import { extname } from 'path'
import { NextRequest } from 'next/server'
import { sanitizeFilename } from './sanitize'
import { ALL_ALLOWED_EXTENSIONS, MODEL_EXTENSIONS, MAX_FILE_SIZE } from './constants'
import type { ParsedFile } from './types'

interface ParsedUpload {
  folderName: string
  files: ParsedFile[]
}

export async function parseMultiUpload(req: NextRequest): Promise<ParsedUpload> {
  const formData = await req.formData()
  const folderValue = formData.get('folderName')
  const folderName = typeof folderValue === 'string' ? folderValue.trim() || 'assets' : 'assets'
  const safeFolderName = sanitizeFilename(folderName).replace(/[^a-zA-Z0-9-_]/g, '-')

  const rawFiles = formData.getAll('files')
  const fileTypes = formData.getAll('fileTypes').filter((value): value is string => typeof value === 'string')
  const textureNames = formData.getAll('textureNames').filter((value): value is string => typeof value === 'string')

  const fileEntries: File[] = []
  for (const entry of rawFiles) {
    if (!(entry instanceof File)) {
      throw new Error('Donnees de fichier invalides')
    }
    fileEntries.push(entry)
  }

  if (fileEntries.length === 0) {
    throw new Error('Aucun fichier recu')
  }

  const parsed: ParsedFile[] = []
  let modelCount = 0

  for (let i = 0; i < fileEntries.length; i++) {
    const file = fileEntries[i]
    if (!file || file.size === 0) continue

    if (file.size > MAX_FILE_SIZE) {
      throw new Error(
        `Fichier "${file.name}" trop volumineux (${(file.size / 1024 / 1024).toFixed(1)} MB). Maximum: ${MAX_FILE_SIZE / 1024 / 1024} MB.`,
      )
    }

    const fileType = fileTypes[i] || 'model'
    const texName = textureNames[i] || ''

    const originalSafe = sanitizeFilename(file.name)
    const ext = extname(originalSafe).toLowerCase()

    if (!ALL_ALLOWED_EXTENSIONS.has(ext)) {
      throw new Error(`Extension non autorisee: "${ext}"`)
    }

    let filename: string
    if (fileType === 'texture' && texName) {
      filename = sanitizeFilename(texName)
    } else {
      filename = originalSafe
    }

    const isModel = MODEL_EXTENSIONS.has(ext)
    if (isModel) {
      if (filename.toLowerCase() !== 'model.gltf') {
        throw new Error('Le modele doit etre nomme model.gltf')
      }
      modelCount += 1
    }
    const buffer = Buffer.from(await file.arrayBuffer())

    parsed.push({ filename, buffer, isModel })
  }

  if (modelCount === 0) {
    throw new Error('model.gltf manquant (obligatoire)')
  }

  if (modelCount > 1) {
    throw new Error('Un seul fichier model.gltf est autorise')
  }

  return { folderName: safeFolderName, files: parsed }
}