/* ----------------------------------------------------------------------------
 * Easy!Appointments - Open Source Web Scheduler
 *
 * @package     EasyAppointments
 * @author      A.Tselegidis <alextselegidis@gmail.com>
 * @copyright   Copyright (c) 2013 - 2017, Alex Tselegidis
 * @license     http://opensource.org/licenses/GPL-3.0 - GPLv3
 * @link        http://easyappointments.org
 * @since       v1.2.0
 * ---------------------------------------------------------------------------- */

window.BackendCalendarTableView = window.BackendCalendarTableView || {};

/**
 * Backend Calendar
 *
 * This module implements the table calendar view of backend.
 *
 * @module BackendCalendarTableView
 */
(function(exports) {

    'use strict';

    /**
     * Sticky Table Header Fix 
     * 
     * @type {Number}
     */
    var stickyTableHeaderInterval; 

    /**
     * Bind page event handlers. 
     */
    function _bindEventHandlers() {
        var $calendarToolbar = $('#calendar-toolbar');
        var $calendar = $('#calendar'); 

        $calendar.on('click', '.calendar-header .btn.previous', function() {
            var endDate = new Date($('#calendar .date-column:first').data('date')).add({days: -1}); 
            var startDate = new Date(endDate.getTime()).add({days: -1 * (parseInt($('#select-filter-item').val()) - 1)});
            $('.select-date').datepicker('setDate', startDate);
            _createView(startDate, endDate);
        });

        $calendar.on('click', '.calendar-header .btn.next', function() {
            var startDate = new Date($('#calendar .date-column:last').data('date')).add({days: 1}); 
            var endDate = new Date(startDate.getTime()).add({days: parseInt($('#select-filter-item').val()) - 1}); 
            $('.select-date').datepicker('setDate', startDate);
            _createView(startDate, endDate);
        });

        $calendarToolbar.on('change', '#select-filter-item', function() {
            var startDate = new Date($('.calendar-view .date-column:first').data('date')); 
            var endDate = new Date(startDate.getTime()).add({days: parseInt($(this).val()) - 1}); 
            _createView(startDate, endDate);

            // Horizontal scrolling fix for sticky table headers. 
            stickyTableHeaderInterval = setInterval(function() {
                $(window).trigger('resize.stickyTableHeaders');
            }, 1000);
        });

        $calendarToolbar.on('click', '#reload-appointments', function() {
            // Remove all the events from the tables. 
            $('.calendar-view .event').remove(); 

            // Fetch the events and place them in the existing HTML format. 
            var startDate = new Date($('.calendar-view .date-column:first').data('date'));
            var endDate = new Date($('.calendar-view .date-column:last').data('date'));
            _getCalendarEvents(startDate, endDate)
                .done(function(response) {
                    if (!GeneralFunctions.handleAjaxExceptions(response)) {
                        return;
                    }

                    var currentDate = startDate; 

                    while(currentDate <= endDate) {
                        $('.calendar-view .date-column').each(function(index, dateColumn) {
                            var $dateColumn = $(dateColumn); 
                            var date = new Date($dateColumn.data('date'));

                            if (currentDate.getTime() !== date.getTime()) {
                                return true;
                            }

                            $(dateColumn).find('.provider-column').each(function(index, providerColumn) {
                                var $providerColumn = $(providerColumn);
                                var provider = $providerColumn.data('provider');

                                // Add the appointments to the column. 
                                _createAppointments($providerColumn, response.appointments); 
                                
                                // Add the unavailabilities to the column. 
                                _createUnavailabilities($providerColumn, response.unavailabilities); 

                                // Add the provider breaks to the column. 
                                var workingPlan = JSON.parse(provider.settings.working_plan); 
                                var day = date.toString('dddd').toLowerCase();
                                if (workingPlan[day]) {
                                    var breaks = workingPlan[day].breaks;
                                    _createBreaks($providerColumn, breaks);
                                }
                            });
                        });

