import { NextRequest, NextResponse } from "next/server"
import { prisma } from "@/lib/db"
import { buildFsrsCard, getRetrievability } from "@/lib/fsrs"

export async function GET(request: NextRequest) {
  const childId = request.nextUrl.searchParams.get("childId")
  if (!childId) {
    return NextResponse.json({ error: "childId required" }, { status: 400 })
  }

  const dueCard = await prisma.fsrsCard.findFirst({
    where: {
      childId,
      dueAt: { lte: new Date() },
    },
    orderBy: { dueAt: "asc" },
  })

  if (dueCard) {
    const card = buildFsrsCard({
      stability: dueCard.stability,
      difficulty: dueCard.difficulty,
      reps: dueCard.reps,
      lapses: dueCard.lapses,
      due: dueCard.dueAt,
    })
    return NextResponse.json({
      ...dueCard,
      cardId: dueCard.id,
      retrievability: getRetrievability(card),
    })
  }

  return NextResponse.json({ skillCode: null })
}