Matrix/entities/event/eventController.go

package event

import (
	"bytes"
	"encoding/json"
	"errors"
	"fmt"
	"log"
	"math/rand"
	"net/http"
	"strconv"
	"time"

	"git.nutfactory.org/hoernschen/Matrix/config"
	"git.nutfactory.org/hoernschen/Matrix/entities/device"
	"git.nutfactory.org/hoernschen/Matrix/entities/user"
	"git.nutfactory.org/hoernschen/Matrix/utils"

	"github.com/cenkalti/backoff/v4"
	"github.com/gorilla/mux"
)

func New(
	roomId string,
	sender string,
	origin string,
	timestamp int64,
	eventType string,
	stateKey string,
	content string,
	txnId string,
) (err error, newEvent *Event) {
	err, eventId := utils.CreateUUID()
	if err != nil {
		return
	}
	id := generateEventId(eventId)
	newEvent = &Event{
		Id:        id,
		RoomId:    roomId,
		Sender:    sender,
		Origin:    origin,
		Timestamp: timestamp,
		EventType: eventType,
		StateKey:  stateKey,
		Content:   content,
		Unsigned: UnsignedData{
			TransactionId: txnId,
		},
	}
	newEvent.AuthEventHashes, err = GetAuthEvents(newEvent)
	if err != nil {
		return
	}
	if eventType != "m.room.create" {
		var depth int
		newEvent.PrevEventHashes, depth, err = ReadEventsWithoutChild(roomId)
		if err != nil {
			return
		}
		newEvent.Depth = depth + 1
	}

	newEvent.AuthEventHashes, err = GetAuthEvents(newEvent)
	if err != nil {
		return
	}

	newEventBytesForHash, err := json.Marshal(newEvent)
	if err != nil {
		return
	}
	err, newEvent.Hashes.SHA256 = utils.Hash(newEventBytesForHash)
	if err != nil {
		return
	}
	newEvent.Unsigned = UnsignedData{}
	newEventBytesForSign, err := json.Marshal(newEvent)
	if err != nil {
		return
	}
	newEvent.Signatures = utils.SignContent(newEventBytesForSign)
	newEvent.Unsigned = UnsignedData{
		TransactionId: txnId,
	}
	return
}

func SendMessageHandler(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "application/json; charset=UTF-8")
	request := SendMessageRequest{}
	errResponse := utils.CheckRequest(r)
	if errResponse != nil {
		w.WriteHeader(http.StatusBadRequest)
		if err := json.NewEncoder(w).Encode(errResponse); err != nil {
			panic(err)
		}
		return
	}
	token, errResponse := utils.GetAccessToken(r)
	if errResponse != nil {
		w.WriteHeader(http.StatusBadRequest)
		if err := json.NewEncoder(w).Encode(errResponse); err != nil {
			panic(err)
		}
		return
	}
	foundUser, err := user.ReadUserFromAccessToken(token)
	if err != nil || foundUser == nil {
		w.WriteHeader(http.StatusBadRequest)
		if err := json.NewEncoder(w).Encode(utils.ErrorResponse{ErrorCode: "M_UNKNOWN_TOKEN", ErrorMessage: fmt.Sprintf("%s", err)}); err != nil {
			panic(err)
		}
		return
	}
	decoder := json.NewDecoder(r.Body)
	err = decoder.Decode(&request)
	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		if err := json.NewEncoder(w).Encode(utils.ErrorResponse{ErrorMessage: fmt.Sprintf("Could not parse JSON: %s", err)}); err != nil {
			panic(err)
		}
		return
	}
	vars := mux.Vars(r)
	roomId := vars["roomId"]
	eventType := vars["eventType"]
	txnId := vars["txnId"]
	if roomId == "" || eventType == "" || txnId == "" {
		w.WriteHeader(http.StatusBadRequest)
		if err := json.NewEncoder(w).Encode(utils.ErrorResponse{ErrorMessage: "Missing Parameter"}); err != nil {
			panic(err)
		}
		return
	}
	content, _ := json.Marshal(request)
	err, newEvent := New(
		roomId,
		foundUser.Id,
		config.Homeserver,
		time.Now().Unix(),
		eventType,
		foundUser.Id,
		string(content),
		txnId,
	)
	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		if err := json.NewEncoder(w).Encode(utils.ErrorResponse{ErrorMessage: fmt.Sprintf("Error Creating Event: %s", err)}); err != nil {
			panic(err)
		}
		return
	}
	err = CreateEvent(newEvent, txnId)
	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		if err := json.NewEncoder(w).Encode(utils.ErrorResponse{ErrorMessage: fmt.Sprintf("Database Error: %s", err)}); err != nil {
			panic(err)
		}
		return
	}
	transaction := &Transaction{
		Id:        txnId,
		Origin:    config.Homeserver,
		Timestamp: time.Now().Unix(),
		PDUS:      []*Event{newEvent},
	}
	servers, err := ReadServers(roomId)
	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		if err := json.NewEncoder(w).Encode(utils.ErrorResponse{ErrorMessage: fmt.Sprintf("Database Error: %s", err)}); err != nil {
			panic(err)
		}
		return
	}
	for _, server := range servers {
		if server != config.Homeserver {
			log.Printf("Send Transaction to %s", server)

