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

/**
 * PATCH /api/flashcards/[id]
 * Update front and/or back of a flashcard.
 */
export async function PATCH(
  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: cardId } = await params
    const body = await request.json()
    const front = typeof body.front === 'string' ? body.front.trim() : undefined
    const back = typeof body.back === 'string' ? body.back.trim() : undefined

    if (!front && !back) {
      return NextResponse.json({ error: 'Nothing to update' }, { status: 400 })
    }

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

    const updated = await prisma.flashcard.update({
      where: { id: cardId },
      data: {
        ...(front !== undefined && { front }),
        ...(back !== undefined && { back }),
      },
    })

    return NextResponse.json({ card: { id: updated.id, front: updated.front, back: updated.back } })
  } catch (error) {
    console.error('[flashcards/[id] PATCH]', error)
    return NextResponse.json({ error: 'Failed to update card' }, { status: 500 })
  }
}

/**
 * DELETE /api/flashcards/[id]
 * Delete a single flashcard.
 */
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: cardId } = await params

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

    await prisma.flashcard.delete({ where: { id: cardId } })

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