#ifndef UTIL_H
#define UTIL_H

#include <algorithm>
#include <cstring>
#include <stdexcept>
#include <string>

namespace util
{

/* TODO */
constexpr char SPACE[] = " ";
constexpr char COLON[] = ":";
constexpr char SEMICOLON[] = ";";

inline void trim(std::string& str)
{
    str.erase(str.begin(), std::find_if_not(str.cbegin(), str.cend(), ::isspace));
    str.erase(std::find_if_not(str.crbegin(), str.crend(), ::isspace).base(), str.end());
}

template<const char* delim, typename Accumulate>
void accumulate(const std::string& str, Accumulate acc)
{
    size_t pos{};
    std::string elem;

    while ((pos = str.find(delim)) != std::string::npos) {
        auto sub = str.substr(0, pos);
        trim(sub);
        acc(sub);
        pos += std::strlen(delim);
    }
}
/* ---- */

/** @brief Discard element from stream by type.
 *
 * @tparam T the type of the element to discard.
 * @param stream the input stream.
 *
 * @return the input stream.
 */
template<typename T, typename CharT, typename Traits>
std::basic_istream<CharT, Traits>& skip(std::basic_istream<CharT, Traits>& stream)
{
    T discard;
    return stream >> discard;
}

/** @brief Skip token in stream.
 *
 * @tparam keyword the token to skip.
 * @param stream the input stream.
 *
 * @return the input stream.
 *
 * @note The token needs to be declared as a `const char[]`, but normally,
 * string literals are `const char*`.
 *
 * ```cpp
 * constexpr char RESULT[] = "Result:";
 *
 * int main(int argc, char* argv[])
 * {
 *     int res;
 *     std::istringstream in{ "Result: 42"}
 *     in >> skip<RESULT> >> res;
 *
 *     // ...
 *
 *     return 0
 * }
 * ```
 */
template<const char* keyword, typename CharT, typename Traits>
std::basic_istream<CharT, Traits>& skip(std::basic_istream<CharT, Traits>& stream)
{
    std::string word;
    stream >> word;
    if (word != keyword)
    {
        throw std::invalid_argument("Malformed input");
    }

    return stream;
}

} // namespace util

#endif //UTIL_H