[feature] Filters v1 (#2594)

* Implement client-side v1 filters

* Exclude linter false positives

* Update test/envparsing.sh

* Fix minor Swagger, style, and Bun usage issues

* Regenerate Swagger

* De-generify filter keywords

* Remove updating filter statuses

This is an operation that the Mastodon v2 filter API doesn't actually have, because filter statuses, unlike keywords, don't have options: the only info they contain is the status ID to be filtered.

* Add a test for filter statuses specifically

* De-generify filter statuses

* Inline FilterEntry

* Use vertical style for Bun operations consistently

* Add comment on Filter DB interface

* Remove GoLand linter control comments

Our existing linters should catch these, or they don't matter very much

* Reduce memory ratio for filters

6 files changed, 470 insertions, 0 deletions

diff --git a/internal/processing/filters/v1/convert.go b/internal/processing/filters/v1/convert.go
new file mode 100644
index 000000000..1e0db5ff1
--- /dev/null
+++ b/internal/processing/filters/v1/convert.go
@@ -0,0 +1,38 @@
+// 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 v1
+
+import (
+	"context"
+	"fmt"
+
+	apimodel "github.com/superseriousbusiness/gotosocial/internal/api/model"
+	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
+	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
+)
+
+// apiFilter is a shortcut to return the API v1 filter version of the given
+// filter keyword, or return an appropriate error if conversion fails.
+func (p *Processor) apiFilter(ctx context.Context, filterKeyword *gtsmodel.FilterKeyword) (*apimodel.FilterV1, gtserror.WithCode) {
+	apiFilter, err := p.converter.FilterKeywordToAPIFilterV1(ctx, filterKeyword)
+	if err != nil {
+		return nil, gtserror.NewErrorInternalError(fmt.Errorf("error converting filter keyword to API v1 filter: %w", err))
+	}
+
+	return apiFilter, nil
+}
diff --git a/internal/processing/filters/v1/create.go b/internal/processing/filters/v1/create.go
new file mode 100644
index 000000000..e36d6800a
--- /dev/null
+++ b/internal/processing/filters/v1/create.go
@@ -0,0 +1,87 @@
+// 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 v1
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"time"
+
+	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/util"
+)
+
+// Create a new filter and filter keyword 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, form *apimodel.FilterCreateUpdateRequestV1) (*apimodel.FilterV1, gtserror.WithCode) {
+	filter := &gtsmodel.Filter{
+		ID:        id.NewULID(),
+		AccountID: account.ID,
+		Title:     form.Phrase,
+		Action:    gtsmodel.FilterActionWarn,
+	}
+	if *form.Irreversible {
+		filter.Action = gtsmodel.FilterActionHide
+	}
+	if form.ExpiresIn != nil {
+		filter.ExpiresAt = time.Now().Add(time.Second * time.Duration(*form.ExpiresIn))
+	}
+	for _, context := range form.Context {
+		switch context {
+		case apimodel.FilterContextHome:
+			filter.ContextHome = util.Ptr(true)
+		case apimodel.FilterContextNotifications:
+			filter.ContextNotifications = util.Ptr(true)
+		case apimodel.FilterContextPublic:
+			filter.ContextPublic = util.Ptr(true)
+		case apimodel.FilterContextThread:
+			filter.ContextThread = util.Ptr(true)
+		case apimodel.FilterContextAccount:
+			filter.ContextAccount = util.Ptr(true)
+		default:
+			return nil, gtserror.NewErrorUnprocessableEntity(
+				fmt.Errorf("unsupported filter context '%s'", context),
+			)
+		}
+	}
+
+	filterKeyword := &gtsmodel.FilterKeyword{
