// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
// See LICENSE.txt for license information.

package sqlstore

import (
	"context"
	"database/sql"
	"fmt"
	"path"
	"strconv"
	"strings"
	"sync"
	"sync/atomic"
	"time"

	sqlUtils "github.com/mattermost/mattermost/server/public/utils/sql"

	sq "github.com/mattermost/squirrel"

	_ "github.com/golang-migrate/migrate/v4/source/file"
	"github.com/jmoiron/sqlx"
	"github.com/lib/pq"
	"github.com/mattermost/morph/models"
	"github.com/pkg/errors"

	"github.com/mattermost/mattermost/server/public/model"
	"github.com/mattermost/mattermost/server/public/shared/mlog"
	"github.com/mattermost/mattermost/server/v8/channels/db"
	"github.com/mattermost/mattermost/server/v8/channels/store"
	"github.com/mattermost/mattermost/server/v8/einterfaces"
)

type migrationDirection string

type Option func(s *SqlStore) error

const (
	IndexTypeFullText              = "full_text"
	IndexTypeFullTextFunc          = "full_text_func"
	IndexTypeDefault               = "default"
	PGDupTableErrorCode            = "42P07" // see https://github.com/lib/pq/blob/master/error.go#L268
	PGForeignKeyViolationErrorCode = "23503"
	PGDuplicateObjectErrorCode     = "42710"
	DBPingAttempts                 = 5
	DBReplicaPingAttempts          = 2
	// This is a numerical version string by postgres. The format is
	// 2 characters for major, minor, and patch version prior to 10.
	// After 10, it's major and minor only.
	// 10.1 would be 100001.
	// 9.6.3 would be 90603.
	minimumRequiredPostgresVersion = 150000

	migrationsDirectionUp   migrationDirection = "up"
	migrationsDirectionDown migrationDirection = "down"

	replicaLagPrefix = "replica-lag"

	RemoteClusterSiteURLUniqueIndex = "remote_clusters_site_url_unique"
)

type SqlStoreStores struct {
	team                       store.TeamStore
	channel                    store.ChannelStore
	post                       store.PostStore
	retentionPolicy            store.RetentionPolicyStore
	thread                     store.ThreadStore
	user                       store.UserStore
	bot                        store.BotStore
	audit                      store.AuditStore
	cluster                    store.ClusterDiscoveryStore
	remoteCluster              store.RemoteClusterStore
	compliance                 store.ComplianceStore
	session                    store.SessionStore
	oauth                      store.OAuthStore
	outgoingOAuthConnection    store.OutgoingOAuthConnectionStore
	system                     store.SystemStore
	webhook                    store.WebhookStore
	command                    store.CommandStore
	commandWebhook             store.CommandWebhookStore
	preference                 store.PreferenceStore
	license                    store.LicenseStore
	token                      store.TokenStore
	emoji                      store.EmojiStore
	status                     store.StatusStore
	fileInfo                   store.FileInfoStore
	uploadSession              store.UploadSessionStore
	reaction                   store.ReactionStore
	job                        store.JobStore
	userAccessToken            store.UserAccessTokenStore
	plugin                     store.PluginStore
	channelMemberHistory       store.ChannelMemberHistoryStore
	role                       store.RoleStore
	scheme                     store.SchemeStore
	TermsOfService             store.TermsOfServiceStore
	productNotices             store.ProductNoticesStore
	group                      store.GroupStore
	UserTermsOfService         store.UserTermsOfServiceStore
	linkMetadata               store.LinkMetadataStore
	sharedchannel              store.SharedChannelStore
	draft                      store.DraftStore
	notifyAdmin                store.NotifyAdminStore
	postPriority               store.PostPriorityStore
	postAcknowledgement        store.PostAcknowledgementStore
	postPersistentNotification store.PostPersistentNotificationStore
	desktopTokens              store.DesktopTokensStore
	channelBookmarks           store.ChannelBookmarkStore
	channelGuard               store.ChannelGuardStore
	scheduledPost              store.ScheduledPostStore
	view                       store.ViewStore
	propertyGroup              store.PropertyGroupStore
	propertyField              store.PropertyFieldStore
	propertyValue              store.PropertyValueStore
	accessControlPolicy        store.AccessControlPolicyStore
	Attributes                 store.AttributesStore
	sessionAttribute           store.SessionAttributeStore
	autotranslation            store.AutoTranslationStore
	ContentFlagging            store.ContentFlaggingStore
	deliveryTracking           store.DeliveryTrackingStore
	recap                      store.RecapStore
	scheduledRecap             store.ScheduledRecapStore
	readReceipt                store.ReadReceiptStore
	temporaryPost              store.TemporaryPostStore
	channelJoinRequest         store.ChannelJoinRequestStore
}

type SqlStore struct {
	// rrCounter and srCounter should be kept first.
	// See https://github.com/mattermost/mattermost/server/v8/channels/pull/7281
	rrCounter int64
	srCounter int64

	masterX *sqlxDBWrapper

	ReplicaXs []*atomic.Pointer[sqlxDBWrapper]

	searchReplicaXs []*atomic.Pointer[sqlxDBWrapper]

	replicaLagHandles []*sql.DB
	stores            SqlStoreStores
	settings          *model.SqlSettings
	lockedToMaster    bool
	license           *model.License
	licenseMutex      sync.RWMutex
	logger            mlog.LoggerIFace
	metrics           einterfaces.MetricsInterface

	isBinaryParam             bool
	pgDefaultTextSearchConfig string
	skipMigrations            bool
	disableMorphLogging       bool
	featureFlagsFn            func() *model.FeatureFlags

	quitMonitor chan struct{}
	wgMonitor   *sync.WaitGroup

	// maxInsertParams overrides defaultMaxInsertParams when > 0. Exposed for
	// tests that need to force multi-chunk behaviour with small row counts.
	maxInsertParams int
}

func (ss *SqlStore) getMaxInsertParams() int {
	if ss.maxInsertParams > 0 {
		return ss.maxInsertParams
	}
	return defaultMaxInsertParams
}

func SkipMigrations() Option {
	return func(s *SqlStore) error {
		s.skipMigrations = true
		return nil
	}
}

func DisableMorphLogging() Option {
	return func(s *SqlStore) error {
		s.disableMorphLogging = true
		return nil
	}
}

