import { NextRequest, NextResponse } from 'next/server'
import prisma from '@/lib/prisma'
import { auth } from '@/auth'
import { pickBestBlockForHint, pickBestPlainPassageForHint } from '@/lib/blocks/extract-blocks'

/**
 * GET /api/blocks/resolve?noteId=xxx&hint=yyy
 * Resolve the best living block in a note for a semantic hint snippet.
 */
export async function GET(request: NextRequest) {
  const session = await auth()
  if (!session?.user?.id) {
    return NextResponse.json({ error: 'Unauthorized' }, { status: 401 })
  }

  const noteId = request.nextUrl.searchParams.get('noteId')
  const hint = request.nextUrl.searchParams.get('hint') || ''

  if (!noteId) {
    return NextResponse.json({ error: 'noteId required' }, { status: 400 })
  }

  const note = await prisma.note.findFirst({
    where: { id: noteId, userId: session.user.id },
    select: {
      id: true,
      title: true,
      content: true,
      notebookId: true,
    },
  })

  if (!note) {
    return NextResponse.json({ error: 'Note not found' }, { status: 404 })
  }

  const liveBlock = pickBestBlockForHint(note.content, hint)
  const block = liveBlock ?? pickBestPlainPassageForHint(note.content, hint)
  if (!block) {
    return NextResponse.json({ error: 'no_block_found' }, { status: 404 })
  }

  const mode = liveBlock?.blockId ? 'live' : 'citation'

  let notebookName = ''
  if (note.notebookId) {
    const notebook = await prisma.notebook.findFirst({
      where: { id: note.notebookId, userId: session.user.id },
      select: { name: true },
    })
    notebookName = notebook?.name || ''
  }

  const words = block.content.split(/\s+/)
  const snippet = words.slice(0, 30).join(' ') + (words.length > 30 ? '…' : '')

  return NextResponse.json({
    mode,
    block: {
      blockId: block.blockId,
      noteId: note.id,
      noteTitle: note.title || '',
      notebookName,
      content: block.content,
      snippet,
    },
  })
}