1 files changed, 217 insertions, 0 deletions
diff --git a/internal/timeline/manager.go b/internal/timeline/manager.go
new file mode 100644
index 000000000..9d28b5060
--- /dev/null
+++ b/internal/timeline/manager.go
@@ -0,0 +1,217 @@
+/*
+   GoToSocial
+   Copyright (C) 2021 GoToSocial Authors admin@gotosocial.org
+
+   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 timeline
+
+import (
+	"fmt"
+	"strings"
+	"sync"
+
+	"github.com/sirupsen/logrus"
+	apimodel "github.com/superseriousbusiness/gotosocial/internal/api/model"
+	"github.com/superseriousbusiness/gotosocial/internal/config"
+	"github.com/superseriousbusiness/gotosocial/internal/db"
+	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
+	"github.com/superseriousbusiness/gotosocial/internal/typeutils"
+)
+
+const (
+	desiredPostIndexLength = 400
+)
+
+// Manager abstracts functions for creating timelines for multiple accounts, and adding, removing, and fetching entries from those timelines.
+//
+// By the time a status hits the manager interface, it should already have been filtered and it should be established that the status indeed
+// belongs in the home timeline of the given account ID.
+//
+// The manager makes a distinction between *indexed* posts and *prepared* posts.
+//
+// Indexed posts consist of just that post's ID (in the database) and the time it was created. An indexed post takes up very little memory, so
+// it's not a huge priority to keep trimming the indexed posts list.
+//
+// Prepared posts consist of the post's database ID, the time it was created, AND the apimodel representation of that post, for quick serialization.
+// Prepared posts of course take up more memory than indexed posts, so they should be regularly pruned if they're not being actively served.
+type Manager interface {
+	// Ingest takes one status and indexes it into the timeline for the given account ID.
+	//
+	// It should already be established before calling this function that the status/post actually belongs in the timeline!
+	Ingest(status *gtsmodel.Status, timelineAccountID string) error
+	// IngestAndPrepare takes one status and indexes it into the timeline for the given account ID, and then immediately prepares it for serving.
+	// This is useful in cases where we know the status will need to be shown at the top of a user's timeline immediately (eg., a new status is created).
+	//
+	// It should already be established before calling this function that the status/post actually belongs in the timeline!
+	IngestAndPrepare(status *gtsmodel.Status, timelineAccountID string) error
+	// HomeTimeline returns limit n amount of entries from the home timeline of the given account ID, in descending chronological order.
+	// If maxID is provided, it will return entries from that maxID onwards, inclusive.
+	HomeTimeline(accountID string, maxID string, sinceID string, minID string, limit int, local bool) ([]*apimodel.Status, error)
+	// GetIndexedLength returns the amount of posts/statuses that have been *indexed* for the given account ID.
+	GetIndexedLength(timelineAccountID string) int
+	// GetDesiredIndexLength returns the amount of posts that we, ideally, index for each user.
+	GetDesiredIndexLength() int
+	// GetOldestIndexedID returns the status ID for the oldest post that we have indexed for the given account.
+	GetOldestIndexedID(timelineAccountID string) (string, error)
+	// PrepareXFromTop prepares limit n amount of posts, based on their indexed representations, from the top of the index.
+	PrepareXFromTop(timelineAccountID string, limit int) error
+	// WipeStatusFromTimeline completely removes a status and from the index and prepared posts of the given account ID
+	//
+	// The returned int indicates how many entries were removed.
+	WipeStatusFromTimeline(timelineAccountID string, statusID string) (int, error)
+	// WipeStatusFromAllTimelines removes the status from the index and prepared posts of all timelines
+	WipeStatusFromAllTimelines(statusID string) error
+}
+
+// NewManager returns a new timeline manager with the given database, typeconverter, config, and log.
