import './text-encoding-polyfill';
import QRCode from 'qrcode';

const QR_SIZE = 240;
const QR_OPTIONS = {
  width: QR_SIZE * 2,
  margin: 0,
  color: { dark: '#1f1a17', light: '#ffffff' },
} as const;

/** 在 2d Canvas 上绘制二维码（小程序 / H5 通用） */
export function drawRedeemQrOnCanvas(
  ctx: CanvasRenderingContext2D,
  token: string,
  sizePx = QR_SIZE,
) {
  const qr = QRCode.create(token, { errorCorrectionLevel: 'M' });
  const count = qr.modules.size;
  const cell = sizePx / count;

  ctx.fillStyle = '#ffffff';
  ctx.fillRect(0, 0, sizePx, sizePx);
  ctx.fillStyle = '#1f1a17';
  for (let row = 0; row < count; row++) {
    for (let col = 0; col < count; col++) {
      if (qr.modules.get(row, col)) {
        ctx.fillRect(col * cell, row * cell, cell, cell);
      }
    }
  }
}

/** H5：Data URL；失败时回退到与 h5-user 相同的外部 QR 服务 */
export async function buildRedeemQrDataUrl(token: string): Promise<string> {
  try {
    return await QRCode.toDataURL(token, QR_OPTIONS);
  } catch {
    return `https://api.qrserver.com/v1/create-qr-code/?size=${QR_SIZE * 2}x${QR_SIZE * 2}&data=${encodeURIComponent(token)}`;
  }
}

export const REDEEM_QR_DISPLAY_SIZE = QR_SIZE;