import { NextRequest, NextResponse } from 'next/server'
import { validateUploadSecret } from '@/lib/auth'
import { parseMultiUpload } from '@/lib/parse-upload'
import { getRemoteFolder } from '@/lib/github'
import { classifyFileChanges } from '@/lib/diff-files'
import { prepareGitAssets } from '@/lib/prepare-git-assets'

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

/**
 * POST /api/upload/check
 * Build the final Git payload, then compare it with the remote folder.
 */
export async function POST(req: NextRequest) {
  const authError = validateUploadSecret(req)
  if (authError) return authError

  let folderName: string
  let destination: string
  let parsedFiles: Awaited<ReturnType<typeof parseMultiUpload>>['files']

  try {
    const parsed = await parseMultiUpload(req)
    folderName = parsed.folderName
    destination = parsed.destination
    parsedFiles = parsed.files
  } catch (err) {
    const message = err instanceof Error ? err.message : 'Erreur inconnue'
    return NextResponse.json({ success: false, error: message }, { status: 400 })
  }

  const folderPath = `public/models/${destination}/${folderName}`

  try {
    const { filesToPush } = await prepareGitAssets({ folderName, destination, parsedFiles })
    const { exists, files } = await getRemoteFolder(folderPath)

    if (exists) {
      const remoteFileMap = new Map(files.map((file) => [file.name.toLowerCase(), file.size]))
      const { fileChanges, deletedFileNames } = classifyFileChanges(filesToPush, remoteFileMap, folderPath)

      const diffs: Array<{ name: string; status: 'new' | 'changed' | 'deleted' }> = []

      for (const [name, status] of fileChanges.entries()) {
        if (status === 'new' || status === 'changed') {
          diffs.push({ name, status })
        }
      }

      diffs.push(...deletedFileNames.map((name) => ({ name, status: 'deleted' as const })))

      return NextResponse.json({
        success: true,
        exists: true,
        path: folderPath,
        diffs,
      })
    }

    return NextResponse.json({ success: true, exists: false })
  } catch (err) {
    const message = err instanceof Error ? err.message : 'Erreur inconnue'
    return NextResponse.json({ success: false, error: message }, { status: 500 })
  }
}