#include "question.h"
#include <stack>
#include <algorithm>
#include <sstream>

using namespace std;

// QuestionGenerator 基类实现
vector<string> QuestionGenerator::GenerateQuestion(int count) {
    vector<string> questions;
    int attempts = 0;
    const int max_attempts = count * 10;

    while (questions.size() < count && attempts < max_attempts) {
        string question = GenerateLogic();

        if (IsQuestionUnique(question)) {
            questions.push_back(question);
            existingqustions.insert(question);
        }

        attempts++;
    }

    return questions;
}

int QuestionGenerator::GetRand(int min, int max) {

    uniform_int_distribution<> dis(min, max);
    return dis(gen);
}

char QuestionGenerator::GetOperator() {
    char operators[] = {'+', '-', '*', '/'};
    return operators[GetRand(0, 3)];
}

bool QuestionGenerator::IsQuestionUnique(const string& question) const {
    return existingqustions.find(question) == existingqustions.end();
}

void QuestionGenerator::ClearQuestions() {
    existingqustions.clear();
}

// PrimaryQuestionGenerator 实现
string PrimaryQuestionGenerator::GenerateLogic() {
    int operands = GetRand(2, 5);

    // 50%概率使用带括号的表达式
    if (GetRand(0, 1) == 1 && operands >= 3) {
        return GenerateWithParentheses(operands);
    }

    // 生成基础表达式
    stringstream ss;
    for (int i = 0; i < operands; i++) {
        ss << GetRand(1, 100);
        if (i < operands - 1) {
            ss << " " << GetOperator() << " ";
        }
    }
    ss << " = ";
    return ss.str();
}

string PrimaryQuestionGenerator::GetType() const {
    return "小学";
}

string PrimaryQuestionGenerator::ParenthesesCaceOne(int operands,
                                                     const vector<int>& numbers) {
    stringstream ss;

    ss << "(" << numbers[0] << " " << GetOperator() << " " << numbers[1] << ")";

    for (int i = 2; i < operands; i++) {
        ss << " " << GetOperator() << " " << numbers[i];
    }

    ss << " = ";
    return ss.str();
}

string PrimaryQuestionGenerator::ParenthesesCaceTwo(int operands,
                                                     const vector<int>& numbers) {
    stringstream ss;

   ss << numbers[0] << " " << GetOperator() << " ";
            ss << "(" << numbers[1] << " " << GetOperator() << " " << numbers[2] << ")";

    for (int i = 3; i < operands; i++) {
            ss << " " << GetOperator() << " " << numbers[i];
        }

    ss << " = ";
    return ss.str();
}
string PrimaryQuestionGenerator::ParenthesesCaceThree(int operands,
                                                       const vector<int>& numbers) {
    stringstream ss;

   if (operands >= 4) {
            int mid = operands / 2;
             ss << "(";
            for (int i = 0; i < mid; i++) {
                if (i > 0) ss << " " << GetOperator() << " ";
                    ss << numbers[i];
                }
               ss << ") " << GetOperator() << " (";
            for (int i = mid; i < operands; i++) {
                if (i > mid) ss << " " << GetOperator() << " ";
                ss << numbers[i];
                }
            ss << ")";
        } else {
            ss << "(" << numbers[0] << " " << GetOperator() << " " << numbers[1] << ")";
            for (int i = 2; i < operands; i++) {
                ss << " " << GetOperator() << " " << numbers[i];
                }
            }

    ss << " = ";
    return ss.str();
}

string PrimaryQuestionGenerator::GenerateWithParentheses(int operands) {
    stringstream ss;
    vector<int> numbers;
    string result;

    for (int i = 0; i < operands; i++) {
        numbers.push_back(GetRand(1, 100));
    }

    int parenthesisType = GetRand(1, 3);

    switch (parenthesisType) {
        case 1:
            result = ParenthesesCaceOne(operands,numbers);
            break;

        case 2:
            result = ParenthesesCaceTwo(operands,numbers);
            break;

        case 3:
            result = ParenthesesCaceThree(operands,numbers);
            break;
    }


    if (!IsValidParentheses(result)) {
        return GenerateLogic(); // 重新生成
    }

    return result;
}

bool PrimaryQuestionGenerator::IsValidParentheses(const string& expr) const {
    stack<char> st;
    for (char c : expr) {
        if (c == '(') st.push(c);
        else if (c == ')') {
            if (st.empty()) return false;
            st.pop();
        }
    }
    return st.empty();
}

// JuniorQuestionGenerator 实现
string JuniorQuestionGenerator::GenerateLogic() {
    int operands = GetRand(1, 5);
    stringstream ss;

    for (int i = 0; i < operands; i++) {
        if(i==0){
            if (GetRand(0, 1) == 1) {
                ss << GetRand(1, 20) << "^2";
            } else {
                ss << "√" << GetRand(1, 100);
            }
            if (i < operands - 1) {
            ss << " " << GetOperator() << " ";
            }
            continue;

            }
        // 30%概率使用平方或开方
        if (GetRand(0, 2) == 0) {
            if (GetRand(0, 1) == 1) {
                ss << GetRand(1, 20) << "^2";
            } else {
                ss << "√" << GetRand(1, 100);
            }
        } else {
            ss << GetRand(1, 100);
        }

        if (i < operands - 1) {
            ss << " " << GetOperator() << " ";
        }
    }
    ss << " = ";
    return ss.str();
}

string JuniorQuestionGenerator::GetType() const {
    return "初中";
}

// SeniorQuestionGenerator 实现
string SeniorQuestionGenerator::GenerateLogic() {
    int operands = GetRand(1, 5);
    stringstream ss;

    for (int i = 0; i < operands; i++) {
        if(i==0){
            string trigFuncs[] = {"sin", "cos", "tan"};
            string func = trigFuncs[GetRand(0, 2)];
            ss << func << "(" << GetRand(1, 90) << ")";
            if (i < operands - 1) {
            ss << " " << GetOperator() << " ";
            }
            continue;
        }
        // 随机决定是否添加三角函数
        if (GetRand(0, 2) == 0 ) {
            string trigFuncs[] = {"sin", "cos", "tan"};
            string func = trigFuncs[GetRand(0, 2)];
            ss << func << "(" << GetRand(1, 90) << ")";
        }
        else{
             ss << GetRand(1, 100);
        }
        if (i < operands - 1) {
            ss << " " << GetOperator() << " ";
        }

    }
    ss << " = ";
    return ss.str();
}

string SeniorQuestionGenerator::GetType() const {
    return "高中";
}

// 工厂函数实现
unique_ptr<QuestionGenerator> CreateQuestionGenerator(const std::string& type) {
    if (type == "小学") {
        return make_unique<PrimaryQuestionGenerator>();
    } else if (type == "初中") {
        return make_unique<JuniorQuestionGenerator>();
    } else if (type == "高中") {
        return make_unique<SeniorQuestionGenerator>();
    }
    return nullptr;
}