import { NextRequest, NextResponse } from 'next/server'
import { auth } from '@/auth'
import prisma from '@/lib/prisma'
import { notebookOrganizerService } from '@/lib/ai/services/notebook-organizer.service'
import { reserveUsageOrThrow, QuotaExceededError } from '@/lib/entitlements'
import { syncNoteLabels } from '@/app/actions/notes'

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

    const { notebookId } = await request.json()
    if (!notebookId) {
      return NextResponse.json({ error: 'notebookId is required' }, { status: 400 })
    }

    try {
      await reserveUsageOrThrow(session.user.id, 'reformulate')
    } catch (err) {
      if (err instanceof QuotaExceededError) {
        const isTierLocked = err.currentQuota === 0
        return NextResponse.json(
          { error: isTierLocked ? 'feature_locked' : 'quota_exceeded', errorKey: isTierLocked ? 'ai.featureLocked' : 'ai.quotaExceeded' },
          { status: 402 },
        )
      }
      throw err
    }

    const notes = await prisma.note.findMany({
      where: { notebookId, trashedAt: null, userId: session.user.id },
      select: { id: true, title: true, content: true },
      orderBy: { order: 'asc' },
    })

    if (notes.length < 2) {
      return NextResponse.json({ error: 'Need at least 2 notes to organize' }, { status: 400 })
    }

    const notesForAnalysis = notes.map(n => ({
      id: n.id,
      title: n.title || 'Sans titre',
      contentPreview: n.content.replace(/<[^>]+>/g, ' ').replace(/\s+/g, ' ').trim().slice(0, 300),
    }))

    const result = await notebookOrganizerService.analyze(notesForAnalysis)


    return NextResponse.json(result)
  } catch (error: any) {
    console.error('[Notebook Organizer] Error:', error)
    return NextResponse.json({ error: error.message || 'Failed to organize notebook' }, { status: 500 })
  }
}

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

    const { action, tagName, noteIds, notebookId } = await request.json()

    if (action === 'apply_tag' && tagName && Array.isArray(noteIds)) {
      // Fetch existing labels for each note, merge with new tag
      for (const noteId of noteIds) {
        const note = await prisma.note.findUnique({
          where: { id: noteId },
          select: { labels: true, notebookId: true },
        })
        if (!note) continue

        let existingLabels: string[] = []
        try { existingLabels = note.labels ? JSON.parse(note.labels) : [] } catch {}

        if (!existingLabels.includes(tagName)) {
          existingLabels.push(tagName)
        }

        await syncNoteLabels(noteId, existingLabels, note.notebookId, session.user.id)
      }

      return NextResponse.json({ success: true, applied: noteIds.length })
    }

    return NextResponse.json({ error: 'Invalid action' }, { status: 400 })
  } catch (error: any) {
    console.error('[Notebook Organizer PATCH] Error:', error)
    return NextResponse.json({ error: error.message }, { status: 500 })
  }
}