[feature] Process outgoing Move from clientAPI (#2750)

* prevent moved accounts from taking create-type actions

* update move logic

* federate move out

* indicate on web profile when an account has moved

* [docs] Add migration docs section

* lock while checking + setting move state

* use redirectFollowers func for clientAPI as well

* comment typo

* linter? i barely know 'er!

* Update internal/uris/uri.go

Co-authored-by: Daenney <daenney@users.noreply.github.com>

* add a couple tests for move

* fix little mistake exposed by tests (thanks tests)

* ensure Move marked as successful

* attach shared util funcs to struct

* lock whole account when doing move

* move moving check to after error check

* replace repeated text with error func

* linterrrrrr!!!!

* catch self follow case

---------

Co-authored-by: Daenney <daenney@users.noreply.github.com>

1 files changed, 240 insertions, 0 deletions

diff --git a/internal/processing/workers/util.go b/internal/processing/workers/util.go
new file mode 100644
index 000000000..a38ecd336
--- /dev/null
+++ b/internal/processing/workers/util.go
@@ -0,0 +1,240 @@
+// 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 workers
+
+import (
+	"context"
+	"errors"
+
+	apimodel "github.com/superseriousbusiness/gotosocial/internal/api/model"
+	"github.com/superseriousbusiness/gotosocial/internal/db"
+	"github.com/superseriousbusiness/gotosocial/internal/gtscontext"
+	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
+	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
+	"github.com/superseriousbusiness/gotosocial/internal/log"
+	"github.com/superseriousbusiness/gotosocial/internal/processing/account"
+	"github.com/superseriousbusiness/gotosocial/internal/processing/media"
+	"github.com/superseriousbusiness/gotosocial/internal/state"
+)
+
+// utilF wraps util functions used by both
+// the fromClientAPI and fromFediAPI functions.
+type utilF struct {
+	state   *state.State
+	media   *media.Processor
+	account *account.Processor
+	surface *surface
+}
+
+// wipeStatus encapsulates common logic
+// used to totally delete a status + all
+// its attachments, notifications, boosts,
+// and timeline entries.
+func (u *utilF) wipeStatus(
+	ctx context.Context,
+	statusToDelete *gtsmodel.Status,
+	deleteAttachments bool,
+) error {
+	var errs gtserror.MultiError
+
+	// Either delete all attachments for this status,
+	// or simply unattach + clean them separately later.
+	//
+	// Reason to unattach rather than delete is that
+	// the poster might want to reattach them to another
+	// status immediately (in case of delete + redraft)
+	if deleteAttachments {
+		// todo:u.state.DB.DeleteAttachmentsForStatus
+		for _, id := range statusToDelete.AttachmentIDs {
+			if err := u.media.Delete(ctx, id); err != nil {
+				errs.Appendf("error deleting media: %w", err)
+			}
+		}
+	} else {
+		// todo:u.state.DB.UnattachAttachmentsForStatus
+		for _, id := range statusToDelete.AttachmentIDs {
+			if _, err := u.media.Unattach(ctx, statusToDelete.Account, id); err != nil {
+				errs.Appendf("error unattaching media: %w", err)
+			}
+		}
+	}
+
+	// delete all mention entries generated by this status
+	// todo:u.state.DB.DeleteMentionsForStatus
+	for _, id := range statusToDelete.MentionIDs {
+		if err := u.state.DB.DeleteMentionByID(ctx, id); err != nil {
+			errs.Appendf("error deleting status mention: %w", err)
+		}
+	}
+
+	// delete all notification entries generated by this status
+	if err := u.state.DB.DeleteNotificationsForStatus(ctx, statusToDelete.ID); err != nil {
+		errs.Appendf("error deleting status notifications: %w", err)
+	}
+
+	// delete all bookmarks that point to this status
+	if err := u.state.DB.DeleteStatusBookmarksForStatus(ctx, statusToDelete.ID); err != nil {
+		errs.Appendf("error deleting status bookmarks: %w", err)
+	}
+
+	// delete all faves of this status
+	if err := u.state.DB.DeleteStatusFavesForStatus(ctx, statusToDelete.ID); err != nil {
+		errs.Appendf("error deleting status faves: %w", err)
+	}
+
+	if pollID := statusToDelete.PollID; pollID != "" {
