'; resultArea.innerHTML = '
' + preview + '
';
        resultArea.classList.add('show');
        // re-bind IDs
        document.getElementById('result-content').textContent = b64;
        document.getElementById('result-meta').textContent = resultMeta.textContent;
        btnMain.disabled = false;
        btnMain.textContent = '处理';
      };
      reader.onerror = function() {
        showError('文件读取失败');
        btnMain.disabled = false;
        btnMain.textContent = '处理';
      };
      reader.readAsDataURL(file);
    } else {
      if (!textInput) {
        showError('请输入 Base64 数据');
        btnMain.disabled = false;
        btnMain.textContent = '处理';
        return;
      }
      var mime = 'image/png';
      var data = textInput.replace(/^data:image\/[a-z]+;base64,/, '');
      var match = textInput.match(/^data:(image\/[a-z]+);base64,/);
      if (match) mime = match[1];
      try {
        var bin = atob(data);
        var bytes = new Uint8Array(bin.length);
        for (var i = 0; i < bin.length; i++) bytes[i] = bin.charCodeAt(i);
        var blob = new Blob([bytes], {type: mime});
        var url = URL.createObjectURL(blob);
        resultContent.textContent = '已生成图片 (下方预览)';
        resultMeta.textContent = 'Base64 → 图片: ' + mime + ', ' + bytes.length + ' 字节';
        var preview = '
图片预览
下载图片
';
        resultArea.innerHTML = '
' + preview + '
';
        resultArea.classList.add('show');
      } catch(err) {
        showError('Base64 解码失败: ' + err.message);
      }
      btnMain.disabled = false;
      btnMain.textContent = '处理';
    }
  });

  btnClear.addEventListener('click', function() {
    document.getElementById('file').value = '';
    document.getElementById('text').value = '';
    document.getElementById('mode').value = 'img2base64';
    // Reset result area
    resultArea.innerHTML = '
';
    resultContent = document.getElementById('result-content');
    resultMeta = document.getElementById('result-meta');
    resultArea.classList.remove('show');
    errorMsg.classList.remove('show');
    document.querySelectorAll('.form-group-text').forEach(function(el){el.style.display='';});
    document.querySelectorAll('.form-group-file').forEach(function(el){el.style.display='';});
  });

  // Toggle text/file fields
  function syncFields() {
    var mode = document.getElementById('mode').value;
    var txtGroup = document.querySelector('.form-group-text');
    var fileGroup = document.querySelector('.form-group-file');
    if (mode === 'img2base64') {
      txtGroup.style.display = 'none';
      fileGroup.style.display = '';
    } else {
      txtGroup.style.display = '';
      fileGroup.style.display = 'none';
    }
  }
  document.getElementById('mode').addEventListener('change', syncFields);
  syncFields();
})();