// WithFeatureFlags provides a callback that returns the current feature flags.
// This allows the store layer to read feature flags without depending on the full config.
func WithFeatureFlags(fn func() *model.FeatureFlags) Option {
	return func(s *SqlStore) error {
		s.featureFlagsFn = fn
		return nil
	}
}

// getFeatureFlags returns the current feature flags, or defaults if no function was configured.
func (ss *SqlStore) getFeatureFlags() *model.FeatureFlags {
	if ss.featureFlagsFn != nil {
		return ss.featureFlagsFn()
	}
	ff := &model.FeatureFlags{}
	ff.SetDefaults()
	return ff
}

func New(settings model.SqlSettings, logger mlog.LoggerIFace, metrics einterfaces.MetricsInterface, options ...Option) (*SqlStore, error) {
	store := &SqlStore{
		rrCounter:   0,
		srCounter:   0,
		settings:    &settings,
		metrics:     metrics,
		logger:      logger,
		quitMonitor: make(chan struct{}),
		wgMonitor:   &sync.WaitGroup{},
	}

	for _, option := range options {
		if err := option(store); err != nil {
			return nil, fmt.Errorf("failed to apply option: %w", err)
		}
	}

	err := store.initConnection()
	if err != nil {
		return nil, errors.Wrap(err, "error setting up connections")
	}

	store.wgMonitor.Add(1)
	go store.monitorReplicas()

	ver, err := store.GetDbVersion(true)
	if err != nil {
		return nil, errors.Wrap(err, "error while getting DB version")
	}

	if err = store.checkVersion(ver); err != nil {
		return nil, errors.Wrap(err, "error while checking DB version")
	}

	if !store.skipMigrations {
		err = store.preMigration()
		if err != nil {
			return nil, errors.Wrap(err, "error while running pre-migrations")
		}

		err = store.migrate(migrationsDirectionUp, false, !store.disableMorphLogging)
		if err != nil {
			return nil, errors.Wrap(err, "failed to apply database migrations")
		}
	}

	store.isBinaryParam, err = store.computeBinaryParam()
	if err != nil {
		return nil, errors.Wrap(err, "failed to compute binary param")
	}

	store.pgDefaultTextSearchConfig, err = store.computeDefaultTextSearchConfig()
	if err != nil {
		return nil, errors.Wrap(err, "failed to compute default text search config")
	}

	store.stores.team = newSqlTeamStore(store)
	store.stores.channel = newSqlChannelStore(store, metrics)
	store.stores.post = newSqlPostStore(store, metrics)
	store.stores.retentionPolicy = newSqlRetentionPolicyStore(store, metrics)
	store.stores.user = newSqlUserStore(store, metrics)
	store.stores.bot = newSqlBotStore(store, metrics)
	store.stores.audit = newSqlAuditStore(store)
	store.stores.cluster = newSqlClusterDiscoveryStore(store)
	store.stores.remoteCluster = newSqlRemoteClusterStore(store)
	store.stores.compliance = newSqlComplianceStore(store)
	store.stores.session = newSqlSessionStore(store)
	store.stores.oauth = newSqlOAuthStore(store)
	store.stores.outgoingOAuthConnection = newSqlOutgoingOAuthConnectionStore(store)
	store.stores.system = newSqlSystemStore(store)
	store.stores.webhook = newSqlWebhookStore(store, metrics)
	store.stores.command = newSqlCommandStore(store)
	store.stores.commandWebhook = newSqlCommandWebhookStore(store)
	store.stores.preference = newSqlPreferenceStore(store)
	store.stores.license = newSqlLicenseStore(store)
	store.stores.token = newSqlTokenStore(store)
	store.stores.emoji = newSqlEmojiStore(store, metrics)
	store.stores.status = newSqlStatusStore(store)
	store.stores.fileInfo = newSqlFileInfoStore(store, metrics)
	store.stores.uploadSession = newSqlUploadSessionStore(store)
	store.stores.thread = newSqlThreadStore(store)
	store.stores.job = newSqlJobStore(store)
	store.stores.userAccessToken = newSqlUserAccessTokenStore(store)
	store.stores.channelMemberHistory = newSqlChannelMemberHistoryStore(store)
	store.stores.plugin = newSqlPluginStore(store)
	store.stores.TermsOfService = newSqlTermsOfServiceStore(store, metrics)
	store.stores.UserTermsOfService = newSqlUserTermsOfServiceStore(store)
	store.stores.linkMetadata = newSqlLinkMetadataStore(store)
	store.stores.sharedchannel = newSqlSharedChannelStore(store)
	store.stores.reaction = newSqlReactionStore(store)
	store.stores.role = newSqlRoleStore(store)
	store.stores.scheme = newSqlSchemeStore(store)
	store.stores.group = newSqlGroupStore(store)
	store.stores.productNotices = newSqlProductNoticesStore(store)
	store.stores.draft = newSqlDraftStore(store, metrics)
	store.stores.notifyAdmin = newSqlNotifyAdminStore(store)
	store.stores.postPriority = newSqlPostPriorityStore(store)
	store.stores.postAcknowledgement = newSqlPostAcknowledgementStore(store)
	store.stores.postPersistentNotification = newSqlPostPersistentNotificationStore(store)
	store.stores.desktopTokens = newSqlDesktopTokensStore(store, metrics)
	store.stores.channelBookmarks = newSqlChannelBookmarkStore(store)
	store.stores.channelGuard = newSqlChannelGuardStore(store)
	store.stores.scheduledPost = newScheduledPostStore(store)
	store.stores.view = newSqlViewStore(store)
	store.stores.propertyGroup = newPropertyGroupStore(store)
	store.stores.propertyField = newPropertyFieldStore(store)
	store.stores.propertyValue = newPropertyValueStore(store)
	store.stores.accessControlPolicy = newSqlAccessControlPolicyStore(store, metrics)
	store.stores.Attributes = newSqlAttributesStore(store, metrics)
	store.stores.sessionAttribute = newSqlSessionAttributeStore(store)
	store.stores.autotranslation = newSqlAutoTranslationStore(store)
	store.stores.ContentFlagging = newContentFlaggingStore(store)
	store.stores.deliveryTracking = newSqlDeliveryTrackingStore(store)
	store.stores.recap = newSqlRecapStore(store)
	store.stores.scheduledRecap = newSqlScheduledRecapStore(store)
	store.stores.readReceipt = newSqlReadReceiptStore(store, metrics)
	store.stores.temporaryPost = newSqlTemporaryPostStore(store, metrics)
	store.stores.channelJoinRequest = newSqlChannelJoinRequestStore(store)

