[chore] Refactor account deleting/block logic, tidy up some other processing things (#1599)

* start refactoring account deletion

* update to use state.DB

* further messing about

* some more tidying up

* more tidying, cleaning, nice-making

* further adventures in refactoring and the woes of technical debt

* update fr accept/reject

* poking + prodding

* fix up deleting

* create fave uri

* don't log using requestingAccount.ID because it might be nil

* move getBookmarks function

* use exists query to check for status bookmark

* use deletenotifications func

* fiddle

* delete follow request notif

* split up some db functions

* Fix possible nil pointer panic

* fix more possible nil pointers

* fix license headers

* warn when follow missing (target) account

* return wrapped err when bookmark/fave models can't be retrieved

* simplify self account delete

* warn log likely race condition

* de-sillify status delete loop

* move error check due north

* warn when unfollowSideEffects has no target account

* warn when no boost account is found

* warn + dump follow when no account

* more warnings

* warn on fave account not set

* move for loop inside anonymous function

* fix funky logic

* don't remove mutual account items on block;
do make sure unfollow occurs in both directions!

internal/processing/status/common.go

@@ -0,0 +1,63 @@
+// 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 status
+
+import (
+	"context"
+	"fmt"
+
+	apimodel "github.com/superseriousbusiness/gotosocial/internal/api/model"
+	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
+	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
+)
+
+func (p *Processor) apiStatus(ctx context.Context, targetStatus *gtsmodel.Status, requestingAccount *gtsmodel.Account) (*apimodel.Status, gtserror.WithCode) {
+	apiStatus, err := p.tc.StatusToAPIStatus(ctx, targetStatus, requestingAccount)
+	if err != nil {
+		err = fmt.Errorf("error converting status %s to frontend representation: %w", targetStatus.ID, err)
+		return nil, gtserror.NewErrorInternalError(err)
+	}
+
+	return apiStatus, nil
+}
+
+func (p *Processor) getVisibleStatus(ctx context.Context, requestingAccount *gtsmodel.Account, targetStatusID string) (*gtsmodel.Status, gtserror.WithCode) {
+	targetStatus, err := p.state.DB.GetStatusByID(ctx, targetStatusID)
+	if err != nil {
+		err = fmt.Errorf("getVisibleStatus: db error fetching status %s: %w", targetStatusID, err)
+		return nil, gtserror.NewErrorNotFound(err)
+	}
+
+	if targetStatus.Account == nil {
+		err = fmt.Errorf("getVisibleStatus: no status owner for status %s", targetStatusID)
+		return nil, gtserror.NewErrorNotFound(err)
+	}
+
+	visible, err := p.filter.StatusVisible(ctx, targetStatus, requestingAccount)
+	if err != nil {
+		err = fmt.Errorf("getVisibleStatus: error seeing if status %s is visible: %w", targetStatus.ID, err)
+		return nil, gtserror.NewErrorNotFound(err)
+	}
+
+	if !visible {
+		err = fmt.Errorf("getVisibleStatus: status %s is not visible to requesting account", targetStatusID)
+		return nil, gtserror.NewErrorNotFound(err)
+	}
+
+	return targetStatus, nil
+}