From df44f7296424efec7b515bf68bd84c8ea44b5f10 Mon Sep 17 00:00:00 2001
From: Alex Tselegidis <alextselegidis@gmail.com>
Date: Tue, 12 May 2020 20:50:55 +0200
Subject: [PATCH] The timezones model got converted into a library (as there is
 no direct database table to manage).

---
 application/controllers/Appointments.php      |  6 +--
 application/controllers/Backend.php           | 22 +++++-----
 application/controllers/Backend_api.php       | 13 +++---
 application/controllers/Captcha.php           |  2 +-
 application/controllers/Consents.php          |  2 +-
 application/controllers/Errors.php            |  2 +-
 application/controllers/Google.php            |  2 +-
 application/controllers/Installation.php      |  2 +-
 application/controllers/Privacy.php           |  2 +-
 application/controllers/User.php              |  2 +-
 application/controllers/api/v1/Admins.php     |  2 +-
 .../controllers/api/v1/Appointments.php       |  2 +-
 .../controllers/api/v1/Availabilities.php     |  2 +-
 application/controllers/api/v1/Categories.php |  2 +-
 application/controllers/api/v1/Customers.php  |  2 +-
 application/controllers/api/v1/Providers.php  |  2 +-
 .../controllers/api/v1/Secretaries.php        |  2 +-
 application/controllers/api/v1/Services.php   |  2 +-
 application/controllers/api/v1/Settings.php   |  2 +-
 .../controllers/api/v1/Unavailabilities.php   |  2 +-
 application/helpers/render_helper.php         |  4 +-
 .../Timezones.php}                            | 44 +++++++++++--------
 application/models/Appointments_model.php     | 12 ++---
 application/models/User_model.php             | 18 +++++++-
 24 files changed, 87 insertions(+), 66 deletions(-)
 rename application/{models/Timezones_model.php => libraries/Timezones.php} (97%)

diff --git a/application/controllers/Appointments.php b/application/controllers/Appointments.php
index 20c1b109..09c8b61d 100755
--- a/application/controllers/Appointments.php
+++ b/application/controllers/Appointments.php
@@ -35,7 +35,7 @@ use EA\Engine\Types\Url;
  * @property Services_Model services_model
  * @property Customers_Model customers_model
  * @property Settings_Model settings_model
- * @property Timezones_Model timezones_model
+ * @property Timezones timezones
  * @property Roles_Model roles_model
  * @property Secretaries_Model secretaries_model
  * @property Admins_Model admins_model
@@ -59,7 +59,7 @@ class Appointments extends CI_Controller {
         $this->load->model('services_model');
         $this->load->model('customers_model');
         $this->load->model('settings_model');
-        $this->load->model('timezones_model');
+        $this->load->library('timezones');
 
         if ($this->session->userdata('language'))
         {
@@ -106,7 +106,7 @@ class Appointments extends CI_Controller {
             $display_privacy_policy = $this->settings_model->get_setting('display_privacy_policy');
             $privacy_policy_content = $this->settings_model->get_setting('privacy_policy_content');
             $display_any_provider = $this->settings_model->get_setting('display_any_provider');
-            $timezones = $this->timezones_model->to_array();
+            $timezones = $this->timezones->to_array();
 
             // Remove the data that are not needed inside the $available_providers array.
             foreach ($available_providers as $index => $provider)
diff --git a/application/controllers/Backend.php b/application/controllers/Backend.php
index f4959994..f6c4e589 100755
--- a/application/controllers/Backend.php
+++ b/application/controllers/Backend.php
@@ -30,7 +30,7 @@
  * @property Services_Model services_model
  * @property Customers_Model customers_model
  * @property Settings_Model settings_model
- * @property Timezones_Model timezones_model
+ * @property Timezones timezones
  * @property Roles_Model roles_model
  * @property Secretaries_Model secretaries_model
  * @property Admins_Model admins_model
@@ -88,7 +88,7 @@ class Backend extends CI_Controller {
         $this->load->model('roles_model');
         $this->load->model('user_model');
         $this->load->model('secretaries_model');
-        $this->load->model('timezones_model');
+        $this->load->library('timezones');
 
         $calendar_view_query_param = $this->input->get('view');
 