                        currentDate.add({days: 1}); 
                    }

                    _setCalendarSize();
                    Backend.placeFooterToBottom();
                })
                .fail(GeneralFunctions.ajaxFailureHandler);
        }); 
        
        $calendar.on('click', '.calendar-view table td', function() {
            if ($(this).index() === 0) {
                return; // Clicked on an hour slot. 
            }

            // Open the appointments modal in the selected hour. 
            var hour = $(this).parent().find('td:first').text().split(':'); 
            var date = new Date($(this).parents('.date-column').data('date'));
            date.set({hour: parseInt(hour[0]), minute: parseInt(hour[1])});

            // Open the appointments dialog. 
            $('#insert-appointment').trigger('click');

            // Update start date field.
            $('#start-datetime').datepicker('setDate', date); 

            // Select Service and provider. 
            var $providerColumn = $(this).parents('.provider-column');
            var serviceId = $providerColumn.find('thead tr:last th').eq($(this).index()).data('id');
            var providerId = $providerColumn.data('provider').id; 
            $('#select-service').val(serviceId).trigger('change');
            $('#select-provider').val(providerId).trigger('change');
        }); 

        var lastFocusedEventData;
        
        /**
         * Event: On Table Event Click
         * 
         * @param {jQuery.Event} event
         */
        $calendar.on('click', '.event', function(event) {
            event.stopPropagation(); 

            if ($(this).hasClass('break')) {
                return; // Do nothing with break events.
            }

            $('.popover').remove(); // Close all open popovers.

            var html;
            var entry = $(this).data(); 

            if ($(this).hasClass('unavailability')) {                
                var notes = '<strong>Notes</strong> ' + entry.notes;

                html =
                        '<style type="text/css">'
                            + '.popover-content strong {min-width: 80px; display:inline-block;}'
                            + '.popover-content button {margin-right: 10px;}'
                            + '</style>' +
                        '<strong>' + EALang['start'] + '</strong> '
                            + GeneralFunctions.formatDate(entry.start_datetime, GlobalVariables.dateFormat, true)
                            + '<br>' +
                        '<strong>' + EALang['end'] + '</strong> '
                            + GeneralFunctions.formatDate(entry.end_datetime, GlobalVariables.dateFormat, true)
                            + '<br>'
                            + notes
                            + '<hr>' +
                        '<center>' +
                            '<button class="edit-popover btn btn-primary">' + EALang['edit'] + '</button>' +
                            '<button class="delete-popover btn btn-danger">' + EALang['delete'] + '</button>' +
                            '<button class="close-popover btn btn-default" data-po=' + event.target + '>' + EALang['close'] + '</button>' +
                        '</center>';
            } else {
                html =
                        '<style type="text/css">'
                            + '.popover-content strong {min-width: 80px; display:inline-block;}'
                            + '.popover-content button {margin-right: 10px;}'
                            + '</style>' +
                        '<strong>' + EALang['start'] + '</strong> '
                            + GeneralFunctions.formatDate(entry.start_datetime, GlobalVariables.dateFormat, true)
                            + '<br>' +
                        '<strong>' + EALang['end'] + '</strong> '
                            + GeneralFunctions.formatDate(entry.end_datetime, GlobalVariables.dateFormat, true)
                            + '<br>' +
                        '<strong>' + EALang['service'] + '</strong> '
                            + entry.service.name
                            + '<br>' +
                        '<strong>' + EALang['provider'] + '</strong> '
                            + entry.provider.first_name + ' '
                            + entry.provider.last_name
                            + '<br>' +
                        '<strong>' + EALang['customer'] + '</strong> '
                            + entry.customer.first_name + ' '
                            + entry.customer.last_name
                            + '<hr>' +
                        '<center>' +
                            '<button class="edit-popover btn btn-primary">' + EALang['edit'] + '</button>' +
                            '<button class="delete-popover btn btn-danger">' + EALang['delete'] + '</button>' +
                            '<button class="close-popover btn btn-default" data-po=' + event.target + '>' + EALang['close'] + '</button>' +
                        '</center>';
            }

            var title = entry.is_unavailable !== '0' ? EALang['unavailable'] : entry.service.name + ' - ' 
                    + entry.customer.first_name + ' ' + entry.customer.last_name;