	store.stores.preference.(*SqlPreferenceStore).deleteUnusedFeatures()

	return store, nil
}

func (ss *SqlStore) Logger() mlog.LoggerIFace {
	return ss.logger
}

func (ss *SqlStore) initConnection() error {
	dataSource := *ss.settings.DataSource

	handle, err := sqlUtils.SetupConnection(ss.Logger(), "master", dataSource, ss.settings, DBPingAttempts)
	if err != nil {
		return err
	}
	ss.masterX = newSqlxDBWrapper(sqlx.NewDb(handle, ss.DriverName()),
		time.Duration(*ss.settings.QueryTimeout)*time.Second,
		*ss.settings.Trace)
	if ss.metrics != nil {
		ss.metrics.RegisterDBCollector(ss.masterX.DB().DB, "master")
	}

	if len(ss.settings.DataSourceReplicas) > 0 {
		ss.ReplicaXs = make([]*atomic.Pointer[sqlxDBWrapper], len(ss.settings.DataSourceReplicas))
		for i, replica := range ss.settings.DataSourceReplicas {
			ss.ReplicaXs[i] = &atomic.Pointer[sqlxDBWrapper]{}
			handle, err = sqlUtils.SetupConnection(ss.Logger(), fmt.Sprintf("replica-%v", i), replica, ss.settings, DBReplicaPingAttempts)
			if err != nil {
				// Initializing to be offline
				ss.ReplicaXs[i].Store(&sqlxDBWrapper{isOnline: &atomic.Bool{}})
				mlog.Warn("Failed to setup connection. Skipping..", mlog.String("db", fmt.Sprintf("replica-%v", i)), mlog.Err(err))
				continue
			}
			ss.setDB(ss.ReplicaXs[i], handle, "replica-"+strconv.Itoa(i))
		}
	}

	if len(ss.settings.DataSourceSearchReplicas) > 0 {
		ss.searchReplicaXs = make([]*atomic.Pointer[sqlxDBWrapper], len(ss.settings.DataSourceSearchReplicas))
		for i, replica := range ss.settings.DataSourceSearchReplicas {
			ss.searchReplicaXs[i] = &atomic.Pointer[sqlxDBWrapper]{}
			handle, err = sqlUtils.SetupConnection(ss.Logger(), fmt.Sprintf("search-replica-%v", i), replica, ss.settings, DBReplicaPingAttempts)
			if err != nil {
				// Initializing to be offline
				ss.searchReplicaXs[i].Store(&sqlxDBWrapper{isOnline: &atomic.Bool{}})
				mlog.Warn("Failed to setup connection. Skipping..", mlog.String("db", fmt.Sprintf("search-replica-%v", i)), mlog.Err(err))
				continue
			}
			ss.setDB(ss.searchReplicaXs[i], handle, "searchreplica-"+strconv.Itoa(i))
		}
	}

	if len(ss.settings.ReplicaLagSettings) > 0 {
		ss.replicaLagHandles = make([]*sql.DB, 0, len(ss.settings.ReplicaLagSettings))
		for i, src := range ss.settings.ReplicaLagSettings {
			if src.DataSource == nil {
				continue
			}
			replicaLagHandle, err := sqlUtils.SetupConnection(ss.Logger(), fmt.Sprintf(replicaLagPrefix+"-%d", i), *src.DataSource, ss.settings, DBReplicaPingAttempts)
			if err != nil {
				mlog.Warn("Failed to setup replica lag handle. Skipping..", mlog.String("db", fmt.Sprintf(replicaLagPrefix+"-%d", i)), mlog.Err(err))
				continue
			}
			ss.replicaLagHandles = append(ss.replicaLagHandles, replicaLagHandle)
		}
	}
	return nil
}

func (ss *SqlStore) DriverName() string {
	return *ss.settings.DriverName
}

// specialSearchChars have special meaning and can be treated as spaces
var specialSearchChars = []string{
	"<",
	">",
	"+",
	"(",
	")",
	"~",
	":",
}

