/**
 * This namespace handles the js functionality of the users backend page. It uses three other
 * classes (defined below) in order to handle the admin, provider and secretary record types. 
 * 
 * @namespace BackendUsers.
 */
var BackendUsers = {
    /**
     * Contains the current tab record methods for the page.
     * 
     * @type AdminsHelper|ProvidersHelper|SecretariesHelper
     */
    helper: {},
    
    /**
     * Initialize the backend users page.
     * 
     * @param {bool} defaultEventHandlers (OPTIONAL) Whether to bind the default event handlers 
     * (default: true).
     */
    initialize: function(defaultEventHandlers) {
        if (defaultEventHandlers == undefined) defaultEventHandlers = true;
        
        // Instanciate default helper object (admin).
        BackendUsers.helper = new AdminsHelper();
        BackendUsers.helper.resetForm();
        BackendUsers.helper.filter('');
        
        // Fill the services and providers list boxes.
        $.each(GlobalVariables.services, function(index, service) {
            var html = '<input type="checkbox" data-id="' + service.id + '" />' 
                    + service.name + '<br>'; 
            $('#provider-services').append(html);
        });
        
        $.each(GlobalVariables.providers, function(index, provider) {
           var html = '<input type="checkbox" data-id="' + provider.id + '" />' 
                   + provider.first_name + ' ' + provider.last_name + '<br>';
            $('#secretary-providers').append(html);
        });
        
        // Bind event handlers.
        if (defaultEventHandlers) BackendUsers.bindEventHandlers();
    },
         
    /**
     * Binds the defauly backend users event handlers. Do not use this method on a different 
     * page because it needs the backend users page DOM.
     */
    bindEventHandlers: function() {
        /**
         * Event: Page Tab Button "Click"
         * 
         * Changes the displayed tab.
         */
        $('.tab').click(function() {
            $('.active').removeClass('active');
            $(this).addClass('active');
            $('.tab-content').hide();
            
            if ($(this).hasClass('admins-tab')) { // display admins tab
                $('#admins').show();
                BackendUsers.helper = new AdminsHelper();
            } else if ($(this).hasClass('providers-tab')) { // display providers tab
                $('#providers').show();
                BackendUsers.helper = new ProvidersHelper();
            } else if ($(this).hasClass('secretaries-tab')) { // display secretaries tab
                $('#secretaries').show();
                BackendUsers.helper = new SecretariesHelper();
                
                // Update the list with the all the available providers.
                var postUrl = GlobalVariables.baseUrl + 'backend_api/ajax_filter_providers';
                var postData = { 'key': '' };
                $.post(postUrl, postData, function(response) {
                    //////////////////////////////////////////////////////////
                    console.log('Get all db providers response:', response);
                    //////////////////////////////////////////////////////////
                    
                    if (!Backend.handleAjaxExceptions(response)) return;
                    
                    GlobalVariables.providers = response;
                    
                    $('#secretary-providers').html('');
                    $.each(GlobalVariables.providers, function(index, provider) {
                        var html = '<input type="checkbox" data-id="' + provider.id + '" />' 
                                + provider.first_name + ' ' + provider.last_name + '<br>';
                         $('#secretary-providers').append(html);
                     });
                     $('#secretary-providers input[type="checkbox"]').prop('disabled', true);
                }, 'json');
            }
            
            BackendUsers.helper.resetForm();
            BackendUsers.helper.filter('');
            $('.filter-key').val('');
        });
        
        /**
         * Event: Filter Admins Button "Click"
         * 
         * Filter the admin records with the given key string.
         */
        $('.filter-admins').click(function() {
            var key = $('#admins .filter-key').val();
            $('.selected-row').removeClass('selected-row');
            BackendUsers.helper.resetForm();
            BackendUsers.helper.filter(key);
        });
        
        /**
         * Event: Filter Admin Row "Click"
         * 
         * Display the selected admin data to the user.
         */
        $(document).on('click', '.admin-row', function() {
            if ($('#admin .filter-admins').prop('disabled')) {
                $('#admin .filter-results').css('color', '#AAA');
                return; // exit because we are currently on edit mode
            }
            
            var admin = { 'id': $(this).attr('data-id') };
            $.each(BackendUsers.helper.filterResults, function(index, item) {
                if (item.id === admin.id) {
                    admin = item;
                    return;
                }
            });
            BackendUsers.helper.display(admin);
            $('.selected-row').removeClass('selected-row');
            $(this).addClass('selected-row');
            $('#edit-admin, #delete-admin').prop('disabled', false);
        });
        
