// src/controller.js
'use strict';

class Controller {
    /**
     * Take a model & view, then act as controller between them
     * @param  {object} model The model instance
     * @param  {object} view  The view instance
     */
    constructor(model, view) {
        this.model = model;
        this.view = view;

        this.view.bind('newTodo', title => this.addItem(title));
        this.view.bind('itemEdit', item => this.editItem(item.id));
        this.view.bind('itemEditDone', item => this.editItemSave(item.id, item.title));
        this.view.bind('itemEditCancel', item => this.editItemCancel(item.id));
        this.view.bind('itemRemove', item => this.removeItem(item.id));
        this.view.bind('itemToggle', item => this.toggleComplete(item.id, item.completed));
        this.view.bind('removeCompleted', () => this.removeCompletedItems());
        this.view.bind('toggleAll', status => this.toggleAll(status.completed));
    }

    /**
     * Load & Initialize the view
     * @param {string}  '' | 'active' | 'completed'
     */
    setView(hash){
        let route = hash.split('/')[1];
        let page = route || '';
        this._updateFilter(page);
    }

    /**
     * Event fires on load. Gets all items & displays them
     */
    showAll(){
        this.model.read(data => this.view.render('showEntries', data));
    }

    /**
     * Renders all active tasks
     */
    showActive(){
        this.model.read({completed: false}, data => this.view.render('showEntries', data));
    }

    /**
     * Renders all completed tasks
     */
    showCompleted(){
        this.model.read({completed: true}, data => this.view.render('showEntries', data));
    }

    /**
     * An event to fire whenever you want to add an item. Simply pass in the event
     * object and it'll handle the DOM insertion and saving of the new item.
     */
    addItem(title){
        if (title.trim() === '') {
            return;
        }

        this.model.create(title, () => {
            this.view.render('clearNewTodo');
            this._filter(true);
        });
    }

    /*
     * Triggers the item editing mode.
     */
    editItem(id){
        this.model.read(id, data => {
            let title = data[0].title;
            this.view.render('editItem', {id, title});
        });
    }

    /*
     * Finishes the item editing mode successfully.
     */
    editItemSave(id, title){
        title = title.trim();

        if (title.length !== 0) {
            this.model.update(id, {title}, () => {
                this.view.render('editItemDone', {id, title});
            });
        } else {
            this.removeItem(id);
        }
    }

    /*
     * Cancels the item editing mode.
     */
    editItemCancel(id){
        this.model.read(id, data => {
            let title = data[0].title;
            this.view.render('editItemDone', {id, title});
        });
    }

    /**
     * Find the DOM element with given ID,
     * Then remove it from DOM & Storage
     */
    removeItem(id){
        this.model.remove(id, () => this.view.render('removeItem', id));
        this._filter();
    }

    /**
     * Will remove all completed items from the DOM and storage.
     */
    removeCompletedItems(){
        this.model.read({completed: true}, data => {
            for (let item of data) {
                this.removeItem(item.id);
            }
        });

        this._filter();
    }

    /**
     * Give it an ID of a model and a checkbox and it will update the item
     * in storage based on the checkbox's state.
     *
     * @param {number} id The ID of the element to complete or uncomplete
     * @param {object} checkbox The checkbox to check the state of complete
     *                          or not
     * @param {boolean|undefined} silent Prevent re-filtering the todo items
     */
    toggleComplete(id, completed, silent){
        this.model.update(id, {completed}, () => {
            this.view.render('elementComplete', {id, completed});
        });

        if (!silent) {
            this._filter();
        }
    }

    /**
     * Will toggle ALL checkboxes' on/off state and completeness of models.
     * Just pass in the event object.
     */
    toggleAll(completed){
        this.model.read({completed: !completed}, data => {
            for (let item of data) {
                this.toggleComplete(item.id, completed, true);
            }
        });

        this._filter();
    }

    /**
     * Updates the pieces of the page which change depending on the remaining
     * number of todos.
     */
    _updateCount(){
        this.model.getCount(todos => {
            const completed = todos.completed;
            const visible = completed > 0;
            const checked = completed === todos.total;

            this.view.render('updateElementCount', todos.active);
            this.view.render('clearCompletedButton', {completed, visible});

            this.view.render('toggleAll', {checked});
            this.view.render('contentBlockVisibility', {visible: todos.total > 0});
        });
    }

