import React, { useState, useEffect } from "react";
import { useSearchParams, useNavigate } from "react-router-dom";
import { Button, message, Typography } from "antd";
import { ArrowLeftOutlined } from "@ant-design/icons";
import type { Question, AnswerResult } from "../types/question";
import * as questionApi from "../api/question";
import QuestionProgress from "../components/QuestionProgress";
import QuestionCard from "../components/QuestionCard";
import CompletionSummary from "../components/CompletionSummary";
import styles from "./Question.module.less";

const { Title } = Typography;

const QuestionPage: React.FC = () => {
  const [searchParams] = useSearchParams();
  const navigate = useNavigate();
  const [currentQuestion, setCurrentQuestion] = useState<Question | null>(null);
  const [selectedAnswer, setSelectedAnswer] = useState<string | string[]>("");
  const [showResult, setShowResult] = useState(false);
  const [answerResult, setAnswerResult] = useState<AnswerResult | null>(null);
  const [loading, setLoading] = useState(false);
  const [autoNextLoading, setAutoNextLoading] = useState(false);
  const [allQuestions, setAllQuestions] = useState<Question[]>([]);
  const [currentIndex, setCurrentIndex] = useState(0);

  // 答题统计
  const [correctCount, setCorrectCount] = useState(0);
  const [wrongCount, setWrongCount] = useState(0);
  const [showSummary, setShowSummary] = useState(false);

  // 从localStorage恢复答题进度
  const getStorageKey = () => {
    const type = searchParams.get("type");
    const mode = searchParams.get("mode");
    return `question_progress_${type || mode || "default"}`;
  };

  // 保存答题进度
  const saveProgress = (index: number, correct: number, wrong: number) => {
    const key = getStorageKey();
    localStorage.setItem(
      key,
      JSON.stringify({
        currentIndex: index,
        correctCount: correct,
        wrongCount: wrong,
        timestamp: Date.now(),
      })
    );
  };

  // 恢复答题进度
  const loadProgress = () => {
    const key = getStorageKey();
    const saved = localStorage.getItem(key);
    if (saved) {
      try {
        const progress = JSON.parse(saved);
        setCurrentIndex(progress.currentIndex || 0);
        setCorrectCount(progress.correctCount || 0);
        setWrongCount(progress.wrongCount || 0);
        return progress.currentIndex || 0;
      } catch (e) {
        console.error("恢复进度失败", e);
      }
    }
    return 0;
  };

  // 加载随机题目
  const loadRandomQuestion = async () => {
    setLoading(true);
    try {
      // 检查是否是错题练习模式
      const mode = searchParams.get("mode");
      const res =
        mode === "wrong"
          ? await questionApi.getRandomWrongQuestion()
          : await questionApi.getRandomQuestion();

      if (res.success && res.data) {
        setCurrentQuestion(res.data);
        setSelectedAnswer(res.data.type === "multiple-selection" ? [] : "");
        setShowResult(false);
        setAnswerResult(null);
      }
    } catch (error: any) {
      if (error.response?.status === 401) {
        message.error("请先登录");
      } else if (error.response?.status === 404) {
        message.error("暂无错题");
      } else {
        message.error("加载题目失败");
      }
    } finally {
      setLoading(false);
    }
  };

  // 加载题目列表（从第一题开始）
  const loadQuestions = async (type?: string) => {
    setLoading(true);
    try {
      const res = await questionApi.getQuestions({ type });
      if (res.success && res.data) {
        setAllQuestions(res.data);

        // 恢复答题进度
        const savedIndex = loadProgress();
        const startIndex = savedIndex < res.data.length ? savedIndex : 0;

        if (res.data.length > 0) {
          setCurrentQuestion(res.data[startIndex]);
          setCurrentIndex(startIndex);
          setSelectedAnswer(
            res.data[startIndex].type === "multiple-selection" ? [] : ""
          );
          setShowResult(false);
          setAnswerResult(null);
        }
      }
    } catch (error) {
      message.error("加载题目列表失败");
    } finally {
      setLoading(false);
    }
  };

  // 提交答案
  const handleSubmit = async () => {
    if (!currentQuestion) return;

    // 检查是否选择了答案
    if (currentQuestion.type === "multiple-selection") {
      if ((selectedAnswer as string[]).length === 0) {
        message.warning("请选择答案");
        return;
      }
    } else if (currentQuestion.type === "fill-in-blank") {
      const answers = selectedAnswer as string[];
      if (answers.length === 0 || answers.some((a) => !a || a.trim() === "")) {
        message.warning("请填写所有空格");
        return;
      }
    } else {
      if (
        !selectedAnswer ||
        (typeof selectedAnswer === "string" && selectedAnswer.trim() === "")
      ) {
        message.warning("请填写答案");
        return;
      }
    }

    setLoading(true);
    try {
      // 处理判断题答案：将字符串 "true"/"false" 转换为布尔值
      let answerToSubmit: string | string[] | boolean = selectedAnswer;
      if (currentQuestion.type === "true-false" && typeof selectedAnswer === "string") {
        answerToSubmit = selectedAnswer === "true";
      }

      const res = await questionApi.submitAnswer({
        question_id: currentQuestion.id,
        answer: answerToSubmit,
      });

      if (res.success && res.data) {
        setAnswerResult(res.data);
        setShowResult(true);