			operation := func() error {
				return SendTransaction(transaction, server, config.HttpString, config.AuthentificationCheck)
			}
			notify := func(err error, duration time.Duration) {
				log.Printf("Error Sending Transaction, retrying in %ss: %s", duration/1000000000, err)
			}
			backoff.RetryNotify(operation, backoff.NewExponentialBackOff(), notify)

		}
	}
	response := createEventResponse{
		EventId: newEvent.Id,
	}
	w.WriteHeader(http.StatusOK)
	if err := json.NewEncoder(w).Encode(response); err != nil {
		panic(err)
	}
}

func CreateStateEventHandler(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "application/json; charset=UTF-8")
	errResponse := utils.CheckRequest(r)
	if errResponse != nil {
		w.WriteHeader(http.StatusBadRequest)
		if err := json.NewEncoder(w).Encode(errResponse); err != nil {
			panic(err)
		}
		return
	}
	token, errResponse := utils.GetAccessToken(r)
	if errResponse != nil {
		w.WriteHeader(http.StatusBadRequest)
		if err := json.NewEncoder(w).Encode(errResponse); err != nil {
			panic(err)
		}
		return
	}
	foundUser, err := user.ReadUserFromAccessToken(token)
	if err != nil || foundUser == nil {
		w.WriteHeader(http.StatusBadRequest)
		if err := json.NewEncoder(w).Encode(utils.ErrorResponse{ErrorCode: "M_UNKNOWN_TOKEN", ErrorMessage: fmt.Sprintf("%s", err)}); err != nil {
			panic(err)
		}
		return
	}
	vars := mux.Vars(r)
	roomId := vars["roomId"]
	eventType := vars["eventType"]
	stateKey := vars["stateKey"]
	if roomId == "" || eventType == "" {
		w.WriteHeader(http.StatusBadRequest)
		if err := json.NewEncoder(w).Encode(utils.ErrorResponse{ErrorMessage: "Missing Parameter"}); err != nil {
			panic(err)
		}
		return
	}
	buf := new(bytes.Buffer)
	buf.ReadFrom(r.Body)
	content := buf.String()
	err, newEvent := New(
		roomId,
		foundUser.Id,
		config.Homeserver,
		time.Now().Unix(),
		eventType,
		stateKey,
		content,
		"",
	)
	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		if err := json.NewEncoder(w).Encode(utils.ErrorResponse{ErrorMessage: fmt.Sprintf("Error Creating Event: %s", err)}); err != nil {
			panic(err)
		}
		return
	}
	err = CreateEvent(newEvent, "")
	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		if err := json.NewEncoder(w).Encode(utils.ErrorResponse{ErrorMessage: fmt.Sprintf("Database Error: %s", err)}); err != nil {
			panic(err)
		}
		return
	}
	err, txnId := utils.CreateUUID()
	transaction := &Transaction{
		Id:        txnId,
		Origin:    config.Homeserver,
		Timestamp: time.Now().Unix(),
		PDUS:      []*Event{newEvent},
	}
	servers, err := ReadServers(roomId)
	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		if err := json.NewEncoder(w).Encode(utils.ErrorResponse{ErrorMessage: fmt.Sprintf("Database Error: %s", err)}); err != nil {
			panic(err)
		}
		return
	}
	for _, server := range servers {
		operation := func() error {
			return SendTransaction(transaction, server, config.HttpString, config.AuthentificationCheck)
		}
		notify := func(err error, duration time.Duration) {
			log.Printf("Error Sending Transaction, retrying in %ss: %s", duration/1000000000, err)
		}
		go backoff.RetryNotify(operation, backoff.NewExponentialBackOff(), notify)
	}

