[feature] Account alias / move API + db models (#2518)

* [feature] Account alias / move API + db models

* go fmt

* fix little cherry-pick issues

* update error checking, formatting

* add and use new util functions to simplify alias logic

internal/api/client/accounts/accountalias.go

@@ -0,0 +1,99 @@
+// 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 accounts
+
+import (
+	"net/http"
+
+	"github.com/gin-gonic/gin"
+	apimodel "github.com/superseriousbusiness/gotosocial/internal/api/model"
+	apiutil "github.com/superseriousbusiness/gotosocial/internal/api/util"
+	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
+	"github.com/superseriousbusiness/gotosocial/internal/oauth"
+)
+
+// AccountAliasPOSTHandler swagger:operation POST /api/v1/accounts/alias accountAlias
+//
+// Alias your account to another account by setting alsoKnownAs to the given URI.
+//
+// This is useful when you want to move from another account this this account.
+//
+// In such cases, you should set the alsoKnownAs of this account to the URI of
+// the account you want to move from.
+//
+//	---
+//	tags:
+//	- accounts
+//
+//	consumes:
+//	- multipart/form-data
+//
+//	parameters:
+//	-
+//		name: also_known_as_uris
+//		in: formData
+//		description: >-
+//			ActivityPub URI/IDs of target accounts to which this account
+//			is being aliased. Eg., `["https://example.org/users/some_account"]`.
+//
+//			Use an empty array to unset alsoKnownAs, clearing the aliases.
+//		type: string
+//		required: true
+//
+//	security:
+//	- OAuth2 Bearer:
+//		- write:accounts
+//
+//	responses:
+//		'200':
+//			description: "The newly updated account."
+//			schema:
+//				"$ref": "#/definitions/account"
+//		'400':
+//			description: bad request
+//		'401':
+//			description: unauthorized
+//		'404':
+//			description: not found
+//		'406':
+//			description: not acceptable
+//		'422':
+//			description: Unprocessable. Check the response body for more details.
+//		'500':
+//			description: internal server error
+func (m *Module) AccountAliasPOSTHandler(c *gin.Context) {
+	authed, err := oauth.Authed(c, true, true, true, true)
+	if err != nil {
+		apiutil.ErrorHandler(c, gtserror.NewErrorUnauthorized(err, err.Error()), m.processor.InstanceGetV1)
+		return
+	}
+
+	form := &apimodel.AccountAliasRequest{}
+	if err := c.ShouldBind(&form); err != nil {
+		apiutil.ErrorHandler(c, gtserror.NewErrorBadRequest(err, err.Error()), m.processor.InstanceGetV1)
+		return
+	}
+
+	resp, errWithCode := m.processor.Account().Alias(c.Request.Context(), authed.Account, form.AlsoKnownAsURIs)
+	if errWithCode != nil {
+		apiutil.ErrorHandler(c, errWithCode, m.processor.InstanceGetV1)
+		return
+	}
+
+	apiutil.JSON(c, http.StatusOK, resp)
+}