            $(event.target).popover({
                placement: 'top',
                title: title,
                content: html,
                html: true,
                container: '#calendar',
                trigger: 'manual'
            });

            lastFocusedEventData = entry;
            $(event.target).popover('toggle');

            // Fix popover position
            if ($('.popover').length > 0 && $('.popover').position().top < 200) {
                $('.popover').css('top', '200px');  
            }
        });

        /**
         * Event: On Window Resize
         */
        $(window).on('resize', _setCalendarSize);

        /**
         * Event: Popover Close Button "Click"
         *
         * Hides the open popover element.
         */
        $calendar.on('click', '.close-popover', function() {
            $(this).parents().eq(2).popover('destroy');
        });

        /**
         * Event: Popover Edit Button "Click"
         *
         * Enables the edit dialog of the selected table event.
         */
        $calendar.on('click', '.edit-popover', function() {
            $(this).parents().eq(2).popover('destroy'); // Hide the popover

            var $dialog;

            if (lastFocusedEventData.is_unavailable == false) {
                var appointment = lastFocusedEventData;
                $dialog = $('#manage-appointment');

                BackendCalendarAppointmentsModal.resetAppointmentDialog();

                // Apply appointment data and show modal dialog.
                $dialog.find('.modal-header h3').text(EALang['edit_appointment_title']);
                $dialog.find('#appointment-id').val(appointment['id']);
                $dialog.find('#select-service').val(appointment['id_services']).trigger('change');
                $dialog.find('#select-provider').val(appointment['id_users_provider']);

                // Set the start and end datetime of the appointment.
                var startDatetime = Date.parseExact(appointment['start_datetime'],
                        'yyyy-MM-dd HH:mm:ss');
                $dialog.find('#start-datetime').datetimepicker('setDate', startDatetime);

                var endDatetime = Date.parseExact(appointment['end_datetime'],
                        'yyyy-MM-dd HH:mm:ss');
                $dialog.find('#end-datetime').datetimepicker('setDate', endDatetime);

                var customer = appointment['customer'];
                $dialog.find('#customer-id').val(appointment['id_users_customer']);
                $dialog.find('#first-name').val(customer['first_name']);
                $dialog.find('#last-name').val(customer['last_name']);
                $dialog.find('#email').val(customer['email']);
                $dialog.find('#phone-number').val(customer['phone_number']);
                $dialog.find('#address').val(customer['address']);
                $dialog.find('#city').val(customer['city']);
                $dialog.find('#zip-code').val(customer['zip_code']);
                $dialog.find('#appointment-notes').val(appointment['notes']);
                $dialog.find('#customer-notes').val(customer['notes']);
            } else {
                var unavailable = lastFocusedEventData;

                // Replace string date values with actual date objects.
                unavailable.start_datetime = Date.parse(lastFocusedEventData.start_datetime);
                unavailable.end_datetime = Date.parse(lastFocusedEventData.end_datetime);

                $dialog = $('#manage-unavailable');
                BackendCalendarUnavailabilitiesModal.resetUnavailableDialog();

                // Apply unvailable data to dialog.
                $dialog.find('.modal-header h3').text('Edit Unavailable Period');
                $dialog.find('#unavailable-start').datetimepicker('setDate', unavailable.start_datetime);
                $dialog.find('#unavailable-id').val(unavailable.id);
                $dialog.find('#unavailable-provider').val(unavailable.id_users_provider);
                $dialog.find('#unavailable-end').datetimepicker('setDate', unavailable.end_datetime);
                $dialog.find('#unavailable-notes').val(unavailable.notes);
            }

            // :: DISPLAY EDIT DIALOG
            $dialog.modal('show');
        });

