrawCommand;

  constructor(
    cg: CandyGraph,
    public readonly xscale: LinearScale | LogScale,
    public readonly yscale: LinearScale | LogScale
  ) {
    super();

    this.scope = cg.regl({
      uniforms: {
        xdomain: cg.regl.prop<Props, "xdomain">("xdomain"),
        ydomain: cg.regl.prop<Props, "ydomain">("ydomain"),
        xrange: cg.regl.prop<Props, "xrange">("xrange"),
        yrange: cg.regl.prop<Props, "yrange">("yrange"),
      },
    });

    const xglsl = xscale.glsl.replace("toDomain", "toXDomain").replace("toRange", "toXRange");
    const yglsl = yscale.glsl.replace("toDomain", "toYDomain").replace("toRange", "toYRange");
    this.glsl = `
      uniform vec2 xdomain, ydomain;
      uniform vec2 xrange, yrange;

      ${xglsl}
      ${yglsl}

      vec2 toRange(vec2 v) {
        return vec2(
          toXRange(v.x, xdomain, xrange),
          toYRange(v.y, ydomain, yrange)
        );
      }

      vec2 toDomain(vec2 v) {
        return vec2(
          toXDomain(v.x, xdomain, xrange),
          toYDomain(v.y, ydomain, yrange)
        );
      }`;
  }

  public toRange(v: Vector2): Vector2 {
    return [this.xscale.toRange(v[0]), this.yscale.toRange(v[1])];
  }

  public toDomain(v: Vector2): Vector2 {
    return [this.xscale.toDomain(v[0]), this.yscale.toDomain(v[1])];
  }

  /** @internal */
  public props(): Props {
    return {
      xdomain: this.xscale.domain,
      ydomain: this.yscale.domain,
      xrange: this.xscale.range,
      yrange: this.yscale.range,
    };
  }
}