// Painter 的 Canvas 2D 实现。Cocos 版本换成 Graphics + Label 即可，BoardView 不用改。
import type { Rect } from '../src/layout';
import type { Painter } from '../src/painter';

/**
 * 盘面字体栈，与 web/style.css 的 --font 完全一致（tests/theme.test.ts 校验）。
 * ui-rounded 让 iOS / macOS 直接拿到系统圆体；其余按平台回退到 PingFang / Noto。
 */
export const BOARD_FONT_FAMILY =
  'ui-rounded, "SF Pro Rounded", "PingFang SC", "Hiragino Sans GB", "Noto Sans SC", system-ui, -apple-system, "Segoe UI", sans-serif';

export class CanvasPainter implements Painter {
  private readonly ctx: CanvasRenderingContext2D;

  constructor(ctx: CanvasRenderingContext2D) {
    this.ctx = ctx;
  }

  private path(r: Rect, radius: number): void {
    const ctx = this.ctx;
    const rad = Math.max(0, Math.min(radius, r.w / 2, r.h / 2));
    ctx.beginPath();
    if (typeof ctx.roundRect === 'function') {
      ctx.roundRect(r.x, r.y, r.w, r.h, rad);
    } else {
      // 老 WebView 兜底
      const { x, y, w, h } = r;
      ctx.moveTo(x + rad, y);
      ctx.arcTo(x + w, y, x + w, y + h, rad);
      ctx.arcTo(x + w, y + h, x, y + h, rad);
      ctx.arcTo(x, y + h, x, y, rad);
      ctx.arcTo(x, y, x + w, y, rad);
      ctx.closePath();
    }
  }

  fillRoundRect(r: Rect, radius: number, color: string, alpha = 1): void {
    if (alpha <= 0 || r.w <= 0 || r.h <= 0) return;
    const ctx = this.ctx;
    ctx.globalAlpha = Math.min(1, alpha);
    ctx.fillStyle = color;
    this.path(r, radius);
    ctx.fill();
    ctx.globalAlpha = 1;
  }

  strokeRoundRect(r: Rect, radius: number, color: string, lineWidth: number, alpha = 1): void {
    if (alpha <= 0) return;
    const ctx = this.ctx;
    ctx.globalAlpha = Math.min(1, alpha);
    ctx.strokeStyle = color;
    ctx.lineWidth = lineWidth;
    this.path(r, radius);
    ctx.stroke();
    ctx.globalAlpha = 1;
  }

  fillCircle(cx: number, cy: number, radius: number, color: string, alpha = 1): void {
    if (alpha <= 0) return;
    const ctx = this.ctx;
    ctx.globalAlpha = Math.min(1, alpha);
    ctx.fillStyle = color;
    ctx.beginPath();
    ctx.arc(cx, cy, radius, 0, Math.PI * 2);
    ctx.fill();
    ctx.globalAlpha = 1;
  }

  /** 数字 800、汉字 700（docs/design.md 盘面字阶）；不加粗时 500 */
  text(s: string, cx: number, cy: number, size: number, color: string, bold = false, alpha = 1): void {
    if (alpha <= 0) return;
    const ctx = this.ctx;
    ctx.globalAlpha = Math.min(1, alpha);
    ctx.fillStyle = color;
    ctx.font = `${bold ? (/^\d+$/.test(s) ? '800' : '700') : '500'} ${size}px ${BOARD_FONT_FAMILY}`;
    ctx.textAlign = 'center';
    ctx.textBaseline = 'middle';
    ctx.fillText(s, cx, cy + size * 0.04);
    ctx.globalAlpha = 1;
  }
}