// gomuks - A terminal Matrix client written in Go.
// Copyright (C) 2019 Tulir Asokan
//
// 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 <https://www.gnu.org/licenses/>.

package matrix

import (
	"bytes"
	"context"
	"crypto/tls"
	"encoding/json"
	"fmt"
	"io"
	"io/ioutil"
	"net/http"
	"net/url"
	"os"
	"path"
	"path/filepath"
	"regexp"
	"runtime"
	dbg "runtime/debug"
	"time"

	"github.com/pkg/errors"

	"maunium.net/go/gomuks/lib/open"
	"maunium.net/go/gomuks/matrix/event"
	"maunium.net/go/mautrix"
	"maunium.net/go/mautrix/format"

	"maunium.net/go/gomuks/config"
	"maunium.net/go/gomuks/debug"
	"maunium.net/go/gomuks/interface"
	"maunium.net/go/gomuks/matrix/pushrules"
	"maunium.net/go/gomuks/matrix/rooms"
)

// Container is a wrapper for a mautrix Client and some other stuff.
//
// It is used for all Matrix calls from the UI and Matrix event handlers.
type Container struct {
	client  *mautrix.Client
	syncer  *GomuksSyncer
	gmx     ifc.Gomuks
	ui      ifc.GomuksUI
	config  *config.Config
	history *HistoryManager
	running bool
	stop    chan bool

	typing int64
}

// NewContainer creates a new Container for the given Gomuks instance.
func NewContainer(gmx ifc.Gomuks) *Container {
	c := &Container{
		config: gmx.Config(),
		ui:     gmx.UI(),
		gmx:    gmx,
	}

	return c
}

// Client returns the underlying mautrix Client.
func (c *Container) Client() *mautrix.Client {
	return c.client
}

type mxLogger struct{}

func (log mxLogger) Debugfln(message string, args ...interface{}) {
	debug.Printf("[Matrix] "+message, args...)
}

// InitClient initializes the mautrix client and connects to the homeserver specified in the config.
func (c *Container) InitClient() error {
	if len(c.config.HS) == 0 {
		return fmt.Errorf("no homeserver entered")
	}

	if c.client != nil {
		c.Stop()
		c.client = nil
	}

	var mxid, accessToken string
	if len(c.config.AccessToken) > 0 {
		accessToken = c.config.AccessToken
		mxid = c.config.UserID
	}

	var err error
	c.client, err = mautrix.NewClient(c.config.HS, mxid, accessToken)
	if err != nil {
		return err
	}
	c.client.Logger = mxLogger{}

	if c.history == nil {
		c.history, err = NewHistoryManager(c.config.HistoryPath)
		if err != nil {
			return errors.Wrap(err, "failed to initialize history")
		}
	}

	allowInsecure := len(os.Getenv("GOMUKS_ALLOW_INSECURE_CONNECTIONS")) > 0
	if allowInsecure {
		c.client.Client = &http.Client{
			Transport: &http.Transport{TLSClientConfig: &tls.Config{InsecureSkipVerify: true}},
		}
	}

	c.stop = make(chan bool, 1)

	if len(accessToken) > 0 {
		go c.Start()
	}
	return nil
}

// Initialized returns whether or not the mautrix client is initialized (see InitClient())
func (c *Container) Initialized() bool {
	return c.client != nil
}

func (c *Container) PasswordLogin(user, password string) error {
	resp, err := c.client.Login(&mautrix.ReqLogin{
		Type: "m.login.password",
		Identifier: mautrix.UserIdentifier{
			Type: "m.id.user",
			User: user,
		},
		Password:                 password,
		InitialDeviceDisplayName: "gomuks",
	})
	if err != nil {
		return err
	}
	c.finishLogin(resp)
	return nil
}

func (c *Container) finishLogin(resp *mautrix.RespLogin) {
	c.client.SetCredentials(resp.UserID, resp.AccessToken)
	c.config.UserID = resp.UserID
	c.config.AccessToken = resp.AccessToken
	c.config.Save()

	go c.Start()
}

func respondHTML(w http.ResponseWriter, status int, message string) {
	w.Header().Add("Content-Type", "text/html")
	w.WriteHeader(status)
	_, _ = w.Write([]byte(fmt.Sprintf(`<!DOCTYPE html>
<html>
<head>
  <title>gomuks single-sign on</title>
  <meta charset="utf-8"/>
</head>
<body>
  <center>
    <h2>%s</h2>
  </center>
</body>
</html>`, message)))
}