+		// Delete this poll by ID from the database.
+		if err := u.state.DB.DeletePollByID(ctx, pollID); err != nil {
+			errs.Appendf("error deleting status poll: %w", err)
+		}
+
+		// Delete any poll votes pointing to this poll ID.
+		if err := u.state.DB.DeletePollVotes(ctx, pollID); err != nil {
+			errs.Appendf("error deleting status poll votes: %w", err)
+		}
+
+		// Cancel any scheduled expiry task for poll.
+		_ = u.state.Workers.Scheduler.Cancel(pollID)
+	}
+
+	// delete all boosts for this status + remove them from timelines
+	boosts, err := u.state.DB.GetStatusBoosts(
+		// we MUST set a barebones context here,
+		// as depending on where it came from the
+		// original BoostOf may already be gone.
+		gtscontext.SetBarebones(ctx),
+		statusToDelete.ID)
+	if err != nil {
+		errs.Appendf("error fetching status boosts: %w", err)
+	}
+
+	for _, boost := range boosts {
+		if err := u.surface.deleteStatusFromTimelines(ctx, boost.ID); err != nil {
+			errs.Appendf("error deleting boost from timelines: %w", err)
+		}
+		if err := u.state.DB.DeleteStatusByID(ctx, boost.ID); err != nil {
+			errs.Appendf("error deleting boost: %w", err)
+		}
+	}
+
+	// delete this status from any and all timelines
+	if err := u.surface.deleteStatusFromTimelines(ctx, statusToDelete.ID); err != nil {
+		errs.Appendf("error deleting status from timelines: %w", err)
+	}
+
+	// finally, delete the status itself
+	if err := u.state.DB.DeleteStatusByID(ctx, statusToDelete.ID); err != nil {
+		errs.Appendf("error deleting status: %w", err)
+	}
+
+	return errs.Combine()
+}
+
+// redirectFollowers redirects all local
+// followers of originAcct to targetAcct.
+//
+// Both accounts must be fully dereferenced
+// already, and the Move must be valid.
+//
+// Return bool will be true if all goes OK.
+func (u *utilF) redirectFollowers(
+	ctx context.Context,
+	originAcct *gtsmodel.Account,
+	targetAcct *gtsmodel.Account,
+) bool {
+	// Any local followers of originAcct should
+	// send follow requests to targetAcct instead,
+	// and have followers of originAcct removed.
+	//
+	// Select local followers with barebones, since
+	// we only need follow.Account and we can get
+	// that ourselves.
+	followers, err := u.state.DB.GetAccountLocalFollowers(
+		gtscontext.SetBarebones(ctx),
+		originAcct.ID,
+	)
+	if err != nil && !errors.Is(err, db.ErrNoEntries) {
+		log.Errorf(ctx,
+			"db error getting follows targeting originAcct: %v",
+			err,
+		)
+		return false
+	}
+
+	for _, follow := range followers {
+		// Fetch the local account that
+		// owns the follow targeting originAcct.
+		if follow.Account, err = u.state.DB.GetAccountByID(
+			gtscontext.SetBarebones(ctx),
+			follow.AccountID,
+		); err != nil {
+			log.Errorf(ctx,
+				"db error getting follow account %s: %v",
+				follow.AccountID, err,
+			)
+			return false
+		}
+
+		// Use the account processor FollowCreate
+		// function to send off the new follow,
+		// carrying over the Reblogs and Notify
+		// values from the old follow to the new.
+		//
+		// This will also handle cases where our
+		// account has already followed the target
+		// account, by just updating the existing
+		// follow of target account.
+		//
+		// Also, ensure new follow wouldn't be a
+		// self follow, since that will error.
+		if follow.AccountID != targetAcct.ID {
+			if _, err := u.account.FollowCreate(
+				ctx,
+				follow.Account,
+				&apimodel.AccountFollowRequest{
+					ID:      targetAcct.ID,
+					Reblogs: follow.ShowReblogs,
+					Notify:  follow.Notify,
+				},
+			); err != nil {
+				log.Errorf(ctx,
+					"error creating new follow for account %s: %v",
+					follow.AccountID, err,
+				)
+				return false
+			}
+		}
+
+		// New follow is in the process of
+		// sending, remove the existing follow.
+		// This will send out an Undo Activity for each Follow.
+		if _, err := u.account.FollowRemove(
+			ctx,
+			follow.Account,
+			follow.TargetAccountID,
+		); err != nil {
+			log.Errorf(ctx,
+				"error removing old follow for account %s: %v",
+				follow.AccountID, err,
+			)
+			return false
+		}
+	}
+
+	return true
+}