        /**
         * Event: Popover Delete Button "Click"
         *
         * Displays a prompt on whether the user wants the appoinmtent to be deleted. If he confirms the
         * deletion then an ajax call is made to the server and deletes the appointment from the database.
         */
        $calendar.on('click', '.delete-popover', function() {
            $(this).parents().eq(2).popover('destroy'); // Hide the popover

            if (lastFocusedEventData.is_unavailable == false) {
                var messageButtons = {};
                messageButtons['OK'] = function() {
                    var postUrl = GlobalVariables.baseUrl + '/index.php/backend_api/ajax_delete_appointment';
                    var postData = {
                        csrfToken: GlobalVariables.csrfToken,
                        appointment_id : lastFocusedEventData['id'],
                        delete_reason: $('#delete-reason').val()
                    };

                    $.post(postUrl, postData, function(response) {
                        $('#message_box').dialog('close');

                        if (response.exceptions) {
                            response.exceptions = GeneralFunctions.parseExceptions(response.exceptions);
                            GeneralFunctions.displayMessageBox(GeneralFunctions.EXCEPTIONS_TITLE,
                                    GeneralFunctions.EXCEPTIONS_MESSAGE);
                            $('#message_box').append(GeneralFunctions.exceptionsToHtml(response.exceptions));
                            return;
                        }

                        if (response.warnings) {
                            response.warnings = GeneralFunctions.parseExceptions(response.warnings);
                            GeneralFunctions.displayMessageBox(GeneralFunctions.WARNINGS_TITLE,
                                    GeneralFunctions.WARNINGS_MESSAGE);
                            $('#message_box').append(GeneralFunctions.exceptionsToHtml(response.warnings));
                        }

                        // Refresh calendar event items.
                        $('#select-filter-item').trigger('change');
                    }, 'json').fail(GeneralFunctions.ajaxFailureHandler);
                };

                messageButtons[EALang['cancel']] = function() {
                    $('#message_box').dialog('close');
                };

                GeneralFunctions.displayMessageBox(EALang['delete_appointment_title'],
                        EALang['write_appointment_removal_reason'], messageButtons);

                $('#message_box').append('<textarea id="delete-reason" rows="3"></textarea>');
                $('#delete-reason').css('width', '100%');
            } else {
                // Do not display confirmation promt.
                var postUrl = GlobalVariables.baseUrl + '/index.php/backend_api/ajax_delete_unavailable';
                var postData = {
                    csrfToken: GlobalVariables.csrfToken,
                    unavailable_id : lastFocusedEventData.id
                };

                $.post(postUrl, postData, function(response) {
                    $('#message_box').dialog('close');

                    if (response.exceptions) {
                        response.exceptions = GeneralFunctions.parseExceptions(response.exceptions);
                        GeneralFunctions.displayMessageBox(GeneralFunctions.EXCEPTIONS_TITLE, GeneralFunctions.EXCEPTIONS_MESSAGE);
                        $('#message_box').append(GeneralFunctions.exceptionsToHtml(response.exceptions));
                        return;
                    }

                    if (response.warnings) {
                        response.warnings = GeneralFunctions.parseExceptions(response.warnings);
                        GeneralFunctions.displayMessageBox(GeneralFunctions.WARNINGS_TITLE, GeneralFunctions.WARNINGS_MESSAGE);
                        $('#message_box').append(GeneralFunctions.exceptionsToHtml(response.warnings));
                    }

                    // Refresh calendar event items.
                    $('#select-filter-item').trigger('change');
                }, 'json').fail(GeneralFunctions.ajaxFailureHandler);
            }
        });
    }

    /**
     * Create table view header container. 
     *
     * The header contains the date navigation elements (buttons and datepicker).
     */
    function _createHeader() {
        var $calendarFilter = $('#calendar-filter'); 

        $calendarFilter
            .find('select')
            .empty()
            .append(new Option('1 ' + EALang['day'] , 1))
            .append(new Option('3 ' + EALang['days'], 3));
        
        var $calendarHeader = $('<div class="calendar-header" />').appendTo('#calendar'); 

