// Copyright 2020 The Matrix.org Foundation C.I.C.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package storage

import (
	"context"

	"github.com/matrix-org/dendrite/internal/eventutil"

	"github.com/matrix-org/dendrite/roomserver/api"
	"github.com/matrix-org/dendrite/syncapi/types"
	userapi "github.com/matrix-org/dendrite/userapi/api"
	"github.com/matrix-org/gomatrixserverlib"
)

type Database interface {
	MaxStreamPositionForPDUs(ctx context.Context) (types.StreamPosition, error)
	MaxStreamPositionForReceipts(ctx context.Context) (types.StreamPosition, error)
	MaxStreamPositionForInvites(ctx context.Context) (types.StreamPosition, error)
	MaxStreamPositionForAccountData(ctx context.Context) (types.StreamPosition, error)
	MaxStreamPositionForSendToDeviceMessages(ctx context.Context) (types.StreamPosition, error)
	MaxStreamPositionForNotificationData(ctx context.Context) (types.StreamPosition, error)

	CurrentState(ctx context.Context, roomID string, stateFilterPart *gomatrixserverlib.StateFilter, excludeEventIDs []string) ([]*gomatrixserverlib.HeaderedEvent, error)
	GetStateDeltasForFullStateSync(ctx context.Context, device *userapi.Device, r types.Range, userID string, stateFilter *gomatrixserverlib.StateFilter) ([]types.StateDelta, []string, error)
	GetStateDeltas(ctx context.Context, device *userapi.Device, r types.Range, userID string, stateFilter *gomatrixserverlib.StateFilter) ([]types.StateDelta, []string, error)
	RoomIDsWithMembership(ctx context.Context, userID string, membership string) ([]string, error)
	MembershipCount(ctx context.Context, roomID, membership string, pos types.StreamPosition) (int, error)

	RecentEvents(ctx context.Context, roomID string, r types.Range, eventFilter *gomatrixserverlib.RoomEventFilter, chronologicalOrder bool, onlySyncEvents bool) ([]types.StreamEvent, bool, error)

	GetBackwardTopologyPos(ctx context.Context, events []types.StreamEvent) (types.TopologyToken, error)
	PositionInTopology(ctx context.Context, eventID string) (pos types.StreamPosition, spos types.StreamPosition, err error)

	InviteEventsInRange(ctx context.Context, targetUserID string, r types.Range) (map[string]*gomatrixserverlib.HeaderedEvent, map[string]*gomatrixserverlib.HeaderedEvent, error)
	PeeksInRange(ctx context.Context, userID, deviceID string, r types.Range) (peeks []types.Peek, err error)
	RoomReceiptsAfter(ctx context.Context, roomIDs []string, streamPos types.StreamPosition) (types.StreamPosition, []types.OutputReceiptEvent, error)