        /**
         * Event: Add New Admin Button "Click"
         */
        $('#add-admin').click(function() {
            BackendUsers.helper.resetForm();
            $('#admins .add-edit-delete-group').hide();
            $('#admins .save-cancel-group').show();
            $('#admins .details').find('input, textarea').prop('readonly', false);
            $('#admins .filter-admins').prop('disabled', true);
            $('#admins .filter-results').css('color', '#AAA');
            $('#admin-password, #admin-password-confirm').addClass('required');
            $('#admin-notifications').prop('disabled', false);
        });
        
        /**
         * Event: Edit Admin Button "Click"
         */
        $('#edit-admin').click(function() {
            $('#admins .add-edit-delete-group').hide();
            $('#admins .save-cancel-group').show();
            $('.filter-admins').prop('disabled', true);
            $('#admins .filter-results').css('color', '#AAA');
            $('#admins .details').find('input, textarea').prop('readonly', false);
            $('#admin-password, #admin-password-confirm').removeClass('required');
            $('#admin-notifications').prop('disabled', false);
        });
        
        /**
         * Event: Delete Admin Button "Click"
         */
        $('#delete-admin').click(function() {
            var adminId = $('#admin-id').val();
            
            var messageBtns = {
                'Delete': function() {
                    BackendUsers.helper.delete(adminId);
                    $('#message_box').dialog('close');
                },
                'Cancel': function() {
                    $('#message_box').dialog('close');
                }
            };
            
            GeneralFunctions.displayMessageBox('Delete Admin', 'Are you sure that you want '
                    + 'to delete this record? This action cannot be undone.', messageBtns);
        });
        
        /**
         * Event: Save Admin Button "Click"
         */
        $('#save-admin').click(function() {
            var admin = {
                'first_name': $('#admin-first-name').val(),
                'last_name': $('#admin-last-name').val(),
                'email': $('#admin-email').val(),
                'mobile_number': $('#admin-mobile-number').val(),
                'phone_number': $('#admin-phone-number').val(),
                'address': $('#admin-address').val(),
                'city': $('#admin-city').val(),
                'state': $('#admin-state').val(),
                'zip_code': $('#admin-zip-code').val(),
                'notes': $('#admin-notes').val(),
                'settings': {
                    'username': $('#admin-username').val(),                    
                    'notifications': $('#admin-notifications').hasClass('active')
                }
            };
            
            // Include password if changed.
            if ($('#admin-password').val() !== '') {
                admin.settings.password = $('#admin-password').val();
            }
            
            // Include id if changed.
            if ($('#admin-id').val() !== '') {
                admin.id = $('#admin-id').val();
            }
            
            if (!BackendUsers.helper.validate(admin)) return;
            
            BackendUsers.helper.save(admin);
        });
        
        /**
         * Event: Cancel Admin Button "Click"
         * 
         * Cancel add or edit of an admin record.
         */
        $('#cancel-admin').click(function() {
            BackendUsers.helper.resetForm();
        });
        
        // ------------------------------------------------------------------------
        
        /**
         * Event: Filter Providers Button "Click"
         * 
         * Filter the provider records with the given key string.
         */
        $('.filter-providers').click(function() {
            var key = $('#providers .filter-key').val();
            $('.selected-row').removeClass('selected-row');
            BackendUsers.helper.resetForm();
            BackendUsers.helper.filter(key);
        });
        
        /**
         * Event: Filter Provider Row "Click"
         * 
         * Display the selected provider data to the user.
         */
        $(document).on('click', '.provider-row', function() {
            if ($('#provider .filter-providers').prop('disabled')) {
                $('#provider .filter-results').css('color', '#AAA');
                return; // exit because we are currently on edit mode
            }
            
            var provider = { 'id': $(this).attr('data-id') };
            $.each(BackendUsers.helper.filterResults, function(index, item) {
                if (item.id === provider.id) {
                    provider = item;
                    return;
                }
            });
            BackendUsers.helper.display(provider);
            $('.selected-row').removeClass('selected-row');
            $(this).addClass('selected-row');
            $('#edit-provider, #delete-provider').prop('disabled', false);
        });
        