@@ -108,7 +108,7 @@ class Backend extends CI_Controller {
         $view['available_services'] = $this->services_model->get_available_services();
         $view['customers'] = $this->customers_model->get_batch();
         $view['calendar_view'] = !empty($calendar_view_query_param) ? $calendar_view_query_param : $user['settings']['calendar_view'];
-        $view['timezones'] = $this->timezones_model->to_array();
+        $view['timezones'] = $this->timezones->to_array();
         $this->set_user_data($view);
 
         if ($this->session->userdata('role_slug') === DB_SLUG_SECRETARY)
@@ -225,7 +225,7 @@ class Backend extends CI_Controller {
         $this->load->model('services_model');
         $this->load->model('settings_model');
         $this->load->model('user_model');
-        $this->load->model('timezones_model');
+        $this->load->library('timezones');
 
         $view['base_url'] = $this->config->item('base_url');
         $view['user_display_name'] = $this->user_model->get_user_display_name($this->session->userdata('user_id'));
@@ -238,7 +238,7 @@ class Backend extends CI_Controller {
         $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();
-        $view['timezones'] = $this->timezones_model->to_array();
+        $view['timezones'] = $this->timezones->to_array();
 
         if ($this->session->userdata('role_slug') === DB_SLUG_SECRETARY)
         {
@@ -278,7 +278,7 @@ class Backend extends CI_Controller {
         $this->load->model('services_model');
         $this->load->model('settings_model');
         $this->load->model('user_model');
-        $this->load->model('timezones_model');
+        $this->load->library('timezones');
 
         $view['base_url'] = $this->config->item('base_url');
         $view['user_display_name'] = $this->user_model->get_user_display_name($this->session->userdata('user_id'));
@@ -289,7 +289,7 @@ class Backend extends CI_Controller {
         $view['first_weekday'] = $this->settings_model->get_setting('first_weekday');
         $view['services'] = $this->services_model->get_batch();
         $view['categories'] = $this->services_model->get_all_categories();
-        $view['timezones'] = $this->timezones_model->to_array();
+        $view['timezones'] = $this->timezones->to_array();
         $this->set_user_data($view);
 
         $this->load->view('backend/header', $view);
@@ -318,7 +318,7 @@ class Backend extends CI_Controller {
         $this->load->model('services_model');
         $this->load->model('settings_model');
         $this->load->model('user_model');
-        $this->load->model('timezones_model');
+        $this->load->library('timezones');
 
         $view['base_url'] = $this->config->item('base_url');
         $view['user_display_name'] = $this->user_model->get_user_display_name($this->session->userdata('user_id'));
@@ -332,7 +332,7 @@ class Backend extends CI_Controller {
         $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');
-        $view['timezones'] = $this->timezones_model->to_array();
+        $view['timezones'] = $this->timezones->to_array();
         $view['extra_working_plan'] = '{}';
         $this->set_user_data($view);
 
@@ -359,7 +359,7 @@ class Backend extends CI_Controller {
 
         $this->load->model('settings_model');
         $this->load->model('user_model');
-        $this->load->model('timezones_model');
+        $this->load->library('timezones');
 
         $this->load->library('session');
         $user_id = $this->session->userdata('user_id');
@@ -374,7 +374,7 @@ class Backend extends CI_Controller {
         $view['role_slug'] = $this->session->userdata('role_slug');
         $view['system_settings'] = $this->settings_model->get_settings();
         $view['user_settings'] = $this->user_model->get_user($user_id);
-        $view['timezones'] = $this->timezones_model->to_array();
+        $view['timezones'] = $this->timezones->to_array();
         $this->set_user_data($view);
 
         $this->load->view('backend/header', $view);
diff --git a/application/controllers/Backend_api.php b/application/controllers/Backend_api.php
index 0345c6ac..da14e19c 100755
--- a/application/controllers/Backend_api.php
+++ b/application/controllers/Backend_api.php
@@ -37,7 +37,7 @@ use EA\Engine\Types\Url;
  * @property Services_Model services_model
  * @property Customers_Model customers_model
  * @property Settings_Model settings_model
- * @property Timezones_Model timezones_model
+ * @property Timezones timezones
  * @property Roles_Model roles_model
  * @property Secretaries_Model secretaries_model
  * @property Admins_Model admins_model
@@ -280,7 +280,8 @@ class Backend_api extends CI_Controller {
             $this->load->model('services_model');
             $this->load->model('customers_model');
             $this->load->model('settings_model');
-            $this->load->model('timezones_model');
+            $this->load->library('timezones');
+            $this->load->model('user_model');
 
             // Save customer changes to the database.
             if ($this->input->post('customer_data'))
@@ -319,14 +320,14 @@ class Backend_api extends CI_Controller {
                     $appointment['id_users_customer'] = $customer['id'];
                 }
 