// computeBinaryParam returns whether the data source uses binary_parameters
func (ss *SqlStore) computeBinaryParam() (bool, error) {
	return DSNHasBinaryParam(*ss.settings.DataSource)
}

func (ss *SqlStore) computeDefaultTextSearchConfig() (string, error) {
	var defaultTextSearchConfig string
	err := ss.GetMaster().Get(&defaultTextSearchConfig, `SHOW default_text_search_config`)
	return defaultTextSearchConfig, err
}

func (ss *SqlStore) IsBinaryParamEnabled() bool {
	return ss.isBinaryParam
}

// GetDbVersion returns the version of the database being used.
// If numerical is set to true, it attempts to return a numerical version string
// that can be parsed by callers.
func (ss *SqlStore) GetDbVersion(numerical bool) (string, error) {
	var sqlVersion string
	if numerical {
		sqlVersion = `SHOW server_version_num`
	} else {
		sqlVersion = `SHOW server_version`
	}

	var version string
	err := ss.GetReplica().Get(&version, sqlVersion)
	if err != nil {
		return "", err
	}

	return version, nil
}

func (ss *SqlStore) GetMaster() *sqlxDBWrapper {
	return ss.masterX
}

func (ss *SqlStore) SetMasterX(db *sql.DB) {
	ss.masterX = newSqlxDBWrapper(sqlx.NewDb(db, ss.DriverName()),
		time.Duration(*ss.settings.QueryTimeout)*time.Second,
		*ss.settings.Trace)
}

func (ss *SqlStore) GetInternalMasterDB() *sql.DB {
	return ss.GetMaster().DB().DB
}

func (ss *SqlStore) GetSearchReplicaX() *sqlxDBWrapper {
	if !ss.hasLicense() {
		return ss.GetMaster()
	}

	if len(ss.settings.DataSourceSearchReplicas) == 0 {
		return ss.GetReplica()
	}

	lenReplicas := len(ss.searchReplicaXs)
	for range lenReplicas {
		rrNum := atomic.AddInt64(&ss.srCounter, 1) % int64(lenReplicas)
		if ss.searchReplicaXs[rrNum].Load().Online() {
			return ss.searchReplicaXs[rrNum].Load()
		}
	}

	// If all search replicas are down, then go with replica.
	return ss.GetReplica()
}

func (ss *SqlStore) GetReplica() *sqlxDBWrapper {
	if len(ss.settings.DataSourceReplicas) == 0 || ss.lockedToMaster || !ss.hasLicense() {
		return ss.GetMaster()
	}

	lenReplicas := len(ss.ReplicaXs)
	for range lenReplicas {
		rrNum := atomic.AddInt64(&ss.rrCounter, 1) % int64(lenReplicas)
		if ss.ReplicaXs[rrNum].Load().Online() {
			return ss.ReplicaXs[rrNum].Load()
		}
	}

	// If all replicas are down, then go with master.
	return ss.GetMaster()
}

func (ss *SqlStore) analyticsContext() (context.Context, context.CancelFunc) {
	return context.WithTimeout(context.Background(), time.Duration(*ss.settings.AnalyticsQueryTimeout)*time.Second)
}

// noTimeoutContext returns a context that suppresses automatic timeout injection
// by ensureQueryTimeout. Use only for queries that legitimately must be unbounded,
// such as schema introspection or long-running migrations.
func (ss *SqlStore) noTimeoutContext() context.Context {
	return context.WithValue(context.Background(), noTimeoutKey{}, true)
}

func (ss *SqlStore) monitorReplicas() {
	t := time.NewTicker(time.Duration(*ss.settings.ReplicaMonitorIntervalSeconds) * time.Second)
	defer func() {
		t.Stop()
		ss.wgMonitor.Done()
	}()
	for {
		select {
		case <-ss.quitMonitor:
			return
		case <-t.C:
			setupReplica := func(r *atomic.Pointer[sqlxDBWrapper], dsn, name string) {
				if r.Load().Online() {
					return
				}

				handle, err := sqlUtils.SetupConnection(ss.Logger(), name, dsn, ss.settings, 1)
				if err != nil {
					mlog.Warn("Failed to setup connection. Skipping..", mlog.String("db", name), mlog.Err(err))
					return
				}
				if ss.metrics != nil && r.Load() != nil && r.Load().db != nil {
					ss.metrics.UnregisterDBCollector(r.Load().DB().DB, name)
				}
				ss.setDB(r, handle, name)
			}
			for i, replica := range ss.ReplicaXs {
				setupReplica(replica, ss.settings.DataSourceReplicas[i], "replica-"+strconv.Itoa(i))
			}

			for i, replica := range ss.searchReplicaXs {
				setupReplica(replica, ss.settings.DataSourceSearchReplicas[i], "search-replica-"+strconv.Itoa(i))
			}
		}
	}
}

func (ss *SqlStore) setDB(replica *atomic.Pointer[sqlxDBWrapper], handle *sql.DB, name string) {
	replica.Store(newSqlxDBWrapper(sqlx.NewDb(handle, ss.DriverName()),
		time.Duration(*ss.settings.QueryTimeout)*time.Second,
		*ss.settings.Trace))
	if ss.metrics != nil {
		ss.metrics.RegisterDBCollector(replica.Load().DB().DB, name)
	}
}

func (ss *SqlStore) GetInternalReplicaDB() *sql.DB {
	if len(ss.settings.DataSourceReplicas) == 0 || ss.lockedToMaster || !ss.hasLicense() {
		return ss.GetMaster().DB().DB
	}

	rrNum := atomic.AddInt64(&ss.rrCounter, 1) % int64(len(ss.ReplicaXs))
	return ss.ReplicaXs[rrNum].Load().DB().DB
}

func (ss *SqlStore) TotalMasterDbConnections() int {
	return ss.GetMaster().Stats().OpenConnections
}

func (ss *SqlStore) MasterDBStats() sql.DBStats {
	return ss.GetMaster().Stats()
}

// ReplicaLagAbs queries all the replica databases to get the absolute replica lag value
// and updates the Prometheus metric with it.
func (ss *SqlStore) ReplicaLagAbs() error {
	for i, item := range ss.settings.ReplicaLagSettings {
		if item.QueryAbsoluteLag == nil || *item.QueryAbsoluteLag == "" {
			continue
		}
		var binDiff float64
		var node string
		err := ss.replicaLagHandles[i].QueryRow(*item.QueryAbsoluteLag).Scan(&node, &binDiff)
		if err != nil {
			return err
		}
		// There is no nil check needed here because it's called from the metrics store.
		ss.metrics.SetReplicaLagAbsolute(node, binDiff)
	}
	return nil
}

