/**
 * Parse rsync --itemize-changes output into a structured change list.
 *
 * rsync itemize format: 11-character code + space + path
 *
 * Code structure: YXcstpoguax
 *   Y = update type: > (transfer), * (message/delete), c (local change), . (no update), h (hard link)
 *   X = file type:   f (file), d (dir), L (symlink), D (device), S (special)
 *   remaining chars = what changed (size, time, perms, etc.) or '+++++++++' for new
 *
 * We care about:
 *   >f... = file transferred (new or modified)
 *   *deleting = file deleted
 *   cd... = directory (ignored for delta purposes)
 */

/**
 * @typedef {{ status: 'added'|'modified'|'deleted', path: string }} Change
 */

/**
 * Parse rsync --itemize-changes stdout into a list of file changes.
 * @param {string} output
 * @returns {Change[]}
 */
export function parseItemize(output) {
  const changes = [];

  for (const raw of output.split('\n')) {
    const line = raw.trimEnd();
    if (!line) continue;

    // Deleted files: "*deleting   path/to/file"
    if (line.startsWith('*deleting ')) {
      const path = line.slice('*deleting '.length).trimStart();
      // Skip directory deletions (trailing slash)
      if (!path.endsWith('/')) {
        changes.push({ status: 'deleted', path });
      }
      continue;
    }

    // File transfers: ">f......... path" (new or modified)
    if (line.length > 12 && line[0] === '>' && line[1] === 'f') {
      const code = line.slice(0, 11);
      const path = line.slice(12);
      const isNew = code.slice(2) === '+++++++++';
      changes.push({ status: isNew ? 'added' : 'modified', path });
      continue;
    }

    // Everything else (dirs, symlinks, attribute-only changes) — ignore
  }

  return changes;
}