add group count query

backend/src/middleware/permissionsMiddleware.js

@@ -312,6 +312,7 @@ export default shield(
       currentUser: allow,
       Group: isAuthenticated,
       GroupMembers: isAllowedSeeingGroupMembers,
+      GroupCount: isAuthenticated,
       Post: allow,
       profilePagePosts: allow,
       Comment: allow,

backend/src/schema/resolvers/groups.js

@@ -81,6 +81,39 @@ export default {
         session.close()
       }
     },
+    GroupCount: async (_object, params, context, _resolveInfo) => {
+      const { isMember } = params
+      const {
+        user: { id: userId },
+      } = context
+      const session = context.driver.session()
+      const readTxResultPromise = session.readTransaction(async (txc) => {
+        let cypher
+        if (isMember) {
+          cypher = `MATCH (user:User)-[membership:MEMBER_OF]->(group:Group)
+                    WHERE user.id = $userId
+                    AND membership.role IN ['usual', 'admin', 'owner']
+                    RETURN toString(count(group)) AS count`
+        } else {
+          cypher = `MATCH (group:Group)
+                    OPTIONAL MATCH (user:User)-[membership:MEMBER_OF]->(group)
+                    WHERE user.id = $userId
+                    WITH group, membership
+                    WHERE group.groupType IN ['public', 'closed']
+                    OR membership.role IN ['usual', 'admin', 'owner']
+                    RETURN toString(count(group)) AS count`
+        }
+        const transactionResponse = await txc.run(cypher, { userId })
+        return transactionResponse.records.map((record) => record.get('count'))
+      })
+      try {
+        return parseInt(await readTxResultPromise)
+      } catch (error) {
+        throw new Error(error)
+      } finally {
+        session.close()
+      }
+    },
   },
   Mutation: {
     CreateGroup: async (_parent, params, context, _resolveInfo) => {

backend/src/schema/types/type/Group.gql

@@ -65,8 +65,8 @@ type Query {
     isMember: Boolean # if 'undefined' or 'null' then get all groups
     id: ID
     slug: String
-    # first: Int # not implemented yet
-    # offset: Int # not implemented yet
+    first: Int # not implemented yet
+    offset: Int # not implemented yet
     # orderBy: [_GroupOrdering] # not implemented yet
     # filter: _GroupFilter # not implemented yet
   ): [Group]
@@ -79,6 +79,8 @@ type Query {
     # filter: _UserFilter # not implemented yet
   ): [User]
 
+  GroupCount(isMember: Boolean): Int
+  
   # AvailableGroupTypes: [GroupType]!
 
   # AvailableGroupActionRadii: [GroupActionRadius]!