game.js update(addFood & moveOneStep)

src/game/game.js

-module.exports = {
-  cellTypes: {
+const cellTypes = {
   EMPTY: 0,
   PLAYERHEAD: 1,
   PLAYERBODY: 2,
   FOOD: 3,
-  },
+};
+
+function createCell(x, y, type) {
+  return {
+    x: x,
+    y: y,
+    type: type,
+    pid: 0,
+    direction: 0,
+    next: null,
+  };
+}
+
+function getRandomInt(max) {
+  return Math.floor(Math.random() * max);
+}
+
+function addFood(gameBoard) {
+  //Find all the empty spaces on the grid
+  let emptySpaces = [];
+  for (let row of gameBoard) {
+    for (let cell of row) {
+      if (cell.type === cellTypes.EMPTY) {
+        emptySpaces.push(cell);
+      }
+    }
+  }
+  
+  //Create food cells randomly
+  if (emptySpaces.length > 0) {
+    let randomCell = emptySpaces[getRandomInt(emptySpaces.length)];
+    randomCell.type = cellTypes.FOOD;
+  }
+
+  return gameBoard;
+}
+
+module.exports = {
+  cellTypes,
 
   createGameBoard: (width, height) => {
     let gameBoard = [];
     for (var i = 0; i < height; i++) {
-      row = [];
+      let row = [];
       for (var j = 0; j < width; j++) {
         row.push(createCell(j, i, cellTypes.EMPTY));
       }
@@ -18,58 +55,108 @@ module.exports = {
     for (var i = 0; i < 10; i++) {
       gameBoard = addFood(gameBoard);
     }
-    return gameBoard;
-  },
-
-  addFood: (gameBoard) => {
-    // select a random cell that is empty
-    // set the cell to FOOD
+	//console.log(gameBoard);
     return gameBoard;
   },
 
   addPlayer: (gameBoard, pid) => {
+	let placedCell = false;
+	while (!placedCell) {
 		let x = getRandomInt(gameBoard[0].length);
 		let y = getRandomInt(gameBoard.length);
 
+		if (gameBoard[y][x].type === cellTypes.EMPTY) {
 			gameBoard[y][x].type = cellTypes.PLAYERHEAD;
 			gameBoard[y][x].pid = pid;
 			gameBoard[y][x].direction = 0;
 
 			let y2 = y - 1;
+			if (y2 >= 0 && gameBoard[y2][x].type === cellTypes.EMPTY) {
 				gameBoard[y2][x].type = cellTypes.PLAYERBODY;
 				gameBoard[y2][x].pid = pid;
 				gameBoard[y2][x].direction = 0;
 				gameBoard[y][x].next = gameBoard[y2][x];
-
+			}
+			placedCell = true;
+		}
+	}
+	//console.log(gameBoard);
     return gameBoard;
   },
 
   moveOneStep: (gameBoard) => {
   //Loop through board until we find a PLAYERHEAD
-    //     Move the head in the direction it is facing
-    //     if the head has a next, move the next to the head's old position
-    //     if the next has a next, move the next's next to the next's old position
-    //     and so on
-    // return the new gameBoard
-  },
+  for (var i = 0; i < gameBoard.length; i++) {
+    for (var j = 0; j < gameBoard[i].length; j++) {
+      let cell = gameBoard[i][j];
+      if (cell.type === cellTypes.PLAYERHEAD) {
+		let oldX = cell.x;
+        let oldY = cell.y;
+        let newX = oldX;
+        let newY = oldY;
 		
-  checkColissions: (gameBoard) => {
-    // returns a list of players that have collided,
-    // and a new gameBoard with the players removed
-  },
-};
+		//New position based on direction
+		if (cell.direction === 0) { // Up
+          newY -= 1;
+        } else if (cell.direction === 1) { // Right
+          newX += 1;
+        } else if (cell.direction === 2) { // Down
+          newY += 1;
+        } else if (cell.direction === 3) { // Left
+          newX -= 1;
+        }
 
-let createCell = (x, y, type) => {
-  return {
-    x: x,
-    y: y,
-    type: type,
-    pid: 0,
-    direction: 0,
-    next: null,
+        //Continue if within bounds
+        if (newX >= 0 && newX < gameBoard[0].length && newY >= 0 && newY < gameBoard.length) {
+			
+          //Snake head to new position by updating cell object
+          gameBoard[newY][newX] = {
+            ...cell,
+            x: newX,
+            y: newY,
           };
+
+          //Remove previous head position
+          gameBoard[oldY][oldX].type = cellTypes.EMPTY;
+          gameBoard[oldY][oldX].pid = 0;
+          gameBoard[oldY][oldX].direction = 0;
+          gameBoard[oldY][oldX].next = null;
+
+          //Snake body to previous locations
+          let currentBody = gameBoard[newY][newX].next;
+          while (currentBody) {
+            let bodyOldX = currentBody.x;
+            let bodyOldY = currentBody.y;
+            currentBody.x = oldX;
+            currentBody.y = oldY;
+
+            //Update cell body position
+            gameBoard[oldY][oldX] = {
+              ...currentBody,
+              type: cellTypes.PLAYERBODY,
             };
+            oldX = bodyOldX;
+            oldY = bodyOldY;
+            currentBody = currentBody.next;
+          }
 
-function getRandomInt(max) {
-  return Math.floor(Math.random() * max);
+          //Remove previous body position
+          gameBoard[oldY][oldX].type = cellTypes.EMPTY;
+          gameBoard[oldY][oldX].pid = 0;
+          gameBoard[oldY][oldX].direction = 0;
+          gameBoard[oldY][oldX].next = null;
+
+		  //console.log(gameBoard);
+          return gameBoard;
+        }
+      }
     }
+  }
+  return gameBoard;
+  },
+
+  checkCollisions: (gameBoard) => {
+    // returns a list of players that have collided,
+    // and a new gameBoard with the players removed
+  },
+};