focusController.js - Move focus

focusController.js

    /**
    * This will take a direction vector and move the focus to the most
    * appropriate item or make no change if there are no items to move to
    * @param {array} direction A direction vector [x, y]
    */
    this.moveFocus = function (direction) {
        // We need an item to move down from
        // TODO: Should initialise focus if not initialised
        if(!currentlyFocusedItem) {
            return;
        }

        var minItemDistance;
        var newItem;
        var minItem;
        var minItemIndex;
        for(var i = 0; i < focusableItems.length; i++) {
            newItem = focusableItems[i];
            if(newItem == currentlyFocusedItem) {
                continue;
            }

            var itemDistance = calculateElementDistance(currentlyFocusedItem, newItem, direction);
            if(itemDistance >= 0 && (minItemDistance === undefined ||
                itemDistance < minItemDistance)) {
                minItemDistance = itemDistance;
                minItem = newItem;
                minItemIndex = i;
            }
        }

        if(minItemIndex >= 0) {
            this.handleFocusChangeToItem(minItemIndex);
        }
    };