MM-18356: Adds ability to paginate channel search. (#12830)

* MM-18356: Adds ability to paginate channel search.

* MM-18356: Minor refactor.

* MM-18356: Adds doc.

* MM-18356: Fixes doc.

* MM-18356: Some commentary, adds the total count to non-paginated responses, and removes a stray fmt.

* MM-18356: Fixes shadowed variable.

* MM-18356: Removes paginate field and API parameter.

* MM-18356: Adds method to check if channel search is a paginated request.

* MM-18356: Vet fix.

store/storetest/channel_store.go

@@ -2689,31 +2689,37 @@ func testChannelStoreSearchAllChannels(t *testing.T, ss store.Store) {
 		Term            string
 		Opts            store.ChannelSearchOpts
 		ExpectedResults *model.ChannelList
+		TotalCount      int
 	}{
-		{"ChannelA", "ChannelA", store.ChannelSearchOpts{IncludeDeleted: false}, &model.ChannelList{&o1, &o2, &o3}},
-		{"ChannelA, include deleted", "ChannelA", store.ChannelSearchOpts{IncludeDeleted: true}, &model.ChannelList{&o1, &o2, &o3, &o13}},
-		{"empty string", "", store.ChannelSearchOpts{IncludeDeleted: false}, &model.ChannelList{&o1, &o2, &o3, &o4, &o5, &o12, &o11, &o8, &o7, &o6, &o10, &o9}},
-		{"no matches", "blargh", store.ChannelSearchOpts{IncludeDeleted: false}, &model.ChannelList{}},
-		{"prefix", "off-", store.ChannelSearchOpts{IncludeDeleted: false}, &model.ChannelList{&o8, &o7, &o6}},
-		{"full match with dash", "off-topic", store.ChannelSearchOpts{IncludeDeleted: false}, &model.ChannelList{&o6}},
-		{"town square", "town square", store.ChannelSearchOpts{IncludeDeleted: false}, &model.ChannelList{&o9}},
-		{"the in name", "the", store.ChannelSearchOpts{IncludeDeleted: false}, &model.ChannelList{&o10}},
-		{"Mobile", "Mobile", store.ChannelSearchOpts{IncludeDeleted: false}, &model.ChannelList{&o11}},
-		{"search purpose", "now searchable", store.ChannelSearchOpts{IncludeDeleted: false}, &model.ChannelList{&o12}},
-		{"pipe ignored", "town square |", store.ChannelSearchOpts{IncludeDeleted: false}, &model.ChannelList{&o9}},
-		{"exclude defaults search 'off'", "off-", store.ChannelSearchOpts{IncludeDeleted: false, ExcludeChannelNames: []string{"off-topic"}}, &model.ChannelList{&o8, &o7}},
-		{"exclude defaults search 'town'", "town", store.ChannelSearchOpts{IncludeDeleted: false, ExcludeChannelNames: []string{"town-square"}}, &model.ChannelList{}},
-		{"exclude by group association", "off", store.ChannelSearchOpts{IncludeDeleted: false, NotAssociatedToGroup: group.Id}, &model.ChannelList{&o8, &o6}},
+		{"ChannelA", "ChannelA", store.ChannelSearchOpts{IncludeDeleted: false}, &model.ChannelList{&o1, &o2, &o3}, 0},
+		{"ChannelA, include deleted", "ChannelA", store.ChannelSearchOpts{IncludeDeleted: true}, &model.ChannelList{&o1, &o2, &o3, &o13}, 0},
+		{"empty string", "", store.ChannelSearchOpts{IncludeDeleted: false}, &model.ChannelList{&o1, &o2, &o3, &o4, &o5, &o12, &o11, &o8, &o7, &o6, &o10, &o9}, 0},
+		{"no matches", "blargh", store.ChannelSearchOpts{IncludeDeleted: false}, &model.ChannelList{}, 0},
+		{"prefix", "off-", store.ChannelSearchOpts{IncludeDeleted: false}, &model.ChannelList{&o8, &o7, &o6}, 0},
+		{"full match with dash", "off-topic", store.ChannelSearchOpts{IncludeDeleted: false}, &model.ChannelList{&o6}, 0},
+		{"town square", "town square", store.ChannelSearchOpts{IncludeDeleted: false}, &model.ChannelList{&o9}, 0},
+		{"the in name", "the", store.ChannelSearchOpts{IncludeDeleted: false}, &model.ChannelList{&o10}, 0},
+		{"Mobile", "Mobile", store.ChannelSearchOpts{IncludeDeleted: false}, &model.ChannelList{&o11}, 0},
+		{"search purpose", "now searchable", store.ChannelSearchOpts{IncludeDeleted: false}, &model.ChannelList{&o12}, 0},
+		{"pipe ignored", "town square |", store.ChannelSearchOpts{IncludeDeleted: false}, &model.ChannelList{&o9}, 0},
+		{"exclude defaults search 'off'", "off-", store.ChannelSearchOpts{IncludeDeleted: false, ExcludeChannelNames: []string{"off-topic"}}, &model.ChannelList{&o8, &o7}, 0},
+		{"exclude defaults search 'town'", "town", store.ChannelSearchOpts{IncludeDeleted: false, ExcludeChannelNames: []string{"town-square"}}, &model.ChannelList{}, 0},
+		{"exclude by group association", "off", store.ChannelSearchOpts{IncludeDeleted: false, NotAssociatedToGroup: group.Id}, &model.ChannelList{&o8, &o6}, 0},
+		{"paginate includes count", "off", store.ChannelSearchOpts{IncludeDeleted: false, PerPage: model.NewInt(100)}, &model.ChannelList{&o8, &o7, &o6}, 3},
+		{"paginate, page 2 correct entries and count", "off", store.ChannelSearchOpts{IncludeDeleted: false, PerPage: model.NewInt(2), Page: model.NewInt(1)}, &model.ChannelList{&o6}, 3},
 	}
 
 	for _, testCase := range testCases {
 		t.Run(testCase.Description, func(t *testing.T) {
-			channels, err := ss.Channel().SearchAllChannels(testCase.Term, testCase.Opts)
+			channels, count, err := ss.Channel().SearchAllChannels(testCase.Term, testCase.Opts)
 			require.Nil(t, err)
 			require.Equal(t, len(*testCase.ExpectedResults), len(*channels))
 			for i, expected := range *testCase.ExpectedResults {
 				require.Equal(t, expected.Id, (*channels)[i].Id)
 			}
+			if testCase.Opts.Page != nil || testCase.Opts.PerPage != nil {
+				require.Equal(t, int64(testCase.TotalCount), count)
+			}
 		})
 	}
 }

store/storetest/mocks/ChannelStore.go

@@ -1440,7 +1440,7 @@ func (_m *ChannelStore) SaveMember(member *model.ChannelMember) (*model.ChannelM
 }
 
 // SearchAllChannels provides a mock function with given fields: term, opts
-func (_m *ChannelStore) SearchAllChannels(term string, opts store.ChannelSearchOpts) (*model.ChannelListWithTeamData, *model.AppError) {
+func (_m *ChannelStore) SearchAllChannels(term string, opts store.ChannelSearchOpts) (*model.ChannelListWithTeamData, int64, *model.AppError) {
 	ret := _m.Called(term, opts)
 
 	var r0 *model.ChannelListWithTeamData
@@ -1461,7 +1461,7 @@ func (_m *ChannelStore) SearchAllChannels(term string, opts store.ChannelSearchO
 		}
 	}
 
-	return r0, r1
+	return r0, 0, r1
 }
 
 // SearchForUserInTeam provides a mock function with given fields: userId, teamId, term, includeDeleted