app.js

// BUDGET CONTROLLER
var budgetController = (function() {

    // function constructors for expenses and incomes
    var Expense = function(id, description, value) {
        this.id = id;
        this.description = description;
        this.value = value;
        this.percentage = -1
    };

    Expense.prototype.calcPercentage = function(totalIncome) {
        if (totalIncome > 0) {
            this.percentage = Math.round((this.value / totalIncome) * 100);
        } else {
            this.percentage = -1;
        }
    };

    Expense.prototype.getPercentage = function() {
        return this.percentage;
    };

    var Income = function(id, description, value) {
        this.id = id;
        this.description = description;
        this.value = value;
    };

    var calculateTotal = function(type) {
        var sum = 0;
        data.allItems[type].forEach(function(currentItem) {
            sum += currentItem.value
        })
        data.totals[type] = sum;
    };

    // all data for expenses and incomes
    var data = {
        allItems: {
            exp: [],
            inc: []
        },
        totals: {
            exp: 0,
            inc: 0
        },
        budget: 0,
        percentage: -1
    };

    return {
        addItem: function(type, desc, value) {
            var newItem, ID;

            // Create new ID
            // ID = last ID + 1 or 0 if empty
            ID = data.allItems[type].length > 0 ? data.allItems[type][data.allItems[type].length - 1].id + 1 : 0;

            // Create new item based on 'exp' or 'inc' type
            if (type === 'exp') {
                newItem = new Expense(ID, desc, value);
            } else if (type === 'inc') {
                newItem = new Income(ID, desc, value);
            }

            // push new item to data structure
            data.allItems[type].push(newItem);

            return newItem;
        },

        deleteItem: function(type, id) {
            var ids, index;

            // create new array of ids to find the index of the id we need to delete
            // as original array of all items can be like [1, 3, 5, 7] with already deleted items
            ids = data.allItems[type].map(function(current) {
                return current.id;
            });

            index = ids.indexOf(id);

            if (index !== -1) {
                data.allItems[type].splice(index, 1);
            }
        },

        calculateBudget: function() {

            // calculate total income and expenses
            calculateTotal('exp');
            calculateTotal('inc');

            // calculate the budget: income - expenses
            data.budget = data.totals.inc - data.totals.exp;

            // calculate the percentage of income that we spent
            if (data.totals.inc > 0) {
                data.percentage = Math.round(data.totals.exp / data.totals.inc * 100);
            } else {
                data.percentage = -1;
            }
        },

        // calculate percentages for each expense
        calculatePercentages: function() {
            data.allItems.exp.forEach(function(cur) {
                cur.calcPercentage(data.totals.inc);
            });
        },

        getPercentages: function() {
            var allPerc = data.allItems.exp.map(function(cur) {
                return cur.getPercentage();
            });

            return allPerc;
        },

        getBudget: function() {
            return {
                budget: data.budget,
                totalInc: data.totals.inc,
                totalExp: data.totals.exp,
                percentage: data.percentage
            }
        },

        testing: function() {
            console.log(data);
        }
    };

})();

// UI CONTROLLER
var UIController = (function() {

    var DOMStrings = {
        inputType: '.add__type',
        inputDescription: '.add__description',
        inputValue: '.add__value',
        inputBtn: '.add__btn',
        incomeContainer: '.income__list',
        expensesContainer: '.expenses__list',
        budgetLabel: '.budget__value',
        incomeLabel: '.budget__income--value',
        expensesLabel: '.budget__expenses--value',
        percentageLabel: '.budget__expenses--percentage',
        container: '.container',
        expensesPercLabel: '.item__percentage',
        dateLabel: '.budget__title--month'
    };

    var formatNumber = function(num, type) {
        var numSplit, int, dec;

        /**
         * + or - before number
         * exactly 2 decimal points
         * comma separates thousand
         *
         * 2310.4567 -> 2,310.46
         * 2000 -> 2,000.00
         */

        num = Math.abs(num);
        num = num.toFixed(2);

        numSplit = num.split('.')

        int = numSplit[0];

        if (int.length > 3) {
            int = int.substr(0, int.length - 3) + ',' + int.substr(int.length - 3, 3);
        }

        dec = numSplit[1];

        return (type === 'exp' ? '-' : '+') + ' ' + int + '.' + dec;

    };

    var nodeListForEach = function(list, callback) {
        for (var i = 0; i < list.length; i++) {
            callback(list[i], i);
        }
    };

    return {
        getInput: function() {
            return {
                type: document.querySelector(DOMStrings.inputType).value, // will be either exp or inc
                description: document.querySelector(DOMStrings.inputDescription).value,
                value: parseFloat(document.querySelector(DOMStrings.inputValue).value)
            }
        },

        addListItem: function(obj, type) {
            var html, newHtml, element;

            // Create HTML string with placeholder text
            if (type === 'inc') {
                element = DOMStrings.incomeContainer;
                html = '<div class="item clearfix" id="inc-%id%">\n' +
                        '<div class="item__description">%description%</div>\n' +
                            '<div class="right clearfix">\n' +
                                '<div class="item__value">%value%</div>\n' +
                                '<div class="item__delete">\n' +
                                    '<button class="item__delete--btn"><i class="ion-ios-close-outline"></i></button>\n' +
                                '</div>\n' +
                            '</div>\n' +
                        ' </div>';
            } else if (type === 'exp') {
                element = DOMStrings.expensesContainer;
                html = '<div class="item clearfix" id="exp-%id%">\n' +
                            '<div class="item__description">%description%</div>\n' +
                            '<div class="right clearfix">\n' +
                                '<div class="item__value">%value%</div>\n' +
                                '<div class="item__percentage">21%</div>\n' +
                                '<div class="item__delete">\n' +
                                    '<button class="item__delete--btn"><i class="ion-ios-close-outline"></i></button>\n' +
                                '</div>\n' +
                            '</div>\n' +
                        '</div>';
            }

