import { execFileSync } from 'node:child_process'
import { mkdir, rename, stat } from 'node:fs/promises'
import { dirname, resolve } from 'node:path'
import { readFile } from 'node:fs/promises'

const root = resolve(new URL('..', import.meta.url).pathname)
const toolchain = JSON.parse(await readFile(new URL('../config/freecad-toolchain.json', import.meta.url), 'utf8'))
const directoryArgument = process.argv.slice(2).find((argument) => argument.startsWith('--directory='))
const target = resolve(root, directoryArgument?.slice('--directory='.length) || toolchain.sourceCheckout.defaultDirectory)
const git = (...args) => execFileSync('git', args, { cwd: root, encoding: 'utf8', stdio: ['ignore', 'pipe', 'inherit'], timeout: 300000 }).trim()
const exists = await stat(target).then(() => true, () => false)
const offline = process.env.FREECAD_SOURCE_OFFLINE === '1'

if (!exists) {
  if (offline) throw new Error(`FREECAD_SOURCE_OFFLINE=1 requires an existing pinned checkout: ${target}`)
  await mkdir(dirname(target), { recursive: true })
  git('clone', '--filter=blob:none', '--no-checkout', toolchain.source.repository, target)
} else {
  const remote = git('-C', target, 'remote', 'get-url', 'origin')
  if (remote !== toolchain.source.repository) throw new Error(`Existing checkout has unexpected origin: ${remote}`)
  const submodulePaths = git('-C', target, 'config', '--file', '.gitmodules', '--get-regexp', 'path')
    .split(/\r?\n/)
    .filter(Boolean)
    .map((line) => line.slice(line.indexOf(' ') + 1).trim())
  const parentDirty = git('-C', target, 'status', '--porcelain')
  const unexpectedDirty = parentDirty.split(/\r?\n/).filter((line) => line && !submodulePaths.some((path) => line.endsWith(` ${path}`) || line.endsWith(`\t${path}`)))
  if (unexpectedDirty.length > 0) throw new Error(`Existing FreeCAD checkout is dirty outside submodules: ${target}`)

  // A previous interrupted clone can leave a non-empty directory without a
  // gitlink checkout. Move only those exact submodule targets into an ignored,
  // recoverable cache before asking Git to initialize them again.
  if (!offline) {
    const staleRoot = resolve(root, '.cache/freecad/stale-submodules', String(Date.now()))
    let moved = 0
    for (const submodulePath of submodulePaths) {
      const submodule = resolve(target, submodulePath)
      const present = await stat(submodule).then(() => true, () => false)
      if (!present) continue
      const hasGitMetadata = await stat(resolve(submodule, '.git')).then(() => true, () => false)
      const childDirty = hasGitMetadata
        ? git('-C', submodule, 'status', '--porcelain').length > 0
        : true
      if (!hasGitMetadata || childDirty) {
        const destination = resolve(staleRoot, submodulePath)
        await mkdir(dirname(destination), { recursive: true })
        await rename(submodule, destination)
        moved += 1
        console.error(`Moved stale FreeCAD submodule ${submodulePath} to ${destination}`)
      }
    }
    if (moved > 0) await mkdir(staleRoot, { recursive: true })
  } else {
    console.error('FREECAD_SOURCE_OFFLINE=1: preserving the pinned source checkout and skipping submodule repair.')
  }
}

const currentRevision = git('-C', target, 'rev-parse', 'HEAD')
if (offline && currentRevision === toolchain.source.commit) {
  console.error(`FREECAD_SOURCE_OFFLINE=1: using pinned FreeCAD source ${currentRevision}.`)
} else {
  git('-C', target, 'fetch', '--depth=1', 'origin', `refs/tags/${toolchain.source.tag}`)
  const fetched = git('-C', target, 'rev-parse', 'FETCH_HEAD')
  if (fetched !== toolchain.source.commit) throw new Error(`Fetched FreeCAD tag resolved to ${fetched}, expected ${toolchain.source.commit}.`)
  git('-C', target, 'checkout', '--detach', toolchain.source.commit)
}
// The locked source graph includes GSL, OndselSolver, AddonManager and the
// test support checkout. Initialize every gitlink so a clean oracle build does
// not silently fall back to a partial module set.
git('-C', target, 'submodule', 'sync', '--recursive')
if (offline) console.error('FREECAD_SOURCE_OFFLINE=1: skipping network-dependent submodule update.')
else git('-C', target, 'submodule', 'update', '--init', '--recursive')
console.log(`FreeCAD source ready: ${target} @ ${toolchain.source.commit}`)