        /**
         * Event: Add New Provider Button "Click"
         */
        $('#add-provider').click(function() {
            BackendUsers.helper.resetForm();
            $('#providers .add-edit-delete-group').hide();
            $('#providers .save-cancel-group').show();
            $('#providers .details').find('input, textarea').prop('readonly', false);
            $('#providers .filter-providers').prop('disabled', true);
            $('#providers .filter-results').css('color', '#AAA');
            $('#provider-password, #provider-password-confirm').addClass('required');
            $('#provider-notifications').prop('disabled', false);
            $('#provider-services input[type="checkbox"]').prop('disabled', false);
        });
        
        /**
         * Event: Edit Provider Button "Click"
         */
        $('#edit-provider').click(function() {
            $('#providers .add-edit-delete-group').hide();
            $('#providers .save-cancel-group').show();
            $('.filter-providers').prop('disabled', true);
            $('#providers .filter-results').css('color', '#AAA');
            $('#providers .details').find('input, textarea').prop('readonly', false);
            $('#provider-password, #provider-password-confirm').removeClass('required');
            $('#provider-notifications').prop('disabled', false);
            $('#provider-services input[type="checkbox"]').prop('disabled', false);
        });
        
        /**
         * Event: Delete Provider Button "Click"
         */
        $('#delete-provider').click(function() {
            var providerId = $('#provider-id').val();
            
            var messageBtns = {
                'Delete': function() {
                    BackendUsers.helper.delete(providerId);
                    $('#message_box').dialog('close');
                },
                'Cancel': function() {
                    $('#message_box').dialog('close');
                }
            };
            
            GeneralFunctions.displayMessageBox('Delete Provider', 'Are you sure that you want '
                    + 'to delete this record? This action cannot be undone.', messageBtns);
        });
        
        /**
         * Event: Save Provider Button "Click"
         */
        $('#save-provider').click(function() {
            var provider = {
                'first_name': $('#provider-first-name').val(),
                'last_name': $('#provider-last-name').val(),
                'email': $('#provider-email').val(),
                'mobile_number': $('#provider-mobile-number').val(),
                'phone_number': $('#provider-phone-number').val(),
                'address': $('#provider-address').val(),
                'city': $('#provider-city').val(),
                'state': $('#provider-state').val(),
                'zip_code': $('#provider-zip-code').val(),
                'notes': $('#provider-notes').val(),
                'settings': {
                    'username': $('#provider-username').val(),                    
                    'notifications': $('#provider-notifications').hasClass('active')
                }
            };
            
            // Include provider services.
            provider.services = [];
            $('#provider-services input[type="checkbox"]').each(function() {
                if ($(this).prop('checked')) {
                    provider.services.push($(this).attr('data-id'));
                }
            });
            
            // Include password if changed.
            if ($('#provider-password').val() !== '') {
                provider.settings.password = $('#provider-password').val();
            }
            
            // Include id if changed.
            if ($('#provider-id').val() !== '') {
                provider.id = $('#provider-id').val();
            }
            
            if (!BackendUsers.helper.validate(provider)) return;
            
            BackendUsers.helper.save(provider);
        });
        
        /**
         * Event: Cancel Provider Button "Click"
         * 
         * Cancel add or edit of an provider record.
         */
        $('#cancel-provider').click(function() {
            BackendUsers.helper.resetForm();
        });
        
        // ------------------------------------------------------------------------
        
        /**
         * Event: Filter Secretaries Button "Click"
         * 
         * Filter the secretary records with the given key string.
         */
        $('.filter-secretaries').click(function() {
            var key = $('#secretaries .filter-key').val();
            $('.selected-row').removeClass('selected-row');
            BackendUsers.helper.resetForm();
            BackendUsers.helper.filter(key);
        });
        
        /**
         * Event: Filter Secretary Row "Click"
         * 
         * Display the selected secretary data to the user.
         */
        $(document).on('click', '.secretary-row', function() {
            if ($('#secretary .filter-secretaries').prop('disabled')) {
                $('#secretary .filter-results').css('color', '#AAA');
                return; // exit because we are currently on edit mode
            }
            
            var secretary = { 'id': $(this).attr('data-id') };
            $.each(BackendUsers.helper.filterResults, function(index, item) {
                if (item.id === secretary.id) {
                    secretary = item;
                    return;
                }
            });
            BackendUsers.helper.display(secretary);
            $('.selected-row').removeClass('selected-row');
            $(this).addClass('selected-row');
            $('#edit-secretary, #delete-secretary').prop('disabled', false);
        });
        
