[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, 231 insertions, 0 deletions

diff --git a/internal/processing/workers/fromclientapi_test.go b/internal/processing/workers/fromclientapi_test.go
index 49a68d27a..35c2c31b7 100644
--- a/internal/processing/workers/fromclientapi_test.go
+++ b/internal/processing/workers/fromclientapi_test.go
@@ -50,6 +50,8 @@ func (suite *FromClientAPITestSuite) newStatus(
 	visibility gtsmodel.Visibility,
 	replyToStatus *gtsmodel.Status,
 	boostOfStatus *gtsmodel.Status,
+	mentionedAccounts []*gtsmodel.Account,
+	createThread bool,
 ) *gtsmodel.Status {
 	var (
 		protocol = config.GetProtocol()
@@ -102,6 +104,39 @@ func (suite *FromClientAPITestSuite) newStatus(
 		newStatus.Visibility = boostOfStatus.Visibility
 	}
 
+	for _, mentionedAccount := range mentionedAccounts {
+		newMention := &gtsmodel.Mention{
+			ID:               id.NewULID(),
+			StatusID:         newStatus.ID,
+			Status:           newStatus,
+			OriginAccountID:  account.ID,
+			OriginAccountURI: account.URI,
+			OriginAccount:    account,
+			TargetAccountID:  mentionedAccount.ID,
+			TargetAccount:    mentionedAccount,
+			Silent:           util.Ptr(false),
+		}
+
+		newStatus.Mentions = append(newStatus.Mentions, newMention)
+		newStatus.MentionIDs = append(newStatus.MentionIDs, newMention.ID)
+
+		if err := state.DB.PutMention(ctx, newMention); err != nil {
+			suite.FailNow(err.Error())
+		}
+	}
+
+	if createThread {
+		newThread := &gtsmodel.Thread{
+			ID: id.NewULID(),
+		}
+
+		newStatus.ThreadID = newThread.ID
+
+		if err := state.DB.PutThread(ctx, newThread); err != nil {
+			suite.FailNow(err.Error())
+		}
+	}
+
 	// Put the status in the db, to mimic what would
 	// have already happened earlier up the flow.
 	if err := state.DB.PutStatus(ctx, newStatus); err != nil {
@@ -168,6 +203,31 @@ func (suite *FromClientAPITestSuite) statusJSON(
 	return string(statusJSON)
 }
 
+func (suite *FromClientAPITestSuite) conversationJSON(
+	ctx context.Context,
+	typeConverter *typeutils.Converter,
+	conversation *gtsmodel.Conversation,
+	requestingAccount *gtsmodel.Account,
+) string {
+	apiConversation, err := typeConverter.ConversationToAPIConversation(
+		ctx,
+		conversation,
+		requestingAccount,
+		nil,
+		nil,
+	)
+	if err != nil {
+		suite.FailNow(err.Error())
+	}
+
+	conversationJSON, err := json.Marshal(apiConversation)
+	if err != nil {
+		suite.FailNow(err.Error())
+	}
+
+	return string(conversationJSON)
+}
+
 func (suite *FromClientAPITestSuite) TestProcessCreateStatusWithNotification() {
 	testStructs := suite.SetupTestStructs()
 	defer suite.TearDownTestStructs(testStructs)
@@ -194,6 +254,8 @@ func (suite *FromClientAPITestSuite) TestProcessCreateStatusWithNotification() {
 			gtsmodel.VisibilityPublic,
 			nil,
 			nil,
+			nil,
+			false,
 		)
 	)
 
@@ -303,6 +365,8 @@ func (suite *FromClientAPITestSuite) TestProcessCreateStatusReply() {
 			gtsmodel.VisibilityPublic,
 			suite.testStatuses["local_account_2_status_1"],
 			nil,
+			nil,
+			false,
 		)
 	)
 
@@ -362,6 +426,8 @@ func (suite *FromClientAPITestSuite) TestProcessCreateStatusReplyMuted() {
 			gtsmodel.VisibilityPublic,
 			suite.testStatuses["local_account_1_status_1"],
 			nil,
+			nil,
+			false,
 		)
 		threadMute = &gtsmodel.ThreadMute{
 			ID:        "01HD3KRMBB1M85QRWHD912QWRE",
@@ -420,6 +486,8 @@ func (suite *FromClientAPITestSuite) TestProcessCreateStatusBoostMuted() {
 			gtsmodel.VisibilityPublic,
 			nil,
 			suite.testStatuses["local_account_1_status_1"],
+			nil,
+			false,
 		)
 		threadMute = &gtsmodel.ThreadMute{
 			ID:        "01HD3KRMBB1M85QRWHD912QWRE",
@@ -483,6 +551,8 @@ func (suite *FromClientAPITestSuite) TestProcessCreateStatusListRepliesPolicyLis
 			gtsmodel.VisibilityPublic,
 			suite.testStatuses["local_account_2_status_1"],
 			nil,
+			nil,
+			false,
 		)
 	)
 
@@ -556,6 +626,8 @@ func (suite *FromClientAPITestSuite) TestProcessCreateStatusListRepliesPolicyLis
 			gtsmodel.VisibilityPublic,
 			suite.testStatuses["local_account_2_status_1"],
 			nil,
+			nil,
+			false,
 		)
 	)
 
@@ -634,6 +706,8 @@ func (suite *FromClientAPITestSuite) TestProcessCreateStatusReplyListRepliesPoli
 			gtsmodel.VisibilityPublic,
 			suite.testStatuses["local_account_2_status_1"],
 			nil,
+			nil,
+			false,
 		)
 	)
 