    /**
     * Re-filters the todo items, based on the active route.
     * @param {boolean|undefined} force  forces a re-painting of todo items.
     */
    _filter(force){
        let active = this._activeRoute;
        const activeRoute = active.charAt(0).toUpperCase() + active.substr(1);

        // Update the elements on the page, which change with each completed todo
        this._updateCount();

        // If the last active route isn't "All", or we're switching routes, we
        // re-create the todo item elements, calling:
        //   this.show[All|Active|Completed]()
        if (force || this._lastActiveRoute !== 'All' || this._lastActiveRoute !== activeRoute) {
            this['show' + activeRoute]();
        }

        this._lastActiveRoute = activeRoute;
    }

    /**
     * Simply updates the filter nav's selected states
     */
    _updateFilter(currentPage){
        // Store a reference to the active route, allowing us to re-filter todo
        // items as they are marked complete or incomplete.
        this._activeRoute = currentPage;

        if (currentPage === '') {
            this._activeRoute = 'All';
        }

        this._filter();

        this.view.render('setFilter', currentPage);
    }
}
// src/helpers.js
'use strict';


// Allow for looping on nodes by chaining:
// qsa('.foo').forEach(function () {})
NodeList.prototype.forEach = Array.prototype.forEach;

// Get element(s) by CSS selector:
function qs(selector, scope) {
    return (scope || document).querySelector(selector);
}

function qsa(selector, scope) {
    return (scope || document).querySelectorAll(selector);
}

// addEventListener wrapper:
function $on(target, type, callback, useCapture) {
    target.addEventListener(type, callback, !!useCapture);
}

// Attach a handler to event for all elements that match the selector,
// now or in the future, based on a root element
function $delegate(target, selector, type, handler) {
    let dispatchEvent = event => {
        const targetElement = event.target;
        const potentialElements = qsa(selector, target);
        const hasMatch = Array.prototype.indexOf.call(potentialElements, targetElement) >= 0;

        if (hasMatch) {
            handler.call(targetElement, event);
        }
    };

    // https://developer.mozilla.org/en-US/docs/Web/Events/blur
    const useCapture = type === 'blur' || type === 'focus';

    $on(target, type, dispatchEvent, useCapture);
}

// Find the element's parent with the given tag name:
// $parent(qs('a'), 'div')
function $parent(element, tagName) {
    if (!element.parentNode) {
        return;
    }

    if (element.parentNode.tagName.toLowerCase() === tagName.toLowerCase()) {
        return element.parentNode;
    }

    return $parent(element.parentNode, tagName);
}
// src/template.js
'use strict';


const htmlEscapes = {
    '&': '&amp',
    '<': '&lt',
    '>': '&gt',
    '"': '&quot',
    '\'': '&#x27',
    '`': '&#x60'
};

const reUnescapedHtml = /[&<>"'`]/g;
const reHasUnescapedHtml = new RegExp(reUnescapedHtml.source);

let escape = str => (str && reHasUnescapedHtml.test(str)) ? str.replace(reUnescapedHtml, escapeHtmlChar) : str;
let escapeHtmlChar = chr => htmlEscapes[chr];

class Template {
    constructor() {
        this.defaultTemplate = `
            <li data-id="{{id}}" class="{{completed}}">
                <div class="view">
                    <input class="toggle" type="checkbox" {{checked}}>
                    <label>{{title}}</label>
                    <button class="destroy"></button>
                </div>
            </li>
        `;
    }

    /**
     * Creates an <li> HTML string and returns it for placement in your app.
     *
     * NOTE: In real life you should be using a templating engine such as Mustache
     * or Handlebars, however, this is a vanilla JS example.
     *
     * @param {object} data The object containing keys you want to find in the
     *                      template to replace.
     * @returns {string} HTML String of an <li> element
     *
     * @example
     * view.show({
         *  id: 1,
         *  title: "Hello World",
         *  completed: 0,
         * })
     */
    show(data){
        let i = 0;
        let view = '';
        const len = data.length;

        for (i; i < len; i++) {
            let completed = '';
            let checked = '';
            let template = this.defaultTemplate;

            if (data[i].completed) {
                completed = 'completed';
                checked = 'checked';
            }

            template = template.replace('{{id}}', data[i].id);
            template = template.replace('{{title}}', escape(data[i].title));
            template = template.replace('{{completed}}', completed);
            template = template.replace('{{checked}}', checked);

            view += template;
        }

        return view;
    }

    /**
     * Displays a counter of how many to dos are left to complete
     *
     * @param {number} activeTodos The number of active todos.
     * @returns {string} String containing the count
     */
    itemCounter(activeTodos){
        let plural = activeTodos === 1 ? '' : 's';
        return `<strong>${activeTodos}</strong> item${plural} left`;
    }