        $calendarHeader
            .html(
                '<button class="btn btn-xs btn-default previous">' +
                    '<span class="glyphicon glyphicon-chevron-left"></span>' +
                '</button>' +
                '<input type="text" class="select-date" value="' + GeneralFunctions.formatDate(new Date(), GlobalVariables.dateFormat) + '" />' +
                '<button class="btn btn-xs btn-default next">' +
                    '<span class="glyphicon glyphicon-chevron-right"></span>' +
                '</button>'
            );

        var dateFormat; 

        switch(GlobalVariables.dateFormat) {
            case 'DMY':
                dateFormat = 'dd/mm/yy';
                break;

            case 'MDY':
                dateFormat = 'mm/dd/yy';
                break;

            case 'YMD':
                dateFormat = 'yy/mm/dd';
                break;

            default:
                throw new Error('Invalid date format setting provided!', GlobalVariables.dateFormat);
        }   


        $calendarHeader.find('.select-date').datepicker({
            defaultDate: new Date(),
            dateFormat: dateFormat,
            onSelect: function(dateText, instance) { 
                var startDate = new Date(instance.currentYear, instance.currentMonth, instance.currentDay);
                var endDate = new Date(startDate.getTime()).add({days: parseInt($('#select-filter-item').val()) - 1}); 
                _createView(startDate, endDate);
            } 
        });
    }

    /**
     * Create table schedule view. 
     *
     * This method will destroy any previous instances and create a new view for displaying the appointments in 
     * a table format. 
     * 
     * @param {Date} startDate Start date to be displayed.
     * @param {Date} endDate End date to be displayed. 
     */
    function _createView(startDate, endDate) {
        // Disable date navigation.
        $('#calendar .calendar-header .btn').addClass('disabled').prop('disabled', true);

        $('#calendar .calendar-view table').stickyTableHeaders('destroy');
        $('#calendar .calendar-view').remove();

        var displayDate = startDate.getTime() !== endDate.getTime();
        var $calendarView = $('<div class="calendar-view" />').appendTo('#calendar'); 

        $calendarView.data({
            startDate: startDate.toString('yyyy-MM-dd'),
            endDate: endDate.toString('yyyy-MM-dd')
        });

        var $wrapper = $('<div />').appendTo($calendarView);

        _getCalendarEvents(startDate, endDate)
            .done(function(response) {
                if (!GeneralFunctions.handleAjaxExceptions(response)) {
                    return;
                }

                var currentDate = startDate; 

                while(currentDate <= endDate) {
                    _createDateColumn($wrapper, currentDate, response, displayDate); 
                    currentDate.add({days: 1}); 
                }

                _setCalendarSize();
                Backend.placeFooterToBottom();

                // Activate calendar navigation.
                $('#calendar .calendar-header .btn').removeClass('disabled').prop('disabled', false)
            })
            .fail(GeneralFunctions.ajaxFailureHandler);
    }

    /**
     * Create Date Column Container 
     *
     * This element will contain the provider columns. 
     * 
     * @param {jQuery} $wrapper The wrapper div element of the table view. 
     * @param {Date} date Selected date for the column.
     * @param {Object[]} events Events to be displayed on this date. 
     * @param {Boolean} displayDate Whether to display the date in the column container. 
     */
    function _createDateColumn($wrapper, date, events, displayDate) {
        var $dateColumn = $('<div class="date-column" />').appendTo($wrapper); 

        $dateColumn.data('date', date.getTime());

        if (displayDate) {
            $dateColumn.append('<h5>' + GeneralFunctions.formatDate(date, GlobalVariables.dateFormat) + '</h5>');
        }

        var providers = GlobalVariables.availableProviders;

        if (GlobalVariables.user.role_slug === 'provider') {
            GlobalVariables.availableProviders.forEach(function (provider) {
                if (provider.id == GlobalVariables.user.id) {
                    providers = [provider]; 
                }
            });
        }

        if (GlobalVariables.user.role_slug === 'secretary') {
            providers = [];
            GlobalVariables.availableProviders.forEach(function (provider) {
                if (GlobalVariables.secretaryProviders.indexOf(provider.id) > -1) {
                    providers.push(provider)
                }
            });
        }

        for (var index in providers) {
            var provider = GlobalVariables.availableProviders[index]; 
            _createProviderColumn($dateColumn, date, provider, events);
        }
    }