	response := createEventResponse{
		EventId: newEvent.Id,
	}
	w.WriteHeader(http.StatusOK)
	if err := json.NewEncoder(w).Encode(response); err != nil {
		panic(err)
	}
}

func GetEventUserHandler(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "application/json; charset=UTF-8")
	request := getEventRequest{}
	errResponse := utils.CheckRequest(r)
	if errResponse != nil {
		w.WriteHeader(http.StatusBadRequest)
		if err := json.NewEncoder(w).Encode(errResponse); err != nil {
			panic(err)
		}
		return
	}
	token, errResponse := utils.GetAccessToken(r)
	if errResponse != nil {
		w.WriteHeader(http.StatusBadRequest)
		if err := json.NewEncoder(w).Encode(errResponse); err != nil {
			panic(err)
		}
		return
	}
	foundUser, err := user.ReadUserFromAccessToken(token)
	if err != nil || foundUser == nil {
		w.WriteHeader(http.StatusBadRequest)
		if err := json.NewEncoder(w).Encode(utils.ErrorResponse{ErrorCode: "M_UNKNOWN_TOKEN", ErrorMessage: fmt.Sprintf("%s", err)}); err != nil {
			panic(err)
		}
		return
	}
	decoder := json.NewDecoder(r.Body)
	err = decoder.Decode(&request)
	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		if err := json.NewEncoder(w).Encode(utils.ErrorResponse{ErrorMessage: fmt.Sprintf("Could not parse JSON: %s", err)}); err != nil {
			panic(err)
		}
		return
	}
	vars := mux.Vars(r)
	roomId := vars["roomId"]
	eventId := vars["eventId"]
	if roomId == "" || eventId == "" {
		w.WriteHeader(http.StatusBadRequest)
		if err := json.NewEncoder(w).Encode(utils.ErrorResponse{ErrorMessage: "Missing Parameter"}); err != nil {
			panic(err)
		}
		return
	}
	foundEvent, err := ReadEvent(eventId)
	if err != nil || foundEvent == nil {
		w.WriteHeader(http.StatusNotFound)
		if err := json.NewEncoder(w).Encode(utils.ErrorResponse{ErrorCode: "M_NOT_FOUND", ErrorMessage: fmt.Sprintf("Event not found. %s", err)}); err != nil {
			panic(err)
		}
		return
	}
	response := getEventResponse{
		Content:   foundEvent.Content,
		EventType: foundEvent.EventType,
	}
	w.WriteHeader(http.StatusOK)
	if err := json.NewEncoder(w).Encode(response); err != nil {
		panic(err)
	}
}

