import * as THREE from 'three';

/**
 * Supported gradient mapping types.
 */
export type GradientType = 'linear' | 'radial' | 'angular' | 'diamond';

/**
 * Numeric IDs mapped to `GradientType` for shader uniforms lookup.
 */
export const GradientTypeIds = {
  Linear: 0,
  Radial: 1,
  Angular: 2,
  Diamond: 3,
};

/**
 * A single keyed position structure for building color ramp gradients.
 */
export interface ColorStop {
  /** Normalized position from 0.0 (start) to 1.0 (end) */
  position: number;
  /** Color representation (Hex, CSS string, or THREE.Color) */
  color: THREE.ColorRepresentation;
}

/**
 * Defines settings for linear or radial gradient fills.
 */
export interface GradientPaint {
  /** The type of gradient layout structure */
  gradientType: GradientType;
  /** Array of boundary nodes containing position and color coordinates */
  stops: ColorStop[];

  /** Rotation angle in degrees (default 0) */
  rotation?: number;
  /** Origin coordinate anchor of the gradient scale mapping (default [0.5, 0.5]) */
  center?: THREE.Vector2 | [number, number];
  /** Scalar scaling offset mapping multipliers (default [1.0, 1.0]) */
  scale?: THREE.Vector2 | [number, number];
}

/**
 * Flat static color representation (CSS, Hex, or THREE.Color).
 */
export type SolidPaint = THREE.ColorRepresentation;

/**
 * Union supported coloring style applied to paths or faces.
 */
export type Paint = SolidPaint | GradientPaint;

/**
 * Numeric IDs indicating solid vs gradient configurations inside uniform structures.
 */
export const PaintTypeIds = {
  Solid: 0,
  Gradient: 1,
};

/**
 * Defines bounding box calculation bias mappings during stroke drawing.
 */
export type StrokeAlign = 'inside' | 'center' | 'outside';

/**
 * Base template signature wrapper containing Three.js shader dictionary binds.
 */
export type ShaderUniforms = {
  [key: string]: THREE.IUniform;
};