<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');

/* ----------------------------------------------------------------------------
 * 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       v1.0.0
 * ---------------------------------------------------------------------------- */

/**
 * Backend Controller
 *
 * @package Controllers
 */
class Backend extends CI_Controller {
    /**
     * Class Constructor
     */
    public function __construct() {
        parent::__construct();
        $this->load->library('session');

		// Set user's selected language.
        if ($this->session->userdata('language')) {
        	$this->config->set_item('language', $this->session->userdata('language'));
        	$this->lang->load('translations', $this->session->userdata('language'));
        } else {
        	$this->lang->load('translations', $this->config->item('language')); // default
        }
    }

    /**
     * Display the main backend page.
     *
     * This method displays the main backend page. All users login permission can
     * view this page which displays a calendar with the events of the selected
     * provider or service. If a user has more privileges he will see more menus
     * at the top of the page.
     *
     * @param string $appointment_hash If given, the appointment edit dialog will
     * appear when the page loads.
     */
    public function index($appointment_hash = '') {
        $this->session->set_userdata('dest_url', site_url('backend'));
        if (!$this->_has_privileges(PRIV_APPOINTMENTS)) return;

        $this->load->model('appointments_model');
        $this->load->model('providers_model');
        $this->load->model('services_model');
        $this->load->model('customers_model');
        $this->load->model('settings_model');
        $this->load->model('roles_model');
        $this->load->model('user_model');
        $this->load->model('secretaries_model');

        $view['base_url'] = $this->config->item('base_url');
        $view['user_display_name'] = $this->user_model->get_user_display_name($this->session->userdata('user_id'));
        $view['active_menu'] = PRIV_APPOINTMENTS;
        $view['book_advance_timeout'] = $this->settings_model->get_setting('book_advance_timeout');
        $view['date_format'] = $this->settings_model->get_setting('date_format');
        $view['company_name'] = $this->settings_model->get_setting('company_name');
        $view['available_providers'] = $this->providers_model->get_available_providers();
        $view['available_services'] = $this->services_model->get_available_services();
        $view['customers'] = $this->customers_model->get_batch();
        $user = $this->user_model->get_settings($this->session->userdata('user_id'));
        $view['calendar_view'] = $user['settings']['calendar_view'];
        $this->set_user_data($view);

        if ($this->session->userdata('role_slug') == DB_SLUG_SECRETARY) {
            $secretary = $this->secretaries_model->get_row($this->session->userdata('user_id'));
            $view['secretary_providers'] = $secretary['providers'];
        } else {
            $view['secretary_providers'] = array();
        }

        $results = $this->appointments_model->get_batch(array('hash' => $appointment_hash));
        if ($appointment_hash != '' && count($results) > 0) {
            $appointment = $results[0];
            $appointment['customer'] = $this->customers_model->get_row($appointment['id_users_customer']);
            $view['edit_appointment'] = $appointment; // This will display the appointment edit dialog on page load.
        } else {
            $view['edit_appointment'] = NULL;
        }

        $this->load->view('backend/header', $view);
        $this->load->view('backend/calendar', $view);
        $this->load->view('backend/footer', $view);
    }

    /**
     * Display the backend customers page.
     *
     * In this page the user can manage all the customer records of the system.
     */
    public function customers() {
        $this->session->set_userdata('dest_url', site_url('backend/customers'));
    	if (!$this->_has_privileges(PRIV_CUSTOMERS)) return;

        $this->load->model('providers_model');
        $this->load->model('customers_model');
        $this->load->model('services_model');
        $this->load->model('settings_model');
        $this->load->model('user_model');

        $view['base_url'] = $this->config->item('base_url');
        $view['user_display_name'] = $this->user_model->get_user_display_name($this->session->userdata('user_id'));
        $view['active_menu'] = PRIV_CUSTOMERS;
        $view['company_name'] = $this->settings_model->get_setting('company_name');
        $view['date_format'] = $this->settings_model->get_setting('date_format');
        $view['customers'] = $this->customers_model->get_batch();
        $view['available_providers'] = $this->providers_model->get_available_providers();
        $view['available_services'] = $this->services_model->get_available_services();
        $this->set_user_data($view);

        $this->load->view('backend/header', $view);
        $this->load->view('backend/customers', $view);
        $this->load->view('backend/footer', $view);
    }

    /**
     * Displays the backend services page.
     *
     * Here the admin user will be able to organize and create the services
     * that the user will be able to book appointments in frontend.
     *
     * NOTICE: The services that each provider is able to service is managed
     * from the backend services page.
     */
    public function services() {
        $this->session->set_userdata('dest_url', site_url('backend/services'));
        if (!$this->_has_privileges(PRIV_SERVICES)) return;

        $this->load->model('customers_model');
        $this->load->model('services_model');
        $this->load->model('settings_model');
        $this->load->model('user_model');

        $view['base_url'] = $this->config->item('base_url');
        $view['user_display_name'] = $this->user_model->get_user_display_name($this->session->userdata('user_id'));
        $view['active_menu'] = PRIV_SERVICES;
        $view['company_name'] = $this->settings_model->get_setting('company_name');
        $view['date_format'] = $this->settings_model->get_setting('date_format');
        $view['services'] = $this->services_model->get_batch();
        $view['categories'] = $this->services_model->get_all_categories();
        $this->set_user_data($view);

        $this->load->view('backend/header', $view);
        $this->load->view('backend/services', $view);
        $this->load->view('backend/footer', $view);
    }

