[chore] remove type switch in Create() and instead move to FederatedCallbacks() (#3697)

* remove type switch in Create() and instead move to FederatedCallbacks()

* add missing (my bad!) federating wrapped callbacks behaviour

* add missing license header 😇

* fix create flag test to use correct function

internal/federation/federatingdb/flag.go

@@ -0,0 +1,91 @@
+// 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 federatingdb
+
+import (
+	"context"
+	"net/http"
+
+	"github.com/miekg/dns"
+	"github.com/superseriousbusiness/activity/streams/vocab"
+	"github.com/superseriousbusiness/gotosocial/internal/ap"
+	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
+	"github.com/superseriousbusiness/gotosocial/internal/id"
+	"github.com/superseriousbusiness/gotosocial/internal/log"
+	"github.com/superseriousbusiness/gotosocial/internal/messages"
+)
+
+func (f *federatingDB) Flag(ctx context.Context, flaggable vocab.ActivityStreamsFlag) error {
+	log.DebugKV(ctx, "flag", serialize{flaggable})
+
+	// Mark activity as handled.
+	f.storeActivityID(flaggable)
+
+	// Extract relevant values from passed ctx.
+	activityContext := getActivityContext(ctx)
+	if activityContext.internal {
+		return nil // Already processed.
+	}
+
+	requesting := activityContext.requestingAcct
+	receiving := activityContext.receivingAcct
+
+	// Convert received AS flag type to internal report model.
+	report, err := f.converter.ASFlagToReport(ctx, flaggable)
+	if err != nil {
+		err := gtserror.Newf("error converting from AS type: %w", err)
+		return gtserror.WrapWithCode(http.StatusBadRequest, err)
+	}
+
+	// Requesting acc's domain must be at
+	// least a subdomain of the reporting
+	// account. i.e. if they're using a
+	// different account domain to host.
+	if dns.CompareDomainName(
+		requesting.Domain,
+		report.Account.Domain,
+	) < 2 {
+		return gtserror.NewfWithCode(http.StatusForbidden, "requester %s does not share a domain with Flag Actor account %s",
+			requesting.URI, report.Account.URI)
+	}
+
+	// Ensure report received by correct account.
+	if report.TargetAccountID != receiving.ID {
+		return gtserror.NewfWithCode(http.StatusForbidden, "receiver %s is not expected object %s",
+			receiving.URI, report.TargetAccount.URI)
+	}
+
+	// Generate new ID for report.
+	report.ID = id.NewULID()
+
+	// Insert the new validated reported into the database.
+	if err := f.state.DB.PutReport(ctx, report); err != nil {
+		return gtserror.Newf("error inserting %s into db: %w", report.URI, err)
+	}
+
+	// Push message to worker queue to handle report side-effects.
+	f.state.Workers.Federator.Queue.Push(&messages.FromFediAPI{
+		APObjectType:   ap.ActivityFlag,
+		APActivityType: ap.ActivityCreate,
+		GTSModel:       report,
+		Receiving:      receiving,
+		Requesting:     requesting,
+	})
+
+	return nil
+}