func GetStateEventHandler(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "application/json; charset=UTF-8")
	errResponse := utils.CheckRequest(r)
	if errResponse != nil {
		w.WriteHeader(http.StatusBadRequest)
		if err := json.NewEncoder(w).Encode(errResponse); err != nil {
			panic(err)
		}
		return
	}
	token, errResponse := utils.GetAccessToken(r)
	if errResponse != nil {
		w.WriteHeader(http.StatusBadRequest)
		if err := json.NewEncoder(w).Encode(errResponse); err != nil {
			panic(err)
		}
		return
	}
	foundUser, err := user.ReadUserFromAccessToken(token)
	if err != nil || foundUser == nil {
		w.WriteHeader(http.StatusBadRequest)
		if err := json.NewEncoder(w).Encode(utils.ErrorResponse{ErrorCode: "M_UNKNOWN_TOKEN", ErrorMessage: fmt.Sprintf("%s", err)}); err != nil {
			panic(err)
		}
		return
	}
	vars := mux.Vars(r)
	roomId := vars["roomId"]
	eventType := vars["eventType"]
	stateKey := vars["stateKey"]
	if roomId == "" || eventType == "" {
		w.WriteHeader(http.StatusBadRequest)
		if err := json.NewEncoder(w).Encode(utils.ErrorResponse{ErrorMessage: "Missing Parameter"}); err != nil {
			panic(err)
		}
		return
	}
	foundEvent, err := ReadStateEvent(roomId, eventType, stateKey)
	if err != nil || foundEvent == nil {
		w.WriteHeader(http.StatusNotFound)
		if err := json.NewEncoder(w).Encode(utils.ErrorResponse{ErrorCode: "M_NOT_FOUND", ErrorMessage: fmt.Sprintf("Event not found. %s", err)}); err != nil {
			panic(err)
		}
		return
	}
	w.WriteHeader(http.StatusOK)
	if err := json.NewEncoder(w).Encode(foundEvent.Content); err != nil {
		panic(err)
	}
}

func SyncEventsServerHandler(w http.ResponseWriter, r *http.Request) {
	packetLossNumber := rand.Intn(100)
	if packetLossNumber > config.Packetloss {
		w.Header().Set("Content-Type", "application/json; charset=UTF-8")
		buf := new(bytes.Buffer)
		buf.ReadFrom(r.Body)
		request := syncEventsServerRequest{}
		errResponse := utils.CheckRequest(r)
		if errResponse != nil {
			w.WriteHeader(http.StatusBadRequest)
			if err := json.NewEncoder(w).Encode(errResponse); err != nil {
				panic(err)
			}
			return
		}
		_ = utils.CheckAuthHeader(r, buf.String())
		/*if errResponse != nil {
			w.WriteHeader(http.StatusBadRequest)
			if err := json.NewEncoder(w).Encode(errResponse); err != nil {
				panic(err)
			}
			return
		}*/
		err := json.Unmarshal(buf.Bytes(), &request)
		if err != nil {
			w.WriteHeader(http.StatusBadRequest)
			if err := json.NewEncoder(w).Encode(utils.ErrorResponse{ErrorMessage: fmt.Sprintf("SyncEventsServerHandler Could not parse JSON Request: %s", err)}); err != nil {
				panic(err)
			}
			return
		}
		vars := mux.Vars(r)
		txnId := vars["txnId"]
		if txnId == "" {
			w.WriteHeader(http.StatusBadRequest)
			if err := json.NewEncoder(w).Encode(utils.ErrorResponse{ErrorMessage: "SyncEventsServerHandler Missing Parameter"}); err != nil {
				panic(err)
			}
			return
		}
		response := syncEventsServerResponse{
			PDUs: make(map[string]pduProcessingResult),
		}
		missingEventIds := make(map[string][]string)
		for _, pdu := range request.PDUs {
			signatureValid := CheckSignature(*pdu)
			if !signatureValid {
				log.Printf("Wrong Signature for Event %s", pdu.Id)
				response.PDUs[pdu.Id] = pduProcessingResult{ProcessingError: "Signature not valid"}
				//continue
			}
			authEventsValid, err := CheckAuthEvents(pdu)
			if !authEventsValid || err != nil {
				log.Printf("Wrong Auth Events for Event %s", pdu.Id)
				response.PDUs[pdu.Id] = pduProcessingResult{ProcessingError: fmt.Sprintf("Error in Auth Check: %s", err)}
				//continue
			}
			missingParentIds, err := CheckParents(pdu)
			if len(missingParentIds) > 0 || err != nil {
				response.PDUs[pdu.Id] = pduProcessingResult{ProcessingError: fmt.Sprintf("Error in Parents Check: %s", err)}
				for _, parentId := range missingParentIds {
					missingEventIds[pdu.RoomId] = append(missingEventIds[pdu.RoomId], parentId)
				}
			}

