#include "string_util.h"

#include <regex>

namespace str_util {

const std::string WHITESPACE = " \n\r\t\f\v";

bool contains(const std::string& s, const std::string& substr) {
  return s.find(substr) != std::string::npos;
}

bool starts_with(const std::string& s, const std::string& prefix) {
  return s.rfind(prefix) == 0;
}

std::string ltrim(const std::string& s) {
  size_t start = s.find_first_not_of(WHITESPACE);
  return (start == std::string::npos) ? "" : s.substr(start);
}

std::string rtrim(const std::string& s) {
  size_t end = s.find_last_not_of(WHITESPACE);
  return (end == std::string::npos) ? "" : s.substr(0, end + 1);
}

std::string trim(const std::string& s) {
  return rtrim(ltrim(s));
}

int line_count(const std::string& str) {
  int result = 0;
  for (auto& c : str) {
    if (c == '\n') {
      result++;
    }
  }
  return result;
}

// NOTE - this won't work running within gk.exe!
bool valid_regex(const std::string& regex) {
  try {
    std::regex re(regex);
  } catch (const std::regex_error& e) {
    return false;
  }
  return true;
}
}  // namespace str_util