import { mat2d, vec2, vec3, vec4 } from 'gl-matrix';
import { codeForColorAccess } from '../../helper/code-for-color-access';
import { DrawableDescriptor } from '../drawable-descriptor';
import { EmptyDrawable } from '../empty-drawable';

/**
 * @category Drawable
 */
class RotatedRectangleBase extends EmptyDrawable {
  constructor(
    public center: vec2,
    public size: vec2,
    public rotation: number
  ) {
    super();
  }
}

/**
 * @category Drawable
 */
export const RotatedRectangleFactory = (
  color: vec3 | vec4 | number
): typeof RotatedRectangleBase => {
  class RotatedRectangle extends RotatedRectangleBase {
    public static descriptor: DrawableDescriptor = {
      sdf: {
        // Source: https://iquilezles.org/www/articles/distfunctions2d/distfunctions2d.htm
        shader: `
          uniform vec2 rotatedRectangleTopCenters[ROTATED_RECTANGLE_COUNT];
          uniform vec2 rotatedRectangleBottomCenters[ROTATED_RECTANGLE_COUNT];
          uniform float rotatedRectangleWidths[ROTATED_RECTANGLE_COUNT];

          float rotatedRectangleMinDistance(vec2 target, out vec4 color) {
            color = ${codeForColorAccess(color)};

            float minDistance = 1000.0;
            for (int i = 0; i < ROTATED_RECTANGLE_COUNT; i++) {
              vec2 top = rotatedRectangleTopCenters[i];
              vec2 bottom = rotatedRectangleBottomCenters[i];
              float height = length(bottom - top);
              vec2 d = height > 0.00000001 ? (bottom - top) / height : vec2(0.0, 1.0);

              vec2 q = (target - (top + bottom) * 0.5);
              q = mat2(d.x, -d.y, d.y, d.x) * q;
              q = abs(q) - vec2(height, rotatedRectangleWidths[i]) * 0.5;
              float dist = length(max(q, 0.0)) + min(max(q.x, q.y), 0.0);
              minDistance = min(minDistance, dist);
            }

            return minDistance;
          }
        `,
        distanceFunctionName: 'rotatedRectangleMinDistance',
      },
      propertyUniformMapping: {
        topCenter: 'rotatedRectangleTopCenters',
        bottomCenter: 'rotatedRectangleBottomCenters',
        width: 'rotatedRectangleWidths',
      },
      uniformCountMacroName: 'ROTATED_RECTANGLE_COUNT',
      shaderCombinationSteps: [0, 1, 2, 3, 8, 16],
      empty: new RotatedRectangle(vec2.create(), vec2.create(), 0),
    };

    /**
     * It is just an estimate by calculating a bounding circle
     * @param target
     */
    public minDistance(target: vec2): number {
      return vec2.distance(this.center, target) - vec2.length(this.size) / 2;
    }

    protected getObjectToSerialize(transform2d: mat2d, transform1d: number): any {
      const rotation = mat2d.fromRotation(mat2d.create(), this.rotation);

      const halfHeight = vec2.fromValues(0, this.size.y / 2);
      vec2.transformMat2d(halfHeight, halfHeight, rotation);

      const topCenter = vec2.add(vec2.create(), this.center, halfHeight);
      vec2.transformMat2d(topCenter, topCenter, transform2d);

      const bottomCenter = vec2.subtract(vec2.create(), this.center, halfHeight);
      vec2.transformMat2d(bottomCenter, bottomCenter, transform2d);

      return {
        topCenter,
        bottomCenter,
        width: this.size.x * transform1d,
      };
    }
  }

  return RotatedRectangle;
};