    /**
     * Updates the text within the "Clear completed" button
     *
     * @param  {[type]} completedTodos The number of completed todos.
     * @returns {string} String containing the count
     */
    clearCompletedButton(completedTodos){
        return (completedTodos > 0) ? 'Clear completed' : '';
    }
}
// src/store.js
/*jshint eqeqeq:false */
'use strict';

/**
 * Creates a new client side storage object and will create an empty
 * collection if no collection already exists.
 *
 * @param {string} name The name of our DB we want to use
 * @param {function} callback Our fake DB uses callbacks because in
 * real life you probably would be making AJAX calls
 */
class Store {
    constructor(name, callback) {
        this._dbName = name;
        this.memoryStorage = this.memoryStorage || {};

        if (!this.memoryStorage[name]) {
            let data = {
                todos: []
            };

            this.memoryStorage[name] = JSON.stringify(data);
        }

        if (callback) {
            callback.call(this, JSON.parse(this.memoryStorage[name]));
        }
    }

    /**
     * Finds items based on a query given as a JS object
     *
     * @param {object} query The query to match against (i.e. {foo: 'bar'})
     * @param {function} callback   The callback to fire when the query has
     * completed running
     *
     * @example
     * db.find({foo: 'bar', hello: 'world'}, function (data) {
         *   // data will return any items that have foo: bar and
         *   // hello: world in their properties
         * })
     */
    find(query, callback){
        if (!callback) {
            return;
        }

        let todos = JSON.parse(this.memoryStorage[this._dbName]).todos;

        callback.call(this, todos.filter(todo => {
            for (let q in query) {
                if (query[q] !== todo[q]) {
                    return false;
                }
            }
            return true;
        }));
    }

    /**
     * Will retrieve all data from the collection
     *
     * @param {function} callback The callback to fire upon retrieving data
     */
    findAll(callback){
        if (callback) {
            callback.call(this, JSON.parse(this.memoryStorage[this._dbName]).todos);
        }
    }

    /**
     * Will save the given data to the DB. If no item exists it will create a new
     * item, otherwise it'll simply update an existing item's properties
     *
     * @param {object} updateData The data to save back into the DB
     * @param {function} callback The callback to fire after saving
     * @param {number} id An optional param to enter an ID of an item to update
     */
    save(updateData, callback, id){
        const data = JSON.parse(this.memoryStorage[this._dbName]);
        let todos = data.todos;
        const len = todos.length;

        // If an ID was actually given, find the item and update each property
        if (id) {
            for (let i = 0; i < len; i++) {
                if (todos[i].id === id) {
                    for (let key in updateData) {
                        todos[i][key] = updateData[key];
                    }
                    break;
                }
            }

            this.memoryStorage[this._dbName] = JSON.stringify(data);

            if (callback) {
                callback.call(this, JSON.parse(this.memoryStorage[this._dbName]).todos);
            }
        } else {
            // Generate an ID
            updateData.id = new Date().getTime();

            todos.push(updateData);
            this.memoryStorage[this._dbName] = JSON.stringify(data);

            if (callback) {
                callback.call(this, [updateData]);
            }
        }
    }

    /**
     * Will remove an item from the Store based on its ID
     *
     * @param {number} id The ID of the item you want to remove
     * @param {function} callback The callback to fire after saving
     */
    remove(id, callback){
        const data = JSON.parse(this.memoryStorage[this._dbName]);
        let todos = data.todos;
        const len = todos.length;

        for (let i = 0; i < todos.length; i++) {
            if (todos[i].id == id) {
                todos.splice(i, 1);
                break;
            }
        }

        this.memoryStorage[this._dbName] = JSON.stringify(data);

        if (callback) {
            callback.call(this, JSON.parse(this.memoryStorage[this._dbName]).todos);
        }
    }

    /**
     * Will drop all storage and start fresh
     *
     * @param {function} callback The callback to fire after dropping the data
     */
    drop(callback){
        this.memoryStorage[this._dbName] = JSON.stringify({todos: []});

        if (callback) {
            callback.call(this, JSON.parse(this.memoryStorage[this._dbName]).todos);
        }
    }
}
// src/model.js
'use strict';