        /**
         * Event: Add New Secretary Button "Click"
         */
        $('#add-secretary').click(function() {
            BackendUsers.helper.resetForm();
            $('#secretaries .add-edit-delete-group').hide();
            $('#secretaries .save-cancel-group').show();
            $('#secretaries .details').find('input, textarea').prop('readonly', false);
            $('#secretaries .filter-secretaries').prop('disabled', true);
            $('#secretaries .filter-results').css('color', '#AAA');
            $('#secretary-password, #secretary-password-confirm').addClass('required');
            $('#secretary-notifications').prop('disabled', false);
            $('#secretary-providers input[type="checkbox"]').prop('disabled', false);
        });
        
        /**
         * Event: Edit Secretary Button "Click"
         */
        $('#edit-secretary').click(function() {
            $('#secretaries .add-edit-delete-group').hide();
            $('#secretaries .save-cancel-group').show();
            $('.filter-secretaries').prop('disabled', true);
            $('#secretaries .filter-results').css('color', '#AAA');
            $('#secretaries .details').find('input, textarea').prop('readonly', false);
            $('#secretary-password, #secretary-password-confirm').removeClass('required');
            $('#secretary-notifications').prop('disabled', false);
            $('#secretary-providers input[type="checkbox"]').prop('disabled', false);
        });
        
        /**
         * Event: Delete Secretary Button "Click"
         */
        $('#delete-secretary').click(function() {
            var providerId = $('#secretary-id').val();
            
            var messageBtns = {
                'Delete': function() {
                    BackendUsers.helper.delete(providerId);
                    $('#message_box').dialog('close');
                },
                'Cancel': function() {
                    $('#message_box').dialog('close');
                }
            };
            
            GeneralFunctions.displayMessageBox('Delete Secretary', 'Are you sure that you want '
                    + 'to delete this record? This action cannot be undone.', messageBtns);
        });
        
        /**
         * Event: Save Secretary Button "Click"
         */
        $('#save-secretary').click(function() {
            var secretary = {
                'first_name': $('#secretary-first-name').val(),
                'last_name': $('#secretary-last-name').val(),
                'email': $('#secretary-email').val(),
                'mobile_number': $('#secretary-mobile-number').val(),
                'phone_number': $('#secretary-phone-number').val(),
                'address': $('#secretary-address').val(),
                'city': $('#secretary-city').val(),
                'state': $('#secretary-state').val(),
                'zip_code': $('#secretary-zip-code').val(),
                'notes': $('#secretary-notes').val(),
                'settings': {
                    'username': $('#secretary-username').val(),                    
                    'notifications': $('#secretary-notifications').hasClass('active')
                }
            };
            
            // Include secretary services.
            secretary.providers = [];
            $('#secretary-providers input[type="checkbox"]').each(function() {
                if ($(this).prop('checked')) {
                    secretary.providers.push($(this).attr('data-id'));
                }
            });
            
            // Include password if changed.
            if ($('#secretary-password').val() !== '') {
                secretary.settings.password = $('#secretary-password').val();
            }
            
            // Include id if changed.
            if ($('#secretary-id').val() !== '') {
                secretary.id = $('#secretary-id').val();
            }
            
            if (!BackendUsers.helper.validate(secretary)) return;
            
            BackendUsers.helper.save(secretary);
        });
        
        /**
         * Event: Cancel Secretary Button "Click"
         * 
         * Cancel add or edit of an secretary record.
         */
        $('#cancel-secretary').click(function() {
            BackendUsers.helper.resetForm();
        });
        
    }    
};

/**
 * This class contains the methods that will be used by the "Admins" tab of the page.
 * 
 * @class AdminsHelper
 */
var AdminsHelper = function() {
    this.filterResults = {}; // Store the results for later use.
};

/**
 * Save admin record to database.
 * 
 * @param {object} admin Contains the admin record data. If an 'id' value is provided
 * then the update operation is going to be executed.
 */
AdminsHelper.prototype.save = function(admin) {
    //////////////////////////////////////////
    console.log('Admin data to save:', admin);
    //////////////////////////////////////////
    
    var postUrl = GlobalVariables.baseUrl + 'backend_api/ajax_save_admin';
    var postData = { 'admin': JSON.stringify(admin) };
    
    $.post(postUrl, postData, function(response) {
        ////////////////////////////////////////////////
        console.log('Save Admin Response:', response);
        ////////////////////////////////////////////////
        if (!Backend.handleAjaxExceptions(response)) return;
        Backend.displayNotification('Admin saved successfully!');
        BackendUsers.helper.resetForm();
        BackendUsers.helper.filter($('#admins .filter-key').val());
    }, 'json');
};

