diff.js

// diff.js - Diff 比对与 HTML 生成模块

/* HTML 转义工具 */
export const escapeHtml = s => String(s).replace(/&/g,'&amp;').replace(/</g,'&lt;').replace(/>/g,'&gt;').replace(/\n/g, '<br>');

/* 生成 Diff HTML */
export function buildDiffHTML(myText, aiText) {
  const DMP = window.diff_match_patch;
  
  if (!DMP) {
    console.error("❌ 错误：diff_match_patch 库未找到。");
    return escapeHtml(aiText) || 'Diff library not loaded.';
  }
  
  const myClean = String(myText || '').trim();
  const aiClean = String(aiText || '').trim();

  if (!myClean || !aiClean) {
    return escapeHtml(aiText) || '';
  }

  const dmp = new DMP();
  let diffs = dmp.diff_main(myClean, aiClean);
  dmp.diff_cleanupSemantic(diffs); 

  let html = '';
  const original = myClean; 
  let originalIndex = 0; 
  
  const isPunctuationOrSpace = char => char.match(/^[\s,.!?;:'"()\[\]@#$%^&*-]$/);
  
  diffs.forEach(([type, text]) => {
    for (let i = 0; i < text.length; i++) {
      const char = text[i];
      const escapedChar = escapeHtml(char); 
      
      if (isPunctuationOrSpace(char) && type === 0) {
        html += escapedChar;
        originalIndex++;
        continue;
      }

      if (type === 0) {
        const originalChar = original[originalIndex]; 
        
        if (originalChar && 
            originalChar.toLowerCase() === char.toLowerCase() && 
            originalChar !== char) {
          html += `<span class="w-case">${escapedChar}</span>`; 
        } else {
          html += escapedChar; 
        }
        originalIndex++;

      } else if (type === 1) {
        html += `<span class="w-add">${escapedChar}</span>`; 

      } else if (type === -1) {
        html += `<span class="w-rem">${escapedChar}</span>`; 
        originalIndex++;
      }
    }
  });

  return html.trim() || 'No differences';
}