[feature] Conversations API (#3013)

* Implement conversations API

* Sort and page conversations by last status ID

* Appease linter

* Fix deleting conversations and statuses

* Refactor to make migrations automatic

* Lint

* Update tests post-merge

* Fixes from live-fire testing

* Linter caught a format problem

* Refactor tests, fix cache

* Negative test for non-DMs

* Run conversations advanced migration on testrig startup as well as regular server startup

* Document (lack of) side effects of API method for deleting a conversation

* Make not-found check less nested for readability

* Rename PutConversation to UpsertConversation

* Use util.Ptr instead of IIFE

* Reduce cache used by conversations

* Remove unnecessary TableExpr/ColumnExpr

* Use struct tags for both unique constraints on Conversation

* Make it clear how paging with GetDirectStatusIDsBatch should be used

* Let conversation paging skip conversations it can't render

* Use Bun NewDropTable

* Convert delete raw query to Bun

* Convert update raw query to Bun

* Convert latestConversationStatusesTempTable raw query partially to Bun

* Convert conversationStatusesTempTable raw query partially to Bun

* Rename field used to store result of MaxDirectStatusID

* Move advanced migrations to their own tiny processor

* Catch up util function name with main

* Remove json.… wrappers

* Remove redundant check

* Combine error checks

* Replace map with slice of structs

* Address processor/type converter comments

- Add context info for errors
- Extract some common processor code into shared methods
- Move conversation eligibility check ahead of populating conversation

* Add error context when dropping temp tables

1 files changed, 115 insertions, 0 deletions

diff --git a/internal/db/bundb/conversation_test.go b/internal/db/bundb/conversation_test.go
new file mode 100644
index 000000000..24d35d482
--- /dev/null
+++ b/internal/db/bundb/conversation_test.go
@@ -0,0 +1,115 @@
+// GoToSocial
+// Copyright (C) GoToSocial Authors admin@gotosocial.org
+// SPDX-License-Identifier: AGPL-3.0-or-later
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package bundb_test
+
+import (
+	"context"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/suite"
+	"github.com/superseriousbusiness/gotosocial/internal/db"
+	"github.com/superseriousbusiness/gotosocial/internal/db/test"
+	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
+)
+
+type ConversationTestSuite struct {
+	BunDBStandardTestSuite
+
+	cf test.ConversationFactory
+
+	// testAccount is the owner of statuses and conversations in these tests (must be local).
+	testAccount *gtsmodel.Account
+	// threadID is the thread used for statuses in any given test.
+	threadID string
+}
+
+func (suite *ConversationTestSuite) SetupSuite() {
+	suite.BunDBStandardTestSuite.SetupSuite()
+
+	suite.cf.SetupSuite(suite)
+
+	suite.testAccount = suite.testAccounts["local_account_1"]
+}
+
+func (suite *ConversationTestSuite) SetupTest() {
+	suite.BunDBStandardTestSuite.SetupTest()
+
+	suite.cf.SetupTest(suite.db)
+
+	suite.threadID = suite.cf.NewULID(0)
+}
+
+// deleteStatus deletes a status from conversations and ends the test if that fails.
+func (suite *ConversationTestSuite) deleteStatus(statusID string) {
+	err := suite.db.DeleteStatusFromConversations(context.Background(), statusID)
+	if err != nil {
+		suite.FailNow(err.Error())
+	}
+}
+
+// getConversation fetches a conversation by ID and ends the test if that fails.
+func (suite *ConversationTestSuite) getConversation(conversationID string) *gtsmodel.Conversation {
+	conversation, err := suite.db.GetConversationByID(context.Background(), conversationID)
+	if err != nil {
+		suite.FailNow(err.Error())
+	}
+	return conversation
+}
+
+// If we delete a status that is in a conversation but not the last status,
+// the conversation's last status should not change.
+func (suite *ConversationTestSuite) TestDeleteNonLastStatus() {
+	conversation := suite.cf.NewTestConversation(suite.testAccount, 0)
+	initial := conversation.LastStatus
+	reply := suite.cf.NewTestStatus(suite.testAccount, conversation.ThreadID, 1*time.Second, initial)
+	conversation = suite.cf.SetLastStatus(conversation, reply)
+
+	suite.deleteStatus(initial.ID)
+	conversation = suite.getConversation(conversation.ID)
+	suite.Equal(reply.ID, conversation.LastStatusID)
+}
+
+// If we delete the last status in a conversation that has other statuses,
+// a previous status should become the new last status.
+func (suite *ConversationTestSuite) TestDeleteLastStatus() {
+	conversation := suite.cf.NewTestConversation(suite.testAccount, 0)
+	initial := conversation.LastStatus
+	reply := suite.cf.NewTestStatus(suite.testAccount, conversation.ThreadID, 1*time.Second, initial)
+	conversation = suite.cf.SetLastStatus(conversation, reply)
+	conversation = suite.getConversation(conversation.ID)
+
+	suite.deleteStatus(reply.ID)
+	conversation = suite.getConversation(conversation.ID)
+	suite.Equal(initial.ID, conversation.LastStatusID)
+}
+
+// If we delete the only status in a conversation,
+// the conversation should be deleted as well.
+func (suite *ConversationTestSuite) TestDeleteOnlyStatus() {
+	conversation := suite.cf.NewTestConversation(suite.testAccount, 0)
+	initial := conversation.LastStatus
+
+	suite.deleteStatus(initial.ID)
+	_, err := suite.db.GetConversationByID(context.Background(), conversation.ID)
+	suite.ErrorIs(err, db.ErrNoEntries)
+}
+
+func TestConversationTestSuite(t *testing.T) {
+	suite.Run(t, new(ConversationTestSuite))
+}