#include "primary_generator.h"

#include <sstream>
#include <string>
#include <vector>

std::vector<std::string> PrimaryGenerator::GenerateQuestions(int count,
                                                           const std::string& username) {
  current_user_ = username;
  std::vector<std::string> questions;
  questions.reserve(count);  // 预分配空间提高效率
  
  for (int i = 0; i < count; ++i) {
    questions.push_back(GenerateSingleQuestion());
  }
  
  return questions;
}

std::string PrimaryGenerator::GenerateSingleQuestion() {
  static const std::vector<char> kOperators = {'+', '-', '*', '/'};
  const int operand_count = GetRandomNumber(kMinOperands, kMaxOperands);
  
  std::stringstream ss;
  ss << GetRandomNumber(kMinNumber, kMaxNumber);  // 第一个操作数
  
  for (int i = 1; i < operand_count; ++i) {
    const char op = GetRandomOperator(kOperators);
    ss << " " << op << " " << GetRandomNumber(kMinNumber, kMaxNumber);
  }
  
  ss << " = ?";
  return ss.str();
}

bool PrimaryGenerator::MeetsDifficultyRequirements(const std::string& question) {
  // 小学题目只需要包含基本运算符：+ - * /
  return question.find('+') != std::string::npos ||
         question.find('-') != std::string::npos ||
         question.find('*') != std::string::npos ||
         question.find('/') != std::string::npos;
}