import { NextRequest, NextResponse } from 'next/server'
import { auth } from '@/auth'
import prisma from '@/lib/prisma'
import { getDeckDetail } from '@/lib/flashcards/deck-queries'

export async function GET(
  _request: NextRequest,
  { params }: { params: Promise<{ id: string }> },
) {
  try {
    const session = await auth()
    if (!session?.user?.id) {
      return NextResponse.json({ error: 'Unauthorized' }, { status: 401 })
    }

    const { id } = await params
    const deck = await getDeckDetail(session.user.id, id)
    if (!deck) {
      return NextResponse.json({ error: 'Deck not found' }, { status: 404 })
    }

    const now = new Date()
    const dueCount = deck.cards.filter((c) => c.due).length
    const masteredCount = deck.cards.filter((c) => c.mastered).length

    return NextResponse.json({
      deck,
      stats: {
        total: deck.cards.length,
        due: dueCount,
        mastered: masteredCount,
      },
    })
  } catch (error) {
    console.error('[flashcards/decks/[id] GET]', error)
    return NextResponse.json({ error: 'Failed to load deck' }, { status: 500 })
  }
}

/**
 * DELETE /api/flashcards/decks/[id]
 * Permanently deletes the deck and all its cards (cascade via Prisma).
 */
export async function DELETE(
  _request: NextRequest,
  { params }: { params: Promise<{ id: string }> },
) {
  try {
    const session = await auth()
    if (!session?.user?.id) {
      return NextResponse.json({ error: 'Unauthorized' }, { status: 401 })
    }

    const { id } = await params

    const deck = await prisma.flashcardDeck.findFirst({
      where: { id, userId: session.user.id },
    })
    if (!deck) {
      return NextResponse.json({ error: 'Deck not found' }, { status: 404 })
    }

    await prisma.flashcardDeck.delete({ where: { id } })

    return NextResponse.json({ ok: true })
  } catch (error) {
    console.error('[flashcards/decks/[id] DELETE]', error)
    return NextResponse.json({ error: 'Failed to delete deck' }, { status: 500 })
  }
}