			err = HandleEvent(pdu, txnId)
			if err != nil {
				response.PDUs[pdu.Id] = pduProcessingResult{ProcessingError: fmt.Sprintf("Error in Event-Handling: %s", err)}
				continue
			}

			response.PDUs[pdu.Id] = pduProcessingResult{}
		}

		if len(missingEventIds) > 0 {
			for roomId, eventIds := range missingEventIds {
				Backfill(eventIds, roomId, request.Origin, config.HttpString, config.AuthentificationCheck)
			}
		}

		w.WriteHeader(http.StatusOK)
		if err := json.NewEncoder(w).Encode(response); err != nil {
			panic(err)
		}
	} else {
		log.Println("Blocking Response")
	}
}

func BackfillHandler(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "application/json; charset=UTF-8")

	errResponse := utils.CheckAuthHeader(r, "")

	if errResponse != nil {
		w.WriteHeader(http.StatusBadRequest)
		if err := json.NewEncoder(w).Encode(errResponse); err != nil {
			panic(err)
		}
		return
	}

	vars := mux.Vars(r)
	roomId := vars["roomId"]
	if roomId == "" {
		w.WriteHeader(http.StatusBadRequest)
		if err := json.NewEncoder(w).Encode(utils.ErrorResponse{ErrorMessage: "Missing Parameter"}); err != nil {
			panic(err)
		}
		return
	}

	limit := 50
	eventIds, ok := r.URL.Query()["v"]
	if !ok || eventIds[0] == "" {
		w.WriteHeader(http.StatusBadRequest)
		if err := json.NewEncoder(w).Encode(utils.ErrorResponse{ErrorMessage: "Missing Parameter"}); err != nil {
			panic(err)
		}
		return
	}
	limitString := r.URL.Query().Get("limit")
	if limitString != "" {
		limit, _ = strconv.Atoi(limitString)
	}
	pdus := []*Event{}
	for len(pdus) < limit {
		newEventIds := []string{}
		for _, eventId := range eventIds {
			foundEvent, err := ReadEvent(eventId)
			if err != nil || foundEvent == nil {
				continue
			}

			for newEventId, _ := range foundEvent.PrevEventHashes {
				newEventIds = append(newEventIds, newEventId)
			}
			pdus = append(pdus, foundEvent)
		}
		eventIds = newEventIds
	}
	response := backfillResponse{
		Origin:    config.Homeserver,
		Timestamp: time.Now().Unix(),
		PDUs:      pdus,
	}
	w.WriteHeader(http.StatusOK)
	if err := json.NewEncoder(w).Encode(response); err != nil {
		panic(err)
	}
}

func SendTransaction(transaction *Transaction, homeserver string, httpString string, authentification bool) (err error) {
	requestUrl := fmt.Sprintf("%s://%s/_matrix/federation/v1/send/%s?", httpString, homeserver, transaction.Id)
	request := syncEventsServerRequest{
		Origin:    transaction.Origin,
		Timestamp: transaction.Timestamp,
		PDUs:      transaction.PDUS,
	}
	reqBody, err := json.Marshal(request)
	if err != nil {
		return
	}
	client := &http.Client{Timeout: 2 * time.Second}
	req, err := http.NewRequest(http.MethodPut, requestUrl, bytes.NewBuffer(reqBody))
	if err != nil {
		return
	}
	if authentification {
		var authHeader string
		authHeader, err = utils.CreateAuthHeader(http.MethodPut, requestUrl, homeserver, string(reqBody))
		if err != nil {
			return
		}
		req.Header["Authorization"] = []string{authHeader}
	}
	req.Header["Content-Type"] = []string{"application/json"}
	r, err := client.Do(req)
	if err != nil {
		return
	}
	if r.StatusCode != http.StatusOK {
		utils.HandleHTTPError(r)
	} else {
		buf := new(bytes.Buffer)
		buf.ReadFrom(r.Body)
		content := buf.String()
		if content == "" {
			err = errors.New("Missing Response")
			return
		}
	}
	return
}

