[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, 33 insertions, 16 deletions

diff --git a/internal/processing/processor.go b/internal/processing/processor.go
index fb6b05d80..a07df76e1 100644
--- a/internal/processing/processor.go
+++ b/internal/processing/processor.go
@@ -27,7 +27,9 @@ import (
 	"github.com/superseriousbusiness/gotosocial/internal/oauth"
 	"github.com/superseriousbusiness/gotosocial/internal/processing/account"
 	"github.com/superseriousbusiness/gotosocial/internal/processing/admin"
+	"github.com/superseriousbusiness/gotosocial/internal/processing/advancedmigrations"
 	"github.com/superseriousbusiness/gotosocial/internal/processing/common"
+	"github.com/superseriousbusiness/gotosocial/internal/processing/conversations"
 	"github.com/superseriousbusiness/gotosocial/internal/processing/fedi"
 	filtersv1 "github.com/superseriousbusiness/gotosocial/internal/processing/filters/v1"
 	filtersv2 "github.com/superseriousbusiness/gotosocial/internal/processing/filters/v2"
@@ -70,22 +72,24 @@ type Processor struct {
 		SUB-PROCESSORS
 	*/
 
-	account   account.Processor
-	admin     admin.Processor
-	fedi      fedi.Processor
-	filtersv1 filtersv1.Processor
-	filtersv2 filtersv2.Processor
-	list      list.Processor
-	markers   markers.Processor
-	media     media.Processor
-	polls     polls.Processor
-	report    report.Processor
-	search    search.Processor
-	status    status.Processor
-	stream    stream.Processor
-	timeline  timeline.Processor
-	user      user.Processor
-	workers   workers.Processor
+	account            account.Processor
+	admin              admin.Processor
+	advancedmigrations advancedmigrations.Processor
+	conversations      conversations.Processor
+	fedi               fedi.Processor
+	filtersv1          filtersv1.Processor
+	filtersv2          filtersv2.Processor
+	list               list.Processor
+	markers            markers.Processor
+	media              media.Processor
+	polls              polls.Processor
+	report             report.Processor
+	search             search.Processor
+	status             status.Processor
+	stream             stream.Processor
+	timeline           timeline.Processor
+	user               user.Processor
+	workers            workers.Processor
 }
 
 func (p *Processor) Account() *account.Processor {
@@ -96,6 +100,14 @@ func (p *Processor) Admin() *admin.Processor {
 	return &p.admin
 }
 
+func (p *Processor) AdvancedMigrations() *advancedmigrations.Processor {
+	return &p.advancedmigrations
+}
+
+func (p *Processor) Conversations() *conversations.Processor {
+	return &p.conversations
+}
+
 func (p *Processor) Fedi() *fedi.Processor {
 	return &p.fedi
 }
@@ -188,6 +200,7 @@ func NewProcessor(
 	// processors + pin them to this struct.
 	processor.account = account.New(&common, state, converter, mediaManager, federator, filter, parseMentionFunc)
 	processor.admin = admin.New(&common, state, cleaner, federator, converter, mediaManager, federator.TransportController(), emailSender)
+	processor.conversations = conversations.New(state, converter, filter)
 	processor.fedi = fedi.New(state, &common, converter, federator, filter)
 	processor.filtersv1 = filtersv1.New(state, converter, &processor.stream)
 	processor.filtersv2 = filtersv2.New(state, converter, &processor.stream)
@@ -200,6 +213,9 @@ func NewProcessor(
 	processor.status = status.New(state, &common, &processor.polls, federator, converter, filter, parseMentionFunc)
 	processor.user = user.New(state, converter, oauthServer, emailSender)
 
+	// The advanced migrations processor sequences advanced migrations from all other processors.
+	processor.advancedmigrations = advancedmigrations.New(&processor.conversations)
+
 	// Workers processor handles asynchronous
 	// worker jobs; instantiate it separately
 	// and pass subset of sub processors it needs.
@@ -212,6 +228,7 @@ func NewProcessor(
 		&processor.account,
 		&processor.media,
 		&processor.stream,
+		&processor.conversations,
 	)
 
 	return processor