import { NextRequest, NextResponse } from 'next/server'
import { validateUploadSecret } from '@/lib/auth'
import { getRemoteFolder, pushAllToGitHub } from '@/lib/github'
import { buildCommitMessage } from '@/lib/commit-message'
import { classifyFileChanges } from '@/lib/diff-files'
import { getModelFolderPath } from '@/lib/model-paths'
import { cleanupStagingUpload, ensurePreparedStagingAssets, readStagedManifest } from '@/lib/upload-staging'
import { acquireUploadLock, releaseUploadLock } from '@/lib/upload-lock'
import { parseStagingRequestBody } from '@/lib/upload-request'
import { getErrorMessage } from '@/lib/guards'

export const runtime = 'nodejs'
export const dynamic = 'force-dynamic'

/**
 * POST /api/upload/git
 * Upload prepared files and push to GitHub via Octokit.
 */
export async function POST(req: NextRequest) {
  const authError = validateUploadSecret(req)
  if (authError) return authError

  let folderName: string
  let stagingId: string

  try {
    const body: unknown = await req.json()
    stagingId = parseStagingRequestBody(body).stagingId
    const manifest = await readStagedManifest(stagingId)
    folderName = manifest.folderName
  } catch (err) {
    const message = getErrorMessage(err)
    return NextResponse.json({ success: false, error: message }, { status: 400 })
  }

  if (!acquireUploadLock(folderName)) {
    return NextResponse.json(
      { success: false, error: 'Un upload est deja en cours pour ce dossier. Patientez quelques secondes.' },
      { status: 409 },
    )
  }

  try {
    const {
      filesToPush,
      modelFilename,
      compressed,
      compressionError,
      assetSummaries,
    } = await ensurePreparedStagingAssets(stagingId)

    const folderPath = getModelFolderPath(folderName)
    const remote = await getRemoteFolder(folderPath)
    const remoteFileMap = new Map(remote.files.map((f) => [f.name.toLowerCase(), f.size]))

    const isReplace = remoteFileMap.size > 0

    const { fileChanges, changedFilesToPush, deletedFileNames, deletePaths } =
      classifyFileChanges(filesToPush, remoteFileMap, folderPath)

    if (changedFilesToPush.length === 0 && deletePaths.length === 0) {
      await cleanupStagingUpload(stagingId).catch(() => {})
      return NextResponse.json({
        success: true,
        folderName,
        filesCount: 0,
        compressed,
        compressionError: compressionError || undefined,
        message: 'Aucun fichier modifie — rien a envoyer.',
      })
    }

    const commitMessage = buildCommitMessage(
      folderName,
      modelFilename,
      assetSummaries,
      isReplace,
      fileChanges,
      deletedFileNames,
    )

    try {
      const { commitUrl } = await pushAllToGitHub(changedFilesToPush, deletePaths, commitMessage)
      await cleanupStagingUpload(stagingId).catch(() => {})

      return NextResponse.json({
        success: true,
        folderName,
        filesCount: changedFilesToPush.length,
        compressed,
        compressionError: compressionError || undefined,
        message: `${changedFilesToPush.length} fichier(s) modifie(s) envoye(s) sur GitHub en un seul commit.`,
        commitUrl,
      })
    } catch (err) {
      const message = getErrorMessage(err, 'Erreur GitHub inconnue')
      return NextResponse.json(
        { success: false, error: `Push GitHub echoue: ${message}` },
        { status: 500 },
      )
    }
  } finally {
    releaseUploadLock(folderName)
  }
}