// ReplicaLagAbs queries all the replica databases to get the time-based replica lag value
// and updates the Prometheus metric with it.
func (ss *SqlStore) ReplicaLagTime() error {
	for i, item := range ss.settings.ReplicaLagSettings {
		if item.QueryTimeLag == nil || *item.QueryTimeLag == "" {
			continue
		}
		var timeDiff float64
		var node string
		err := ss.replicaLagHandles[i].QueryRow(*item.QueryTimeLag).Scan(&node, &timeDiff)
		if err != nil {
			return err
		}
		// There is no nil check needed here because it's called from the metrics store.
		ss.metrics.SetReplicaLagTime(node, timeDiff)
	}
	return nil
}

func (ss *SqlStore) TotalReadDbConnections() int {
	if len(ss.settings.DataSourceReplicas) == 0 {
		return 0
	}

	count := 0
	for _, db := range ss.ReplicaXs {
		if !db.Load().Online() {
			continue
		}
		count = count + db.Load().Stats().OpenConnections
	}

	return count
}

func (ss *SqlStore) ReplicaDBStats() sql.DBStats {
	var stats sql.DBStats
	for _, db := range ss.ReplicaXs {
		if !db.Load().Online() {
			continue
		}

		dbStats := db.Load().Stats()
		stats.OpenConnections += dbStats.OpenConnections
		stats.InUse += dbStats.InUse
		stats.Idle += dbStats.Idle
		stats.WaitCount += dbStats.WaitCount
		stats.WaitDuration += dbStats.WaitDuration
		stats.MaxIdleClosed += dbStats.MaxIdleClosed
		stats.MaxIdleTimeClosed += dbStats.MaxIdleTimeClosed
		stats.MaxLifetimeClosed += dbStats.MaxLifetimeClosed
	}

	return stats
}

func (ss *SqlStore) TotalSearchDbConnections() int {
	if len(ss.settings.DataSourceSearchReplicas) == 0 {
		return 0
	}

	count := 0
	for _, db := range ss.searchReplicaXs {
		if !db.Load().Online() {
			continue
		}
		count = count + db.Load().Stats().OpenConnections
	}

	return count
}

func (ss *SqlStore) MarkSystemRanUnitTests() {
	props, err := ss.System().Get()
	if err != nil {
		return
	}

	unitTests := props[model.SystemRanUnitTests]
	if unitTests == "" {
		systemTests := &model.System{Name: model.SystemRanUnitTests, Value: "1"}
		ss.System().Save(systemTests)
	}
}

func IsUniqueConstraintError(err error, indexName []string) bool {
	unique := false
	if pqErr, ok := err.(*pq.Error); ok && pqErr.Code == "23505" {
		unique = true
	}

	field := false
	for _, contain := range indexName {
		if strings.Contains(err.Error(), contain) {
			field = true
			break
		}
	}

	return unique && field
}

func (ss *SqlStore) GetAllConns() []*sqlxDBWrapper {
	all := make([]*sqlxDBWrapper, 0, len(ss.ReplicaXs)+1)
	for i := range ss.ReplicaXs {
		if !ss.ReplicaXs[i].Load().Online() {
			continue
		}
		all = append(all, ss.ReplicaXs[i].Load())
	}
	all = append(all, ss.masterX)
	return all
}

// RecycleDBConnections closes active connections by setting the max conn lifetime
// to d, and then resets them back to their original duration.
func (ss *SqlStore) RecycleDBConnections(d time.Duration) {
	// Get old time.
	originalDuration := time.Duration(*ss.settings.ConnMaxLifetimeMilliseconds) * time.Millisecond
	// Set the max lifetimes for all connections.
	for _, conn := range ss.GetAllConns() {
		conn.SetConnMaxLifetime(d)
	}
	// Wait for that period with an additional 2 seconds of scheduling delay.
	time.Sleep(d + 2*time.Second)
	// Reset max lifetime back to original value.
	for _, conn := range ss.GetAllConns() {
		conn.SetConnMaxLifetime(originalDuration)
	}
}

func (ss *SqlStore) Close() {
	ss.masterX.Close()
	// Closing monitor and waiting for it to be done.
	// This needs to be done before closing the replica handles.
	close(ss.quitMonitor)
	ss.wgMonitor.Wait()

	for _, replica := range ss.ReplicaXs {
		if replica.Load().Online() {
			replica.Load().Close()
		}
	}

	for _, replica := range ss.searchReplicaXs {
		if replica.Load().Online() {
			replica.Load().Close()
		}
	}

	for _, replica := range ss.replicaLagHandles {
		replica.Close()
	}
}

func (ss *SqlStore) LockToMaster() {
	ss.lockedToMaster = true
}

func (ss *SqlStore) UnlockFromMaster() {
	ss.lockedToMaster = false
}

func (ss *SqlStore) Team() store.TeamStore {
	return ss.stores.team
}

func (ss *SqlStore) Channel() store.ChannelStore {
	return ss.stores.channel
}

func (ss *SqlStore) Post() store.PostStore {
	return ss.stores.post
}

func (ss *SqlStore) RetentionPolicy() store.RetentionPolicyStore {
	return ss.stores.retentionPolicy
}

func (ss *SqlStore) User() store.UserStore {
	return ss.stores.user
}

func (ss *SqlStore) Bot() store.BotStore {
	return ss.stores.bot
}

func (ss *SqlStore) Session() store.SessionStore {
	return ss.stores.session
}

func (ss *SqlStore) Audit() store.AuditStore {
	return ss.stores.audit
}

func (ss *SqlStore) ClusterDiscovery() store.ClusterDiscoveryStore {
	return ss.stores.cluster
}