+		ID:        id.NewULID(),
+		AccountID: account.ID,
+		FilterID:  filter.ID,
+		Filter:    filter,
+		Keyword:   form.Phrase,
+		WholeWord: util.Ptr(util.PtrValueOr(form.WholeWord, false)),
+	}
+	filter.Keywords = []*gtsmodel.FilterKeyword{filterKeyword}
+
+	if err := p.state.DB.PutFilter(ctx, filter); err != nil {
+		if errors.Is(err, db.ErrAlreadyExists) {
+			err = errors.New("you already have a filter with this title")
+			return nil, gtserror.NewErrorConflict(err, err.Error())
+		}
+		return nil, gtserror.NewErrorInternalError(err)
+	}
+
+	return p.apiFilter(ctx, filterKeyword)
+}
diff --git a/internal/processing/filters/v1/delete.go b/internal/processing/filters/v1/delete.go
new file mode 100644
index 000000000..f2312f039
--- /dev/null
+++ b/internal/processing/filters/v1/delete.go
@@ -0,0 +1,67 @@
+// 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 v1
+
+import (
+	"context"
+	"errors"
+
+	"github.com/superseriousbusiness/gotosocial/internal/db"
+	"github.com/superseriousbusiness/gotosocial/internal/gtscontext"
+	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
+	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
+)
+
+// Delete an existing filter keyword and (if empty afterwards) filter for the given account.
+func (p *Processor) Delete(
+	ctx context.Context,
+	account *gtsmodel.Account,
+	filterKeywordID string,
+) gtserror.WithCode {
+	// Get enough of the filter keyword that we can look up its filter ID.
+	filterKeyword, err := p.state.DB.GetFilterKeywordByID(gtscontext.SetBarebones(ctx), filterKeywordID)
+	if err != nil {
+		if errors.Is(err, db.ErrNoEntries) {
+			return gtserror.NewErrorNotFound(err)
+		}
+		return gtserror.NewErrorInternalError(err)
+	}
+	if filterKeyword.AccountID != account.ID {
+		return gtserror.NewErrorNotFound(nil)
+	}
+
+	// Get the filter for this keyword.
+	filter, err := p.state.DB.GetFilterByID(ctx, filterKeyword.FilterID)
+	if err != nil {
+		return gtserror.NewErrorNotFound(err)
+	}
+
+	if len(filter.Keywords) > 1 || len(filter.Statuses) > 0 {
+		// The filter has other keywords or statuses. Delete only the requested filter keyword.
+		if err := p.state.DB.DeleteFilterKeywordByID(ctx, filterKeyword.ID); err != nil {
+			return gtserror.NewErrorInternalError(err)
+		}
+	} else {
+		// Delete the entire filter.
+		if err := p.state.DB.DeleteFilterByID(ctx, filter.ID); err != nil {
+			return gtserror.NewErrorInternalError(err)
+		}
+	}
+
+	return nil
+}
diff --git a/internal/processing/filters/v1/filters.go b/internal/processing/filters/v1/filters.go
new file mode 100644
index 000000000..d46c9e72c
--- /dev/null
+++ b/internal/processing/filters/v1/filters.go
@@ -0,0 +1,35 @@
+// 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 v1
+
+import (
+	"github.com/superseriousbusiness/gotosocial/internal/state"
+	"github.com/superseriousbusiness/gotosocial/internal/typeutils"
+)
+
+type Processor struct {
+	state     *state.State
+	converter *typeutils.Converter
+}
+
+func New(state *state.State, converter *typeutils.Converter) Processor {
+	return Processor{
+		state:     state,
+		converter: converter,
+	}
+}
diff --git a/internal/processing/filters/v1/get.go b/internal/processing/filters/v1/get.go
new file mode 100644
index 000000000..39575dd94
--- /dev/null
+++ b/internal/processing/filters/v1/get.go
@@ -0,0 +1,78 @@
+// 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 v1
+
+import (
+	"context"
+	"errors"
+	"slices"
+	"strings"
+
