import type { Graphics } from 'pixi.js';
import { Theme } from './Theme';

export interface ControlBoxOptions {
  fill: number;
  border: number;
  radius?: number;
  x?: number;
  y?: number;
}

/**
 * The shared look of every control. The stroke is inset by half a pixel so it lands on whole
 * device pixels and stays crisp instead of blurring over two.
 */
export function drawControlBox(g: Graphics, w: number, h: number, options: ControlBoxOptions): void {
  const { fill, border, radius = Theme.radius, x = 0, y = 0 } = options;
  g.roundRect(x, y, w, h, radius).fill(fill);
  g.roundRect(x + 0.5, y + 0.5, w - 1, h - 1, radius).stroke({ width: 1, color: border });
}

export interface GridOptions {
  /** Where the origin of the drawn space sits on screen, in the same pixels as `w`/`h`. */
  originX: number;
  originY: number;
  /** Spacing in screen pixels (world/graph step times zoom). */
  step: number;
  w: number;
  h: number;
  alpha: number;
  /** Alpha of the two lines through the origin; omitted = no axes. */
  axisAlpha?: number;
}

/**
 * White at a low alpha rather than a fixed colour, so the grid reads on whatever background the
 * scene sets. `g` is cleared by the caller.
 */
export function drawGrid(g: Graphics, options: GridOptions): void {
  const { originX, originY, step, w, h, alpha, axisAlpha } = options;
  const startX = ((originX % step) + step) % step;
  const startY = ((originY % step) + step) % step;
  for (let x = startX; x < w; x += step) g.moveTo(x, 0).lineTo(x, h);
  for (let y = startY; y < h; y += step) g.moveTo(0, y).lineTo(w, y);
  g.stroke({ width: 1, color: GRID_COLOR, alpha });
  if (axisAlpha === undefined) return;
  const axis = { width: 1, color: GRID_COLOR, alpha: axisAlpha };
  if (originX >= 0 && originX <= w) g.moveTo(originX, 0).lineTo(originX, h).stroke(axis);
  if (originY >= 0 && originY <= h) g.moveTo(0, originY).lineTo(w, originY).stroke(axis);
}

const GRID_COLOR = 0xffffff;