        // 更新统计
        if (res.data.correct) {
          const newCorrect = correctCount + 1;
          setCorrectCount(newCorrect);
          saveProgress(currentIndex, newCorrect, wrongCount);
        } else {
          const newWrong = wrongCount + 1;
          setWrongCount(newWrong);
          saveProgress(currentIndex, correctCount, newWrong);
        }

        // 如果答案正确，1秒后自动进入下一题
        if (res.data.correct) {
          setAutoNextLoading(true);
          setTimeout(() => {
            setAutoNextLoading(false);
            handleNext();
          }, 1000);
        }
      }
    } catch (error) {
      message.error("提交失败");
    } finally {
      setLoading(false);
    }
  };

  // 下一题
  const handleNext = () => {
    if (allQuestions.length > 0) {
      // 检查是否完成所有题目
      if (currentIndex + 1 >= allQuestions.length) {
        // 显示统计摘要
        setShowSummary(true);
        // 清除进度
        localStorage.removeItem(getStorageKey());
        return;
      }

      const nextIndex = currentIndex + 1;
      setCurrentIndex(nextIndex);
      setCurrentQuestion(allQuestions[nextIndex]);
      setSelectedAnswer(
        allQuestions[nextIndex].type === "multiple-selection" ? [] : ""
      );
      setShowResult(false);
      setAnswerResult(null);

      // 保存进度
      saveProgress(nextIndex, correctCount, wrongCount);

      // 滚动到页面顶部
      window.scrollTo({ top: 0, behavior: 'smooth' });
    }
  };

  // 初始化
  useEffect(() => {
    const typeParam = searchParams.get("type");
    const mode = searchParams.get("mode");

    // 错题练习模式
    if (mode === "wrong") {
      loadRandomQuestion();
      return;
    }

    // 普通练习模式 - 从第一题开始
    loadQuestions(typeParam || undefined);
  }, [searchParams]);

  // 重试处理
  const handleRetry = () => {
    setShowSummary(false);
    setCurrentIndex(0);
    setCorrectCount(0);
    setWrongCount(0);
    localStorage.removeItem(getStorageKey());
    const typeParam = searchParams.get("type");
    loadQuestions(typeParam || undefined);
  };

  return (
    <div className={styles.container}>
      {/* 固定顶栏：包含导航和进度 */}
      <div className={styles.fixedTopBar}>
        <div className={styles.topBarContent}>
          <div className={styles.topBarCard}>
            {/* 头部导航 */}
            <div className={styles.header}>
              <Button
                icon={<ArrowLeftOutlined />}
                onClick={() => navigate("/")}
                className={styles.backButton}
                type="text"
              >
                返回
              </Button>
              <Title level={3} className={styles.title}>
                AnKao 刷题
              </Title>
              <div className={styles.statsGroup}>
                <div className={styles.statItem}>
                  <span className={styles.statLabel}>正确</span>
                  <span className={styles.statValue} style={{ color: '#52c41a' }}>{correctCount}</span>
                </div>
                <div className={styles.statItem}>
                  <span className={styles.statLabel}>错误</span>
                  <span className={styles.statValue} style={{ color: '#ff4d4f' }}>{wrongCount}</span>
                </div>
              </div>
            </div>

            {/* 进度条 */}
            <div className={styles.progressWrapper}>
              <QuestionProgress
                currentIndex={currentIndex}
                totalQuestions={allQuestions.length}
                correctCount={correctCount}
                wrongCount={wrongCount}
              />
            </div>
          </div>
        </div>
      </div>

      {/* 主内容区 */}
      <div className={styles.content}>
        {/* 题目卡片 */}
        {currentQuestion && (
          <QuestionCard
            question={currentQuestion}
            selectedAnswer={selectedAnswer}
            showResult={showResult}
            answerResult={answerResult}
            loading={loading}
            autoNextLoading={autoNextLoading}
            onAnswerChange={setSelectedAnswer}
            onSubmit={handleSubmit}
            onNext={handleNext}
          />
        )}
      </div>

      {/* 完成统计摘要 */}
      <CompletionSummary
        visible={showSummary}
        totalQuestions={allQuestions.length}
        correctCount={correctCount}
        wrongCount={wrongCount}
        category={currentQuestion?.category}
        onClose={() => {
          setShowSummary(false);
          navigate("/");
        }}
        onRetry={handleRetry}
      />
    </div>
  );
};

export default QuestionPage;