import { NextRequest, NextResponse } from 'next/server'
import { auth } from '@/auth'
import { notebookSuggestionService } from '@/lib/ai/services/notebook-suggestion.service'
import { hasUserAiConsent } from '@/lib/consent/server-consent'
import { withAiQuota, handleQuotaHttpError } from '@/lib/ai-quota'

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

    if (!(await hasUserAiConsent())) {
      return NextResponse.json({ error: 'ai_consent_required' }, { status: 403 })
    }

    const body = await req.json()
    const { noteContent, language = 'en' } = body

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

    const wordCount = noteContent.trim().split(/\s+/).length
    if (wordCount < 20) {
      return NextResponse.json({
        suggestion: null,
        reason: 'content_too_short',
        message: 'Note content too short for meaningful suggestion'
      })
    }

    const suggestedNotebook = await withAiQuota(
      session.user.id,
      'auto_tag',
      () => notebookSuggestionService.suggestNotebook(
        noteContent,
        session.user!.id,
        language
      ),
      { lane: 'tags' },
    )

    return NextResponse.json({
      suggestion: suggestedNotebook,
      confidence: suggestedNotebook ? 0.8 : 0
    })
  } catch (error) {
    const quotaResp = handleQuotaHttpError(error)
    if (quotaResp) return quotaResp
    console.error('[/api/ai/suggest-notebook] Error:', error)
    return NextResponse.json(
      { error: 'Failed to generate suggestion' },
      { status: 500 }
    )
  }
}