    /**
     * Create Provider Column Container 
     * 
     * @param {jQuery} $dateColumn Element to container the provider's column.
     * @param {Date} date Selected date for the column.
     * @param {Object} provider Contains the provider data. 
     * {Object[]} events Events to be displayed on this date. 
     */
    function _createProviderColumn($dateColumn, date, provider, events) {
        if (provider.services.length === 0) {
            return;
        }

        var $providerColumn = $('<div class="provider-column" />').appendTo($dateColumn); 

        $providerColumn.data('provider', provider); 

        // Create the table slots. 
        _createSlots($providerColumn, date, provider); 

        // Add the appointments to the column. 
        _createAppointments($providerColumn, events.appointments); 
        
        // Add the unavailabilities to the column. 
        _createUnavailabilities($providerColumn, events.unavailabilities); 

        // Add the provider breaks to the column. 
        var workingPlan = JSON.parse(provider.settings.working_plan); 
        var day = date.toString('dddd').toLowerCase();
        if (workingPlan[day]) {
            var breaks = workingPlan[day].breaks;
            _createBreaks($providerColumn, breaks);
        }
    }

    /**
     * Create Table View Slots 
     *
     * The time slots will be added to a specific provider's column. 
     * 
     * @param {jQuery} $providerColumn The selected provider column.
     * @param {Date} date Selected date for the slot.
     * @param {Object} provider Contains the provider data.
     */
    function _createSlots($providerColumn, date, provider) {
        var day = date.toString('dddd').toLowerCase(); 
        var plan = JSON.parse(provider.settings.working_plan)[day]; 

        if (!plan) {
            $providerColumn.append('<div class="not-working">' 
                    + (provider.first_name + ' ' + provider.last_name).trim() +' <br> ' + EALang['not_working'] 
                    + '</div>');
            return;
        }

        var $table = $('<table class="slots" />')
            .appendTo($providerColumn)
            .addClass('table table-condensed table-responsive table-hover table-striped')
            .html(
                '<thead>' +
                    '<tr>' +
                        '<th colspan="' + (provider.services.length + 1) + '">' + 
                            (provider.first_name + ' ' + provider.last_name).trim() + 
                        '</th>' +
                    '</tr>' + 
                    '<tr>' +
                        '<th>' + EALang['time'] + '</th>' +
                    '</tr>' + 
                '</thead>' +
                '<tbody></tbody>'
            );

        for (var index in GlobalVariables.availableServices) {
            var service = GlobalVariables.availableServices[index]; 

            if (provider.services.indexOf(service.id) > -1) {
                $table.find('thead tr:last').append('<th data-id="' + service.id + '">' + service.name + '</th>'); 
            }
        }

        var start = parseInt(plan.start.split(':')[0]); 
        var end = parseInt(plan.end.split(':')[0]) + 1;
        var current = start;
        var $tbody = $table.find('tbody'); 

        while(current <= end) {
            var $tr = $('<tr/>').appendTo($tbody); 

            var time = (current < 10 ? '0' + parseInt(current) : parseInt(current)) + (current % 1 === 0 ? ':00' : ':30'); 

