Add group membership filter widget in contact list

src/Content/Widget.php

@@ -13,6 +13,7 @@ use Friendica\DI;
 use Friendica\Model\Contact;
 use Friendica\Model\FileTag;
 use Friendica\Model\GContact;
+use Friendica\Model\Group;
 use Friendica\Model\Item;
 use Friendica\Model\Profile;
 use Friendica\Util\DateTimeFormat;
@@ -174,6 +175,38 @@ class Widget
 		]);
 	}
 
+	/**
+	 * Return group membership widget
+	 *
+	 * @param string $baseurl
+	 * @param string $selected
+	 * @return string
+	 * @throws \Exception
+	 */
+	public static function groups($baseurl, $selected = '')
+	{
+		if (!local_user()) {
+			return '';
+		}
+
+		$options = array_map(function ($group) {
+			return [
+				'ref'  => $group['id'],
+				'name' => $group['name']
+			];
+		}, Group::getByUserId(local_user()));
+
+		return self::filter(
+			'group',
+			DI::l10n()->t('Groups'),
+			'',
+			DI::l10n()->t('Everyone'),
+			$baseurl,
+			$options,
+			$selected
+		);
+	}
+
 	/**
 	 * Return contact relationship widget
 	 *

src/Module/Contact.php

@@ -326,6 +326,12 @@ class Contact extends BaseModule
 			$follow_widget = '';
 			$networks_widget = '';
 			$rel_widget = '';
+
+			if ($contact['uid'] != 0) {
+				$groups_widget = Model\Group::sidebarWidget('contact', 'group', 'full', 'everyone', $contact_id);
+			} else {
+				$groups_widget = '';
+			}
 		} else {
 			$vcard_widget = '';
 			$findpeople_widget = Widget::findPeople();
@@ -337,12 +343,7 @@ class Contact extends BaseModule
 
 			$networks_widget = Widget::networks($_SERVER['REQUEST_URI'], $nets);
 			$rel_widget = Widget::contactRels($_SERVER['REQUEST_URI'], $rel);
-		}
+			$groups_widget = Widget::groups($_SERVER['REQUEST_URI'], $group);
-
-		if ($contact['uid'] != 0) {
-			$groups_widget = Model\Group::sidebarWidget('contact', 'group', 'full', 'everyone', $contact_id);
-		} else {
-			$groups_widget = null;
 		}
 
 		DI::page()['aside'] .= $vcard_widget . $findpeople_widget . $follow_widget . $groups_widget . $networks_widget . $rel_widget;
@@ -710,6 +711,11 @@ class Contact extends BaseModule
 				break;
 		}
 
+		if ($group) {
+			$sql_extra = " AND EXISTS(SELECT `id` FROM `group_member` WHERE `gid` = ? AND `contact`.`id` = `contact-id`)";
+			$sql_values[] = $group;
+		}
+
 		$sql_extra .= Widget::unavailableNetworks();
 
 		$total = 0;