/** 微信小程序基础库未内置 TextEncoder，qrcode 库依赖它编码 payload */
function installTextEncodingPolyfill() {
  const root = (typeof globalThis !== 'undefined'
    ? globalThis
    : typeof global !== 'undefined'
      ? global
      : typeof wx !== 'undefined'
        ? wx
        : {}) as typeof globalThis & { TextEncoder?: typeof TextEncoder };

  if (typeof root.TextEncoder !== 'undefined') return;

  class MiniTextEncoder implements TextEncoder {
    readonly encoding = 'utf-8';

    encode(input?: string): Uint8Array {
      const str = input ?? '';
      const bytes: number[] = [];
      for (let i = 0; i < str.length; i++) {
        let code = str.charCodeAt(i);
        if (code < 0x80) {
          bytes.push(code);
        } else if (code < 0x800) {
          bytes.push(0xc0 | (code >> 6), 0x80 | (code & 0x3f));
        } else if (code >= 0xd800 && code <= 0xdbff && i + 1 < str.length) {
          const next = str.charCodeAt(i + 1);
          if (next >= 0xdc00 && next <= 0xdfff) {
            i += 1;
            code = 0x10000 + ((code - 0xd800) << 10) + (next - 0xdc00);
            bytes.push(
              0xf0 | (code >> 18),
              0x80 | ((code >> 12) & 0x3f),
              0x80 | ((code >> 6) & 0x3f),
              0x80 | (code & 0x3f),
            );
          } else {
            bytes.push(0xe0 | (code >> 12), 0x80 | ((code >> 6) & 0x3f), 0x80 | (code & 0x3f));
          }
        } else {
          bytes.push(0xe0 | (code >> 12), 0x80 | ((code >> 6) & 0x3f), 0x80 | (code & 0x3f));
        }
      }
      return new Uint8Array(bytes);
    }
  }

  root.TextEncoder = MiniTextEncoder as unknown as typeof TextEncoder;
}

installTextEncodingPolyfill();

export {};