// A GOOD PART OF THIS CODE IS BASED ON THE ONE WRITTEN BY JUAN GABRIEL RODRÍGUEZ CARRIÓN IN JLAB STUDIO. YOU CAN SEE IT IN http://www.jlabstudio.com/webgl/2013/09/tutorial-de-algoritmos-en-javascript-minimax-tres-en-raya/

var player = {
	human:1,
	cpu:2
}
var state = {
	playing:0,
	waiting:1,
	done:2
}

var pick;

function board() {
	this.panel=[];

	this.cells=[];
	for (var i=0;i<9;i++) {
		this.cells.push(document.getElementById("cell"+ (i+1)));
	}
}

board.prototype.reset = function() {
	this.panel = [0,0,0,0,0,0,0,0,0];
}

board.prototype.markable = function(pos) {
	return this.panel[pos]==0;
}

board.prototype.mark = function(turn, pos) {
	this.panel[pos] = turn;
}

board.prototype.checkWin = function(player) {
	var bool = (this.panel[0] === player && this.panel[1] === player && this.panel[2] === player);
	bool = bool || (this.panel[3] === player && this.panel[4] === player && this.panel[5] === player);
	bool = bool || (this.panel[3] === player && this.panel[4] === player && this.panel[5] === player);
	bool = bool || (this.panel[6] === player && this.panel[7] === player && this.panel[8] === player);

	bool = bool || (this.panel[0] === player && this.panel[3] === player && this.panel[6] === player);
	bool = bool || (this.panel[1] === player && this.panel[4] === player && this.panel[7] === player);
	bool = bool || (this.panel[2] === player && this.panel[5] === player && this.panel[8] === player);

	bool = bool || (this.panel[0] === player && this.panel[4] === player && this.panel[8] === player);
	bool = bool || (this.panel[2] === player && this.panel[4] === player && this.panel[6] === player);
	return bool;
}

board.prototype.emptyCells = function() {
	var n = this.panel.length;
	for (var i=0;i<n;i++) {
		if (this.panel[i] === 0) {
			return true;
		}
	}
	return false;
}

board.prototype.draw = function() {
	var n = this.panel.length;
	var humanSign = pick;
	var cpuSign = (pick === "X")? "O":"X";
	for (var i=0;i<n;i++) {
		if (this.panel[i] === 0) {
			this.cells[i].innerHTML = "";
		} else {
			this.cells[i].innerHTML = (this.panel[i] === player.human)? humanSign:cpuSign;
		}
	}
}

function game() {
	this.games = 0;
	this.board = new board();
	this.state = null;

	this.reset();
}

game.prototype.reset = function() {
	this.board.reset();
	this.board.mark(player.cpu, Math.floor(Math.random() * 9));
	this.status = state.playing;
	this.board.draw();
};

game.prototype.logic = function(pos) {
	if (this.status === state.playing) {
		if (this.board.markable(pos)) {
			this.board.mark(player.human, pos);

			if (this.board.checkWin(player.human)) {
				this.status = state.done;
			} else if (!this.board.emptyCells()) {
				this.status = state.done;
			} else {
				this.status = state.waiting;
				this.moveAI();

				if (this.board.checkWin(player.cpu)) {
					this.status = state.done;
				} else if (!this.board.emptyCells()) {
					this.status = state.done;
				} else {
					this.status = state.playing;
				}
			}
		}
		this.board.draw();
	} else if(this.status === state.done) {
		this.win();
	}
    if (this.board.checkWin(player.cpu)) {
        	this.win();
        }
};

game.prototype.win = function() {
	var div = $("<div/>").addClass("container-fluid");
	div.append($("<h4/>").html("GAME OVER"));
	div.append($("<button/>").addClass("btn btn-primary").html("New Game"));
	$("body").append(div);
	$("button").on("click", resetGame);
}

game.prototype.moveAI=function(){
        var pos=0;
        var n=this.board.panel.length;
        var aux, best=-9999;

        for (var i=0;i<n;i++)
        {
            if (this.board.markable(i))
            {
                this.board.mark(player.cpu,i);
                aux=this.min();
                if (aux>best)
                {
                    best=aux;
                    posicion=i;
                }
                this.board.mark(0,i);
            }
        }

        this.board.mark(player.cpu,posicion);
};

game.prototype.min=function(){
        if (this.board.checkWin(player.cpu)) return 1;
        if (!this.board.emptyCells()) return 0;
        var n=this.board.panel.length;
        var aux,best=9999;

        for (var i=0;i<n;i++)
        {
            if (this.board.markable(i))
            {
                this.board.mark(player.human,i);
                aux=this.max();
                if (aux<best)
                {
                    best=aux;
                }
                this.board.mark(0,i);
            }
        }
        return best;
};

game.prototype.max=function(){
        if (this.board.checkWin(player.human)) return -1;
        if (!this.board.emptyCells()) return 0;
        var n=this.board.panel.length;
        var aux,best=-9999;

        for (var i=0;i<n;i++)
        {
            if (this.board.markable(i))
            {
                this.board.mark(player.cpu,i);
                aux=this.min();
                if (aux>best)
                {
                    best=aux;
                }
                this.board.mark(0,i);
            }
        }
        return best;
};

function logicPicker(e) {
	Game.logic(parseInt(e.target.getAttribute("cell")));
}

function init(e) {
	pick = (e.target.getAttribute("pick") === "1")? "X":"O";

		$(".container-fluid").remove();

		Game = new game();

		$(".square").on("click", logicPicker);
}

function resetGame() {
	Game.reset();
	$(".container-fluid").remove();
}

$(document).ready(function() {
	$("button").on("click", init);
});