import { NextRequest, NextResponse } from 'next/server'
import { getMobileUserId } from '@/lib/mobile-auth'
import { paragraphRefactorService } from '@/lib/ai/services/paragraph-refactor.service'
import { reserveUsageOrThrow, QuotaExceededError } from '@/lib/entitlements'

const MODE_MAP: Record<string, 'clarify' | 'shorten' | 'improveStyle' | 'fix_grammar'> = {
  improve: 'improveStyle',
  shorten: 'shorten',
  clarify: 'clarify',
  fix_grammar: 'fix_grammar',
}

export async function POST(req: NextRequest) {
  const userId = getMobileUserId(req)
  if (!userId) return NextResponse.json({ error: 'Non autorisé' }, { status: 401 })

  const { text, mode = 'improve' } = await req.json().catch(() => ({}))
  if (!text?.trim()) return NextResponse.json({ error: 'Texte requis' }, { status: 400 })

  const refactorMode = MODE_MAP[mode]
  if (!refactorMode) {
    return NextResponse.json({ error: 'Mode invalide. Valeurs: improve, shorten, clarify, fix_grammar' }, { status: 400 })
  }

  const validation = paragraphRefactorService.validateWordCount(text)
  if (!validation.valid) return NextResponse.json({ error: validation.error }, { status: 400 })

  try {
    await reserveUsageOrThrow(userId, 'reformulate')
  } catch (err) {
    if (err instanceof QuotaExceededError) {
      return NextResponse.json({ error: 'quota_exceeded' }, { status: 402 })
    }
    throw err
  }

  const result = await paragraphRefactorService.refactor(text, refactorMode, 'markdown', undefined)

  return NextResponse.json({ improved: result.refactored, original: result.original })
}