[feature] Allow import of following and blocks via CSV (#3150)

* [feature] Import follows + blocks via settings panel

* test import follows

internal/api/client/import/import.go

@@ -0,0 +1,195 @@
+// 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 importdata
+
+import (
+	"errors"
+	"fmt"
+	"net/http"
+	"slices"
+	"strings"
+
+	"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"
+	"github.com/superseriousbusiness/gotosocial/internal/processing"
+)
+
+const (
+	BasePath = "/v1/import"
+)
+
+var types = []string{
+	"following",
+	"blocks",
+}
+
+var modes = []string{
+	"merge",
+	"overwrite",
+}
+
+type Module struct {
+	processor *processing.Processor
+}
+
+func New(processor *processing.Processor) *Module {
+	return &Module{
+		processor: processor,
+	}
+}
+
+func (m *Module) Route(attachHandler func(method string, path string, f ...gin.HandlerFunc) gin.IRoutes) {
+	attachHandler(http.MethodPost, BasePath, m.ImportPOSTHandler)
+}
+
+// ImportPOSTHandler swagger:operation POST /api/v1/import importData
+//
+// Upload some CSV-formatted data to your account.
+//
+// This can be used to migrate data from a Mastodon-compatible CSV file to a GoToSocial account.
+//
+// Uploaded data will be processed asynchronously, and not all entries may be processed depending
+// on domain blocks, user-level blocks, network availability of referenced accounts and statuses, etc.
+//
+//	---
+//	tags:
+//	- import-export
+//
+//	consumes:
+//	- multipart/form-data
+//
+//	produces:
+//	- application/json
+//
+//	parameters:
+//	-
+//		name: data
+//		in: formData
+//		description: The CSV data file to upload.
+//		type: file
+//		required: true
+//	-
+//		name: type
+//		in: formData
+//		description: >-
+//			Type of entries contained in the data file:
+//
+//			- `following` - accounts to follow.
+//			- `blocks` - accounts to block.
+//		type: string
+//		required: true
+//	-
+//		name: mode
+//		in: formData
+//		description: >-
+//			Mode to use when creating entries from the data file:
+//
+//			- `merge` to merge entries in file with existing entries.
+//			- `overwrite` to replace existing entries with entries in file.
+//		type: string
+//		default: merge
+//
+//	security:
+//	- OAuth2 Bearer:
+//		- write:accounts
+//
+//	responses:
+//		'202':
+//			description: Upload accepted.
+//		'400':
+//			description: bad request
+//		'401':
+//			description: unauthorized
+//		'406':
+//			description: not acceptable
+//		'500':
+//			description: internal server error
+func (m *Module) ImportPOSTHandler(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
+	}
+
+	if authed.Account.IsMoving() {
+		apiutil.ForbiddenAfterMove(c)
+		return
+	}
+
+	if _, err := apiutil.NegotiateAccept(c, apiutil.JSONAcceptHeaders...); err != nil {
+		apiutil.ErrorHandler(c, gtserror.NewErrorNotAcceptable(err, err.Error()), m.processor.InstanceGetV1)
+		return
+	}
+
+	form := &apimodel.ImportRequest{}
+	if err := c.ShouldBind(form); err != nil {
+		apiutil.ErrorHandler(c, gtserror.NewErrorBadRequest(err, err.Error()), m.processor.InstanceGetV1)
+		return
+	}
+
+	if form.Data == nil {
+		const text = "no data file provided"
+		err := errors.New(text)
+		apiutil.ErrorHandler(c, gtserror.NewErrorBadRequest(err, text), m.processor.InstanceGetV1)
+		return
+	}
+
+	if form.Type == "" {
+		const text = "no type provided"
+		err := errors.New(text)
+		apiutil.ErrorHandler(c, gtserror.NewErrorBadRequest(err, text), m.processor.InstanceGetV1)
+		return
+	}
+
+	form.Type = strings.ToLower(form.Type)
+	if !slices.Contains(types, form.Type) {
+		text := fmt.Sprintf("type %s not recognized, valid types are: %+v", form.Type, types)
+		err := errors.New(text)
+		apiutil.ErrorHandler(c, gtserror.NewErrorBadRequest(err, text), m.processor.InstanceGetV1)
+		return
+	}
+
+	if form.Mode != "" {
+		form.Mode = strings.ToLower(form.Mode)
+		if !slices.Contains(modes, form.Mode) {
+			text := fmt.Sprintf("mode %s not recognized, valid modes are: %+v", form.Mode, modes)
+			err := errors.New(text)
+			apiutil.ErrorHandler(c, gtserror.NewErrorBadRequest(err, text), m.processor.InstanceGetV1)
+			return
+		}
+	}
+	overwrite := form.Mode == "overwrite"
+
+	// Trigger the import.
+	errWithCode := m.processor.Account().ImportData(
+		c.Request.Context(),
+		authed.Account,
+		form.Data,
+		form.Type,
+		overwrite,
+	)
+	if errWithCode != nil {
+		apiutil.ErrorHandler(c, errWithCode, m.processor.InstanceGetV1)
+		return
+	}
+
+	apiutil.JSON(c, http.StatusAccepted, gin.H{"status": "accepted"})
+}