#include <cassert>
#include <algorithm>
#include <random>
#include "Game.h"

using std::vector;

GameState::GameState(int n) : n(n), cp(0), win(-1), B(n, vector<int>(n)) {
	C[0].resize(n);
	C[1].resize(n);
	assert(n % 2 == 1);
}

bool GameState::_checkEnd() const {
	int v = 0;
	for (int i = 0; i < n; ++i) {
		if (C[cp][i] >= (n + 1) / 2)
			v += 1;
	}
	return v >= (n + 1) / 2;
}

bool GameState::move(int x, int y) {
	if (x < 0 || x >= n || y < 0 || y >= n) {
		return false;
	}

	if (B[x][y] == -1) {
		return false;
	}

	const int dx[] = {0, 0, 1, -1};
	const int dy[] = {1, -1, 0, 0};
	for (int i = 0; i < 4; ++i) {
		int xx = x + dx[i], yy = y + dy[i];
		if (xx < 0 || xx >= n || yy < 0 || yy >= n || B[xx][yy] == -1)
			goto OK;
	}
	return false;

OK:
	C[cp][B[x][y]] += 1;
	if (C[cp][B[x][y]] >= (n + 1) / 2) {
		int t = B[x][y];
		for (int i = 0; i < n; ++i) {
			for (int j = 0; j < n; ++j) {
				if (B[i][j] == t)
					B[i][j] = -1;
			}
		}
		if (_checkEnd())
			win = cp;
	}

	B[x][y] = -1;
	cp ^= 1;
	return true;
}

void GameState::randomBoard() {
	using namespace std;
	vector<int> z;
	mt19937 rng(random_device{}());
	for (int i = 0; i < n; ++i) {
		for (int j = 0; j < n; ++j)
			z.push_back(i);
	}

	shuffle(z.begin(), z.end(), rng);
	for (int i = 0; i < n; ++i) {
		for (int j = 0; j < n; ++j)
			B[i][j] = z[i * n + j];
	}
}

std::string GameState::boardString() const {
	std::string res;
	for (int i = 0; i < n; ++i) {
		for (int j = 0; j < n; ++j) {
			res += std::to_string(B[i][j]);
			res += " \n"[j == n - 1];
		}
	}
	return res;
}