/**
 * Delete an admin record from database.
 * 
 * @param {int} id Record id to be deleted. 
 */
AdminsHelper.prototype.delete = function(id) {
    var postUrl = GlobalVariables.baseUrl + 'backend_api/ajax_delete_admin';
    var postData = { 'admin_id': id };
    
    $.post(postUrl, postData, function(response) {
        ////////////////////////////////////////////////////
        console.log('Delete admin response:', response);
        ////////////////////////////////////////////////////
        if (!Backend.handleAjaxExceptions(response)) return;
        Backend.displayNotification('Admin deleted successfully!');
        BackendUsers.helper.resetForm();
        BackendUsers.helper.filter($('#admins .filter-key').val());
    });
};

/**
 * Validates an admin record.
 * 
 * @param {object} admin Contains the admin data to be validated.
 * @returns {bool} Returns the validation result.
 */
AdminsHelper.prototype.validate = function(admin) {
    $('#admins .required').css('border', '');
    $('#admin-password, #admin-password-confirm').css('border', '');
    
    try {
        // Validate required fields.
        var missingRequired = false;
        $('#admins .required').each(function() {
            if ($(this).val() == '' || $(this).val() == undefined) {
                $(this).css('border', '2px solid red');
                missingRequired = true;
            }
        });
        if (missingRequired) {
            throw 'Fields with * are  required.';
        }
        
        // Validate passwords.
        if ($('#admin-password').val() != $('#admin-password-confirm').val()) {
            $('#admin-password, #admin-password-confirm').css('border', '2px solid red');
            throw 'Passwords mismatch!';
        }
        
        return true;
    } catch(exc) {
        $('#admins .form-message').text(exc);
        $('#admins .form-message').show();
        return false;
    }
};

/**
 * Resets the admin tab form back to its initial state. 
 */
AdminsHelper.prototype.resetForm = function() {
    $('#admins .details').find('input, textarea').val('');
    $('#admins .add-edit-delete-group').show();
    $('#admins .save-cancel-group').hide();
    $('#edit-admin, #delete-admin').prop('disabled', true);
    $('#admins .details').find('input, textarea').prop('readonly', true);
    $('.filter-admins').prop('disabled', false);
    $('#admins .filter-results').css('color', '');
    $('#admins .form-message').hide();    
    $('#admin-notifications').removeClass('active');
    $('#admin-notifications').prop('disabled', true);
};

/**
 * Display a admin record into the admin form.
 * 
 * @param {object} admin Contains the admin record data.
 */
AdminsHelper.prototype.display = function(admin) {
    $('#admin-id').val(admin.id);
    $('#admin-first-name').val(admin.first_name);
    $('#admin-last-name').val(admin.last_name);
    $('#admin-email').val(admin.email);
    $('#admin-mobile-number').val(admin.mobile_number);
    $('#admin-phone-number').val(admin.phone_number);
    $('#admin-address').val(admin.address);
    $('#admin-city').val(admin.city);
    $('#admin-state').val(admin.state);
    $('#admin-zip-code').val(admin.zip_code);
    $('#admin-notes').val(admin.notes);
    
    $('#admin-username').val(admin.settings.username);
    if (admin.settings.notifications == true) {
        $('#admin-notifications').addClass('active');
    } else {
        $('#admin-notifications').removeClass('active');
    }
};

/**
 * Filters admin records depending a string key.
 * 
 * @param {string} key This is used to filter the admin records of the database.
 */
AdminsHelper.prototype.filter = function(key) {
    var postUrl = GlobalVariables.baseUrl + 'backend_api/ajax_filter_admins';
    var postData = { 'key': key };
    
    $.post(postUrl, postData, function(response) {
        /////////////////////////////////////////////////////
        console.log('Filter admins response:', response);
        /////////////////////////////////////////////////////
        
        if (!Backend.handleAjaxExceptions(response)) return;
        
        BackendUsers.helper.filterResults = response;
        
        $('#admins .filter-results').html('');
        $.each(response, function(index, admin) {
            var html = AdminsHelper.prototype.getFilterHtml(admin);
            $('#admins .filter-results').append(html);
        });
    }, 'json');
};

