//====================== Cell object ================================

function Cell(x, y, populated) {
   this.px = x;
   this.py = y;
   this.isGoner = false;
   this.isPregned = false;


   if (populated) this.populated = populated;
   else this.populated = false;
}

Cell.prototype.setPopulate = function (val) {
   this.populated = val;
};

Cell.prototype.isPopulated = function () {
   return this.populated;
};

Cell.prototype.willDie = function () {
   this.isGoner = true;
   this.isPregned = false;
};

Cell.prototype.resetState = function () {
   this.isGoner = false;
   this.isPregned = false;
};

Cell.prototype.fertilize = function () {
   this.isGoner = false;
   this.isPregned = true;
};


//================================= ENVIRONMENT =================================

function Environment(w, h, target) {
   this.target = $(target);
   this.w = w;
   this.h = h;

   this.fields = new Array(w);

   for (var i = 0; i < w; i++) {
       //define cada elemento como una matriz de longitud w
       this.fields[i] = new Array(h);
       for (var j = 0; j < h; j++) {
           /* asigna a cada elemento de la matriz bidimensional 
            * los valores de i y j */
           this.fields[i][j] = new Cell(i, j);
       }
   }
}

Environment.prototype.NORTH = 'N';
Environment.prototype.NOREAST = 'NE';
Environment.prototype.NORWEST = 'NW';
Environment.prototype.SOUTH = 'S';
Environment.prototype.SOUTHEAST = 'SE';
Environment.prototype.SOUTHWEST = 'SW';
Environment.prototype.EAST = 'E';
Environment.prototype.WEST = 'W';

Environment.prototype.init = function () {

   var tr = "";
   var td = "";
   var css = "";
   for (i = 0; i < this.w; i++) {

       tr = "<tr id='row_" + i + "'>";
       td = "";

       for (j = 0; j < this.h; j++) {
           css = "";
           if (this.getCell(i, j) !== null && this.getCell(i, j).isPopulated()) css = "alive";
           td += "<td class='" + css + "' ondblclick='ConwaysLifeGame.togglePopulated(" + i + "," + j + ");'></td>";

       }

       tr += td;
       tr += "</tr>";

       this.target.append(tr);
   }
};

Environment.prototype.refreshEnvironment = function () {
   this.target.html("");
   this.init();
};

Environment.prototype.setCell = function (Cell) {
   if (this.fields[Cell.px][Cell.py] === null) this.fields[Cell.px][Cell.py] = Cell;
};

Environment.prototype.getCell = function (x, y) {
   return this.fields[x][y];
};

Environment.prototype.hasNeighborAt = function (Cell, DIR) {

   var neighborgCell = this.doesCellExist(Cell, DIR);

   if (neighborgCell) return neighborgCell.isPopulated();

   return false;

};

Environment.prototype.doesCellExist = function (Cell, DIR) {

   if (Cell) {

       if (DIR === this.NORTH && Cell.px > 0) {
           //NORTH
           return this.getCell(Cell.px - 1, Cell.py);

       } else if (DIR === this.SOUTH && Cell.px < this.h - 1) {
           //SOUTH
           return this.getCell(Cell.px + 1, Cell.py);

       } else if (DIR === this.EAST && Cell.py < this.w - 1) {
           //EAST
           return this.getCell(Cell.px, Cell.py + 1);

       } else if (DIR === this.WEST && Cell.py > 0) { /// West default
           //WEST
           return this.getCell(Cell.px, Cell.py - 1);

       } else if (DIR === this.NOREAST) {
           //NOREAST
           return this.doesCellExist(this.doesCellExist(Cell, this.NORTH), this.EAST);

       } else if (DIR === this.NORWEST) {
           //NORWEST
           return this.doesCellExist(this.doesCellExist(Cell, this.NORTH), this.WEST);

       } else if (DIR === this.SOUTHEAST) {
           //SOUTHEAST
           return this.doesCellExist(this.doesCellExist(Cell, this.SOUTH), this.EAST);

       } else if (DIR === this.SOUTHWEST) {
           //SOUTHWEST
           return this.doesCellExist(this.doesCellExist(Cell, this.SOUTH), this.WEST);
       } else {
           return false;
       }

