import { NextRequest, NextResponse } from 'next/server'
import { getMobileUserId } from '@/lib/mobile-auth'
import { runLaneWithBillingUser, willUseByokForLane } from '@/lib/ai/provider-for-user'
import { getSystemConfig } from '@/lib/config'
import { reserveUsageOrThrow, QuotaExceededError } from '@/lib/entitlements'

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

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

  const wordCount = content.split(/\s+/).length
  if (wordCount < 5) return NextResponse.json({ error: 'Contenu trop court (min 5 mots)' }, { status: 400 })

  const config = await getSystemConfig()
  const { usedByok: willUseByok } = await willUseByokForLane('tags', config, userId)
  if (!willUseByok) {
    try {
      await reserveUsageOrThrow(userId, 'auto_title')
    } catch (err) {
      if (err instanceof QuotaExceededError) {
        return NextResponse.json({ error: 'quota_exceeded' }, { status: 402 })
      }
      throw err
    }
  }

  const prompt = `Génère 3 titres concis pour ce texte. Réponds UNIQUEMENT avec un tableau JSON: [{"title":"titre1"},{"title":"titre2"},{"title":"titre3"}]\n\nTexte: ${content.slice(0, 400)}`

  const { result: titles } = await runLaneWithBillingUser(
    'tags',
    config,
    userId,
    (provider) => provider.generateTitles(prompt),
  )

  return NextResponse.json({ suggestions: (titles ?? []).map((t: any) => t.title ?? t) })
}