import { NextRequest, NextResponse } from 'next/server'
import prisma from '@/lib/prisma'
import { auth } from '@/auth'

// GET /api/notes/[id]/backlinks
// Returns all notes that link TO this note via [[wikilinks]]
export async function GET(
  request: NextRequest,
  { params }: { params: Promise<{ id: string }> }
) {
  const session = await auth()
  if (!session?.user?.id) {
    return NextResponse.json({ error: 'Unauthorized' }, { status: 401 })
  }

  const { id } = await params

  // Verify the note belongs to the user
  const note = await prisma.note.findUnique({ where: { id }, select: { userId: true } })
  if (!note || note.userId !== session.user.id) {
    return NextResponse.json({ error: 'Not found' }, { status: 404 })
  }

  const backlinks = await (prisma as any).noteLink.findMany({
    where: { targetNoteId: id },
    include: {
      sourceNote: {
        select: { id: true, title: true, updatedAt: true, notebookId: true },
      },
    },
    orderBy: { createdAt: 'desc' },
  })

  return NextResponse.json({
    backlinks: backlinks.map((bl: any) => ({
      id: bl.id,
      sourceNote: bl.sourceNote,
      contextSnippet: bl.contextSnippet,
      createdAt: bl.createdAt,
    })),
  })
}