/**
 * Get an admin row html code that is going to be displayed on the filter results list.
 * 
 * @param {object} admin Contains the admin record data.
 * @returns {string} The html code that represents the record on the filter results list.
 */
AdminsHelper.prototype.getFilterHtml = function(admin) {
    var html =
            '<div class="admin-row" data-id="' + admin.id + '">' + 
                '<strong>' + admin.first_name + ' ' + admin.last_name + '</strong><br>' +
                admin.email + ', ' + admin.mobile_number + ', ' + admin.phone_number + '<br>' + 
            '</div>';

    return html;
};

/**
 * This class contains the methods that will be used by the "Providers" tab of the page.
 * 
 * @class ProvidersHelper
 */
var ProvidersHelper = function() {
    this.filterResults = {}; // Store the results for later use.
};

/**
 * Save provider record to database.
 * 
 * @param {object} provider Contains the admin record data. If an 'id' value is provided
 * then the update operation is going to be executed.
 */
ProvidersHelper.prototype.save = function(provider) {
    //////////////////////////////////////////
    console.log('Provider data to save:', provider);
    //////////////////////////////////////////
    
    var postUrl = GlobalVariables.baseUrl + 'backend_api/ajax_save_provider';
    var postData = { 'provider': JSON.stringify(provider) };
    
    $.post(postUrl, postData, function(response) {
        ////////////////////////////////////////////////
        console.log('Save Provider Response:', response);
        ////////////////////////////////////////////////
        if (!Backend.handleAjaxExceptions(response)) return;
        Backend.displayNotification('Provider saved successfully!');
        BackendUsers.helper.resetForm();
        BackendUsers.helper.filter($('#providers .filter-key').val());
    }, 'json');
};

/**
 * Delete a provider record from database.
 * 
 * @param {int} id Record id to be deleted. 
 */
ProvidersHelper.prototype.delete = function(id) {
    var postUrl = GlobalVariables.baseUrl + 'backend_api/ajax_delete_provider';
    var postData = { 'provider_id': id };
    
    $.post(postUrl, postData, function(response) {
        ////////////////////////////////////////////////////
        console.log('Delete provider response:', response);
        ////////////////////////////////////////////////////
        if (!Backend.handleAjaxExceptions(response)) return;
        Backend.displayNotification('Provider deleted successfully!');
        BackendUsers.helper.resetForm();
        BackendUsers.helper.filter($('#providers .filter-key').val());
    });
};

/**
 * Validates a provider record.
 * 
 * @param {object} provider Contains the admin data to be validated.
 * @returns {bool} Returns the validation result.
 */
ProvidersHelper.prototype.validate = function(provider) {
    $('#providers .required').css('border', '');
    $('#provider-password, #provider-password-confirm').css('border', '');
    
    try {
        // Validate required fields.
        var missingRequired = false;
        $('#providers .required').each(function() {
            if ($(this).val() == '' || $(this).val() == undefined) {
                $(this).css('border', '2px solid red');
                missingRequired = true;
            }
        });
        if (missingRequired) {
            throw 'Fields with * are  required.';
        }
        
        // Validate passwords.
        if ($('#provider-password').val() != $('#provider-password-confirm').val()) {
            $('#provider-password, #provider-password-confirm').css('border', '2px solid red');
            throw 'Passwords mismatch!';
        }
        
        return true;
    } catch(exc) {
        $('#providers .form-message').text(exc);
        $('#providers .form-message').show();
        return false;
    }
};

/**
 * Resets the admin tab form back to its initial state. 
 */
ProvidersHelper.prototype.resetForm = function() {
    $('#providers .details').find('input, textarea').val('');
    $('#providers .add-edit-delete-group').show();
    $('#providers .save-cancel-group').hide();
    $('#edit-provider, #delete-provider').prop('disabled', true);
    $('#providers .details').find('input, textarea').prop('readonly', true);
    $('.filter-providers').prop('disabled', false);
    $('#providers .filter-results').css('color', '');
    $('#providers .form-message').hide();    
    $('#provider-notifications').removeClass('active');
    $('#provider-notifications').prop('disabled', true);
    $('#provider-services input[type="checkbox"]').prop('checked', false);
    $('#provider-services input[type="checkbox"]').prop('disabled', true);
};

/**
 * Display a provider record into the admin form.
 * 
 * @param {object} provider Contains the provider record data.
 */
ProvidersHelper.prototype.display = function(provider) {
    $('#provider-id').val(provider.id);
    $('#provider-first-name').val(provider.first_name);
    $('#provider-last-name').val(provider.last_name);
    $('#provider-email').val(provider.email);
    $('#provider-mobile-number').val(provider.mobile_number);
    $('#provider-phone-number').val(provider.phone_number);
    $('#provider-address').val(provider.address);
    $('#provider-city').val(provider.city);
    $('#provider-state').val(provider.state);
    $('#provider-zip-code').val(provider.zip_code);
    $('#provider-notes').val(provider.notes);
    
