import { NextRequest, NextResponse } from 'next/server'
import { join } from 'path'
import { mkdir, writeFile, readFile, unlink, rm } from 'fs/promises'
import { existsSync } from 'fs'
import { validateUploadSecret } from '@/lib/auth'
import { parseMultiUpload } from '@/lib/parse-upload'
import { compressWithBlender } from '@/lib/blender'
import { getRemoteFolder, pushAllToGitHub } from '@/lib/github'
import { buildCommitMessage } from '@/lib/commit-message'
import { TMP_DIR } from '@/lib/constants'
import type { FileChange } from '@/lib/types'

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

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

  // --- Parse all files ---
  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 })
  }

  // --- Process files (compress model if possible) ---
  const filesToPush: { path: string; contentBase64: string }[] = []
  let modelFilename = ''
  let compressed = false
  let compressionError: string | undefined
  const textureNames: string[] = []

  for (const pf of parsedFiles) {
    let content = pf.buffer

    if (pf.isModel) {
      modelFilename = pf.filename

      // Write to /tmp for Blender compression
      const tmpFolder = join(TMP_DIR, folderName)
      await mkdir(tmpFolder, { recursive: true })
      const tmpFilePath = join(tmpFolder, pf.filename)
      await writeFile(tmpFilePath, pf.buffer)

      const stem = pf.filename.replace(/\.[^.]+$/, '')
      const compressedPath = join(tmpFolder, `${stem}_compressed.glb`)

      try {
        const result = await compressWithBlender(tmpFilePath, compressedPath)

        if (result.success && existsSync(compressedPath)) {
          content = await readFile(compressedPath)
          compressed = true
          await unlink(compressedPath).catch(() => {})
        } else {
          compressionError = result.error
        }
      } finally {
        // Always cleanup temp files
        await unlink(tmpFilePath).catch(() => {})
        await rm(tmpFolder, { recursive: true, force: true }).catch(() => {})
      }
    } else {
      textureNames.push(pf.filename)
    }

    filesToPush.push({
      path: `public/models/${destination}/${folderName}/${pf.filename}`,
      contentBase64: content.toString('base64'),
    })
  }

  // --- Detect existing files and compare size to classify changes (LFS-compatible) ---
  const folderPath = `public/models/${destination}/${folderName}`
  let remoteFileMap: Map<string, number>

  try {
    const remote = await getRemoteFolder(folderPath)
    remoteFileMap = new Map(remote.files.map((f) => [f.name.toLowerCase(), f.size]))
  } catch {
    remoteFileMap = new Map()
  }

  const isReplace = remoteFileMap.size > 0

  // Classify each file: changed, new, or unchanged
  const fileChanges = new Map<string, FileChange>()
  const changedFilesToPush: { path: string; contentBase64: string }[] = []

  for (const f of filesToPush) {
    const filename = f.path.split('/').pop() ?? ''
    const localSize = Buffer.from(f.contentBase64, 'base64').length
    const remoteSize = remoteFileMap.get(filename.toLowerCase())

    if (remoteSize === undefined) {
      fileChanges.set(filename.toLowerCase(), 'new')
      changedFilesToPush.push(f)
    } else if (remoteSize !== localSize) {
      fileChanges.set(filename.toLowerCase(), 'changed')
      changedFilesToPush.push(f)
    } else {
      fileChanges.set(filename.toLowerCase(), 'unchanged')
    }
  }

  // Files on remote not in the new upload → deleted (orphans)
  const newFileNames = new Set(filesToPush.map((f) => (f.path.split('/').pop() ?? '').toLowerCase()))
  const deletedFileNames: string[] = []
  const deletePaths: string[] = []
  for (const [name] of remoteFileMap) {
    if (!newFileNames.has(name)) {
      deletedFileNames.push(name)
      deletePaths.push(`${folderPath}/${name}`)
    }
  }

  // If nothing changed, don't create an empty commit
  if (changedFilesToPush.length === 0 && deletePaths.length === 0) {
    return NextResponse.json({
      success: true,
      folderName,
      filesCount: 0,
      compressed,
      compressionError: compressionError || undefined,
      message: 'Aucun fichier modifie — rien a envoyer.',
    })
  }

  // --- Build commit message ---
  const commitMessage = buildCommitMessage(
    folderName, destination, modelFilename, textureNames,
    compressed, isReplace, fileChanges, deletedFileNames,
  )

  // --- Push all in one commit ---
  try {
    const { commitUrl } = await pushAllToGitHub(changedFilesToPush, deletePaths, commitMessage)

    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 = err instanceof Error ? err.message : 'Erreur GitHub inconnue'
    return NextResponse.json(
      { success: false, error: `Push GitHub echoue: ${message}` },
      { status: 500 },
    )
  }
}