[feature] add support for polls + receiving federated status edits (#2330)

internal/processing/polls/vote.go

@@ -0,0 +1,108 @@
+// 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 polls
+
+import (
+	"context"
+	"errors"
+
+	"github.com/superseriousbusiness/gotosocial/internal/ap"
+	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"
+	"github.com/superseriousbusiness/gotosocial/internal/messages"
+)
+
+func (p *Processor) PollVote(ctx context.Context, requester *gtsmodel.Account, pollID string, choices []int) (*apimodel.Poll, gtserror.WithCode) {
+	// Get (+ check visibility of) requested poll with ID.
+	poll, errWithCode := p.getTargetPoll(ctx, requester, pollID)
+	if errWithCode != nil {
+		return nil, errWithCode
+	}
+
+	switch {
+	// Poll author isn't allowed to vote in their own poll.
+	case requester.ID == poll.Status.AccountID:
+		const text = "you can't vote in your own poll"
+		return nil, gtserror.NewErrorUnprocessableEntity(errors.New(text), text)
+
+	// Poll has already closed, no more voting!
+	case !poll.ClosedAt.IsZero():
+		const text = "poll already closed"
+		return nil, gtserror.NewErrorUnprocessableEntity(errors.New(text), text)
+
+	// No choices given, or multiple given for single-choice poll.
+	case len(choices) == 0 || (!*poll.Multiple && len(choices) > 1):
+		const text = "invalid number of choices for poll"
+		return nil, gtserror.NewErrorBadRequest(errors.New(text), text)
+	}
+
+	for _, choice := range choices {
+		if choice < 0 || choice >= len(poll.Options) {
+			// This is an invalid choice (index out of range).
+			const text = "invalid option index for poll"
+			return nil, gtserror.NewErrorBadRequest(errors.New(text), text)
+		}
+	}
+
+	// Wrap the choices in a PollVote model.
+	vote := &gtsmodel.PollVote{
+		ID:        id.NewULID(),
+		Choices:   choices,
+		AccountID: requester.ID,
+		Account:   requester,
+		PollID:    pollID,
+		Poll:      poll,
+	}
+
+	// Insert the new poll votes into the database.
+	err := p.state.DB.PutPollVote(ctx, vote)
+	switch {
+
+	case err == nil:
+		// no issue.
+
+	case errors.Is(err, db.ErrAlreadyExists):
+		// Users cannot vote multiple *times* (not choices).
+		const text = "you have already voted in poll"
+		return nil, gtserror.NewErrorUnprocessableEntity(err, text)
+
+	default:
+		// Any other irrecoverable database error.
+		err := gtserror.Newf("error inserting poll vote: %w", err)
+		return nil, gtserror.NewErrorInternalError(err)
+	}
+
+	// Enqueue worker task to handle side-effects of user poll vote(s).
+	p.state.Workers.EnqueueClientAPI(ctx, messages.FromClientAPI{
+		APActivityType: ap.ActivityCreate,
+		APObjectType:   ap.ActivityQuestion,
+		GTSModel:       vote, // the vote choices
+		OriginAccount:  requester,
+	})
+
+	// Before returning the converted poll model,
+	// increment the vote counts on our local copy
+	// to get latest, instead of another db query.
+	poll.IncrementVotes(choices)
+
+	// Return converted API model poll.
+	return p.toAPIPoll(ctx, requester, poll)
+}