func (ss *SqlStore) RemoteCluster() store.RemoteClusterStore {
	return ss.stores.remoteCluster
}

func (ss *SqlStore) Compliance() store.ComplianceStore {
	return ss.stores.compliance
}

func (ss *SqlStore) OAuth() store.OAuthStore {
	return ss.stores.oauth
}

func (ss *SqlStore) OutgoingOAuthConnection() store.OutgoingOAuthConnectionStore {
	return ss.stores.outgoingOAuthConnection
}

func (ss *SqlStore) System() store.SystemStore {
	return ss.stores.system
}

func (ss *SqlStore) Webhook() store.WebhookStore {
	return ss.stores.webhook
}

func (ss *SqlStore) Command() store.CommandStore {
	return ss.stores.command
}

func (ss *SqlStore) CommandWebhook() store.CommandWebhookStore {
	return ss.stores.commandWebhook
}

func (ss *SqlStore) Preference() store.PreferenceStore {
	return ss.stores.preference
}

func (ss *SqlStore) License() store.LicenseStore {
	return ss.stores.license
}

func (ss *SqlStore) Token() store.TokenStore {
	return ss.stores.token
}

func (ss *SqlStore) Emoji() store.EmojiStore {
	return ss.stores.emoji
}

func (ss *SqlStore) Status() store.StatusStore {
	return ss.stores.status
}

func (ss *SqlStore) FileInfo() store.FileInfoStore {
	return ss.stores.fileInfo
}

func (ss *SqlStore) UploadSession() store.UploadSessionStore {
	return ss.stores.uploadSession
}

func (ss *SqlStore) Reaction() store.ReactionStore {
	return ss.stores.reaction
}

func (ss *SqlStore) Job() store.JobStore {
	return ss.stores.job
}

func (ss *SqlStore) UserAccessToken() store.UserAccessTokenStore {
	return ss.stores.userAccessToken
}

func (ss *SqlStore) ChannelMemberHistory() store.ChannelMemberHistoryStore {
	return ss.stores.channelMemberHistory
}

func (ss *SqlStore) Plugin() store.PluginStore {
	return ss.stores.plugin
}

func (ss *SqlStore) Thread() store.ThreadStore {
	return ss.stores.thread
}

func (ss *SqlStore) Role() store.RoleStore {
	return ss.stores.role
}

func (ss *SqlStore) TermsOfService() store.TermsOfServiceStore {
	return ss.stores.TermsOfService
}

func (ss *SqlStore) ProductNotices() store.ProductNoticesStore {
	return ss.stores.productNotices
}

func (ss *SqlStore) UserTermsOfService() store.UserTermsOfServiceStore {
	return ss.stores.UserTermsOfService
}

func (ss *SqlStore) Scheme() store.SchemeStore {
	return ss.stores.scheme
}

func (ss *SqlStore) Group() store.GroupStore {
	return ss.stores.group
}

func (ss *SqlStore) LinkMetadata() store.LinkMetadataStore {
	return ss.stores.linkMetadata
}

func (ss *SqlStore) NotifyAdmin() store.NotifyAdminStore {
	return ss.stores.notifyAdmin
}

func (ss *SqlStore) SharedChannel() store.SharedChannelStore {
	return ss.stores.sharedchannel
}

func (ss *SqlStore) PostPriority() store.PostPriorityStore {
	return ss.stores.postPriority
}

func (ss *SqlStore) Draft() store.DraftStore {
	return ss.stores.draft
}

func (ss *SqlStore) PostAcknowledgement() store.PostAcknowledgementStore {
	return ss.stores.postAcknowledgement
}

func (ss *SqlStore) PostPersistentNotification() store.PostPersistentNotificationStore {
	return ss.stores.postPersistentNotification
}

func (ss *SqlStore) DesktopTokens() store.DesktopTokensStore {
	return ss.stores.desktopTokens
}

func (ss *SqlStore) ChannelBookmark() store.ChannelBookmarkStore {
	return ss.stores.channelBookmarks
}

func (ss *SqlStore) ChannelGuard() store.ChannelGuardStore {
	return ss.stores.channelGuard
}

func (ss *SqlStore) View() store.ViewStore {
	return ss.stores.view
}

func (ss *SqlStore) PropertyGroup() store.PropertyGroupStore {
	return ss.stores.propertyGroup
}

func (ss *SqlStore) PropertyField() store.PropertyFieldStore {
	return ss.stores.propertyField
}

func (ss *SqlStore) PropertyValue() store.PropertyValueStore {
	return ss.stores.propertyValue
}

func (ss *SqlStore) AccessControlPolicy() store.AccessControlPolicyStore {
	return ss.stores.accessControlPolicy
}

func (ss *SqlStore) Attributes() store.AttributesStore {
	return ss.stores.Attributes
}

func (ss *SqlStore) SessionAttribute() store.SessionAttributeStore {
	return ss.stores.sessionAttribute
}

func (ss *SqlStore) AutoTranslation() store.AutoTranslationStore {
	return ss.stores.autotranslation
}

func (ss *SqlStore) Recap() store.RecapStore {
	return ss.stores.recap
}

func (ss *SqlStore) ScheduledRecap() store.ScheduledRecapStore {
	return ss.stores.scheduledRecap
}

func (ss *SqlStore) ReadReceipt() store.ReadReceiptStore {
	return ss.stores.readReceipt
}

func (ss *SqlStore) TemporaryPost() store.TemporaryPostStore {
	return ss.stores.temporaryPost
}

func (ss *SqlStore) ChannelJoinRequest() store.ChannelJoinRequestStore {
	return ss.stores.channelJoinRequest
}

func (ss *SqlStore) DropAllTables() {
	ss.masterX.Exec(`DO
		$func$
		BEGIN
		   EXECUTE
		   (SELECT 'TRUNCATE TABLE ' || string_agg(oid::regclass::text, ', ') || ' CASCADE'
		    FROM   pg_class
		    WHERE  relkind = 'r'  -- only tables
		    AND    relnamespace = 'public'::regnamespace
			AND NOT relname = 'db_migrations'
		   );
		END
		$func$;`)
}

func (ss *SqlStore) getQueryBuilder() sq.StatementBuilderType {
	return sq.StatementBuilder.PlaceholderFormat(ss.getQueryPlaceholder())
}

func (ss *SqlStore) getQueryPlaceholder() sq.PlaceholderFormat {
	return sq.Dollar
}