            $tr
                .append('<td>' + time + '</td>')
                .append('<td/>'.repeat(provider.services.length)); 

            current += 0.5; 
        }

        $table.stickyTableHeaders();
    }

    /**
     * Create Appointment Events 
     *
     * This method will add the appointment events on the table view. 
     * 
     * @param {jQuery} $providerColumn The provider column container.
     * @param {Object[]} appointments Contains the appointment events data. 
     */
    function _createAppointments($providerColumn, appointments) {
        if (appointments.length === 0) {
            return;
        }

        var currentDate = new Date($providerColumn.parents('.date-column').data('date')); 
        var $tbody = $providerColumn.find('table tbody');

        for (var index in appointments) {
            var appointment = appointments[index]; 

            if (appointment.id_users_provider !== $providerColumn.data('provider').id) {
                continue;
            }

            var eventDate = Date.parse(appointment.start_datetime); 
            var $event = $('<div class="event appointment" />'); 
            var startDate = Date.parse(appointment.start_datetime);
            var endDate = Date.parse(appointment.end_datetime);
            var eventDuration = Math.round((endDate - startDate) / 60000);

            $event.html(            
                appointment.customer.first_name.charAt(0) + '. ' + appointment.customer.last_name +
                ' <span class="hour">' + startDate.toString('HH:mm') + '</span> '
                + (eventDuration !== parseInt(appointment.service.duration) ? '(' + eventDuration + '\')' : '') 
            );

            $event.data(appointment);

            $tbody.find('tr').each(function(index, tr) {
                var $td = $(tr).find('td:first'); 

                var cellDate = new Date(currentDate.getTime()).set({
                    hour: parseInt($td.text().split(':')[0]),
                    minute: parseInt($td.text().split(':')[1])
                }); 

                if (eventDate < cellDate) {
                    var cellIndex = $providerColumn
                        .find('thead tr:last th[data-id="' + appointment.service.id + '"]')
                        .index();

                    $event.appendTo($(tr).prev().find('td').eq(cellIndex));

                    // Remove the hour from the event if it is the same as the row. 
                    if (eventDate.toString('HH:mm') === $(tr).prev().find('td').eq(0).text()) {
                        $event.find('.hour').remove();
                    }

                    return false;
                }
            }); 
        }
    }

    /**
     * Create Unavailabilities Events 
     *
     * This method will add the unavailability events on the table view. 
     * 
     * @param {jQuery} $providerColumn The provider column container.
     * @param {Object[]} unavailabilities Contains the unavailability events data. 
     */
    function _createUnavailabilities($providerColumn, unavailabilities) {
        if (unavailabilities.length === 0) {
            return;
        }

        var currentDate = new Date($providerColumn.parents('.date-column').data('date')); 
        var $tbody = $providerColumn.find('table tbody');

        for (var index in unavailabilities) {
            var unavailability = unavailabilities[index]; 

            if (unavailability.id_users_provider !== $providerColumn.data('provider').id) {
                continue;
            }

            var eventDate = Date.parse(unavailability.start_datetime); 
            var endDate = Date.parse(unavailability.end_datetime);
            var eventDuration = Math.round((endDate - eventDate) / 60000);
            var $event = $('<div class="event unavailability" />'); 

            $event.html((unavailability.notes || EALang['unavailable']) + 
                ' <span class="hour">' + eventDate.toString('HH:mm') + '</span> (' + eventDuration + '\')');

            $event.data(unavailability);

            $tbody.find('tr').each(function(index, tr) {
                var $td = $(tr).find('td:first'); 

                var cellDate = new Date(currentDate.getTime()).set({
                    hour: parseInt($td.text().split(':')[0]),
                    minute: parseInt($td.text().split(':')[1])
                }); 

                if (eventDate < cellDate) {
                    $event.appendTo($(tr).prev().find('td').eq(1));