@@ -704,6 +778,8 @@ func (suite *FromClientAPITestSuite) TestProcessCreateStatusBoost() {
 			gtsmodel.VisibilityPublic,
 			nil,
 			suite.testStatuses["local_account_2_status_1"],
+			nil,
+			false,
 		)
 	)
 
@@ -765,6 +841,8 @@ func (suite *FromClientAPITestSuite) TestProcessCreateStatusBoostNoReblogs() {
 			gtsmodel.VisibilityPublic,
 			nil,
 			suite.testStatuses["local_account_2_status_1"],
+			nil,
+			false,
 		)
 	)
 
@@ -807,6 +885,159 @@ func (suite *FromClientAPITestSuite) TestProcessCreateStatusBoostNoReblogs() {
 	)
 }
 
+// A DM to a local user should create a conversation and accompanying notification.
+func (suite *FromClientAPITestSuite) TestProcessCreateStatusWhichBeginsConversation() {
+	testStructs := suite.SetupTestStructs()
+	defer suite.TearDownTestStructs(testStructs)
+
+	var (
+		ctx              = context.Background()
+		postingAccount   = suite.testAccounts["local_account_2"]
+		receivingAccount = suite.testAccounts["local_account_1"]
+		streams          = suite.openStreams(ctx,
+			testStructs.Processor,
+			receivingAccount,
+			nil,
+		)
+		homeStream   = streams[stream.TimelineHome]
+		directStream = streams[stream.TimelineDirect]
+
+		// turtle posts a new top-level DM mentioning zork.
+		status = suite.newStatus(
+			ctx,
+			testStructs.State,
+			postingAccount,
+			gtsmodel.VisibilityDirect,
+			nil,
+			nil,
+			[]*gtsmodel.Account{receivingAccount},
+			true,
+		)
+	)
+
+	// Process the new status.
+	if err := testStructs.Processor.Workers().ProcessFromClientAPI(
+		ctx,
+		&messages.FromClientAPI{
+			APObjectType:   ap.ObjectNote,
+			APActivityType: ap.ActivityCreate,
+			GTSModel:       status,
+			Origin:         postingAccount,
+		},
+	); err != nil {
+		suite.FailNow(err.Error())
+	}
+
+	// Locate the conversation which should now exist for zork.
+	conversation, err := testStructs.State.DB.GetConversationByThreadAndAccountIDs(
+		ctx,
+		status.ThreadID,
+		receivingAccount.ID,
+		[]string{postingAccount.ID},
+	)
+	if err != nil {
+		suite.FailNow(err.Error())
+	}
+
+	// Check status in home stream.
+	suite.checkStreamed(
+		homeStream,
+		true,
+		"",
+		stream.EventTypeUpdate,
+	)
+
+	// Check mention notification in home stream.
+	suite.checkStreamed(
+		homeStream,
+		true,
+		"",
+		stream.EventTypeNotification,
+	)
+
+	// Check conversation in direct stream.
+	conversationJSON := suite.conversationJSON(
+		ctx,
+		testStructs.TypeConverter,
+		conversation,
+		receivingAccount,
+	)
+	suite.checkStreamed(
+		directStream,
+		true,
+		conversationJSON,
+		stream.EventTypeConversation,
+	)
+}
+
+// A public message to a local user should not result in a conversation notification.
+func (suite *FromClientAPITestSuite) TestProcessCreateStatusWhichShouldNotCreateConversation() {
+	testStructs := suite.SetupTestStructs()
+	defer suite.TearDownTestStructs(testStructs)
+
+	var (
+		ctx              = context.Background()
+		postingAccount   = suite.testAccounts["local_account_2"]
+		receivingAccount = suite.testAccounts["local_account_1"]
+		streams          = suite.openStreams(ctx,
+			testStructs.Processor,
+			receivingAccount,
+			nil,
+		)
+		homeStream   = streams[stream.TimelineHome]
+		directStream = streams[stream.TimelineDirect]
+
+		// turtle posts a new top-level public message mentioning zork.
+		status = suite.newStatus(
+			ctx,
+			testStructs.State,
+			postingAccount,
+			gtsmodel.VisibilityPublic,
+			nil,
+			nil,
+			[]*gtsmodel.Account{receivingAccount},
+			true,
+		)
+	)
+
+	// Process the new status.
+	if err := testStructs.Processor.Workers().ProcessFromClientAPI(
+		ctx,
+		&messages.FromClientAPI{
+			APObjectType:   ap.ObjectNote,
+			APActivityType: ap.ActivityCreate,
+			GTSModel:       status,
+			Origin:         postingAccount,
+		},
+	); err != nil {
+		suite.FailNow(err.Error())
+	}
+
+	// Check status in home stream.
+	suite.checkStreamed(
+		homeStream,
+		true,
+		"",
+		stream.EventTypeUpdate,
+	)
+
+	// Check mention notification in home stream.
+	suite.checkStreamed(
+		homeStream,
+		true,
+		"",
+		stream.EventTypeNotification,
+	)
+
+	// Check for absence of conversation notification in direct stream.
+	suite.checkStreamed(
+		directStream,
+		false,
+		"",
+		"",
+	)
+}
+
 func (suite *FromClientAPITestSuite) TestProcessStatusDelete() {
 	testStructs := suite.SetupTestStructs()
 	defer suite.TearDownTestStructs(testStructs)