func (c *Container) SingleSignOn() error {
	loginURL := c.client.BuildURLWithQuery([]string{"login", "sso", "redirect"}, map[string]string{
		"redirectUrl": "http://localhost:29325",
	})
	err := open.Open(loginURL)
	if err != nil {
		return err
	}
	errChan := make(chan error, 1)
	server := &http.Server{Addr: ":29325"}
	server.Handler = http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		loginToken := r.URL.Query().Get("loginToken")
		if len(loginToken) == 0 {
			respondHTML(w, http.StatusBadRequest, "Missing loginToken parameter")
			return
		}
		resp, err := c.client.Login(&mautrix.ReqLogin{
			Type:                     "m.login.token",
			Token:                    loginToken,
			InitialDeviceDisplayName: "gomuks",
		})
		if err != nil {
			respondHTML(w, http.StatusForbidden, err.Error())
			errChan <- err
			return
		}
		respondHTML(w, http.StatusOK, fmt.Sprintf("Successfully logged in as %s", resp.UserID))
		c.finishLogin(resp)
		go func() {
			ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
			defer cancel()
			err = server.Shutdown(ctx)
			if err != nil {
				debug.Printf("Failed to shut down SSO server: %v\n", err)
			}
			errChan <- err
		}()
	})
	err = server.ListenAndServe()
	if err != nil {
		return err
	}
	err = <-errChan
	return err
}

// Login sends a password login request with the given username and password.
func (c *Container) Login(user, password string) error {
	resp, err := c.client.GetLoginFlows()
	if err != nil {
		return err
	}
	if len(resp.Flows) == 1 && resp.Flows[0].Type == "m.login.password" {
		return c.PasswordLogin(user, password)
	} else if len(resp.Flows) == 2 && resp.Flows[0].Type == "m.login.sso" && resp.Flows[1].Type == "m.login.token" {
		return c.SingleSignOn()
	} else {
		return fmt.Errorf("no supported login flows")
	}
}

// Logout revokes the access token, stops the syncer and calls the OnLogout() method of the UI.
func (c *Container) Logout() {
	c.client.Logout()
	c.config.DeleteSession()
	c.Stop()
	c.client = nil
	c.ui.OnLogout()
}

// Stop stops the Matrix syncer.
func (c *Container) Stop() {
	if c.running {
		debug.Print("Stopping Matrix container...")
		c.stop <- true
		c.client.StopSync()
		debug.Print("Closing history manager...")
		err := c.history.Close()
		if err != nil {
			debug.Print("Error closing history manager:", err)
		}
		c.history = nil
	}
}

// UpdatePushRules fetches the push notification rules from the server and stores them in the current Session object.
func (c *Container) UpdatePushRules() {
	debug.Print("Updating push rules...")
	resp, err := pushrules.GetPushRules(c.client)
	if err != nil {
		debug.Print("Failed to fetch push rules:", err)
		c.config.PushRules = &pushrules.PushRuleset{}
	} else {
		c.config.PushRules = resp
	}
	c.config.SavePushRules()
}

// PushRules returns the push notification rules. If no push rules are cached, UpdatePushRules() will be called first.
func (c *Container) PushRules() *pushrules.PushRuleset {
	if c.config.PushRules == nil {
		c.UpdatePushRules()
	}
	return c.config.PushRules
}

var AccountDataGomuksPreferences = mautrix.NewEventType("net.maunium.gomuks.preferences")

// OnLogin initializes the syncer and updates the room list.
func (c *Container) OnLogin() {
	c.ui.OnLogin()

	c.client.Store = c.config

	debug.Print("Initializing syncer")
	c.syncer = NewGomuksSyncer(c.config)
	c.syncer.OnEventType(mautrix.EventMessage, c.HandleMessage)
	c.syncer.OnEventType(mautrix.EventEncrypted, c.HandleMessage)
	c.syncer.OnEventType(mautrix.EventSticker, c.HandleMessage)
	c.syncer.OnEventType(mautrix.EventReaction, c.HandleMessage)
	c.syncer.OnEventType(mautrix.EventRedaction, c.HandleRedaction)
	c.syncer.OnEventType(mautrix.StateAliases, c.HandleMessage)
	c.syncer.OnEventType(mautrix.StateCanonicalAlias, c.HandleMessage)
	c.syncer.OnEventType(mautrix.StateTopic, c.HandleMessage)
	c.syncer.OnEventType(mautrix.StateRoomName, c.HandleMessage)
	c.syncer.OnEventType(mautrix.StateMember, c.HandleMembership)
	c.syncer.OnEventType(mautrix.EphemeralEventReceipt, c.HandleReadReceipt)
	c.syncer.OnEventType(mautrix.EphemeralEventTyping, c.HandleTyping)
	c.syncer.OnEventType(mautrix.AccountDataDirectChats, c.HandleDirectChatInfo)
	c.syncer.OnEventType(mautrix.AccountDataPushRules, c.HandlePushRules)
	c.syncer.OnEventType(mautrix.AccountDataRoomTags, c.HandleTag)
	c.syncer.OnEventType(AccountDataGomuksPreferences, c.HandlePreferences)
	c.syncer.InitDoneCallback = func() {
		debug.Print("Initial sync done")
		c.config.AuthCache.InitialSyncDone = true
		debug.Print("Updating title caches")
		for _, room := range c.config.Rooms.Map {
			room.GetTitle()
		}
		debug.Print("Cleaning cached rooms from memory")
		c.config.Rooms.ForceClean()
		debug.Print("Saving all data")
		c.config.SaveAll()
		debug.Print("Adding rooms to UI")
		c.ui.MainView().SetRooms(c.config.Rooms)
		c.ui.Render()
		// The initial sync can be a bit heavy, so we force run the GC here
		// after cleaning up rooms from memory above.
		debug.Print("Running GC")
		runtime.GC()
		dbg.FreeOSMemory()
	}
	c.client.Syncer = c.syncer

