import { createHash } from 'node:crypto'
import { mkdirSync, readFileSync, writeFileSync } from 'node:fs'
import path from 'node:path'

const MAX_ANDROID_VERSION_CODE = 2_100_000_000

function readPreviousVersionCode(cacheFile) {
  try {
    return Number(JSON.parse(readFileSync(cacheFile, 'utf8')).versionCode) || 0
  } catch {
    return 0
  }
}

/**
 * 为同一 versionName 的连续测试包生成可安装的新构建身份。
 *
 * 本地缓存只负责同一工作区内的单调递增；CI 若需要跨工作区全局唯一，必须通过
 * XUQM_VERSION_CODE 注入流水线唯一编号。
 */
export function createAndroidReleaseIdentity({
  projectRoot,
  environment = process.env,
  now = Date.now(),
  entropy = `${process.pid}:${Math.random()}`,
}) {
  const cacheFile = path.join(projectRoot, '.xuqm-cache', 'release-build.json')
  const previousVersionCode = readPreviousVersionCode(cacheFile)
  const requestedText = environment.XUQM_VERSION_CODE
  const requested = requestedText === undefined ? undefined : Number(requestedText)
  if (
    requestedText !== undefined &&
    (!Number.isInteger(requested) || requested <= 0 || requested > MAX_ANDROID_VERSION_CODE)
  ) {
    throw new Error(
      `XUQM_VERSION_CODE must be an integer between 1 and ${MAX_ANDROID_VERSION_CODE}`,
    )
  }
  const epochSeconds = Math.floor(now / 1_000)
  const versionCode = requested ?? Math.max(epochSeconds, previousVersionCode + 1)
  if (versionCode > MAX_ANDROID_VERSION_CODE) {
    throw new Error('Generated Android versionCode exceeds limit')
  }

  const buildId =
    environment.XUQM_BUILD_ID ??
    createHash('sha256').update(`${versionCode}:${now}:${entropy}`).digest('hex').slice(0, 32)
  if (!/^[A-Za-z0-9._-]{1,128}$/.test(buildId)) {
    throw new Error('XUQM_BUILD_ID must contain only letters, numbers, dot, underscore or hyphen')
  }

  mkdirSync(path.dirname(cacheFile), { recursive: true })
  writeFileSync(
    cacheFile,
    `${JSON.stringify(
      {
        versionCode,
        buildId,
        generatedAt: new Date(now).toISOString(),
      },
      null,
      2,
    )}\n`,
  )
  return { versionCode, buildId }
}