+func NewManager(db db.DB, tc typeutils.TypeConverter, config *config.Config, log *logrus.Logger) Manager {
+	return &manager{
+		accountTimelines: sync.Map{},
+		db:               db,
+		tc:               tc,
+		config:           config,
+		log:              log,
+	}
+}
+
+type manager struct {
+	accountTimelines sync.Map
+	db               db.DB
+	tc               typeutils.TypeConverter
+	config           *config.Config
+	log              *logrus.Logger
+}
+
+func (m *manager) Ingest(status *gtsmodel.Status, timelineAccountID string) error {
+	l := m.log.WithFields(logrus.Fields{
+		"func":              "Ingest",
+		"timelineAccountID": timelineAccountID,
+		"statusID":          status.ID,
+	})
+
+	t := m.getOrCreateTimeline(timelineAccountID)
+
+	l.Trace("ingesting status")
+	return t.IndexOne(status.CreatedAt, status.ID)
+}
+
+func (m *manager) IngestAndPrepare(status *gtsmodel.Status, timelineAccountID string) error {
+	l := m.log.WithFields(logrus.Fields{
+		"func":              "IngestAndPrepare",
+		"timelineAccountID": timelineAccountID,
+		"statusID":          status.ID,
+	})
+
+	t := m.getOrCreateTimeline(timelineAccountID)
+
+	l.Trace("ingesting status")
+	return t.IndexAndPrepareOne(status.CreatedAt, status.ID)
+}
+
+func (m *manager) Remove(statusID string, timelineAccountID string) (int, error) {
+	l := m.log.WithFields(logrus.Fields{
+		"func":              "Remove",
+		"timelineAccountID": timelineAccountID,
+		"statusID":          statusID,
+	})
+
+	t := m.getOrCreateTimeline(timelineAccountID)
+
+	l.Trace("removing status")
+	return t.Remove(statusID)
+}
+
+func (m *manager) HomeTimeline(timelineAccountID string, maxID string, sinceID string, minID string, limit int, local bool) ([]*apimodel.Status, error) {
+	l := m.log.WithFields(logrus.Fields{
+		"func":              "HomeTimelineGet",
+		"timelineAccountID": timelineAccountID,
+	})
+
+	t := m.getOrCreateTimeline(timelineAccountID)
+
+	statuses, err := t.Get(limit, maxID, sinceID, minID)
+	if err != nil {
+		l.Errorf("error getting statuses: %s", err)
+	}
+	return statuses, nil
+}
+
+func (m *manager) GetIndexedLength(timelineAccountID string) int {
+	t := m.getOrCreateTimeline(timelineAccountID)
+
+	return t.PostIndexLength()
+}
+
+func (m *manager) GetDesiredIndexLength() int {
+	return desiredPostIndexLength
+}
+
+func (m *manager) GetOldestIndexedID(timelineAccountID string) (string, error) {
+	t := m.getOrCreateTimeline(timelineAccountID)
+
+	return t.OldestIndexedPostID()
+}
+
+func (m *manager) PrepareXFromTop(timelineAccountID string, limit int) error {
+	t := m.getOrCreateTimeline(timelineAccountID)
+
+	return t.PrepareFromTop(limit)
+}
+
+func (m *manager) WipeStatusFromTimeline(timelineAccountID string, statusID string) (int, error) {
+	t := m.getOrCreateTimeline(timelineAccountID)
+
+	return t.Remove(statusID)
+}
+
+func (m *manager) WipeStatusFromAllTimelines(statusID string) error {
+	errors := []string{}
+	m.accountTimelines.Range(func(k interface{}, i interface{}) bool {
+		t, ok := i.(Timeline)
+		if !ok {
+			panic("couldn't parse entry as Timeline, this should never happen so panic")
+		}
+
+		if _, err := t.Remove(statusID); err != nil {
+			errors = append(errors, err.Error())
+		}
+
+		return false
+	})
+
+	var err error
+	if len(errors) > 0 {
+		err = fmt.Errorf("one or more errors removing status %s from all timelines: %s", statusID, strings.Join(errors, ";"))
+	}
+
+	return err
+}
+
+func (m *manager) getOrCreateTimeline(timelineAccountID string) Timeline {
+	var t Timeline
+	i, ok := m.accountTimelines.Load(timelineAccountID)
+	if !ok {
+		t = NewTimeline(timelineAccountID, m.db, m.tc, m.log)
+		m.accountTimelines.Store(timelineAccountID, t)
+	} else {
+		t, ok = i.(Timeline)
+		if !ok {
+			panic("couldn't parse entry as Timeline, this should never happen so panic")
+		}
+	}
+
+	return t
+}