    $('#provider-username').val(provider.settings.username);
    if (provider.settings.notifications == true) {
        $('#provider-notifications').addClass('active');
    } else {
        $('#provider-notifications').removeClass('active');
    }
    
    $('#provider-services input[type="checkbox"]').prop('checked', false);
    $.each(provider.services, function(index, serviceId) {
        $('#provider-services input[type="checkbox"]').each(function() {
            if ($(this).attr('data-id') == serviceId) {
                $(this).prop('checked', true);
            }
        });
    });
};

/**
 * Filters provider records depending a string key.
 * 
 * @param {string} key This is used to filter the provider records of the database.
 */
ProvidersHelper.prototype.filter = function(key) {
    var postUrl = GlobalVariables.baseUrl + 'backend_api/ajax_filter_providers';
    var postData = { 'key': key };
    
    $.post(postUrl, postData, function(response) {
        /////////////////////////////////////////////////////
        console.log('Filter providers response:', response);
        /////////////////////////////////////////////////////
        
        if (!Backend.handleAjaxExceptions(response)) return;
        
        BackendUsers.helper.filterResults = response;
        
        $('#providers .filter-results').html('');
        $.each(response, function(index, provider) {
            var html = ProvidersHelper.prototype.getFilterHtml(provider);
            $('#providers .filter-results').append(html);
        });
    }, 'json');
};

/**
 * Get an provider row html code that is going to be displayed on the filter results list.
 * 
 * @param {object} provider Contains the provider record data.
 * @returns {string} The html code that represents the record on the filter results list.
 */
ProvidersHelper.prototype.getFilterHtml = function(provider) {
    var html =
            '<div class="provider-row" data-id="' + provider.id + '">' + 
                '<strong>' + provider.first_name + ' ' + provider.last_name + '</strong><br>' +
                provider.email + ', ' + provider.mobile_number + ', ' + provider.phone_number + '<br>' + 
            '</div>';

    return html;
};

/**
 * This class contains the methods that will be used by the "Secretaries" tab of the page.
 * 
 * @class SecretariesHelper
 */
var SecretariesHelper = function() {
    this.filterResults = {}; // Store the results for later use.
};

/**
 * Save secretary record to database.
 * 
 * @param {object} secretary Contains the admin record data. If an 'id' value is provided
 * then the update operation is going to be executed.
 */
SecretariesHelper.prototype.save = function(secretary) {
    //////////////////////////////////////////
    console.log('Secretary data to save:', secretary);
    //////////////////////////////////////////
    
    var postUrl = GlobalVariables.baseUrl + 'backend_api/ajax_save_secretary';
    var postData = { 'secretary': JSON.stringify(secretary) };
    
    $.post(postUrl, postData, function(response) {
        ////////////////////////////////////////////////
        console.log('Save Secretary Response:', response);
        ////////////////////////////////////////////////
        if (!Backend.handleAjaxExceptions(response)) return;
        Backend.displayNotification('Secretary saved successfully!');
        BackendUsers.helper.resetForm();
        BackendUsers.helper.filter($('#secretaries .filter-key').val());
    }, 'json');
};

/**
 * Delete a secretary record from database.
 * 
 * @param {int} id Record id to be deleted. 
 */
SecretariesHelper.prototype.delete = function(id) {
    var postUrl = GlobalVariables.baseUrl + 'backend_api/ajax_delete_secretary';
    var postData = { 'secretary_id': id };
    
    $.post(postUrl, postData, function(response) {
        ////////////////////////////////////////////////////
        console.log('Delete secretary response:', response);
        ////////////////////////////////////////////////////
        if (!Backend.handleAjaxExceptions(response)) return;
        Backend.displayNotification('Secretary deleted successfully!');
        BackendUsers.helper.resetForm();
        BackendUsers.helper.filter($('#secretaries .filter-key').val());
    });
};

