import { NextRequest, NextResponse } from "next/server";
import { db } from "@/lib/db";
import { getServerSession } from "next-auth";
import { authOptions } from "@/lib/auth";
import { Prisma } from "@/lib/generated/prisma";

async function adminOnly(req: NextRequest) {
  const session = await getServerSession(authOptions);
  if (!session || (session.user as any).role !== "ADMIN") return null;
  return session;
}

function validateTierConfig(input: {
  goldWinnersCount: number;
  silverWinnersCount: number;
  bronzeWinnersCount: number;
  goldMinCorrect: number | null;
  silverMinCorrect: number | null;
  bronzeMinCorrect: number | null;
}) {
  if (input.goldWinnersCount < 0 || input.silverWinnersCount < 0 || input.bronzeWinnersCount < 0) {
    return "Winner counts cannot be negative";
  }

  if (input.goldWinnersCount + input.silverWinnersCount + input.bronzeWinnersCount <= 0) {
    return "At least one winner must be configured";
  }

  if (input.goldWinnersCount > 0 && input.goldMinCorrect == null) {
    return "Gold minimum correct answers is required";
  }

  if (input.silverWinnersCount > 0 && input.silverMinCorrect == null) {
    return "Silver minimum correct answers is required";
  }

  if (input.bronzeWinnersCount > 0 && input.bronzeMinCorrect == null) {
    return "Bronze minimum correct answers is required";
  }

  return null;
}

// GET /api/admin/quiz - list all quizzes
export async function GET(req: NextRequest) {
  const session = await adminOnly(req);
  if (!session) return NextResponse.json({ error: "Unauthorized" }, { status: 401 });

  const quizzes = await db.dailyQuiz.findMany({
    orderBy: { date: "desc" },
    include: {
      questions: { orderBy: { order: "asc" } },
      _count: { select: { submissions: true } },
    },
  });

  return NextResponse.json(quizzes);
}

// POST /api/admin/quiz - create quiz
export async function POST(req: NextRequest) {
  try {
    const session = await adminOnly(req);
    if (!session) return NextResponse.json({ error: "Unauthorized" }, { status: 401 });

    const {
      date,
      windowStart,
      windowEnd,
      goldWinnersCount,
      silverWinnersCount,
      bronzeWinnersCount,
      goldMinCorrect,
      silverMinCorrect,
      bronzeMinCorrect,
      questions,
    } = await req.json();

    const parsedInput = {
      goldWinnersCount: Number(goldWinnersCount),
      silverWinnersCount: Number(silverWinnersCount),
      bronzeWinnersCount: Number(bronzeWinnersCount),
      goldMinCorrect: goldMinCorrect == null ? null : Number(goldMinCorrect),
      silverMinCorrect: silverMinCorrect == null ? null : Number(silverMinCorrect),
      bronzeMinCorrect: bronzeMinCorrect == null ? null : Number(bronzeMinCorrect),
    };

    const validationError = validateTierConfig(parsedInput);
    if (validationError) {
      return NextResponse.json({ error: validationError }, { status: 400 });
    }

    if (!Array.isArray(questions) || questions.length === 0) {
      return NextResponse.json({ error: "At least one question is required" }, { status: 400 });
    }

    const quiz = await db.dailyQuiz.create({
      data: {
        date: new Date(`${date}T00:00:00.000Z`),
        windowStart: new Date(windowStart),
        windowEnd: new Date(windowEnd),
        goldWinnersCount: parsedInput.goldWinnersCount,
        silverWinnersCount: parsedInput.silverWinnersCount,
        bronzeWinnersCount: parsedInput.bronzeWinnersCount,
        goldMinCorrect: parsedInput.goldMinCorrect,
        silverMinCorrect: parsedInput.silverMinCorrect,
        bronzeMinCorrect: parsedInput.bronzeMinCorrect,
        questions: {
          create: questions.map((q: any, i: number) => ({
            questionText: q.questionText,
            options: q.options,
            correctAnswer: Number(q.correctAnswer),
            order: i,
          })),
        },
      },
      include: { questions: true },
    });

    return NextResponse.json(quiz, { status: 201 });
  } catch (error) {
    console.error("Failed to create quiz", error);

    if (error instanceof Prisma.PrismaClientKnownRequestError) {
      if (error.code === "P2002") {
        return NextResponse.json({ error: "Quiz date already exists" }, { status: 409 });
      }
    }

    return NextResponse.json({ error: "Failed to create quiz" }, { status: 500 });
  }
}