func Backfill(eventIds []string, roomId string, homeserver string, httpString string, authentification bool) (err error) {
	requestUrl := fmt.Sprintf("%s://%s/_matrix/federation/v1/backfill/%s?", httpString, homeserver, roomId)
	for _, eventId := range eventIds {
		requestUrl = fmt.Sprintf("%sv=%s&", requestUrl, eventId)
	}
	client := &http.Client{Timeout: 2 * time.Second}
	var req *http.Request
	req, err = http.NewRequest(http.MethodGet, requestUrl, bytes.NewBuffer(nil))
	if err != nil {
		return
	}
	if authentification {
		var authHeader string
		authHeader, err = utils.CreateAuthHeader(http.MethodGet, requestUrl, homeserver, "")
		if err != nil {
			return
		}
		req.Header["Authorization"] = []string{authHeader}
	}
	req.Header["Content-Type"] = []string{"application/json"}
	r, err := client.Do(req)
	if err != nil {
		return
	}
	if r.StatusCode != http.StatusOK {
		errResponse := utils.HandleHTTPError(r)
		log.Fatalf("%s (%s)", errResponse.ErrorMessage, errResponse.ErrorCode)
	}
	response := backfillResponse{}
	defer r.Body.Close()
	decoder := json.NewDecoder(r.Body)
	err = decoder.Decode(&response)
	if err != nil {
		return
	}
	var missingEventIds []string
	for _, pdu := range response.PDUs {
		for i, eventId := range missingEventIds {
			if pdu.Id == eventId {
				missingEventIds = append(missingEventIds[:i], missingEventIds[i+1:]...)
			}
		}
		signatureValid := CheckSignature(*pdu)
		if !signatureValid {
			log.Printf("Wrong Signature for Event %s", pdu.Id)
			missingEventIds = append(missingEventIds, pdu.Id)
			continue
		}
		authEventsValid, err := CheckAuthEvents(pdu)
		if !authEventsValid || err != nil {
			log.Printf("Wrong Auth Events for Event %s", pdu.Id)
			missingEventIds = append(missingEventIds, pdu.Id)
		}
		missingParentIds, err := CheckParents(pdu)
		if len(missingParentIds) > 0 || err != nil {
			for _, parentId := range missingParentIds {
				missingEventIds = append(missingEventIds, parentId)
			}
		}

		err = HandleEvent(pdu, "")
		if err != nil {
			log.Printf("Error in Event-Handling: %s", err)
			continue
		}
	}

	if len(missingEventIds) > 0 {
		Backfill(missingEventIds, roomId, homeserver, config.HttpString, config.AuthentificationCheck)
	}

	return
}

func generateEventId(id string) string {
	return fmt.Sprintf("$%s:%s", id, config.Homeserver)
}

func GetAuthChain(newEvent *Event) (authChain []*Event, err error) {
	if !config.AuthentificationCheck {
		return
	}
	createEvent, err := ReadStateEvent(newEvent.RoomId, "m.room.create", "")
	if err != nil {
		return
	}
	if createEvent != nil {
		authChain = append(authChain, createEvent)
	}

	powerLevelEvent, err := ReadStateEvent(newEvent.RoomId, "m.room.power_levels", "")
	if err != nil {
		return
	}
	if powerLevelEvent != nil {
		authChain = append(authChain, powerLevelEvent)
	}

	stateKey := newEvent.Sender
	if newEvent.EventType == "m.room.member" {
		stateKey = newEvent.StateKey
	}

