// 從 git log 產生更新紀錄資料，輸出到 src/data/changelog.json
// 正式版（build 後）沒有 git 也能直接讀 JSON 顯示；dev 與 build 前會自動重新產生。
import { execFileSync } from 'node:child_process'
import { mkdirSync, writeFileSync } from 'node:fs'
import { dirname, resolve } from 'node:path'
import { fileURLToPath } from 'node:url'

const here = dirname(fileURLToPath(import.meta.url))
const outFile = resolve(here, '../src/data/changelog.json')

const UNIT = '\x1f' // 欄位分隔（unit separator）
const RECORD = '\x1e' // 紀錄分隔（record separator）

function readGitLog() {
  const format = ['%H', '%h', '%ad', '%s', '%b'].join(UNIT) + RECORD
  const raw = execFileSync(
    'git',
    ['log', `--pretty=format:${format}`, '--date=format:%Y-%m-%d'],
    { cwd: resolve(here, '..'), encoding: 'utf8', maxBuffer: 1024 * 1024 * 16 },
  )

  return raw
    .split(RECORD)
    .map((chunk) => chunk.replace(/^\s+/, ''))
    .filter(Boolean)
    .map((chunk) => {
      const [hash, shortHash, date, subject, body = ''] = chunk.split(UNIT)
      return {
        hash,
        shortHash,
        date,
        subject: subject.trim(),
        body: body.trim(),
      }
    })
}

function main() {
  let entries = []

  try {
    entries = readGitLog()
  } catch (error) {
    console.warn('[generate-changelog] 讀取 git log 失敗，輸出空清單：', error.message)
  }

  const payload = {
    generatedAt: new Date().toISOString(),
    entries,
  }

  mkdirSync(dirname(outFile), { recursive: true })
  writeFileSync(outFile, JSON.stringify(payload, null, 2) + '\n', 'utf8')
  console.log(`[generate-changelog] 已輸出 ${entries.length} 筆更新紀錄到 ${outFile}`)
}

main()