+	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"
+)
+
+// Get looks up a filter keyword by ID and returns it as a v1 filter.
+func (p *Processor) Get(ctx context.Context, account *gtsmodel.Account, filterKeywordID string) (*apimodel.FilterV1, gtserror.WithCode) {
+	filterKeyword, err := p.state.DB.GetFilterKeywordByID(ctx, filterKeywordID)
+	if err != nil {
+		if errors.Is(err, db.ErrNoEntries) {
+			return nil, gtserror.NewErrorNotFound(err)
+		}
+		return nil, gtserror.NewErrorInternalError(err)
+	}
+	if filterKeyword.AccountID != account.ID {
+		return nil, gtserror.NewErrorNotFound(nil)
+	}
+
+	return p.apiFilter(ctx, filterKeyword)
+}
+
+// GetAll looks up all filter keywords for the current account and returns them as v1 filters.
+func (p *Processor) GetAll(ctx context.Context, account *gtsmodel.Account) ([]*apimodel.FilterV1, gtserror.WithCode) {
+	filters, err := p.state.DB.GetFilterKeywordsForAccountID(
+		ctx,
+		account.ID,
+	)
+	if err != nil {
+		if errors.Is(err, db.ErrNoEntries) {
+			return nil, nil
+		}
+		return nil, gtserror.NewErrorInternalError(err)
+	}
+
+	apiFilters := make([]*apimodel.FilterV1, 0, len(filters))
+	for _, list := range filters {
+		apiFilter, errWithCode := p.apiFilter(ctx, list)
+		if errWithCode != nil {
+			return nil, errWithCode
+		}
+
+		apiFilters = append(apiFilters, apiFilter)
+	}
+
+	// Sort them by ID so that they're in a stable order.
+	// Clients may opt to sort them lexically in a locale-aware manner.
+	slices.SortFunc(apiFilters, func(lhs *apimodel.FilterV1, rhs *apimodel.FilterV1) int {
+		return strings.Compare(lhs.ID, rhs.ID)
+	})
+
+	return apiFilters, nil
+}
diff --git a/internal/processing/filters/v1/update.go b/internal/processing/filters/v1/update.go
new file mode 100644
index 000000000..1fe49721b
--- /dev/null
+++ b/internal/processing/filters/v1/update.go
@@ -0,0 +1,165 @@
+// 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 v1
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"strings"
+	"time"
+
+	apimodel "github.com/superseriousbusiness/gotosocial/internal/api/model"
+	"github.com/superseriousbusiness/gotosocial/internal/db"
+	"github.com/superseriousbusiness/gotosocial/internal/gtscontext"
+	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
+	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
+	"github.com/superseriousbusiness/gotosocial/internal/util"
+)
+
+// Update an existing filter and filter keyword 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) Update(
+	ctx context.Context,
+	account *gtsmodel.Account,
+	filterKeywordID string,
+	form *apimodel.FilterCreateUpdateRequestV1,
+) (*apimodel.FilterV1, gtserror.WithCode) {
+	// Get enough of the filter keyword that we can look up its filter ID.
+	filterKeyword, err := p.state.DB.GetFilterKeywordByID(gtscontext.SetBarebones(ctx), filterKeywordID)
+	if err != nil {
+		if errors.Is(err, db.ErrNoEntries) {
+			return nil, gtserror.NewErrorNotFound(err)
+		}
+		return nil, gtserror.NewErrorInternalError(err)
+	}
+	if filterKeyword.AccountID != account.ID {
+		return nil, gtserror.NewErrorNotFound(nil)
+	}
+
+	// Get the filter for this keyword.
+	filter, err := p.state.DB.GetFilterByID(ctx, filterKeyword.FilterID)
+	if err != nil {
+		if errors.Is(err, db.ErrNoEntries) {
+			return nil, gtserror.NewErrorNotFound(err)
+		}
+		return nil, gtserror.NewErrorInternalError(err)
+	}
+
+	title := form.Phrase
+	action := gtsmodel.FilterActionWarn
+	if *form.Irreversible {
+		action = gtsmodel.FilterActionHide
