Add initial implementation of Simple Gantt chart and sample names list

- Created index.html for the Gantt chart with sample tasks and configurations.
- Added styles for the Gantt chart and linked necessary CSS and JS files.
- Introduced a names.txt file containing a list of names for potential use in the application.

autoload/factory/class.Tasks.php

@@ -5,6 +5,46 @@ class Tasks
 {
   public static $statuses = [ 0 => 'nowe', 3 => 'do rozliczenia', 5 => 'do zrobienia', 4 => 'zaplanowane', 1 => 'do sprawdzenia', 6 => 'faktury', 2 => 'zamknięte' ];
 
+  static public function task_change_dates( $task_id, $date_start, $date_end )
+  {
+    global $mdb;
+
+    if ( !$task_id )
+      return false;
+
+    return $mdb -> update( 'tasks', [
+      'date_start' => $date_start,
+      'date_end' => $date_end
+    ], [
+      'id' => $task_id
+    ] );
+  }
+
+  static public function get_tasks_gantt() {
+    global $mdb;
+
+    $tasks = $mdb -> query( 'SELECT t.id, t.name, t.date_start, t.date_end, t.status, t.client_id FROM tasks AS t WHERE show_in_calendar = 1 AND status != 2 ORDER BY date_start ASC' ) -> fetchAll( \PDO::FETCH_ASSOC );
+    foreach ( $tasks as $task ) {
+      $task_json = [];
+      $task_json['name'] = $task['client_id'] ? \factory\Crm::get_client_name( (int)$task['client_id'] ) : $task['name'];
+      // start
+      $task_json['start'] = $task['date_start'];
+      // end
+      $task_json['end'] = $task['date_end'];
+      // id
+      $task_json['id'] = $task['id'];
+      // custom class
+      if ( $task['date_start'] <= date( 'Y-m-d H:i:s' ) )
+        $task_json['custom_class'] = 'gantt-task-backlog';
+      // progress
+      $task_json['progress'] = 0;
+
+      $data[] = $task_json;
+    }
+
+    return $data;
+  }
+
   static public function work_delete( $work_id ) {
     global $mdb;
     return $mdb -> update( 'tasks_work', [ 'deleted' => 1 ], [ 'id' => $work_id ] );