#include "clock.h"

#include <cstring>

namespace date_independent {

namespace {

const minutes_t minutes_per_hour = 60;
const hours_t   hours_per_day    = 24;
const total_t   minutes_per_day  = hours_per_day * minutes_per_hour;

inline void make_date_independent(total_t total_minutes)
{
    while (total_minutes < 0)
        total_minutes += minutes_per_day;

    total_minutes = total_minutes % minutes_per_day;
}

}


clock::clock(hours_t hours, minutes_t minutes)
{
    total_minutes_ = minutes_per_hour*hours + minutes;
    make_date_independent(total_minutes_);
}

bool clock::operator==(const clock &other) const
{
    return total_minutes_ == other.total_minutes_;
}

bool clock::operator!=(const clock &other) const
{
    return !(*this == other);
}

clock clock::at(hours_t hours, minutes_t minutes)
{
    return clock(hours, minutes);
}

clock clock::plus(minutes_t minutes) const
{
    clock result(*this);

    result.total_minutes_ += minutes;
    make_date_independent(result.total_minutes_);

    return result;
}

clock clock::minus(minutes_t minutes) const
{
    return plus(-minutes);
}

clock::operator std::string() const
{
    minutes_t minutes = total_minutes_ % minutes_per_hour
    hours_t   hours   = total_minutes_ / minutes_per_hour;

    char buff[6];
    snprintf(buff, 6, "%.2i:%.2i", hours, minutes);

    return buff;
}

}