function update_collaborators_invitation($Workroom_Id, $Action, $Collaborator_Id, $Alert_Id = '')
 {
     update_collaborators_invitation($Workroom_Id, $Action, $Collaborator_Id, $Alert_Id);
 }
function accept_invitation()
{
    if (!wp_verify_nonce($_REQUEST['accept_invitation_nonce'], "accept_invitation_nonce")) {
    }
    $Workroom_Id = $_GET['Workroom_Id'];
    $Action = 'Accepted';
    $Collaborator_Id = $_GET['Collaborator_Id'];
    $Alert_Id = $_GET['Alert_Id'];
    $Create_Invitation_Status = get_post_meta($Workroom_Id, 'Invitation_Status', true);
    if (!is_array($Create_Invitation_Status)) {
        $Create_Invitation_Status = array();
    }
    $size = sizeof($Create_Invitation_Status);
    $i = 0;
    $What_Do = "";
    $Invited_Data = '';
    foreach ($Create_Invitation_Status as $value) {
        $i++;
        if ($value['Alert_Id'] == $Alert_Id && $value['Collaborator_Id'] == $Collaborator_Id) {
            $What_Do = "Accept";
            $Invited_Data = $value['Invited_Data'];
            break;
        }
    }
    $ExpiryDate = (int) get_option('maxtime_to_accept_invitation');
    $t1 = strtotime($Invited_Data);
    $t2 = strtotime(date("Y-m-d H:i:s"));
    $diff = $t2 - $t1;
    $hours = $diff / (60 * 60);
    $Inv = new stdClass();
    if ($ExpiryDate >= $hours) {
        $Inv->Status = 'Accepted';
        update_post_meta($Alert_Id, 'Is_Alert_Read', 'YES');
        update_collaborators_invitation($Workroom_Id, $Action, $Collaborator_Id, $Alert_Id);
    } else {
        $Inv->Status = 'Expired';
    }
    $Inv->Collaborator_Name = get_the_author_meta('display_name', $Collaborator_Id);
    $Inv->Workroom_Name = get_the_title($Workroom_Id);
    $Inv->Site_Link = get_site_url();
    $Inv->Site_Name = get_bloginfo('name');
    ob_start();
    include collaboration_plugin_dir . 'templates/frontend/emails/collaboration-invitation-accept-template.php';
    $Accept_Invitation = ob_get_clean();
    echo $Accept_Invitation;
    die;
}