/**
 * Creates a new Model instance and hooks up the storage.
 * @constructor
 * @param {object} storage A reference to the client side storage class
 */
class Model {
    constructor(storage) {
        this.storage = storage;
    }

    /**
     * Creates a new todo model
     *
     * @param {string} [title] The title of the task
     * @param {function} [callback] The callback to fire after the model is created
     */
    create(title, callback){
        title = title || '';

        let newItem = {
            title: title.trim(),
            completed: false
        };

        this.storage.save(newItem, callback);
    }

    /**
     * Finds and returns a model in storage. If no query is given it'll simply
     * return everything. If you pass in a string or number it'll look that up as
     * the ID of the model to find. Lastly, you can pass it an object to match
     * against.
     *
     * @param {string|number|object} [query] A query to match models against
     * @param {function} [callback] The callback to fire after the model is found
     *
     * @example
     * model.read(1, func) // Will find the model with an ID of 1
     * model.read('1') // Same as above
     * //Below will find a model with foo equalling bar and hello equalling world.
     * model.read({ foo: 'bar', hello: 'world' })
     */
    read(query, callback){
        const queryType = typeof query;

        if (queryType === 'function') {
            callback = query;
            this.storage.findAll(callback);
        } else if (queryType === 'string' || queryType === 'number') {
            query = parseInt(query, 10);
            this.storage.find({id: query}, callback);
        } else {
            this.storage.find(query, callback);
        }
    }

    /**
     * Updates a model by giving it an ID, data to update, and a callback to fire when
     * the update is complete.
     *
     * @param {number} id The id of the model to update
     * @param {object} data The properties to update and their new value
     * @param {function} callback The callback to fire when the update is complete.
     */
    update(id, data, callback){
        this.storage.save(data, callback, id);
    }

    /**
     * Removes a model from storage
     *
     * @param {number} id The ID of the model to remove
     * @param {function} callback The callback to fire when the removal is complete.
     */
    remove(id, callback){
        this.storage.remove(id, callback);
    }

    /**
     * WARNING: Will remove ALL data from storage.
     *
     * @param {function} callback The callback to fire when the storage is wiped.
     */
    removeAll(callback){
        this.storage.drop(callback);
    }

    /**
     * Returns a count of all todos
     */
    getCount(callback){
        let todos = {
            active: 0,
            completed: 0,
            total: 0
        };

        this.storage.findAll(data => {
            for (let todo of data) {
                if (todo.completed) {
                    todos.completed++;
                } else {
                    todos.active++;
                }

                todos.total++;
            }

            if (callback) {
                callback(todos);
            }
        });
    }
}
// src/view.js
'use strict';


// import {qs, qsa, $on, $parent, $delegate} from './helpers';

let _itemId = element => parseInt($parent(element, 'li').dataset.id, 10);

let _setFilter = currentPage => {
    qs('.filters .selected').className = '';
    qs(`.filters [href="#/${currentPage}"]`).className = 'selected';
};

let _elementComplete = (id, completed) => {
    let listItem = qs(`[data-id="${id}"]`);

    if (!listItem) {
        return;
    }

    listItem.className = completed ? 'completed' : '';

    // In case it was toggled from an event and not by clicking the checkbox
    qs('input', listItem).checked = completed;
};

let _editItem = (id, title) => {
    let listItem = qs(`[data-id="${id}"]`);

    if (!listItem) {
        return;
    }

    listItem.className += ' editing';

    let input = document.createElement('input');
    input.className = 'edit';

    listItem.appendChild(input);
    input.focus();
    input.value = title;
};

