Move remaining Go-NEB code into gomatrix

sync.go

@@ -1,35 +1,218 @@
 package gomatrix
 
+import (
+	"encoding/json"
+	"fmt"
+	"runtime/debug"
+	"time"
+)
+
+// Syncer represents an interface that must be satisfied in order to do /sync requests on a client.
+type Syncer interface {
+	// Process the /sync response. The since parameter is the since= value that was used to produce the response.
+	// This is useful for detecting the very first sync (since=""). If an error is return, Syncing will be stopped
+	// permanently.
+	ProcessResponse(resp *RespSync, since string) error
+	// Interface for saving and loading the "next_batch" sync token.
+	NextBatchStorer() NextBatchStorer
+	// Interface for saving and loading the filter ID for sync.
+	FilterStorer() FilterStorer
+	// OnFailedSync returns either the time to wait before retrying or an error to stop syncing permanently.
+	OnFailedSync(res *RespSync, err error) (time.Duration, error)
+}
+
+// DefaultSyncer is the default syncing implementation. You can either write your own syncer, or selectively
+// replace parts of this default syncer (e.g. the NextBatch/Filter storers, or the ProcessResponse method).
+type DefaultSyncer struct {
+	UserID         string
+	Rooms          map[string]*Room
+	NextBatchStore NextBatchStorer
+	FilterStore    FilterStorer
+	listeners      map[string][]OnEventListener // event type to listeners array
+}
+
+// OnEventListener can be used with DefaultSyncer.OnEventType to be informed of incoming events.
+type OnEventListener func(*Event)
+
+// NewDefaultSyncer returns an instantiated DefaultSyncer
+func NewDefaultSyncer(userID string, nextBatch NextBatchStorer, filterStore FilterStorer) *DefaultSyncer {
+	return &DefaultSyncer{
+		UserID:         userID,
+		Rooms:          make(map[string]*Room),
+		NextBatchStore: nextBatch,
+		FilterStore:    filterStore,
+		listeners:      make(map[string][]OnEventListener),
+	}
+}
+
+// ProcessResponse processes the /sync response in a way suitable for bots. "Suitable for bots" means a stream of
+// unrepeating events.
+func (s *DefaultSyncer) ProcessResponse(res *RespSync, since string) (err error) {
+	if !s.shouldProcessResponse(res, since) {
+		return
+	}
+
+	defer func() {
+		if r := recover(); r != nil {
+			err = fmt.Errorf("ProcessResponse panicked! userID=%s since=%s panic=%s\n%s", s.UserID, since, r, debug.Stack())
+		}
+	}()
+
+	for roomID, roomData := range res.Rooms.Join {
+		room := s.getOrCreateRoom(roomID)
+		for _, event := range roomData.State.Events {
+			event.RoomID = roomID
+			room.UpdateState(&event)
+			s.notifyListeners(&event)
+		}
+		for _, event := range roomData.Timeline.Events {
+			event.RoomID = roomID
+			s.notifyListeners(&event)
+		}
+	}
+	for roomID, roomData := range res.Rooms.Invite {
+		room := s.getOrCreateRoom(roomID)
+		for _, event := range roomData.State.Events {
+			event.RoomID = roomID
+			room.UpdateState(&event)
+			s.notifyListeners(&event)
+		}
+	}
+	return
+}
+
+// OnEventType allows callers to be notified when there are new events for the given event type.
+// There are no duplicate checks.
+func (s *DefaultSyncer) OnEventType(eventType string, callback OnEventListener) {
+	_, exists := s.listeners[eventType]
+	if !exists {
+		s.listeners[eventType] = []OnEventListener{}
+	}
+	s.listeners[eventType] = append(s.listeners[eventType], callback)
+}
+
+// shouldProcessResponse returns true if the response should be processed. May modify the response to remove
+// stuff that shouldn't be processed.
+func (s *DefaultSyncer) shouldProcessResponse(resp *RespSync, since string) bool {
+	if since == "" {
+		return false
+	}
+	// This is a horrible hack because /sync will return the most recent messages for a room
+	// as soon as you /join it. We do NOT want to process those events in that particular room
+	// because they may have already been processed (if you toggle the bot in/out of the room).
+	//
+	// Work around this by inspecting each room's timeline and seeing if an m.room.member event for us
+	// exists and is "join" and then discard processing that room entirely if so.
+	// TODO: We probably want to process messages from after the last join event in the timeline.
+	for roomID, roomData := range resp.Rooms.Join {
+		for i := len(roomData.Timeline.Events) - 1; i >= 0; i-- {
+			e := roomData.Timeline.Events[i]
+			if e.Type == "m.room.member" && e.StateKey == s.UserID {
+				m := e.Content["membership"]
+				mship, ok := m.(string)
+				if !ok {
+					continue
+				}
+				if mship == "join" {
+					_, ok := resp.Rooms.Join[roomID]
+					if !ok {
+						continue
+					}
+					delete(resp.Rooms.Join, roomID)   // don't re-process messages
+					delete(resp.Rooms.Invite, roomID) // don't re-process invites
+					break
+				}
+			}
+		}
+	}
+	return true
+}
+
+// getOrCreateRoom must only be called by the Sync() goroutine which calls ProcessResponse()
+func (s *DefaultSyncer) getOrCreateRoom(roomID string) *Room {
+	room := s.Rooms[roomID]
+	if room == nil { // create a new Room
+		room = NewRoom(roomID)
+		s.Rooms[roomID] = room
+	}
+	return room
+}
+
+func (s *DefaultSyncer) notifyListeners(event *Event) {
+	listeners, exists := s.listeners[event.Type]
+	if !exists {
+		return
+	}
+	for _, fn := range listeners {
+		fn(event)
+	}
+}
+
+// NextBatchStorer returns the provided NextBatchStorer
+func (s *DefaultSyncer) NextBatchStorer() NextBatchStorer {
+	return s.NextBatchStore
+}
+
+// FilterStorer returns the provided FilterStorer
+func (s *DefaultSyncer) FilterStorer() FilterStorer {
+	return s.FilterStore
+}
+
+// OnFailedSync always returns a 10 second wait period between failed /syncs.
+func (s *DefaultSyncer) OnFailedSync(res *RespSync, err error) (time.Duration, error) {
+	return 10 * time.Second, nil
+}
+
 // NextBatchStorer controls loading/saving of next_batch tokens for users
 type NextBatchStorer interface {
-	// Save a next_batch token for a given user. Best effort.
-	Save(userID, nextBatch string)
-	// Load a next_batch token for a given user. Return an empty string if no token exists.
-	Load(userID string) string
+	// SaveNextBatch saves a next_batch token for a given user. Best effort.
+	SaveNextBatch(userID, nextBatch string)
+	// LoadNextBatch loads a next_batch token for a given user. Return an empty string if no token exists.
+	LoadNextBatch(userID string) string
 }
 
