#include "time.h"
#include <sstream>
#include <iomanip>
#include <cctype>
#include <algorithm>

using namespace std;

__BadTimeException::__BadTimeException(const string& s) : time(s) { }

// predicate that determines if a character is a digit
struct is_digit
{
	typedef char argument_type; // needed so that we can pass it to not1
	bool operator()(char c) const
	{
		return isdigit(c);
	}
};

// are all the digits in the range digits?
bool all_digits(string::iterator begin, string::iterator end)
{
	return find_if(begin, end, not1(is_digit())) == end;
}

void Time::parse_time(const std::string& time)
{
	// find the colon
	size_t colon_pos = time.find(':');
	if (colon_pos == string::npos) // colon not found
	{
		throw Time::BadTimeException(time);
	}
	
	// split it up into two parts
	string hours_str = time.substr(0, colon_pos);
	string minutes_str = time.substr(colon_pos+ 1);
	if (hours_str.size() == 0 || minutes_str.size() == 0)
	{
		throw Time::BadTimeException(time);
	}
	
	// check that they consist entirely of digits (with optional leading minus sign)
	if (!all_digits(hours_str.begin() + (hours_str[0] == '-'), hours_str.end()) ||
		!all_digits(minutes_str.begin() + (minutes_str[0] == '-'), minutes_str.end()))
	{
		throw Time::BadTimeException(time);
	}
	
	stringstream hours_ss(hours_str), minutes_ss(minutes_str);
	int h, m;
	hours_ss >> h;
	minutes_ss >> m;
	
	set_time(h, m);
}

Time::Time(int m)
{
	set_total_minutes(m);
}

Time::Time(int h, int m)
{
	set_time(h, m);
}

Time::Time(const std::string& time) : minutes(0)
{
	parse_time(time);
}

pair<int, int> Time::get_time() const
{
	return make_pair(minutes / MINUTES_IN_HOUR, minutes % MINUTES_IN_HOUR);
}

void Time::set_time(int h, int m)
{
	set_total_minutes(h * MINUTES_IN_HOUR + m);
}

int Time::get_total_minutes() const
{
	return minutes;
}

void Time::set_total_minutes(int m)
{
	minutes = m % MINUTES_IN_DAY;
	if (minutes < 0)
	{
		minutes += MINUTES_IN_DAY;
	}
}

Time Time::operator+(const Time& t) const
{
	Time ret = *this;
	ret += t;
	return ret;
}

Time Time::operator-(const Time& t) const
{
	Time ret = *this;
	ret -= t;
	return ret;
}

Time& Time::operator+=(const Time& t)
{
	set_total_minutes(minutes + t.get_total_minutes());
}

Time& Time::operator-=(const Time& t)
{
	set_total_minutes(minutes - t.get_total_minutes());
}

std::string Time::to_string() const
{
	std::stringstream ss;
	int h = minutes / MINUTES_IN_HOUR;
	int m = minutes % MINUTES_IN_HOUR;
	ss << setw(2) << setfill('0') << h << ":" << setw(2) << m;
	std::string ret;
	ss >> ret;
	return ret;
}

bool Time::operator==(const Time& other) const
{
	return minutes == other.minutes;
}

std::ostream& operator<<(std::ostream& out, const Time& t)
{
	return cout << t.to_string();
}

std::istream& operator>>(std::istream& in, Time& t)
{
	std::string temp;
	in >> temp;
	t = Time(temp);
}