-                $provider_timezone = $this->timezones_model->get_user_timezone($appointment['id_users_provider']);
+                $provider_timezone = $this->user_model->get_user_timezone($appointment['id_users_provider']);
 
-                $session_timezone = $this->timezones_model->get_session_timezone();
+                $session_timezone = $this->timezones->get_session_timezone();
 
-                $appointment['start_datetime'] = $this->timezones_model->convert($appointment['start_datetime'],
+                $appointment['start_datetime'] = $this->timezones->convert($appointment['start_datetime'],
                     $session_timezone, $provider_timezone);
 
-                $appointment['end_datetime'] = $this->timezones_model->convert($appointment['end_datetime'],
+                $appointment['end_datetime'] = $this->timezones->convert($appointment['end_datetime'],
                     $session_timezone, $provider_timezone);
 
                 $appointment['id'] = $this->appointments_model->add($appointment);
diff --git a/application/controllers/Captcha.php b/application/controllers/Captcha.php
index 634f6d95..86bd4b90 100644
--- a/application/controllers/Captcha.php
+++ b/application/controllers/Captcha.php
@@ -30,7 +30,7 @@
  * @property Services_Model services_model
  * @property Customers_Model customers_model
  * @property Settings_Model settings_model
- * @property Timezones_Model timezones_model
+ * @property Timezones timezones
  * @property Roles_Model roles_model
  * @property Secretaries_Model secretaries_model
  * @property Admins_Model admins_model
diff --git a/application/controllers/Consents.php b/application/controllers/Consents.php
index 30c5dd69..60494828 100644
--- a/application/controllers/Consents.php
+++ b/application/controllers/Consents.php
@@ -33,7 +33,7 @@
  * @property Customers_Model customers_model
  * @property Consents_Model consents_model
  * @property Settings_Model settings_model
- * @property Timezones_Model timezones_model
+ * @property Timezones timezones
  * @property Roles_Model roles_model
  * @property Secretaries_Model secretaries_model
  * @property Admins_Model admins_model
diff --git a/application/controllers/Errors.php b/application/controllers/Errors.php
index a831a993..49c01f45 100644
--- a/application/controllers/Errors.php
+++ b/application/controllers/Errors.php
@@ -30,7 +30,7 @@
  * @property Services_Model services_model
  * @property Customers_Model customers_model
  * @property Settings_Model settings_model
- * @property Timezones_Model timezones_model
+ * @property Timezones timezones
  * @property Roles_Model roles_model
  * @property Secretaries_Model secretaries_model
  * @property Admins_Model admins_model
diff --git a/application/controllers/Google.php b/application/controllers/Google.php
index 7f589f40..cde455b2 100644
--- a/application/controllers/Google.php
+++ b/application/controllers/Google.php
@@ -32,7 +32,7 @@
  * @property Services_Model services_model
  * @property Customers_Model customers_model
  * @property Settings_Model settings_model
- * @property Timezones_Model timezones_model
+ * @property Timezones timezones
  * @property Roles_Model roles_model
  * @property Secretaries_Model secretaries_model
  * @property Admins_Model admins_model
diff --git a/application/controllers/Installation.php b/application/controllers/Installation.php
index 023b62eb..4c1aaa1e 100644
--- a/application/controllers/Installation.php
+++ b/application/controllers/Installation.php
@@ -33,7 +33,7 @@
  * @property Services_Model services_model
  * @property Customers_Model customers_model
  * @property Settings_Model settings_model
- * @property Timezones_Model timezones_model
+ * @property Timezones timezones
  * @property Roles_Model roles_model
  * @property Secretaries_Model secretaries_model
  * @property Admins_Model admins_model
diff --git a/application/controllers/Privacy.php b/application/controllers/Privacy.php
index 8d54b72d..77186cba 100644
--- a/application/controllers/Privacy.php
+++ b/application/controllers/Privacy.php
@@ -30,7 +30,7 @@
  * @property Services_Model services_model
  * @property Customers_Model customers_model
  * @property Settings_Model settings_model
- * @property Timezones_Model timezones_model
+ * @property Timezones timezones
  * @property Roles_Model roles_model
  * @property Secretaries_Model secretaries_model
  * @property Admins_Model admins_model
diff --git a/application/controllers/User.php b/application/controllers/User.php
index e2d07c88..37e0e6fc 100644
--- a/application/controllers/User.php
+++ b/application/controllers/User.php
@@ -34,7 +34,7 @@ use EA\Engine\Types\NonEmptyText;
  * @property Services_Model services_model
  * @property Customers_Model customers_model
  * @property Settings_Model settings_model
- * @property Timezones_Model timezones_model
+ * @property Timezones timezones
  * @property Roles_Model roles_model
  * @property Secretaries_Model secretaries_model
  * @property Admins_Model admins_model
diff --git a/application/controllers/api/v1/Admins.php b/application/controllers/api/v1/Admins.php
index d33985b9..f67ec3c6 100644
--- a/application/controllers/api/v1/Admins.php
+++ b/application/controllers/api/v1/Admins.php
@@ -36,7 +36,7 @@ use EA\Engine\Types\NonEmptyText;
  * @property Services_Model services_model
  * @property Customers_Model customers_model
  * @property Settings_Model settings_model
- * @property Timezones_Model timezones_model
+ * @property Timezones timezones
  * @property Roles_Model roles_model
  * @property Secretaries_Model secretaries_model
  * @property Admins_Model admins_model
diff --git a/application/controllers/api/v1/Appointments.php b/application/controllers/api/v1/Appointments.php
index c549d355..b2b46890 100644
--- a/application/controllers/api/v1/Appointments.php
