import { createWriteStream, existsSync, mkdirSync, readFileSync, rmSync, type WriteStream } from 'node:fs'
import { readFile } from 'node:fs/promises'
import { dirname, join, relative, resolve, sep } from 'node:path'

export function projectDir(projectId: string) {
  return join(dataDir(), 'projects', projectId)
}

/** 章节文件相对 data 目录的路径，例如 projects/xxx/chapters/0003-v2.md */
export function chapterFileRel(projectId: string, index: number, version: number) {
  return ['projects', projectId, 'chapters', `${String(index).padStart(4, '0')}-v${version}.md`].join('/')
}

export function absPath(rel: string) {
  const root = dataDir()
  const p = resolve(root, rel)
  if (p !== root && !p.startsWith(root + sep)) throw new Error('非法路径')
  return p
}

export function openChapterWriter(rel: string): WriteStream {
  const p = absPath(rel)
  mkdirSync(dirname(p), { recursive: true })
  return createWriteStream(p, { encoding: 'utf8' })
}

export async function readChapterFile(rel: string) {
  const p = absPath(rel)
  if (!existsSync(p)) return ''
  return readFile(p, 'utf8')
}

export function readChapterFileSync(rel: string) {
  const p = absPath(rel)
  return existsSync(p) ? readFileSync(p, 'utf8') : ''
}

export function removeProjectFiles(projectId: string) {
  const dir = projectDir(projectId)
  if (existsSync(dir)) rmSync(dir, { recursive: true, force: true })
}

export function relToData(abs: string) {
  return relative(dataDir(), abs).split(sep).join('/')
}

/** 统计字数：中日韩字符按 1 字，英文按单词计 */
export function countWords(text: string) {
  const cjk = text.match(/[㐀-鿿豈-﫿぀-ヿ가-힯]/g)?.length ?? 0
  const latin = text.replace(/[㐀-鿿豈-﫿぀-ヿ가-힯]/g, ' ').match(/[A-Za-z0-9]+(?:['’-][A-Za-z0-9]+)*/g)?.length ?? 0
  return cjk + latin
}