/**
 * Validates a secretary record.
 * 
 * @param {object} secretary Contains the admin data to be validated.
 * @returns {bool} Returns the validation result.
 */
SecretariesHelper.prototype.validate = function(secretary) {
    $('#secretaries .required').css('border', '');
    $('#secretary-password, #secretary-password-confirm').css('border', '');
    
    try {
        // Validate required fields.
        var missingRequired = false;
        $('#secretaries .required').each(function() {
            if ($(this).val() == '' || $(this).val() == undefined) {
                $(this).css('border', '2px solid red');
                missingRequired = true;
            }
        });
        if (missingRequired) {
            throw 'Fields with * are  required.';
        }
        
        // Validate passwords.
        if ($('#secretary-password').val() != $('#secretary-password-confirm').val()) {
            $('#secretary-password, #secretary-password-confirm').css('border', '2px solid red');
            throw 'Passwords mismatch!';
        }
        
        return true;
    } catch(exc) {
        $('#secretaries .form-message').text(exc);
        $('#secretaries .form-message').show();
        return false;
    }
};

/**
 * Resets the admin tab form back to its initial state. 
 */
SecretariesHelper.prototype.resetForm = function() {
    $('#secretaries .details').find('input, textarea').val('');
    $('#secretaries .add-edit-delete-group').show();
    $('#secretaries .save-cancel-group').hide();
    $('#edit-secretary, #delete-secretary').prop('disabled', true);
    $('#secretaries .details').find('input, textarea').prop('readonly', true);
    $('.filter-secretaries').prop('disabled', false);
    $('#secretaries .filter-results').css('color', '');
    $('#secretaries .form-message').hide();    
    $('#secretary-notifications').removeClass('active');
    $('#secretary-notifications').prop('disabled', true);
    $('#secretary-providers input[type="checkbox"]').prop('checked', false);
    $('#secretary-providers input[type="checkbox"]').prop('disabled', true);
};

/**
 * Display a secretary record into the admin form.
 * 
 * @param {object} secretary Contains the secretary record data.
 */
SecretariesHelper.prototype.display = function(secretary) {
    $('#secretary-id').val(secretary.id);
    $('#secretary-first-name').val(secretary.first_name);
    $('#secretary-last-name').val(secretary.last_name);
    $('#secretary-email').val(secretary.email);
    $('#secretary-mobile-number').val(secretary.mobile_number);
    $('#secretary-phone-number').val(secretary.phone_number);
    $('#secretary-address').val(secretary.address);
    $('#secretary-city').val(secretary.city);
    $('#secretary-state').val(secretary.state);
    $('#secretary-zip-code').val(secretary.zip_code);
    $('#secretary-notes').val(secretary.notes);
    
    $('#secretary-username').val(secretary.settings.username);
    if (secretary.settings.notifications == true) {
        $('#secretary-notifications').addClass('active');
    } else {
        $('#secretary-notifications').removeClass('active');
    }
    
    $('#secretary-providers input[type="checkbox"]').prop('checked', false);
    $.each(secretary.providers, function(index, providerId) {
        $('#secretary-providers input[type="checkbox"]').each(function() {
            if ($(this).attr('data-id') == providerId) {
                $(this).prop('checked', true);
            }
        });
    });
};

/**
 * Filters secretary records depending a string key.
 * 
 * @param {string} key This is used to filter the secretary records of the database.
 */
SecretariesHelper.prototype.filter = function(key) {
    var postUrl = GlobalVariables.baseUrl + 'backend_api/ajax_filter_secretaries';
    var postData = { 'key': key };
    
    $.post(postUrl, postData, function(response) {
        /////////////////////////////////////////////////////
        console.log('Filter secretaries response:', response);
        /////////////////////////////////////////////////////
        
        if (!Backend.handleAjaxExceptions(response)) return;
        
        BackendUsers.helper.filterResults = response;
        
        $('#secretaries .filter-results').html('');
        $.each(response, function(index, secretary) {
            var html = SecretariesHelper.prototype.getFilterHtml(secretary);
            $('#secretaries .filter-results').append(html);
        });
    }, 'json');
};

/**
 * Get an secretary row html code that is going to be displayed on the filter results list.
 * 
 * @param {object} secretary Contains the secretary record data.
 * @returns {string} The html code that represents the record on the filter results list.
 */
SecretariesHelper.prototype.getFilterHtml = function(secretary) {
    var html =
            '<div class="secretary-row" data-id="' + secretary.id + '">' + 
                '<strong>' + secretary.first_name + ' ' + secretary.last_name + '</strong><br>' +
                secretary.email + ', ' + secretary.mobile_number + ', ' + secretary.phone_number + '<br>' + 
            '</div>';

    return html;
};