/**
 * View that abstracts away the browser's DOM completely.
 * It has two simple entry points:
 *
 *   - bind(eventName, handler)
 *     Takes a todo application event and registers the handler
 *   - render(command, parameterObject)
 *     Renders the given command with the options
 */
class View {
    constructor(template) {
        this.template = template;

        this.ENTER_KEY = 13;
        this.ESCAPE_KEY = 27;

        this.$todoList = qs('.todo-list');
        this.$todoItemCounter = qs('.todo-count');
        this.$clearCompleted = qs('.clear-completed');
        this.$main = qs('.main');
        this.$footer = qs('.footer');
        this.$toggleAll = qs('.toggle-all');
        this.$newTodo = qs('.new-todo');

        this.viewCommands = {
            showEntries: parameter => this.$todoList.innerHTML = this.template.show(parameter),
            removeItem: parameter => this._removeItem(parameter),
            updateElementCount: parameter => this.$todoItemCounter.innerHTML = this.template.itemCounter(parameter),
            clearCompletedButton: parameter => this._clearCompletedButton(parameter.completed, parameter.visible),
            contentBlockVisibility: parameter => this.$main.style.display = this.$footer.style.display = parameter.visible ? 'block' : 'none',
            toggleAll: parameter => this.$toggleAll.checked = parameter.checked,
            setFilter: parameter => _setFilter(parameter),
            clearNewTodo: parameter => this.$newTodo.value = '',
            elementComplete: parameter => _elementComplete(parameter.id, parameter.completed),
            editItem: parameter => _editItem(parameter.id, parameter.title),
            editItemDone: parameter => this._editItemDone(parameter.id, parameter.title),
        };
    }

    _removeItem(id) {
        let elem = qs(`[data-id="${id}"]`);

        if (elem) {
            this.$todoList.removeChild(elem);
        }
    }

    _clearCompletedButton(completedCount, visible) {
        this.$clearCompleted.innerHTML = this.template.clearCompletedButton(completedCount);
        this.$clearCompleted.style.display = visible ? 'block' : 'none';
    }

    _editItemDone(id, title) {
        let listItem = qs(`[data-id="${id}"]`);

        if (!listItem) {
            return;
        }

        let input = qs('input.edit', listItem);
        listItem.removeChild(input);

        listItem.className = listItem.className.replace(' editing', '');

        qsa('label', listItem).forEach(label => label.textContent = title);
    }

    render(viewCmd, parameter) {
        this.viewCommands[viewCmd](parameter);
    }

    _bindItemEditDone(handler) {
        let self = this;

        $delegate(self.$todoList, 'li .edit', 'blur', function () {
            if (!this.dataset.iscanceled) {
                handler({
                    id: _itemId(this),
                    title: this.value
                });
            }
        });

        // Remove the cursor from the input when you hit enter just like if it were a real form
        $delegate(self.$todoList, 'li .edit', 'keypress', function (event) {
            if (event.keyCode === self.ENTER_KEY) {
                this.blur();
            }
        });
    }

    _bindItemEditCancel(handler) {
        let self = this;

        $delegate(self.$todoList, 'li .edit', 'keyup', function (event) {
            if (event.keyCode === self.ESCAPE_KEY) {
                let id = _itemId(this);
                this.dataset.iscanceled = true;
                this.blur();

                handler({ id });
            }
        });
    }

    bind(event, handler) {
        if (event === 'newTodo') {
            $on(this.$newTodo, 'change', () => handler(this.$newTodo.value));
        } else if (event === 'removeCompleted') {
            $on(this.$clearCompleted, 'click', handler);
        } else if (event === 'toggleAll') {
            $on(this.$toggleAll, 'click', function(){
                handler({completed: this.checked});
            });
        } else if (event === 'itemEdit') {
            $delegate(this.$todoList, 'li label', 'dblclick', function(){
                handler({id: _itemId(this)});
            });
        } else if (event === 'itemRemove') {
            $delegate(this.$todoList, '.destroy', 'click', function(){
                handler({id: _itemId(this)});
            });
        } else if (event === 'itemToggle') {
            $delegate(this.$todoList, '.toggle', 'click', function(){
                handler({
                    id: _itemId(this),
                    completed: this.checked
                });
            });
        } else if (event === 'itemEditDone') {
            this._bindItemEditDone(handler);
        } else if (event === 'itemEditCancel') {
            this._bindItemEditCancel(handler);
        }
    }
}
// src/app.js
'use strict';

let todo;
const setView = () => todo.controller.setView(document.location.hash);

class Todo {
    /**
     * Init new Todo List
     * @param  {string} The name of your list
     */
    constructor(name) {
        this.storage = new Store(name);
        this.model = new Model(this.storage);

        this.template = new Template();
        this.view = new View(this.template);

        this.controller = new Controller(this.model, this.view);
    }
}

$on(window, 'load', () => {
    todo = new Todo('todos-vanillajs');
    setView();
});

$on(window, 'hashchange', setView);