#!/usr/bin/env node
/**
 * vr —— vibe-registry CLI(M1)
 *
 * 用法:
 *   vr list                     列出包内可用预设布局
 *   vr add <layout> [--force]   物化预设到项目 registry/layouts/(防覆盖)
 *   vr update <layout> [--force] 对比包内新版,拉 diff(防覆盖,不静默改你的代码)
 *
 * 防覆盖原则(v0.5 决策):
 *   - 目标文件已存在且与预设不同(被用户改过)→ 拒绝,绝不静默覆盖
 *   - 内容相同 → 提示 already up-to-date
 *   - 显式 --force 才允许覆盖(用户自己确认)
 */
import { readdirSync, readFileSync, writeFileSync, existsSync, mkdirSync, statSync } from 'node:fs'
import { fileURLToPath } from 'node:url'
import { dirname, join, relative } from 'node:path'

const root = join(dirname(fileURLToPath(import.meta.url)), '..')
const presetsDir = join(root, 'presets', 'layouts')
const targetDir = join(process.cwd(), 'registry', 'layouts')

function listPresets(): string[] {
  return readdirSync(presetsDir)
    .filter((f) => f.endsWith('.ts'))
    .map((f) => f.replace(/\.ts$/, ''))
    .sort()
}

function presetFile(id: string): string | undefined {
  const f = join(presetsDir, `${id}.ts`)
  return existsSync(f) && statSync(f).isFile() ? f : undefined
}

function targetFile(id: string): string {
  return join(targetDir, `${id}.ts`)
}

function showDiff(target: string, preset: string, id: string): void {
  const tLines = target.split(/\r?\n/)
  const pLines = preset.split(/\r?\n/)
  const max = Math.max(tLines.length, pLines.length)
  const diffs: string[] = []
  for (let i = 0; i < max; i++) {
    const a = tLines[i] ?? ''
    const b = pLines[i] ?? ''
    if (a !== b) diffs.push(`  L${i + 1}: 你的 "${a.slice(0, 60)}"  →  新版 "${b.slice(0, 60)}"`)
    if (diffs.length >= 8) break
  }
  console.log(`  差异预览(最多 8 行,${id}.ts):`)
  diffs.forEach((d) => console.log(d))
}

function cmdList(): void {
  const presets = listPresets()
  console.log(`可用预设布局(${presets.length}):`)
  presets.forEach((id) => {
    const f = presetFile(id)!
    const head = readFileSync(f, 'utf8').split(/\r?\n/).slice(0, 3).join(' ')
    console.log(`  - ${id}`)
    console.log(`      ${head.replace(/^\/\*\*?\s?/, '').slice(0, 80)}`)
  })
}

function cmdAdd(id: string, force: boolean): void {
  const src = presetFile(id)
  if (!src) {
    console.error(`✗ 未知预设布局:'${id}'`)
    console.error(`  可用:${listPresets().join(', ')}`)
    process.exit(1)
  }
  const content = readFileSync(src, 'utf8')
  const dest = targetFile(id)

  if (existsSync(dest)) {
    const existing = readFileSync(dest, 'utf8')
    if (existing === content) {
      console.log(`• '${id}' 已物化且与预设一致(already up-to-date)`)
      return
    }
    if (!force) {
      console.error(`✗ 防覆盖:registry/layouts/${id}.ts 已存在且被修改过`)
      console.error(`  不静默覆盖。选项:`)
      console.error(`    1) 看差异:vr update ${id}   (仅预览,不写文件)`)
      console.error(`    2) 确认覆盖:vr add ${id} --force`)
      process.exit(2)
    }
    console.log(`⚠ 强制覆盖 registry/layouts/${id}.ts`)
  }
  mkdirSync(targetDir, { recursive: true })
  writeFileSync(dest, content, 'utf8')
  console.log(`✓ 已物化预设 '${id}' → ${relative(process.cwd(), dest)}`)
  console.log(`  从此它是你的源码,可直接修改;升级用 vr update ${id}`)
}

function cmdUpdate(id: string, force: boolean): void {
  const src = presetFile(id)
  if (!src) {
    console.error(`✗ 未知预设布局:'${id}'`)
    process.exit(1)
  }
  const dest = targetFile(id)
  if (!existsSync(dest)) {
    console.log(`• '${id}' 尚未物化,执行 vr add ${id}`)
    return
  }
  const existing = readFileSync(dest, 'utf8')
  const preset = readFileSync(src, 'utf8')
  if (existing === preset) {
    console.log(`• '${id}' 已是最新版`)
    return
  }
  showDiff(existing, preset, id)
  if (force) {
    writeFileSync(dest, preset, 'utf8')
    console.log(`✓ 已更新 ${id}(--force)`)
  } else {
    console.log(`  未写文件。确认升级请:vr update ${id} --force`)
  }
}

const [cmd, arg, ...rest] = process.argv.slice(2)
const force = rest.includes('--force') || arg === '--force'

switch (cmd) {
  case 'list':
    cmdList()
    break
  case 'add':
    if (!arg || arg === '--force') {
      console.error('用法:vr add <layout> [--force]')
      process.exit(1)
    }
    cmdAdd(arg, force)
    break
  case 'update':
    if (!arg || arg === '--force') {
      console.error('用法:vr update <layout> [--force]')
      process.exit(1)
    }
    cmdUpdate(arg, force)
    break
  default:
    console.error('用法:vr list | vr add <layout> [--force] | vr update <layout> [--force]')
    process.exit(1)
}