+	}
+	expiresAt := time.Time{}
+	if form.ExpiresIn != nil {
+		expiresAt = time.Now().Add(time.Second * time.Duration(*form.ExpiresIn))
+	}
+	contextHome := false
+	contextNotifications := false
+	contextPublic := false
+	contextThread := false
+	contextAccount := false
+	for _, context := range form.Context {
+		switch context {
+		case apimodel.FilterContextHome:
+			contextHome = true
+		case apimodel.FilterContextNotifications:
+			contextNotifications = true
+		case apimodel.FilterContextPublic:
+			contextPublic = true
+		case apimodel.FilterContextThread:
+			contextThread = true
+		case apimodel.FilterContextAccount:
+			contextAccount = true
+		default:
+			return nil, gtserror.NewErrorUnprocessableEntity(
+				fmt.Errorf("unsupported filter context '%s'", context),
+			)
+		}
+	}
+
+	// v1 filter APIs can't change certain fields for a filter with multiple keywords or any statuses,
+	// since it would be an unexpected side effect on filters that, to the v1 API, appear separate.
+	// See https://docs.joinmastodon.org/methods/filters/#update-v1
+	if len(filter.Keywords) > 1 || len(filter.Statuses) > 0 {
+		forbiddenFields := make([]string, 0, 4)
+		if title != filter.Title {
+			forbiddenFields = append(forbiddenFields, "phrase")
+		}
+		if action != filter.Action {
+			forbiddenFields = append(forbiddenFields, "irreversible")
+		}
+		if expiresAt != filter.ExpiresAt {
+			forbiddenFields = append(forbiddenFields, "expires_in")
+		}
+		if contextHome != util.PtrValueOr(filter.ContextHome, false) ||
+			contextNotifications != util.PtrValueOr(filter.ContextNotifications, false) ||
+			contextPublic != util.PtrValueOr(filter.ContextPublic, false) ||
+			contextThread != util.PtrValueOr(filter.ContextThread, false) ||
+			contextAccount != util.PtrValueOr(filter.ContextAccount, false) {
+			forbiddenFields = append(forbiddenFields, "context")
+		}
+		if len(forbiddenFields) > 0 {
+			return nil, gtserror.NewErrorUnprocessableEntity(
+				fmt.Errorf("v1 filter backwards compatibility: can't change these fields for a filter with multiple keywords or any statuses: %s", strings.Join(forbiddenFields, ", ")),
+			)
+		}
+	}
+
+	// Now that we've checked that the changes are legal, apply them to the filter and keyword.
+	filter.Title = title
+	filter.Action = action
+	filter.ExpiresAt = expiresAt
+	filter.ContextHome = &contextHome
+	filter.ContextNotifications = &contextNotifications
+	filter.ContextPublic = &contextPublic
+	filter.ContextThread = &contextThread
+	filter.ContextAccount = &contextAccount
+	filterKeyword.Keyword = form.Phrase
+	filterKeyword.WholeWord = util.Ptr(util.PtrValueOr(form.WholeWord, false))
+
+	// We only want to update the relevant filter keyword.
+	filter.Keywords = []*gtsmodel.FilterKeyword{filterKeyword}
+	filter.Statuses = nil
+	filterKeyword.Filter = filter
+
+	filterColumns := []string{
+		"title",
+		"action",
+		"expires_at",
+		"context_home",
+		"context_notifications",
+		"context_public",
+		"context_thread",
+		"context_account",
+	}
+	filterKeywordColumns := []string{
+		"keyword",
+		"whole_word",
+	}
+	if err := p.state.DB.UpdateFilter(ctx, filter, filterColumns, filterKeywordColumns, nil, nil); err != nil {
+		if errors.Is(err, db.ErrAlreadyExists) {
+			err = errors.New("you already have a filter with this title")
+			return nil, gtserror.NewErrorConflict(err, err.Error())
+		}
+		return nil, gtserror.NewErrorInternalError(err)
+	}
+
+	return p.apiFilter(ctx, filterKeyword)
+}