-// NopNextBatchStore does not load or save next_batch tokens.
-type NopNextBatchStore struct{}
+// InMemoryNextBatchStore stores next batch tokens in memory.
+type InMemoryNextBatchStore struct {
+	UserToNextBatch map[string]string
+}
 
-// Save does nothing
-func (s NopNextBatchStore) Save(userID, nextBatch string) {}
+// SaveNextBatch saves the mapping in-memory.
+func (s *InMemoryNextBatchStore) SaveNextBatch(userID, nextBatch string) {
+	s.UserToNextBatch[userID] = nextBatch
+}
 
-// Load does nothing
-func (s NopNextBatchStore) Load(userID string) string { return "" }
+// LoadNextBatch loads an existing mapping. Returns an empty string if not found
+func (s *InMemoryNextBatchStore) LoadNextBatch(userID string) string {
+	return s.UserToNextBatch[userID]
+}
 
 // FilterStorer controls loading/saving of filter IDs for users
 type FilterStorer interface {
-	// Save a filter ID for a given user. Best effort.
-	Save(userID, filterID string)
-	// Load a filter ID for a given user. Return an empty string if no token exists.
-	Load(userID string) string
+	// SaveFilter saves a filter ID for a given user. Best effort.
+	SaveFilter(userID, filterID string)
+	// LoadFilter loads a filter ID for a given user. Return an empty string if no token exists.
+	LoadFilter(userID string) string
+	// GetFilterJSON for the given user ID.
+	GetFilterJSON(userID string) json.RawMessage
 }
 
-// NopFilterStore does not load or save filter IDs.
-type NopFilterStore struct{}
+// InMemoryFilterStore stores filter IDs in memory. It always returns the filter JSON given in the struct.
+type InMemoryFilterStore struct {
+	Filter       json.RawMessage
+	UserToFilter map[string]string
+}
 
-// Save does nothing
-func (s NopFilterStore) Save(userID, filterID string) {}
+// SaveFilter saves the user->filter ID mapping in memory
+func (s *InMemoryFilterStore) SaveFilter(userID, filterID string) {
+	s.UserToFilter[userID] = filterID
+}
 
-// Load does nothing
-func (s NopFilterStore) Load(userID string) string { return "" }
+// LoadFilter loads a previously saved user->filter ID mapping from memory. Returns the empty string if not found.
+func (s *InMemoryFilterStore) LoadFilter(userID string) string {
+	return s.UserToFilter[userID]
+}
+
+// GetFilterJSON returns InMemoryFilterStore.Filter
+func (s *InMemoryFilterStore) GetFilterJSON(userID string) json.RawMessage {
+	return s.Filter
+}