	memberEvent, err := ReadStateEvent(newEvent.RoomId, "m.room.member", stateKey)
	if err != nil {
		return
	}
	if memberEvent != nil {
		authChain = append(authChain, memberEvent)
	}

	joinRuleEvent, err := ReadStateEvent(newEvent.RoomId, "m.room.join_rules", "")
	if err != nil {
		return
	}
	if joinRuleEvent != nil && newEvent.EventType == "m.room.member" {
		authChain = append(authChain, joinRuleEvent)
	}

	return
}

func GetAuthEvents(newEvent *Event) (authEventHashes map[string]EventHash, err error) {
	authEventHashes = make(map[string]EventHash)
	authChain, err := GetAuthChain(newEvent)
	if err != nil {
		return
	}

	for _, authEvent := range authChain {
		authEventHashes[authEvent.Id] = authEvent.Hashes
	}

	return
}

func CheckEventHash(id string, hash EventHash) (correct bool, eventFound bool, err error) {
	foundEvent, err := ReadEvent(id)
	correct = true
	eventFound = true
	if err != nil {
		return
	}
	if foundEvent == nil {
		eventFound = false
		return
	}
	if hash.SHA256 != foundEvent.Hashes.SHA256 {
		correct = false
		return
	}
	return
}

func CheckParents(eventToCheck *Event) (missingParentIds []string, err error) {
	if config.Consensus {
		for key, hash := range eventToCheck.PrevEventHashes {
			correctHash, foundEvent, err := CheckEventHash(key, hash)
			if !correctHash || !foundEvent || err != nil {
				missingParentIds = append(missingParentIds, key)
			}
		}
	}
	return
}

func CheckAuthEvents(eventToCheck *Event) (correct bool, err error) {
	correct = true
	if !config.AuthentificationCheck {
		return
	}
	authEvents, err := GetAuthEvents(eventToCheck)
	if err != nil {
		return
	}
	for key, hash := range authEvents {
		if eventToCheck.AuthEventHashes[key].SHA256 != hash.SHA256 {
			//correct = false
			return
		}
	}
	return
}

func CheckSignature(eventToCheck Event) (correct bool) {
	if !config.Signing {
		correct = true
		return
	}
	correct = false
	signatures := eventToCheck.Signatures
	eventToCheck.Unsigned = UnsignedData{}
	eventToCheck.Signatures = nil
	jsonString, err := json.Marshal(eventToCheck)
	if err != nil {
		return
	}
	for id, signature := range signatures[eventToCheck.Origin] {
		verifyKey, err := device.GetVerifyKey(eventToCheck.Origin, id)
		if err == nil && verifyKey != nil {
			correct = utils.VerifySignature(verifyKey, jsonString, signature)
		}
	}
	return
}

func HandleEvents(events []*Event, txnId string) (err error) {
	for _, eventToHandle := range events {
		err = HandleEvent(eventToHandle, txnId)
	}
	return
}

func HandleEvent(eventToHandle *Event, txnId string) (err error) {
	log.Printf("EventType: %s", eventToHandle.EventType)
	foundEvent, err := ReadEvent(eventToHandle.Id)
	if foundEvent == nil && err == nil {
		err = CreateEvent(eventToHandle, txnId)
	}
	if err != nil {
		return
	}
	if eventToHandle.EventType == "m.room.message" {
		log.Printf("%s: %s", eventToHandle.Sender, eventToHandle.Content)
	} else if eventToHandle.EventType == "m.room.member" {
		message := MemberEventContent{}
		err = json.Unmarshal([]byte(eventToHandle.Content), &message)
		if err != nil {
			return
		}
		if message.Membership == "join" {
			log.Printf("Join %s to Room %s", eventToHandle.StateKey, eventToHandle.RoomId)
		}
		err = CreateRoomMember(eventToHandle.RoomId, eventToHandle.StateKey, eventToHandle.Origin)
		if err != nil {
			return
		}
	}
	return
}