   } else {
       return false;
   }


};

Environment.prototype.countNeighbors = function (Cell) {
   var neighborgs = 0;
   if (this.hasNeighborAt(Cell, this.NORTH)) neighborgs++;
   if (this.hasNeighborAt(Cell, this.NOREAST)) neighborgs++;
   if (this.hasNeighborAt(Cell, this.NORWEST)) neighborgs++;
   if (this.hasNeighborAt(Cell, this.SOUTH)) neighborgs++;
   if (this.hasNeighborAt(Cell, this.SOUTHEAST)) neighborgs++;
   if (this.hasNeighborAt(Cell, this.SOUTHWEST)) neighborgs++;
   if (this.hasNeighborAt(Cell, this.EAST)) neighborgs++;
   if (this.hasNeighborAt(Cell, this.WEST)) neighborgs++;

   return neighborgs;
};


//================= Conways life object ========================

var ConwaysLifeGame = {

   environment: null,
   daysGoBy: null,
   running: false,
   lifeCycles: 0,

   setUp: function () {
       ConwaysLifeGame.environment = new Environment(50, 50, "#environment");
       ConwaysLifeGame.environment.init();
   },

   start: function () {
       ConwaysLifeGame.running = true;
       if (ConwaysLifeGame.daysGoBy === null) ConwaysLifeGame.daysGoBy = setInterval(function () {
           ConwaysLifeGame.executeLifeCicle();
       }, 500);
   },

   pause: function () {
       ConwaysLifeGame.running = false;
   },

   stop: function () {
       clearInterval(ConwaysLifeGame.daysGoBy);
       ConwaysLifeGame.pause();
       ConwaysLifeGame.daysGoBy = null;
   },

   isNotZeroGeneration: function () {
       if (ConwaysLifeGame.lifeCycles > 0) return true;
       else return false;
   },

   executeLifeCicle: function () {

       if (ConwaysLifeGame.running) {

           if (ConwaysLifeGame.isNotZeroGeneration()) ConwaysLifeGame.prepareEnvironment();


           var _env = ConwaysLifeGame.environment;
           var cell = null;

           var i, j;
           for (i = 0; i < _env.fields.length; i++) {
               for (j = 0; j < _env.fields[i].length; j++) {

                   cell = _env.getCell(i, j);

                   if (cell.isPopulated()) {
                       ConwaysLifeGame.evaluatePopulatedCell(cell);
                   } else {
                       ConwaysLifeGame.evaluateUnpopulatedCell(cell);
                   }
               }
           }

           _env.refreshEnvironment();

       }

       ConwaysLifeGame.lifeCycles++;
   },

   prepareEnvironment: function () {
       var _env = ConwaysLifeGame.environment;
       var cell = null;
       var i, j;
       for (i = 0; i < _env.fields.length; i++) {
           for (j = 0; j < _env.fields[i].length; j++) {

               cell = _env.getCell(i, j);

               if (cell.isGoner) cell.setPopulate(false);
               else if (cell.isPregned) cell.setPopulate(true);

           }
       }
   },

   evaluatePopulatedCell: function (cell) {

       var neighbors = ConwaysLifeGame.environment.countNeighbors(cell);

       if (neighbors <= 1) { // Each cell with one or no neighbors dies, as if by loneliness.
           cell.willDie();
       } else if (neighbors >= 4) {
           // Each cell with four or more neighbors dies, as if by overpopulation.
           cell.willDie(false);
       }
       // else Each cell with two or three neighbors survives.
   },

   evaluateUnpopulatedCell: function (cell) {
       // Each cell with three neighbors becomes populated.																						   		   
       if (ConwaysLifeGame.environment.countNeighbors(cell) == 3) { // Each cell with one or no neighbors dies, as if by loneliness.
           cell.fertilize();
       }
   },

   togglePopulated: function (x, y) {
       if (ConwaysLifeGame.environment.getCell(x, y).isPopulated()) ConwaysLifeGame.environment.getCell(x, y).setPopulate(false);
       else ConwaysLifeGame.environment.getCell(x, y).setPopulate(true);

       ConwaysLifeGame.environment.refreshEnvironment();
   }
};