Function applyFileEdits

src/filesystem/lib.ts:194–282

(
  filePath: string,
  edits: FileEdit[],
  dryRun: boolean = false
)

}

export async function applyFileEdits(
  filePath: string,
  edits: FileEdit[],
  dryRun: boolean = false
): Promise<string> {
  // Read file content and normalize line endings
  const content = normalizeLineEndings(await fs.readFile(filePath, 'utf-8'));

  // Apply edits sequentially
  let modifiedContent = content;
  for (const edit of edits) {
    const normalizedOld = normalizeLineEndings(edit.oldText);
    const normalizedNew = normalizeLineEndings(edit.newText);

    // If exact match exists, use it
    if (modifiedContent.includes(normalizedOld)) {
      modifiedContent = modifiedContent.replace(normalizedOld, () => normalizedNew);
      continue;
    }

    // Otherwise, try line-by-line matching with flexibility for whitespace
    const oldLines = normalizedOld.split('\n');
    const contentLines = modifiedContent.split('\n');
    let matchFound = false;

    for (let i = 0; i <= contentLines.length - oldLines.length; i++) {
      const potentialMatch = contentLines.slice(i, i + oldLines.length);

      // Compare lines with normalized whitespace
      const isMatch = oldLines.every((oldLine, j) => {
        const contentLine = potentialMatch[j];
        return oldLine.trim() === contentLine.trim();
      });

      if (isMatch) {
        // Preserve original indentation of first line
        const originalIndent = contentLines[i].match(/^\s*/)?.[0] || '';
        const newLines = normalizedNew.split('\n').map((line, j) => {
          if (j === 0) return originalIndent + line.trimStart();
          // For subsequent lines, try to preserve relative indentation
          const oldIndent = oldLines[j]?.match(/^\s*/)?.[0] || '';
          const newIndent = line.match(/^\s*/)?.[0] || '';
          if (oldIndent && newIndent) {
            const relativeIndent = newIndent.length - oldIndent.length;
            return originalIndent + ' '.repeat(Math.max(0, relativeIndent)) + line.trimStart();
          }
          return line;
        });

        contentLines.splice(i, oldLines.length, ...newLines);
        modifiedContent = contentLines.join('\n');
        matchFound = true;
        break;
      }
    }

    if (!matchFound) {
      throw new Error(`Could not find exact match for edit:\n${edit.oldText}`);