// getSubQueryBuilder is necessary to generate the SQL query and args to pass to sub-queries because squirrel does not support WHERE clause in sub-queries.
func (ss *SqlStore) getSubQueryBuilder() sq.StatementBuilderType {
	return sq.StatementBuilder.PlaceholderFormat(sq.Question)
}

func (ss *SqlStore) CheckIntegrity() <-chan model.IntegrityCheckResult {
	results := make(chan model.IntegrityCheckResult)
	go CheckRelationalIntegrity(ss, results)
	return results
}

func (ss *SqlStore) UpdateLicense(license *model.License) {
	ss.licenseMutex.Lock()
	defer ss.licenseMutex.Unlock()
	ss.license = license
}

func (ss *SqlStore) GetLicense() *model.License {
	return ss.license
}

func (ss *SqlStore) hasLicense() bool {
	ss.licenseMutex.Lock()
	hasLicense := ss.license != nil
	ss.licenseMutex.Unlock()

	return hasLicense
}

// IsDuplicate checks whether an error is a duplicate key error, which comes when processes are competing on creating the same
// tables in the database.
func IsDuplicate(err error) bool {
	var pqErr *pq.Error
	if errors.As(errors.Cause(err), &pqErr) {
		if pqErr.Code == PGDupTableErrorCode {
			return true
		}
	}

	return false
}

// checkVersion returns an error if the given Postgres version cannot be
// determined. An unsupported version is only logged: running one is discouraged,
// but not prevented.
func (ss *SqlStore) checkVersion(ver string) error {
	intVer, err := strconv.Atoi(ver)
	if err != nil {
		return fmt.Errorf("cannot parse DB version: %v", err)
	}

	if intVer < minimumRequiredPostgresVersion {
		ss.logger.Error("Unsupported Postgres version. Running an unsupported version may lead to unexpected behaviour.",
			mlog.String("version", versionString(intVer)),
			mlog.String("min_version", versionString(minimumRequiredPostgresVersion)),
		)
	}

	return nil
}

// versionString converts an integer representation of a Postgres DB version
// to a pretty-printed string.
// From 10.0 onwards, the version is the major version multiplied by 10000 plus
// the minor version, e.g. 10.1 is 100001. Prior to 10, the version used two
// digits for each of the three parts, e.g. 9.1.5 is 90105:
// https://www.postgresql.org/docs/13/libpq-status.html#LIBPQ-PQSERVERVERSION.
func versionString(v int) string {
	major := v / 10000
	if major < 10 {
		return fmt.Sprintf("%d.%d.%d", major, (v/100)%100, v%100)
	}

	return fmt.Sprintf("%d.%d", major, v%10000)
}

func (ss *SqlStore) toReserveCase(str string) string {
	return fmt.Sprintf("%q", str)
}

func (ss *SqlStore) GetLocalSchemaVersion() (int, error) {
	assets := db.Assets()

	assetsList, err := assets.ReadDir(path.Join("migrations", ss.DriverName()))
	if err != nil {
		return 0, err
	}

	maxVersion := 0
	for _, entry := range assetsList {
		// parse the version name from the file name
		m := models.Regex.FindStringSubmatch(entry.Name())
		if len(m) < 2 {
			return 0, fmt.Errorf("migration file name incorrectly formed: %s", entry.Name())
		}

		version, err := strconv.Atoi(m[1])
		if err != nil {
			return 0, err
		}
		// store the highest version
		if maxVersion < version {
			maxVersion = version
		}
	}
	return maxVersion, nil
}

func (ss *SqlStore) GetDBSchemaVersion() (int, error) {
	var version int
	if err := ss.GetMaster().Get(&version, "SELECT Version FROM db_migrations ORDER BY Version DESC LIMIT 1"); err != nil {
		return 0, errors.Wrap(err, "unable to select from db_migrations")
	}
	return version, nil
}

func (ss *SqlStore) GetAppliedMigrations() ([]model.AppliedMigration, error) {
	migrations := []model.AppliedMigration{}
	if err := ss.GetMaster().Select(&migrations, "SELECT Version, Name FROM db_migrations ORDER BY Version DESC"); err != nil {
		return nil, errors.Wrap(err, "unable to select from db_migrations")
	}

	return migrations, nil
}

func (ss *SqlStore) determineMaxColumnSize(tableName, columnName string) (int, error) {
	var columnSizeBytes int32
	ss.getQueryPlaceholder()

	if err := ss.GetReplica().Get(&columnSizeBytes, `
		SELECT
			COALESCE(character_maximum_length, 0)
		FROM
			information_schema.columns
		WHERE
			lower(table_name) = lower($1)
		AND	lower(column_name) = lower($2)
	`, tableName, columnName); err != nil {
		mlog.Warn("Unable to determine the maximum supported column size for Postgres", mlog.Err(err))
		return 0, err
	}

	// Assume a worst-case representation of four bytes per rune.
	maxColumnSize := int(columnSizeBytes) / 4

	mlog.Info("Column has size restrictions", mlog.String("table_name", tableName), mlog.String("column_name", columnName), mlog.Int("max_characters", maxColumnSize), mlog.Int("max_bytes", columnSizeBytes))

	return maxColumnSize, nil
}

func (ss *SqlStore) ScheduledPost() store.ScheduledPostStore {
	return ss.stores.scheduledPost
}

func (ss *SqlStore) ContentFlagging() store.ContentFlaggingStore {
	return ss.stores.ContentFlagging
}

func (ss *SqlStore) DeliveryTracking() store.DeliveryTrackingStore {
	return ss.stores.deliveryTracking
}

