#include "Problem.h"

#include <cmath>
#include <locale.h>
#include <syslog.h>
#include <stdexcept>

bool Problem::seeded = false;

Problem::Problem(PROBLEM_TYPE type, unsigned short max_digits, unsigned win_x, unsigned win_y)
	: problem_type(type), window_x(win_x), window_y(win_y)
{
	// NOTE(dev): Only ever seed rand ONCE!
	// TODO(dev): Should this be in main.cpp?
	if(!seeded)
	{
		// srand(time());
		srand(0);
		setlocale(LC_NUMERIC, ""); // apostrophe to enable thousands separator in printf statements.
		seeded = true;
	}

	input = "";

	GenerateNumbers(type, (max_digits > 5 ? 5 : max_digits));

	GenerateWindow(win_x, win_y);
}

Problem::~Problem()
{
	if(win)
		delwin(win);
}

void Problem::Draw(bool selected, const INPUT_STYLE &input_style)
{
	if(!win)
		return;

	// Draw the window:
	if(selected)
		box(win, '*', '*'); // 0, 0 gives default characters for the vertical and horizontal lines
	else
		wborder(win, ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ');

	mvwprintw(win, 2, 4, "%'6d", number_top);
	mvwprintw(win, 3, 4, "%'6d", number_bottom);
	switch(problem_type)
	{
	case EASY_ADDITION:
	case HARD_ADDITION:
		mvwprintw(win, 3, 2, "+");
		break;
	case EASY_SUBTRACTION:
	case HARD_SUBTRACTION:
		mvwprintw(win, 3, 2, "-");
		break;
	case EASY_MULTIPLICATION:
	case HARD_MULTIPLICATION:
		mvwprintw(win, 3, 2, "*");
		break;
	case EASY_DIVISION:
	case HARD_DIVISION:
		mvwprintw(win, 3, 2, "÷");
		break;
	};
	mvwprintw(win, 4, 2, "========");
	if(Input() > 999999)
		mvwprintw(win, 5, 3, " FAILED");
	else if(Input() != 0 || selected) // if it's not selected then the answer could have been zero
		mvwprintw(win, 5, 3, "%'7d", Input());
	else if(selected)
		mvwprintw(win, 5, 3, "       ");

	// Place the cursor in the correct position!
	int length = input.length() + ((input.length() - 1) / 3); // add commas, too!
	if(input_style == INPUT_STYLE::INPUT_PREPEND)
		mvwprintw(win, 5, 9 - length, "");
	else
		mvwprintw(win, 5, 10, "");
	wrefresh(win);
}

void Problem::GenerateNumbers(PROBLEM_TYPE type, unsigned short max_digits)
{
	// Determine how many digits long these numbers should be:
	unsigned short digits = rand() % (max_digits) + 1; // at least one digit
	number_top = 0;
	number_bottom = 0;

	switch(problem_type)
	{
	default:
	case EASY_ADDITION:
		for(auto digit = 0; digit < digits; ++digit)
		{
			unsigned short temp_number_top = rand() % 10;
			unsigned short temp_number_bottom;
			if(temp_number_top == 9)
				temp_number_bottom = 0;
			else
				temp_number_bottom = rand() % (10 - temp_number_top);

			// Place into correct digit posititon:
			number_top += temp_number_top * (pow(10, digit));
			number_bottom += temp_number_bottom * (pow(10, digit));
		}
		break;
	case EASY_SUBTRACTION:
		for(auto digit = 0; digit < digits; ++digit)
		{
			unsigned short temp_number_bottom = rand() % 10;
			// NOTE(dev): top number must be higher than bottom number
			unsigned short temp_number_top;
			if(temp_number_bottom == 9)
				temp_number_top = 9; // can't mod by zero
			else
				temp_number_top = 9 - (rand() % (9 - temp_number_bottom));

			// Place into correct digit posititon:
			number_top += temp_number_top * (pow(10, digit));
			number_bottom += temp_number_bottom * (pow(10, digit));
		}
		break;
	case EASY_MULTIPLICATION:
		number_top = rand() % 13;
		number_bottom = rand() % 13;
		break;
	case EASY_DIVISION:
		// TODO(dev):
		number_top = 1;
		number_bottom = 1;
		break;
	case HARD_ADDITION:
		number_top    = rand() % int(pow(10, digits));
		number_bottom = rand() % int(pow(10, digits));
		break;
	case HARD_SUBTRACTION:
		number_top    = rand() % int(pow(10, digits));
		number_bottom = rand() % int(pow(10, digits));
		// NOTE(dev): don't allow negative numbers:
		if(number_bottom > number_top)
		{
			if(number_top)
				number_bottom %= number_top;
			else
				number_bottom = 0; // lol, 0 - 0 is hard?
		}
		break;
	case HARD_MULTIPLICATION:
		number_top = rand() % 130;
		number_bottom = rand() % 130;
		break;
	case HARD_DIVISION:
		// TODO(dev):
		number_top = 10;
		number_bottom = 10;
		break;
	};
}

void Problem::GenerateWindow(unsigned win_x, unsigned win_y)
{
	// NOTE(dev): Max problem dimensions:
	// Width: 13 characters
	// Height: 8 characters
	// +-----------+
	// |           |
	// |   12,345  |
	// | + 99,999  |
	// | ========  |
	// |  112,344  |
	// |           |
	// +-----------+

	auto height = 8;
	auto width = 13;
	win = newwin(height, width, win_y, win_x);
	if(!win)
		return;
}

int Problem::Input() const
{
	return atoi(input.c_str());
	// int rtn = 0;
	// try {
	// 	rtn = std::stoi(input.c_str());
	// } catch (std::invalid_argument &e) {
	// 	syslog(LOG_USER|LOG_DEBUG, "%s:%d:%s Invalid std::stoi: \"%s\".",
	// 	       __FILE__,__LINE__,__FUNCTION__,e.what());
	// 	exit(-1); // INVALID INPUT!!!
	// }
	// return rtn;
}

void Problem::Input(const INPUT_STYLE input_style, char character)
{
	if(input.length() > 6)
		return;
	// TODO(dev): ASSERT
	if(character < '0' || character > '9')
		exit(-1);

	if(input_style == INPUT_STYLE::INPUT_PREPEND)
		input = character + input;
	else
		input += character;
}

bool Problem::Correct() const
{
	// NOTE(dev): I know I don't need "break;", but it just makes me happier knowing they're there.
	switch(problem_type)
	{
	case EASY_ADDITION:
	case HARD_ADDITION:
		return number_top + number_bottom == Input();
		break;
	case EASY_SUBTRACTION:
	case HARD_SUBTRACTION:
		return number_top - number_bottom == Input();
		break;
	case EASY_MULTIPLICATION:
	case HARD_MULTIPLICATION:
		return number_top * number_bottom == Input();
		break;
	case EASY_DIVISION:
	case HARD_DIVISION:
		return number_top / number_bottom == Input();
		break;
	};

	// TODO(dev): Assert that all conditions are handled!
	exit(-1);
	return false;
}