            // Replace placeholder text with some actual data
            newHtml = html.replace('%id%', obj.id);
            newHtml = newHtml.replace('%description%', obj.description);
            newHtml = newHtml.replace('%value%', formatNumber(obj.value, type));

            // Insert HTML into the DOM
            document.querySelector(element).insertAdjacentHTML('beforeend', newHtml);
        },

        deleteListItem: function(selectorID) {
            var el = document.getElementById(selectorID);

            el.parentNode.removeChild(el);
        },

        // clear descript and value input fields after adding list item
        clearFields: function() {
            var fields, fieldsArr;

            fields = document.querySelectorAll(DOMStrings.inputDescription + ', ' + DOMStrings.inputValue);

            var fieldsArr = Array.prototype.slice.call(fields);

            fieldsArr.forEach(function(current, index, array) {
                current.value = '';
            });
            fieldsArr[0].focus();
        },

        // display budget with income/expenses/percentage after adding item
        displayBudget: function(obj) {
            var type;

            obj.budget > 0 ? type = 'inc' : type = 'exp';

            // 1. Update  budget
            document.querySelector(DOMStrings.budgetLabel).textContent = formatNumber(obj.budget, type);

            // 2. Update income
            document.querySelector(DOMStrings.incomeLabel).textContent = formatNumber(obj.totalInc, 'inc');

            // 3. Update expenses
            document.querySelector(DOMStrings.expensesLabel).textContent = formatNumber(obj.totalExp, 'exp');

            // 4. Update percentage
            if (obj.percentage > 0) {
                document.querySelector(DOMStrings.percentageLabel).textContent = obj.percentage + '%';
            } else {
                document.querySelector(DOMStrings.percentageLabel).textContent = '---';
            }
        },

        displayPercentages: function(percentages) {
            var fields = document.querySelectorAll(DOMStrings.expensesPercLabel);

            nodeListForEach(fields, function(current, index) {
                if (percentages[index] > 0) {
                    current.textContent = percentages[index] + '%';
                } else {
                    current.textContent = '---';
                }
            });
        },

        displayMonth: function() {
            var now, month, year, months;
            months = ['January', 'February', 'March', 'April', 'May', 'June', 'July', 'August', 'September', 'October', 'November', 'December'];

            now = new Date();
            month = now.getMonth();
            year = now.getFullYear();

            document.querySelector(DOMStrings.dateLabel).textContent = months[month] + ' ' + year;
        },

        changedType: function() {

            var fields = document.querySelectorAll(
                DOMStrings.inputType + ',' +
                DOMStrings.inputDescription + ',' +
                DOMStrings.inputValue
            );

            nodeListForEach(fields, function(current) {
                current.classList.toggle('red-focus');
            });

            document.querySelector(DOMStrings.inputBtn).classList.toggle('red');
        },

        getDomStrings: function() {
            return DOMStrings;
        }
    }
})();

// GLOBAL APP CONTROLLER
var controller = (function(budgetCtrl, UICtrl) {

    var setupEventListeners = function() {
        var DOM = UICtrl.getDomStrings();

        document.querySelector(DOM.inputBtn).addEventListener('click', ctrlAddItem);

        document.addEventListener('keypress', function(event) {
            if (event.key === 'Enter' || event.code === 'Enter') {
                ctrlAddItem();
            }
        });

        document.querySelector(DOM.container).addEventListener('click', ctrlDeleteItem);

        document.querySelector(DOM.inputType).addEventListener('change', UICtrl.changedType);
    };

    var updateBudget = function() {

        // 1. Calculate budget
        budgetCtrl.calculateBudget();

        // 2. Return budget
        var budget = budgetCtrl.getBudget();

        // 3. Display budget on the UI
        UICtrl.displayBudget(budget);
    };

    var updatePercentages = function() {

        // 1. Calculate percentages
        budgetCtrl.calculatePercentages();

        // 2. Read percentages from the budget controller
        var percentages = budgetCtrl.getPercentages();

        // 3. Update the UI with new percentages
        UICtrl.displayPercentages(percentages);
    };

    var ctrlAddItem = function() {
        var input, newItem;

        // 1. get field input data
        input = UICtrl.getInput();

        if (input.description.length !== "" && !isNaN(input.value) && input.value > 0) {

            // 2. Add item to the budget controller
            newItem = budgetCtrl.addItem(input.type, input.description, input.value);

            // 3. Add item to the UI
            UICtrl.addListItem(newItem, input.type);

            // 4. Clear fields
            UICtrl.clearFields();

            // 5. Calculate and update budget
            updateBudget();

            // 6. Calculate and update percentages
            updatePercentages();
        }
    };

    var ctrlDeleteItem = function(event) {
        var itemID, splitID, type, ID;

        itemID = event.target.parentNode.parentNode.parentNode.parentNode.id;

        if (itemID) {
            splitID = itemID.split('-');
            type = splitID[0];
            ID = parseInt(splitID[1]);

            // 1. Delete item from data structure
            budgetCtrl.deleteItem(type, ID);

            // 2. Delete item from UI
            UICtrl.deleteListItem(itemID);

            // 3. Update and show new budget
            updateBudget();

            // 4. Calculate and update percentages
            updatePercentages();
        }
    };

    return {
        init: function() {
            console.log('Application has started.');
            UICtrl.displayMonth();

            // set budget, income, expenses to zero
            UICtrl.displayBudget({
                budget: 0,
                totalInc: 0,
                totalExp: 0,
                percentage: -1
            });

            setupEventListeners();
        }
    }
})(budgetController, UIController);

controller.init();