    /**
     * Display the backend users page.
     *
     * In this page the admin user will be able to manage the system users.
     * By this, we mean the provider, secretary and admin users. This is also
     * the page where the admin defines which service can each provider provide.
     */
    public function users() {
        $this->session->set_userdata('dest_url', site_url('backend/users'));
        if (!$this->_has_privileges(PRIV_USERS)) return;

        $this->load->model('providers_model');
        $this->load->model('secretaries_model');
        $this->load->model('admins_model');
        $this->load->model('services_model');
        $this->load->model('settings_model');
        $this->load->model('user_model');

        $view['base_url'] = $this->config->item('base_url');
        $view['user_display_name'] = $this->user_model->get_user_display_name($this->session->userdata('user_id'));
        $view['active_menu'] = PRIV_USERS;
        $view['company_name'] = $this->settings_model->get_setting('company_name');
        $view['date_format'] = $this->settings_model->get_setting('date_format');
        $view['admins'] = $this->admins_model->get_batch();
        $view['providers'] = $this->providers_model->get_batch();
        $view['secretaries'] = $this->secretaries_model->get_batch();
        $view['services'] = $this->services_model->get_batch();
        $view['working_plan'] = $this->settings_model->get_setting('company_working_plan');
        $this->set_user_data($view);

        $this->load->view('backend/header', $view);
        $this->load->view('backend/users', $view);
        $this->load->view('backend/footer', $view);
    }

    /**
     * Display the user/system settings.
     *
     * This page will display the user settings (name, password etc). If current user is
     * an administrator, then he will be able to make change to the current Easy!Appointment
     * installation (core settings like company name, book timeout etc).
     */
    public function settings() {
        $this->session->set_userdata('dest_url', site_url('backend/settings'));
        if (!$this->_has_privileges(PRIV_SYSTEM_SETTINGS, FALSE)
                && !$this->_has_privileges(PRIV_USER_SETTINGS)) return;

        $this->load->model('settings_model');
        $this->load->model('user_model');

        $this->load->library('session');
        $user_id = $this->session->userdata('user_id');

        $view['base_url'] = $this->config->item('base_url');
        $view['user_display_name'] = $this->user_model->get_user_display_name($user_id);
        $view['active_menu'] = PRIV_SYSTEM_SETTINGS;
        $view['company_name'] = $this->settings_model->get_setting('company_name');
        $view['date_format'] = $this->settings_model->get_setting('date_format');
        $view['role_slug'] = $this->session->userdata('role_slug');
        $view['system_settings'] = $this->settings_model->get_settings();
        $view['user_settings'] = $this->user_model->get_settings($user_id);
        $this->set_user_data($view);

        $this->load->view('backend/header', $view);
        $this->load->view('backend/settings', $view);
        $this->load->view('backend/footer', $view);
    }

    /**
     * Check whether current user is logged in and has the required privileges to
     * view a page.
     *
     * The backend page requires different privileges from the users to display pages. Not all
     * pages are available to all users. For example secretaries should not be able to edit the
     * system users.
     *
     * @see Constant Definition In application/config/constants.php
     *
     * @param string $page This argument must match the roles field names of each section
     * (eg "appointments", "users" ...).
     * @param bool $redirect (OPTIONAL - TRUE) If the user has not the required privileges
     * (either not logged in or insufficient role privileges) then the user will be redirected
     * to another page. Set this argument to FALSE when using ajax.
     *
     * @return bool Returns whether the user has the required privileges to view the page or
     * not. If the user is not logged in then he will be prompted to log in. If he hasn't the
     * required privileges then an info message will be displayed.
     */
    protected function _has_privileges($page, $redirect = TRUE) {
        // Check if user is logged in.
        $user_id = $this->session->userdata('user_id');
        if ($user_id == FALSE) { // User not logged in, display the login view.
            if ($redirect) {
                header('Location: ' . site_url('user/login'));
            }
            return FALSE;
        }

        // Check if the user has the required privileges for viewing the selected page.
        $role_slug = $this->session->userdata('role_slug');
        $role_priv = $this->db->get_where('ea_roles', array('slug' => $role_slug))->row_array();
        if ($role_priv[$page] < PRIV_VIEW) { // User does not have the permission to view the page.
             if ($redirect) {
                header('Location: ' . site_url('user/no_privileges'));
            }
            return FALSE;
        }

        return TRUE;
    }

    /**
     * This method will update the installation to the latest available
     * version in the server. IMPORTANT: The code files must exist in the
     * server, this method will not fetch any new files but will update
     * the database schema.
     *
     * This method can be used either by loading the page in the browser
     * or by an ajax request. But it will answer with json encoded data.
     */
    public function update() {
        try {
            if (!$this->_has_privileges(PRIV_SYSTEM_SETTINGS, TRUE))
                throw new Exception('You do not have the required privileges for this task!');

            $this->load->library('migration');

            if (!$this->migration->current())
                throw new Exception($this->migration->error_string());

            echo json_encode(AJAX_SUCCESS);

        } catch(Exception $exc) {
            echo json_encode(array(
                'exceptions' => array(exceptionToJavaScript($exc))
            ));
        }
    }

    /**
     * Set the user data in order to be available at the view and js code.
     *
     * @param array $view Contains the view data.
     */
    protected function set_user_data(&$view) {
        $this->load->model('roles_model');

        // Get privileges
        $view['user_id'] = $this->session->userdata('user_id');
        $view['user_email'] = $this->session->userdata('user_email');
        $view['role_slug'] = $this->session->userdata('role_slug');
        $view['privileges'] = $this->roles_model->get_privileges($this->session->userdata('role_slug'));
    }
}