                    // Remove the hour from the event if it is the same as the row. 
                    if (eventDate.toString('HH:mm') === $(tr).prev().find('td').eq(0).text()) {
                        $event.find('.hour').remove();
                    }

                    return false;
                }
            }); 
        }
    }

    /**
     * Create break events in the table view. 
     * 
     * @param {jQuery} $providerColumn The provider column container.
     * @param {Object[]} breaks Contains the break events data.
     */
    function _createBreaks($providerColumn, breaks) {
        if (breaks.length === 0) {
            return;
        }

        var currentDate = new Date($providerColumn.parents('.date-column').data('date')); 
        var $tbody = $providerColumn.find('table tbody');

        for (var index in breaks) {
            var entry = breaks[index];
            var startHour = entry.start.split(':');
            var eventDate = new Date(currentDate.getFullYear(), currentDate.getMonth(), currentDate.getDate(), startHour[0], startHour[1]); 
            var endHour = entry.end.split(':');
            var endDate = new Date(currentDate.getFullYear(), currentDate.getMonth(), currentDate.getDate(), endHour[0], endHour[1]); 
            var eventDuration = Math.round((endDate - eventDate) / 60000);
            var $event = $('<div class="event unavailability break" />'); 

            $event.html(
                EALang['break'] + 
                ' <span class="hour">' + eventDate.toString('HH:mm') + '</span> (' + eventDuration + '\')');

            $event.data(entry);

            $tbody.find('tr').each(function(index, tr) {
                var $td = $(tr).find('td:first'); 

                var cellDate = new Date(currentDate.getTime()).set({
                    hour: parseInt($td.text().split(':')[0]),
                    minute: parseInt($td.text().split(':')[1])
                }); 

                if (eventDate < cellDate) {
                    // Remove the hour from the event if it is the same as the row. 
                    if (eventDate.toString('HH:mm') === $(tr).prev().find('td').eq(0).text()) {
                        $event.find('.hour').remove();
                    }

                    $(tr).prev().find('td:gt(0)').each(function(index, td) {
                        $event.clone().appendTo($(td));
                    });
                    return false;
                }
            }); 
        }
    }

    /**
     * Set Table Calendar View 
     *
     * This method will set the optimal size in the calendar view elements in order to fit in the page without
     * using scrollbars.
     */
    function _setCalendarSize() {
        var height = window.innerHeight - $('#header').outerHeight() - $('#footer').outerHeight() 
                - $('#calendar-toolbar').outerHeight() - $('.calendar-header').outerHeight() - 50;

        if (height < 500) {
            height = 500;
        }

        // $('.calendar-view').height(height); 

        $('.calendar-view > div').css('min-width', '1000%');

        var width = 0; 

        $('.date-column').each(function(index, dateColumn) {
            width += $(dateColumn).outerWidth();
        });

        $('.calendar-view > div').css('min-width', width + 200);

        var dateColumnHeight = $('.date-column').outerHeight();
  
        $('.calendar-view .not-working').outerHeight((dateColumnHeight > height ? dateColumnHeight : height ) - 70);
    }

    /**
     * Get the calendar events. 
     * 
     * @param {Date} startDate The start date of the selected period.
     * @param {Date} endDate The end date of the selected period.
     * 
     * @return {jQuery.jqXHR}
     */
    function _getCalendarEvents(startDate, endDate) {
        var url = GlobalVariables.baseUrl + '/index.php/backend_api/ajax_get_calendar_events'; 
        var data = {
            csrfToken: GlobalVariables.csrfToken,
            startDate: startDate.toString('yyyy-MM-dd'),
            endDate: endDate.toString('yyyy-MM-dd')
        };

        return $.ajax({
            url: url, 
            data: data, 
            method: 'POST',
            beforeSend: function() {
                $('#loading').css('visibility', 'hidden');
            }, 
            complete: function() {
               $('#loading').css('visibility', ''); 
            }
        }); 
    }

    /**
     * Initialize Page 
     */
    exports.initialize = function() {
        _createHeader(); 
        _createView(Date.today(), Date.today().add({days: parseInt($('#select-filter-item').val() - 1)}));
        _bindEventHandlers();
        
        // Hide Google Calendar Sync buttons cause they can not be used within this view. 
        $('#enable-sync, #google-sync').hide();

        // Auto-reload the results every one minute.
        setInterval(function() {
            $('#reload-appointments').trigger('click');
        }, 20000); 
    };

})(window.BackendCalendarTableView);