+++ b/application/controllers/api/v1/Appointments.php
@@ -36,7 +36,7 @@ use EA\Engine\Types\NonEmptyText;
  * @property Services_Model services_model
  * @property Customers_Model customers_model
  * @property Settings_Model settings_model
- * @property Timezones_Model timezones_model
+ * @property Timezones timezones
  * @property Roles_Model roles_model
  * @property Secretaries_Model secretaries_model
  * @property Admins_Model admins_model
diff --git a/application/controllers/api/v1/Availabilities.php b/application/controllers/api/v1/Availabilities.php
index 66e0e1c8..945f848b 100644
--- a/application/controllers/api/v1/Availabilities.php
+++ b/application/controllers/api/v1/Availabilities.php
@@ -35,7 +35,7 @@ use EA\Engine\Types\UnsignedInteger;
  * @property Services_Model services_model
  * @property Customers_Model customers_model
  * @property Settings_Model settings_model
- * @property Timezones_Model timezones_model
+ * @property Timezones timezones
  * @property Roles_Model roles_model
  * @property Secretaries_Model secretaries_model
  * @property Admins_Model admins_model
diff --git a/application/controllers/api/v1/Categories.php b/application/controllers/api/v1/Categories.php
index d3899a0e..6fb0cbf0 100644
--- a/application/controllers/api/v1/Categories.php
+++ b/application/controllers/api/v1/Categories.php
@@ -36,7 +36,7 @@ use EA\Engine\Types\NonEmptyText;
  * @property Services_Model services_model
  * @property Customers_Model customers_model
  * @property Settings_Model settings_model
- * @property Timezones_Model timezones_model
+ * @property Timezones timezones
  * @property Roles_Model roles_model
  * @property Secretaries_Model secretaries_model
  * @property Admins_Model admins_model
diff --git a/application/controllers/api/v1/Customers.php b/application/controllers/api/v1/Customers.php
index 6e5f26d8..4fb1f25c 100644
--- a/application/controllers/api/v1/Customers.php
+++ b/application/controllers/api/v1/Customers.php
@@ -36,7 +36,7 @@ use EA\Engine\Types\NonEmptyText;
  * @property Services_Model services_model
  * @property Customers_Model customers_model
  * @property Settings_Model settings_model
- * @property Timezones_Model timezones_model
+ * @property Timezones timezones
  * @property Roles_Model roles_model
  * @property Secretaries_Model secretaries_model
  * @property Admins_Model admins_model
diff --git a/application/controllers/api/v1/Providers.php b/application/controllers/api/v1/Providers.php
index e641472a..695666eb 100644
--- a/application/controllers/api/v1/Providers.php
+++ b/application/controllers/api/v1/Providers.php
@@ -36,7 +36,7 @@ use EA\Engine\Types\NonEmptyText;
  * @property Services_Model services_model
  * @property Customers_Model customers_model
  * @property Settings_Model settings_model
- * @property Timezones_Model timezones_model
+ * @property Timezones timezones
  * @property Roles_Model roles_model
  * @property Secretaries_Model secretaries_model
  * @property Admins_Model admins_model
diff --git a/application/controllers/api/v1/Secretaries.php b/application/controllers/api/v1/Secretaries.php
index ff5bfb80..5aa8fb42 100644
--- a/application/controllers/api/v1/Secretaries.php
+++ b/application/controllers/api/v1/Secretaries.php
@@ -36,7 +36,7 @@ use EA\Engine\Types\NonEmptyText;
  * @property Services_Model services_model
  * @property Customers_Model customers_model
  * @property Settings_Model settings_model
- * @property Timezones_Model timezones_model
+ * @property Timezones timezones
  * @property Roles_Model roles_model
  * @property Secretaries_Model secretaries_model
  * @property Admins_Model admins_model
diff --git a/application/controllers/api/v1/Services.php b/application/controllers/api/v1/Services.php
index 2330519a..cd3427e4 100644
--- a/application/controllers/api/v1/Services.php
+++ b/application/controllers/api/v1/Services.php
@@ -36,7 +36,7 @@ use EA\Engine\Types\NonEmptyText;
  * @property Services_Model services_model
  * @property Customers_Model customers_model
  * @property Settings_Model settings_model
- * @property Timezones_Model timezones_model
+ * @property Timezones timezones
  * @property Roles_Model roles_model
  * @property Secretaries_Model secretaries_model
  * @property Admins_Model admins_model
diff --git a/application/controllers/api/v1/Settings.php b/application/controllers/api/v1/Settings.php
index 3acfb500..07a694ce 100644
--- a/application/controllers/api/v1/Settings.php
+++ b/application/controllers/api/v1/Settings.php
@@ -35,7 +35,7 @@ use EA\Engine\Api\V1\Response;
  * @property Services_Model services_model
  * @property Customers_Model customers_model
  * @property Settings_Model settings_model
- * @property Timezones_Model timezones_model
+ * @property Timezones timezones
  * @property Roles_Model roles_model
  * @property Secretaries_Model secretaries_model
  * @property Admins_Model admins_model
diff --git a/application/controllers/api/v1/Unavailabilities.php b/application/controllers/api/v1/Unavailabilities.php
index 9b34a37f..f3534b60 100644
--- a/application/controllers/api/v1/Unavailabilities.php
+++ b/application/controllers/api/v1/Unavailabilities.php
@@ -36,7 +36,7 @@ use EA\Engine\Types\NonEmptyText;
  * @property Services_Model services_model
  * @property Customers_Model customers_model
  * @property Settings_Model settings_model
- * @property Timezones_Model timezones_model
+ * @property Timezones timezones
  * @property Roles_Model roles_model
  * @property Secretaries_Model secretaries_model
  * @property Admins_Model admins_model
diff --git a/application/helpers/render_helper.php b/application/helpers/render_helper.php
index c59f6d54..84e6a595 100644
--- a/application/helpers/render_helper.php
+++ b/application/helpers/render_helper.php
@@ -21,9 +21,9 @@ function render_timezone_dropdown($attributes = '')
 {
     $framework = get_instance();
 
