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

export async function GET(req: NextRequest) {
  const userId = getMobileUserId(req)
  if (!userId) return NextResponse.json({ error: 'Unauthorized' }, { status: 401 })

  const now = new Date()
  const decks = await prisma.flashcardDeck.findMany({
    where: { userId },
    include: {
      notebook: { select: { name: true } },
      flashcards: {
        select: {
          id: true,
          interval: true,
          nextReviewAt: true,
          front: true,
        },
      },
    },
    orderBy: { updatedAt: 'desc' },
  })

  const result = decks.map((deck) => ({
    id: deck.id,
    name: deck.name,
    notebookId: deck.notebookId,
    notebookName: deck.notebook?.name ?? null,
    totalCards: deck.flashcards.length,
    dueCount: deck.flashcards.filter((c) => c.nextReviewAt <= now).length,
    masteredCount: deck.flashcards.filter((c) => c.interval >= 7).length,
  }))

  return NextResponse.json({ decks: result })
}