/**
 * public/title-util.ts — derive a short tab title from a terminal OSC title.
 *
 * Pure, dependency-free (no xterm/DOM) so it's unit-testable in node.
 */

/**
 * Derive the **current folder** from the terminal's OSC title.
 *
 * Most shells emit titles like `user@host:~/path/to/dir` (zsh/bash default).
 * Take the part after the last ':' (the path), then its last segment (the
 * folder name). `~` (home) stays `~`. Returns null for an empty title; falls
 * back to the raw-ish basename when there's no `user@host:` shape (e.g. a
 * running command title).
 */
export function folderFromTitle(title: string): string | null {
  let s = title.trim()
  if (!s) return null
  const colon = s.lastIndexOf(':')
  if (colon !== -1) s = s.slice(colon + 1).trim()
  s = s.replace(/\/+$/, '') // strip trailing slash
  const slash = s.lastIndexOf('/')
  if (slash !== -1) s = s.slice(slash + 1)
  return s || null
}

/**
 * Parse the full cwd path from an OSC 7 sequence payload (M6).
 *   data = "file://host/Users/me/dir"  →  "/Users/me/dir"
 * Returns null if it isn't a file:// URL.
 */
export function cwdFromOsc7(data: string): string | null {
  const m = /^file:\/\/[^/]*(\/.*)$/.exec(data.trim())
  if (m === null) return null
  const path = m[1] as string
  try {
    return decodeURIComponent(path)
  } catch {
    return path
  }
}