-    $framework->load->model('timezones_model');
+    $framework->load->library('timezones');
 
-    $timezones = $framework->timezones_model->to_grouped_array();
+    $timezones = $framework->timezones->to_grouped_array();
 
     ob_start();
 
diff --git a/application/models/Timezones_model.php b/application/libraries/Timezones.php
similarity index 97%
rename from application/models/Timezones_model.php
rename to application/libraries/Timezones.php
index 48a9fd9f..befa61d5 100644
--- a/application/models/Timezones_model.php
+++ b/application/libraries/Timezones.php
@@ -12,14 +12,18 @@
  * ---------------------------------------------------------------------------- */
 
 /**
- * Timezones Model
+ * Timezones
  *
- * @property CI_DB_query_builder db
  * @property CI_Loader load
  *
  * @package Models
  */
-class Timezones_Model extends CI_Model {
+class Timezones {
+    /**
+     * @var CI_Controller
+     */
+    protected $framework;
+
     /**
      * @var string
      */
@@ -460,6 +464,15 @@ class Timezones_Model extends CI_Model {
         ],
     ];
 
+    public function __construct()
+    {
+        $this->framework = & get_instance();
+
+        $this->framework->load->model('user_model');
+
+        $this->framework->load->library('session');
+    }
+
     /**
      * Get all timezones to a grouped array (by continent).
      *
@@ -474,7 +487,9 @@ class Timezones_Model extends CI_Model {
      * Convert the dates of an event to the timezone of the user.
      *
      * @param array $event Must contain the "start_datetime", "end_datetime" and "id_users_provider" properties.
+     *
      * @return array
+     *
      * @throws Exception
      */
     public function convert_event_timezone($event)
@@ -484,7 +499,7 @@ class Timezones_Model extends CI_Model {
             throw new Exception('The provided event does not have the required properties: ' . print_r($event));
         }
 
