graphql: Add channel stats under channel (#19804)

* graphql: Add channel stats under channel

* add permission check

api4/resolver_channel.go

@@ -29,6 +29,36 @@ func (ch *channel) Team(ctx context.Context) (*model.Team, error) {
 	return getGraphQLTeam(ctx, ch.TeamId)
 }
 
+// match with api4.getChannelStats
+func (ch *channel) Stats(ctx context.Context) (*model.ChannelStats, error) {
+	c, err := getCtx(ctx)
+	if err != nil {
+		return nil, err
+	}
+
+	if !c.App.SessionHasPermissionToChannel(*c.AppContext.Session(), ch.Id, model.PermissionReadChannel) {
+		c.SetPermissionError(model.PermissionReadChannel)
+		return nil, c.Err
+	}
+
+	memberCount, appErr := c.App.GetChannelMemberCount(ch.Id)
+	if appErr != nil {
+		return nil, appErr
+	}
+
+	guestCount, appErr := c.App.GetChannelGuestCount(ch.Id)
+	if appErr != nil {
+		return nil, appErr
+	}
+
+	pinnedPostCount, appErr := c.App.GetChannelPinnedPostCount(ch.Id)
+	if appErr != nil {
+		return nil, appErr
+	}
+
+	return &model.ChannelStats{ChannelId: ch.Id, MemberCount: memberCount, GuestCount: guestCount, PinnedPostCount: pinnedPostCount}, nil
+}
+
 func (ch *channel) Cursor() *string {
 	cursor := string(channelCursorPrefix) + "-" + ch.Id
 	encoded := base64.StdEncoding.EncodeToString([]byte(cursor))

api4/resolver_channel_test.go

@@ -43,6 +43,12 @@ func TestGraphQLChannels(t *testing.T) {
 				ID          string `json:"id"`
 				DisplayName string `json:"displayName"`
 			} `json:"team"`
+			Stats struct {
+				ChannelId       string  `json:"channelId"`
+				MemberCount     float64 `json:"memberCount"`
+				GuestCount      float64 `json:"guestCount"`
+				PinnedPostCount float64 `json:"pinnedpostCount"`
+			} `json:"stats"`
 		} `json:"channels"`
 	}
 
@@ -366,6 +372,39 @@ func TestGraphQLChannels(t *testing.T) {
 		require.NoError(t, json.Unmarshal(resp.Data, &q))
 		assert.Len(t, q.Channels, 5)
 	})
+
+	t.Run("stats", func(t *testing.T) {
+		query := `query channels($teamId: String, $first: Int) {
+	  channels(userId: "me", teamId: $teamId, first: $first) {
+		id
+		stats {
+		  channelId
+		  memberCount
+		}
+	  }
+	}
+	`
+		input := graphQLInput{
+			OperationName: "channels",
+			Query:         query,
+			Variables: map[string]interface{}{
+				"first":  10,
+				"teamId": myTeam.Id,
+			},
+		}
+
+		resp, err := th.MakeGraphQLRequest(&input)
+		require.NoError(t, err)
+		require.Len(t, resp.Errors, 0)
+		require.NoError(t, json.Unmarshal(resp.Data, &q))
+		require.Len(t, q.Channels, 2)
+		for _, ch := range q.Channels {
+			require.Equal(t, ch.ID, ch.Stats.ChannelId)
+			count, appErr := th.App.GetChannelMemberCount(ch.Stats.ChannelId)
+			require.Nil(t, appErr)
+			require.Equal(t, float64(count), ch.Stats.MemberCount)
+		}
+	})
 }
 
 func TestGetPrettyDNForUsers(t *testing.T) {

api4/schema.graphqls

@@ -52,6 +52,7 @@ type Channel {
 	shared: Boolean
 	lastPostAt: Float!
 	totalMsgCount: Float!
+	stats: ChannelStats
 	cursor: String
 }
 
@@ -170,4 +171,11 @@ type Session {
 	token: String!
 	createAt: Float!
 	expiresAt: Float!
-}
+}
+
+type ChannelStats {
+	channelId: String!
+	memberCount: Float!
+	guestCount: Float!
+	pinnedPostCount: Float!
+}