[feature] Add List functionality (#1802)

* start working on lists

* further list work

* test list db functions nicely

* more work on lists

* peepoopeepoo

* poke

* start list timeline func

* we're getting there lads

* couldn't be me working on stuff... could it?

* hook up handlers

* fiddling

* weeee

* woah

* screaming, pissing

* fix streaming being a whiny baby

* lint, small test fix, swagger

* tidying up, testing

* fucked! by the linter

* move timelines to state like a boss

* add timeline start to tests using state

* invalidate lists

internal/processing/list/create.go

@@ -0,0 +1,50 @@
+// 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 list
+
+import (
+	"context"
+	"errors"
+
+	apimodel "github.com/superseriousbusiness/gotosocial/internal/api/model"
+	"github.com/superseriousbusiness/gotosocial/internal/db"
+	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
+	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
+	"github.com/superseriousbusiness/gotosocial/internal/id"
+)
+
+// Create creates one a new list for the given account, using the provided parameters.
+// These params should have already been validated by the time they reach this function.
+func (p *Processor) Create(ctx context.Context, account *gtsmodel.Account, title string, repliesPolicy gtsmodel.RepliesPolicy) (*apimodel.List, gtserror.WithCode) {
+	list := &gtsmodel.List{
+		ID:            id.NewULID(),
+		Title:         title,
+		AccountID:     account.ID,
+		RepliesPolicy: repliesPolicy,
+	}
+
+	if err := p.state.DB.PutList(ctx, list); err != nil {
+		if errors.Is(err, db.ErrAlreadyExists) {
+			err = errors.New("you already have a list with this title")
+			return nil, gtserror.NewErrorConflict(err, err.Error())
+		}
+		return nil, gtserror.NewErrorInternalError(err)
+	}
+
+	return p.apiList(ctx, list)
+}