-        $user_timezone = $this->get_user_timezone($event['id_users_provider']);
+        $user_timezone = $this->framework->user_model->get_user_timezone($event['id_users_provider']);
 
         $session_timezone = $this->get_session_timezone();
 
@@ -497,18 +512,6 @@ class Timezones_Model extends CI_Model {
         return $event;
     }
 
-    /**
-     * Get the timezone of a user.
-     *
-     * @param int $id Database ID of the user.
-     * @return string|null
-     */
-    public function get_user_timezone($id)
-    {
-        $row = $this->db->get_where('users', ['id' => $id])->row_array();
-
-        return $row ? $row['timezone'] : NULL;
-    }
 
     /**
      * Returns the session timezone or the default timezone as a fallback.
@@ -517,11 +520,11 @@ class Timezones_Model extends CI_Model {
      */
     public function get_session_timezone()
     {
-        $this->load->library('session');
-
         $default_timezone = $this->get_default_timezone();
 
-        return isset($this->session->timezone) ? $this->session->timezone : $default_timezone;
+        return $this->framework->session->has_userdata('timezone')
+            ? $this->framework->session->userdata('timezone')
+            : $default_timezone;
     }
 
     /**
@@ -540,7 +543,9 @@ class Timezones_Model extends CI_Model {
      * @param string $value Provide a date time value as a string (format Y-m-d H:i:s).
      * @param string $from_timezone From timezone value.
      * @param string $to_timezone To timezone value.
+     *
      * @return string
+     *
      * @throws Exception
      */
     public function convert($value, $from_timezone, $to_timezone)
@@ -565,6 +570,7 @@ class Timezones_Model extends CI_Model {
      * Get the timezone name for the provided value.
      *
      * @param string $value
+     *
      * @return string|null
      */
     public function get_timezone_name($value)
diff --git a/application/models/Appointments_model.php b/application/models/Appointments_model.php
index a1b7127b..539a6e18 100644
--- a/application/models/Appointments_model.php
+++ b/application/models/Appointments_model.php
@@ -302,9 +302,9 @@ class Appointments_Model extends CI_Model {
 
         $appointment = $this->db->get_where('appointments', ['id' => $appointment_id])->row_array();
 
-        $this->load->model('timezones_model');
+        $this->load->library('timezones');
 
-        $appointment = $this->timezones_model->convert_event_timezone($appointment);
+        $appointment = $this->timezones->convert_event_timezone($appointment);
 
         return $appointment;
     }
@@ -348,9 +348,9 @@ class Appointments_Model extends CI_Model {
             throw new Exception('The given field name does not exist in the database: ' . $field_name);
         }
 
-        $this->load->model('timezones_model');
+        $this->load->library('timezones');
 
-        $row_data = $this->timezones_model->convert_event_timezone($row_data);
+        $row_data = $this->timezones->convert_event_timezone($row_data);
 
         return $row_data[$field_name];
     }
@@ -385,11 +385,11 @@ class Appointments_Model extends CI_Model {
 
         $appointments = $this->db->get('appointments', $limit, $offset)->result_array();
 
-        $this->load->model('timezones_model');
+        $this->load->library('timezones');
 
         foreach ($appointments as &$appointment)
         {
-            $appointment = $this->timezones_model->convert_event_timezone($appointment);
+            $appointment = $this->timezones->convert_event_timezone($appointment);
 
             if ($aggregates)
             {
diff --git a/application/models/User_model.php b/application/models/User_model.php
index 6ed2b763..904544ad 100644
--- a/application/models/User_model.php
+++ b/application/models/User_model.php
@@ -109,9 +109,9 @@ class User_Model extends CI_Model {
             return NULL;
         }
 
-        $this->load->model('timezones_model');
+        $this->load->library('timezones');
 
-        $default_timezone = $this->timezones_model->get_default_timezone();
+        $default_timezone = $this->timezones->get_default_timezone();
 
         return [
             'user_id' => $user['id'],
@@ -192,4 +192,18 @@ class User_Model extends CI_Model {
 
         return $new_password;
     }
+
+    /**
+     * Get the timezone of a user.
+     *
+     * @param int $id Database ID of the user.
+     *
+     * @return string|null
+     */
+    public function get_user_timezone($id)
+    {
+        $row = $this->db->get_where('users', ['id' => $id])->row_array();
+
+        return $row ? $row['timezone'] : NULL;
+    }
 }