	// AllJoinedUsersInRooms returns a map of room ID to a list of all joined user IDs.
	AllJoinedUsersInRooms(ctx context.Context) (map[string][]string, error)
	// AllPeekingDevicesInRooms returns a map of room ID to a list of all peeking devices.
	AllPeekingDevicesInRooms(ctx context.Context) (map[string][]types.PeekingDevice, error)
	// Events lookups a list of event by their event ID.
	// Returns a list of events matching the requested IDs found in the database.
	// If an event is not found in the database then it will be omitted from the list.
	// Returns an error if there was a problem talking with the database.
	// Does not include any transaction IDs in the returned events.
	Events(ctx context.Context, eventIDs []string) ([]*gomatrixserverlib.HeaderedEvent, error)
	// WriteEvent into the database. It is not safe to call this function from multiple goroutines, as it would create races
	// when generating the sync stream position for this event. Returns the sync stream position for the inserted event.
	// Returns an error if there was a problem inserting this event.
	WriteEvent(ctx context.Context, ev *gomatrixserverlib.HeaderedEvent, addStateEvents []*gomatrixserverlib.HeaderedEvent,
		addStateEventIDs []string, removeStateEventIDs []string, transactionID *api.TransactionID, excludeFromSync bool) (types.StreamPosition, error)
	// PurgeRoomState completely purges room state from the sync API. This is done when
	// receiving an output event that completely resets the state.
	PurgeRoomState(ctx context.Context, roomID string) error
	// GetStateEvent returns the Matrix state event of a given type for a given room with a given state key
	// If no event could be found, returns nil
	// If there was an issue during the retrieval, returns an error
	GetStateEvent(ctx context.Context, roomID, evType, stateKey string) (*gomatrixserverlib.HeaderedEvent, error)
	// GetStateEventsForRoom fetches the state events for a given room.
	// Returns an empty slice if no state events could be found for this room.
	// Returns an error if there was an issue with the retrieval.
	GetStateEventsForRoom(ctx context.Context, roomID string, stateFilterPart *gomatrixserverlib.StateFilter) (stateEvents []*gomatrixserverlib.HeaderedEvent, err error)
	// GetAccountDataInRange returns all account data for a given user inserted or
	// updated between two given positions
	// Returns a map following the format data[roomID] = []dataTypes
	// If no data is retrieved, returns an empty map
	// If there was an issue with the retrieval, returns an error
	GetAccountDataInRange(ctx context.Context, userID string, r types.Range, accountDataFilterPart *gomatrixserverlib.EventFilter) (map[string][]string, error)
	// UpsertAccountData keeps track of new or updated account data, by saving the type
	// of the new/updated data, and the user ID and room ID the data is related to (empty)
	// room ID means the data isn't specific to any room)
	// If no data with the given type, user ID and room ID exists in the database,
	// creates a new row, else update the existing one
	// Returns an error if there was an issue with the upsert
	UpsertAccountData(ctx context.Context, userID, roomID, dataType string) (types.StreamPosition, error)
	// AddInviteEvent stores a new invite event for a user.
	// If the invite was successfully stored this returns the stream ID it was stored at.
	// Returns an error if there was a problem communicating with the database.
	AddInviteEvent(ctx context.Context, inviteEvent *gomatrixserverlib.HeaderedEvent) (types.StreamPosition, error)
	// RetireInviteEvent removes an old invite event from the database. Returns the new position of the retired invite.
	// Returns an error if there was a problem communicating with the database.
	RetireInviteEvent(ctx context.Context, inviteEventID string) (types.StreamPosition, error)
	// AddPeek adds a new peek to our DB for a given room by a given user's device.
	// Returns an error if there was a problem communicating with the database.
	AddPeek(ctx context.Context, RoomID, UserID, DeviceID string) (types.StreamPosition, error)
	// DeletePeek removes an existing peek from the database for a given room by a user's device.
	// Returns an error if there was a problem communicating with the database.
	DeletePeek(ctx context.Context, roomID, userID, deviceID string) (sp types.StreamPosition, err error)
	// DeletePeek deletes all peeks for a given room by a given user
	// Returns an error if there was a problem communicating with the database.
	DeletePeeks(ctx context.Context, RoomID, UserID string) (types.StreamPosition, error)
	// GetEventsInTopologicalRange retrieves all of the events on a given ordering using the given extremities and limit.
	GetEventsInTopologicalRange(ctx context.Context, from, to *types.TopologyToken, roomID string, limit int, backwardOrdering bool) (events []types.StreamEvent, err error)
	// EventPositionInTopology returns the depth and stream position of the given event.
	EventPositionInTopology(ctx context.Context, eventID string) (types.TopologyToken, error)
	// BackwardExtremitiesForRoom returns a map of backwards extremity event ID to a list of its prev_events.
	BackwardExtremitiesForRoom(ctx context.Context, roomID string) (backwardExtremities map[string][]string, err error)
	// MaxTopologicalPosition returns the highest topological position for a given room.
	MaxTopologicalPosition(ctx context.Context, roomID string) (types.TopologyToken, error)
	// StreamEventsToEvents converts streamEvent to Event. If device is non-nil and
	// matches the streamevent.transactionID device then the transaction ID gets
	// added to the unsigned section of the output event.
	StreamEventsToEvents(device *userapi.Device, in []types.StreamEvent) []*gomatrixserverlib.HeaderedEvent
	// SendToDeviceUpdatesForSync returns a list of send-to-device updates. It returns the
	// relevant events within the given ranges for the supplied user ID and device ID.
	SendToDeviceUpdatesForSync(ctx context.Context, userID, deviceID string, from, to types.StreamPosition) (pos types.StreamPosition, events []types.SendToDeviceEvent, err error)
	// StoreNewSendForDeviceMessage stores a new send-to-device event for a user's device.
	StoreNewSendForDeviceMessage(ctx context.Context, userID, deviceID string, event gomatrixserverlib.SendToDeviceEvent) (types.StreamPosition, error)
	// CleanSendToDeviceUpdates removes all send-to-device messages BEFORE the specified
	// from position, preventing the send-to-device table from growing indefinitely.
	CleanSendToDeviceUpdates(ctx context.Context, userID, deviceID string, before types.StreamPosition) (err error)
	// GetFilter looks up the filter associated with a given local user and filter ID.
	// Returns a filter structure. Otherwise returns an error if no such filter exists
	// or if there was an error talking to the database.
	GetFilter(ctx context.Context, localpart string, filterID string) (*gomatrixserverlib.Filter, error)
	// PutFilter puts the passed filter into the database.
	// Returns the filterID as a string. Otherwise returns an error if something
	// goes wrong.
	PutFilter(ctx context.Context, localpart string, filter *gomatrixserverlib.Filter) (string, error)
	// RedactEvent wipes an event in the database and sets the unsigned.redacted_because key to the redaction event
	RedactEvent(ctx context.Context, redactedEventID string, redactedBecause *gomatrixserverlib.HeaderedEvent) error
	// StoreReceipt stores new receipt events
	StoreReceipt(ctx context.Context, roomId, receiptType, userId, eventId string, timestamp gomatrixserverlib.Timestamp) (pos types.StreamPosition, err error)
	// GetRoomReceipts gets all receipts for a given roomID
	GetRoomReceipts(ctx context.Context, roomIDs []string, streamPos types.StreamPosition) ([]types.OutputReceiptEvent, error)

	// UpsertRoomUnreadNotificationCounts updates the notification statistics about a (user, room) key.
	UpsertRoomUnreadNotificationCounts(ctx context.Context, userID, roomID string, notificationCount, highlightCount int) (types.StreamPosition, error)

	// GetUserUnreadNotificationCounts returns statistics per room a user is interested in.
	GetUserUnreadNotificationCounts(ctx context.Context, userID string, from, to types.StreamPosition) (map[string]*eventutil.NotificationData, error)

	SelectContextEvent(ctx context.Context, roomID, eventID string) (int, gomatrixserverlib.HeaderedEvent, error)
	SelectContextBeforeEvent(ctx context.Context, id int, roomID string, filter *gomatrixserverlib.RoomEventFilter) ([]*gomatrixserverlib.HeaderedEvent, error)
	SelectContextAfterEvent(ctx context.Context, id int, roomID string, filter *gomatrixserverlib.RoomEventFilter) (int, []*gomatrixserverlib.HeaderedEvent, error)

	StreamToTopologicalPosition(ctx context.Context, roomID string, streamPos types.StreamPosition, backwardOrdering bool) (types.TopologyToken, error)
}