import type { ExecSyncOptions } from 'node:child_process'
import { execSync } from 'node:child_process'

export const BUILD_CHANNELS = ['dev', 'rc', 'stable'] as const
export type BuildChannel = (typeof BUILD_CHANNELS)[number]

export type BuildInfo = {
  version: string
  commit: string
  buildDate: string
  channel: BuildChannel
  minDify: string
  maxDify: string
}

export type Env = Record<string, string | undefined>

export type GitProbe = (cmd: string) => string | null

const GIT_PROBE_OPTS: ExecSyncOptions = {
  stdio: ['ignore', 'pipe', 'ignore'],
}

export const defaultGitProbe: GitProbe = (cmd) => {
  try {
    return execSync(cmd, GIT_PROBE_OPTS).toString().trim() || null
  }
  catch {
    return null
  }
}

export type ResolveOptions = {
  env?: Env
  git?: GitProbe
  now?: () => Date
}

export function resolveBuildInfo(opts: ResolveOptions = {}): BuildInfo {
  const env = opts.env ?? process.env
  const git = opts.git ?? defaultGitProbe
  const now = opts.now ?? (() => new Date())

  const channel = env.DIFYCTL_CHANNEL ?? 'dev'
  if (!(BUILD_CHANNELS as readonly string[]).includes(channel)) {
    throw new Error(
      `invalid DIFYCTL_CHANNEL: ${channel} (expected ${BUILD_CHANNELS.join(' | ')})`,
    )
  }

  const version
    = env.DIFYCTL_VERSION
      ?? git('git describe --tags --dirty --always')
      ?? '0.0.0-dev'

  const commit
    = env.DIFYCTL_COMMIT
      ?? git('git rev-parse HEAD')
      ?? 'none'

  const buildDate = env.DIFYCTL_BUILD_DATE ?? now().toISOString()
  const minDify = env.DIFYCTL_MIN_DIFY ?? '0.0.0'
  const maxDify = env.DIFYCTL_MAX_DIFY ?? '0.0.0'

  return { version, commit, buildDate, channel: channel as BuildChannel, minDify, maxDify }
}