import { NextRequest, NextResponse } from 'next/server'
import { auth } from '@/auth'
import { withAiQuota, handleQuotaHttpError } from '@/lib/ai-quota'
import { hasUserAiConsent, aiConsentForbiddenResponse } from '@/lib/consent/server-consent'
import { generateSlideDeck } from '@/lib/ai/services/slide-deck-generator.service'

export async function POST(request: NextRequest) {
  try {
    const session = await auth()
    if (!session?.user?.id) {
      return NextResponse.json({ error: 'Unauthorized' }, { status: 401 })
    }

    if (!(await hasUserAiConsent())) {
      return aiConsentForbiddenResponse()
    }
    const userId = session.user.id

    const body = await request.json()
    const { notebookId, theme, purpose, audience, slideCount, language } = body

    if (!notebookId || typeof notebookId !== 'string') {
      return NextResponse.json({ error: 'notebookId is required' }, { status: 400 })
    }

    const intent =
      purpose || audience || slideCount
        ? {
            purpose: purpose || 'auto',
            audience: audience || 'auto',
            slideCount: typeof slideCount === 'number' ? slideCount : undefined,
            template: 'auto' as const,
          }
        : null

    const result = await withAiQuota(
      userId,
      'slide_generate',
      () =>
        generateSlideDeck({
          userId,
          sourceNotebookId: notebookId,
          theme: theme && theme !== 'auto' ? theme : null,
          lang: language === 'en' ? 'en' : 'fr',
          intent,
        }),
      { lane: 'chat' },
    )

    if (!result.success) {
      return NextResponse.json({ error: result.error || 'Failed to generate slides' }, { status: 500 })
    }

    return NextResponse.json(result)
  } catch (error: unknown) {
    const quotaResp = handleQuotaHttpError(error)
    if (quotaResp) return quotaResp
    console.error('[NotebookSlides] Error:', error)
    const message = error instanceof Error ? error.message : 'Failed to generate slides'
    return NextResponse.json({ error: message }, { status: 500 })
  }
}