// preMigration	runs before running the actual Morph migrations.
// The main reason for having a preMigration is to fix https://mattermost.atlassian.net/browse/MM-68848?focusedCommentId=217769
// However, using that as an opportunity, a general purpose system is created that allows running
// arbitrary code just before the Morph migrations run. This allows us to have a way to fix
// any issues in the DB that might prevent the Morph migrations from running successfully.
// The pre-migrations are tracked in the Systems table to make sure they run only once.
func (ss *SqlStore) preMigration() error {
	type sqlMigration struct {
		name string
		// minDBMigration is the schema migration version that must already have
		// been applied (recorded in db_migrations) before this pre-migration is
		// allowed to run. A pre-migration that touches data in a table created
		// by schema migration N should set this to N.
		minDBMigration int
		handler        func() error
	}

	migrations := []sqlMigration{
		{"renumber_roles_schemeid_migrations", 144, ss.doRenumberRolesSchemeIdMigrations},
	}

	// To check for empty DB and skip
	exists, err := ss.tableExists("db_migrations")
	if err != nil {
		return errors.Wrap(err, "failed to check if db_migrations table exists")
	}
	if !exists {
		return nil
	}

	// Checking for systems table because that's where the run status of individual pre migrations are stored
	exists, err = ss.tableExists("systems")
	if err != nil {
		return errors.Wrap(err, "failed to check if Systems table exists")
	}
	if !exists {
		return nil
	}

	for _, m := range migrations {
		applied, err := ss.isDBMigrationApplied(m.minDBMigration)
		if err != nil {
			return errors.Wrapf(err, "failed to check DB migration %d status", m.minDBMigration)
		}
		if !applied {
			continue
		}

		done, err := ss.isPreMigrationComplete(m.name)
		if err != nil {
			return errors.Wrapf(err, "failed to check pre-migration %q status", m.name)
		}
		if done {
			continue
		}

		ss.logger.Debug("Running pre-migration", mlog.String("name", m.name), mlog.Int("min_db_migration", m.minDBMigration))
		if err := m.handler(); err != nil {
			return errors.Wrapf(err, "failed to run pre-migration %q", m.name)
		}

		if err := ss.markPreMigrationComplete(m.name); err != nil {
			return errors.Wrapf(err, "failed to mark pre-migration %q complete", m.name)
		}
		ss.logger.Debug("Completed pre-migration", mlog.String("name", m.name))
	}

	return nil
}

// This is for resolving the issue described here - https://mattermost.atlassian.net/browse/MM-68848?focusedCommentId=217769
// Briefly describing here for quick reference -
// The DB migrations originally numbered 156, 157 and 158 were cherrypicked onto v10.11 release branch but their numbers
// were changed. When upgrading from v10.11.17 to v11.7, the migrations which were actually supposed to be 142, 143 and 144
// could never run due to migration version conflict in db_migrations table.
// This pre-migration functon fixes that issue. When someone upgrades from v10.11 to new release, this function fixes the migration
// numbers to what they originally were. For example, 142 gets renamed to 156. This lets the missing migrations run successfully and complete the upgrade.
func (ss *SqlStore) doRenumberRolesSchemeIdMigrations() error {
	query := `
UPDATE db_migrations
SET Version = CASE
    WHEN Version = 142 AND Name = 'add_schemeid_to_roles'    THEN 156
    WHEN Version = 143 AND Name = 'backfill_roles_schemeid'  THEN 157
    WHEN Version = 144 AND Name = 'add_roles_schemeid_index' THEN 158
END
WHERE (Version, Name) IN (
    (142, 'add_schemeid_to_roles'),
    (143, 'backfill_roles_schemeid'),
    (144, 'add_roles_schemeid_index')
)`

	if _, err := ss.GetMaster().Exec(query); err != nil {
		return errors.Wrap(err, "failed to renumber schema ID related migrations")
	}

	return nil
}

func (ss *SqlStore) isDBMigrationApplied(version int) (bool, error) {
	var exists bool
	if err := ss.GetMaster().Get(&exists, `
		SELECT EXISTS (
			SELECT 1 FROM db_migrations WHERE Version >= $1
		)
	`, version); err != nil {
		return false, errors.Wrap(err, "unable to query db_migrations")
	}
	return exists, nil
}

func (ss *SqlStore) tableExists(tableName string) (bool, error) {
	var exists bool
	if err := ss.GetMaster().Get(&exists, `
		SELECT EXISTS (
			SELECT 1 FROM information_schema.tables
			WHERE LOWER(table_name) = $1
		    AND table_schema = current_schema()
		)
	`, strings.ToLower(tableName)); err != nil {
		return false, errors.Wrap(err, "unable to query information_schema.tables")
	}
	return exists, nil
}

func (ss *SqlStore) isPreMigrationComplete(name string) (bool, error) {
	var value string
	err := ss.GetMaster().Get(&value, "SELECT Value FROM Systems WHERE Name = $1", name)
	if errors.Is(err, sql.ErrNoRows) {
		return false, nil
	}
	if err != nil {
		return false, errors.Wrap(err, "unable to select from Systems")
	}
	return value == "true", nil
}

func (ss *SqlStore) markPreMigrationComplete(name string) error {
	if _, err := ss.GetMaster().Exec(
		`INSERT INTO Systems (Name, Value) VALUES ($1, $2)
		 ON CONFLICT (Name) DO UPDATE SET Value = $2`,
		name, "true",
	); err != nil {
		return errors.Wrap(err, "failed to upsert system property")
	}
	return nil
}