#include <iostream>
#include <cstdlib>   //for rand and exit functions
#include "rabbit.h"
using namespace std;

rabbit::rabbit(const terminal& init_t, unsigned init_x, unsigned init_y):
	t {&init_t}, x {init_x}, y {init_y}, c {'r'}
{

	if (!t->in_range(x, y)) {
		cerr << "Initial rabbit position (" << x << ", " << y
			<< ") off " << t->xmax() << " by " << t->ymax()
			<< " terminal.\n";
		exit(EXIT_FAILURE);
	}

	const char other {t->get(x, y)};
	const char background {t->background()};

	if (other != background) {
		cerr << "Initial rabbit position (" << x << ", " << y
			<< ") already occupied by '" << other << "'.\n";
		exit(EXIT_FAILURE);
	}

	if (c == background) {
		cerr << "Rabbit character '" << c << "' can't be the same as "
			"the terminal's background character.\n";
		exit(EXIT_FAILURE);
	}

	t->put(x, y, c);
}

//Return false if this rabbit was eaten, true otherwise.

bool rabbit::move()
{
	//The values of dx and dy are either -1, 0, or 1.
	const int dx {rand() % 3 - 1};
	const int dy {rand() % 3 - 1};

	if (dx == 0 && dy == 0) {
		return true;   //This rabbit decided not to move.
	}

	const unsigned newx {x + dx};
	const unsigned newy {y + dy};

	if (!t->in_range(newx, newy)) {
		return true;   //Can't move off the screen.
	}

	const char other {t->get(newx, newy)};

	if (other != t->background()) {
		if (other == c) {
			//This rabbit collided with another rabbit.
			return true;
		} else {
			//This rabbit blundered into the wolf and was eaten.
			return false;
		}
	}

	t->put(x, y);      //Erase this rabbit from its old location.
	x = newx;
	y = newy;
	t->put(x, y, c);   //Redraw this rabbit at its new location.

	return true;
}