import { Router, Response } from "express";
import prisma from "../lib/prisma";
import { getDeepSeekClient, getPrompt } from "../lib/deepseek";
import type { AuthRequest } from "../middleware/auth";

const router = Router();

const DEFAULT_TEST_PROMPT = `Ты — составитель тестов. Сгенерируй тест из РОВНО 10 вопросов.

Требования к вопросам:
- Вопросы должны проверять ПОНИМАНИЕ темы, а не запоминание фактов
- Сложность: 3 лёгких, 4 средних, 3 сложных
- Каждый вопрос имеет 4 варианта ответа (a, b, c, d) и ровно один правильный
- Неправильные варианты должны быть правдоподобными (не абсурдными)
- Вопросы на русском языке

ВАЖНО: Верни ТОЛЬКО JSON-массив, без markdown-обёрток (\`\`\`json), без пояснений, ЧИСТЫЙ JSON:
[{"question":"текст вопроса","options":{"a":"вариант А","b":"вариант Б","c":"вариант В","d":"вариант Г"},"correct":"a"}]`;

/** Контекст пары: id назначенного ученика (общие тесты для наставника и ученика). */
function pairStudentScopeId(req: AuthRequest): number {
  return req.studentId!;
}

const authorSelect = { username: true, displayName: true } as const;

router.get("/", async (req: AuthRequest, res: Response) => {
  const scopeId = pairStudentScopeId(req);
  const tests = await prisma.test.findMany({
    where: { studentId: scopeId },
    orderBy: { createdAt: "desc" },
    include: {
      author: { select: authorSelect },
      results: {
        where: { studentId: scopeId },
        orderBy: { createdAt: "asc" },
      },
    },
  });
  res.json(tests);
});

router.get("/:id", async (req: AuthRequest, res: Response) => {
  const id = parseInt(req.params.id as string, 10);
  const scopeId = pairStudentScopeId(req);
  const test = await prisma.test.findFirst({
    where: { id, studentId: scopeId },
    include: {
      author: { select: authorSelect },
      results: {
        where: { studentId: scopeId },
        orderBy: { createdAt: "asc" },
      },
    },
  });

  if (!test) {
    res.status(404).json({ error: "Test not found" });
    return;
  }

  res.json(test);
});

router.post("/generate", async (req: AuthRequest, res: Response) => {
  const { topic, fromQuestions } = req.body;
  const scopeId = pairStudentScopeId(req);
  const questionBankStudentId = req.studentId!;

  const client = await getDeepSeekClient();
  const systemPrompt = await getPrompt("prompt_test", DEFAULT_TEST_PROMPT);

  let userMessage: string;

  if (fromQuestions) {
    const questions = await prisma.question.findMany({
      where: { studentId: questionBankStudentId },
      orderBy: { createdAt: "desc" },
      take: 20,
    });
    const questionTexts = questions.map((q: { text: string }) => q.text).join("\n");
    userMessage = `Составь тест на основе этих вопросов, которые задавал пользователь ранее:\n${questionTexts}`;
  } else {
    if (!topic) {
      res.status(400).json({ error: "Topic is required" });
      return;
    }
    userMessage = `Тема: ${topic}`;
  }

  try {
    const response = await client.chat.completions.create({
      model: "deepseek-chat",
      messages: [
        { role: "system", content: systemPrompt },
        { role: "user", content: userMessage },
      ],
    });

    const raw = response.choices[0]?.message?.content || "[]";
    const jsonMatch = raw.match(/\[[\s\S]*\]/);
    const questionsJson = jsonMatch ? jsonMatch[0] : "[]";

    const test = await prisma.test.create({
      data: {
        topic: topic || "По прошлым вопросам",
        questions: questionsJson,
        studentId: scopeId,
        authorId: req.user!.id,
      },
      include: {
        author: { select: authorSelect },
        results: true,
      },
    });

    res.json(test);
  } catch (err: any) {
    res.status(500).json({ error: err.message });
  }
});

router.post("/:id/submit", async (req: AuthRequest, res: Response) => {
  const id = parseInt(req.params.id as string, 10);
  const scopeId = pairStudentScopeId(req);
  const { answers } = req.body as { answers: Record<string, string> };

  const test = await prisma.test.findFirst({ where: { id, studentId: scopeId } });
  if (!test) {
    res.status(404).json({ error: "Test not found" });
    return;
  }

  const questions = JSON.parse(test.questions);
  let score = 0;
  const total = questions.length;

  for (const q of questions as { question: string; correct: string }[]) {
    if (answers[q.question] === q.correct) {
      score++;
    }
  }

  if (req.user!.role === "TUTOR") {
    res.json({ score, total, persisted: false as const });
    return;
  }

  const result = await prisma.testResult.create({
    data: {
      testId: id,
      studentId: req.user!.id,
      answers: JSON.stringify(answers),
      score,
      total,
    },
  });

  res.json({ ...result, persisted: true as const });
});

export default router;