	debug.Print("Setting existing rooms")
	c.ui.MainView().SetRooms(c.config.Rooms)

	debug.Print("OnLogin() done.")
}

// Start moves the UI to the main view, calls OnLogin() and runs the syncer forever until stopped with Stop()
func (c *Container) Start() {
	defer debug.Recover()

	c.OnLogin()

	if c.client == nil {
		return
	}

	debug.Print("Starting sync...")
	c.running = true
	for {
		select {
		case <-c.stop:
			debug.Print("Stopping sync...")
			c.running = false
			return
		default:
			if err := c.client.Sync(); err != nil {
				if httpErr, ok := err.(mautrix.HTTPError); ok && httpErr.Code == http.StatusUnauthorized {
					debug.Print("Sync() errored with ", err, " -> logging out")
					c.Logout()
				} else {
					debug.Print("Sync() errored", err)
				}
			} else {
				debug.Print("Sync() returned without error")
			}
		}
	}
}

func (c *Container) HandlePreferences(source EventSource, evt *mautrix.Event) {
	if source&EventSourceAccountData == 0 {
		return
	}
	orig := c.config.Preferences
	err := json.Unmarshal(evt.Content.VeryRaw, &c.config.Preferences)
	if err != nil {
		debug.Print("Failed to parse updated preferences:", err)
		return
	}
	debug.Print("Updated preferences:", orig, "->", c.config.Preferences)
	if c.config.AuthCache.InitialSyncDone {
		c.ui.HandleNewPreferences()
	}
}

func (c *Container) SendPreferencesToMatrix() {
	defer debug.Recover()
	debug.Print("Sending updated preferences:", c.config.Preferences)
	u := c.client.BuildURL("user", c.config.UserID, "account_data", "net.maunium.gomuks.preferences")
	_, err := c.client.MakeRequest("PUT", u, &c.config.Preferences, nil)
	if err != nil {
		debug.Print("Failed to update preferences:", err)
	}
}

func (c *Container) HandleRedaction(source EventSource, evt *mautrix.Event) {
	room := c.GetOrCreateRoom(evt.RoomID)
	var redactedEvt *event.Event
	err := c.history.Update(room, evt.Redacts, func(redacted *event.Event) error {
		redacted.Unsigned.RedactedBy = evt.ID
		redacted.Unsigned.RedactedBecause = evt
		redactedEvt = redacted
		return nil
	})
	if err != nil {
		debug.Print("Failed to mark", evt.Redacts, "as redacted:", err)
		return
	} else if !c.config.AuthCache.InitialSyncDone || !room.Loaded() {
		return
	}

	roomView := c.ui.MainView().GetRoom(evt.RoomID)
	if roomView == nil {
		debug.Printf("Failed to handle event %v: No room view found.", evt)
		return
	}

	roomView.AddRedaction(redactedEvt)
	if c.syncer.FirstSyncDone {
		c.ui.Render()
	}
}

func (c *Container) HandleEdit(room *rooms.Room, editsID string, editEvent *event.Event) {
	var origEvt *event.Event
	err := c.history.Update(room, editsID, func(evt *event.Event) error {
		evt.Gomuks.Edits = append(evt.Gomuks.Edits, editEvent)
		origEvt = evt
		return nil
	})
	if err != nil {
		debug.Print("Failed to store edit in history db:", err)
		return
	} else if !c.config.AuthCache.InitialSyncDone || !room.Loaded() {
		return
	}

	roomView := c.ui.MainView().GetRoom(editEvent.RoomID)
	if roomView == nil {
		debug.Printf("Failed to handle edit event %v: No room view found.", editEvent)
		return
	}

	roomView.AddEdit(origEvt)
	if c.syncer.FirstSyncDone {
		c.ui.Render()
	}
}

func (c *Container) HandleReaction(room *rooms.Room, reactsTo string, reactEvent *event.Event) {
	rel := reactEvent.Content.GetRelatesTo()
	var origEvt *event.Event
	err := c.history.Update(room, reactsTo, func(evt *event.Event) error {
		if evt.Unsigned.Relations.Annotations.Map == nil {
			evt.Unsigned.Relations.Annotations.Map = make(map[string]int)
		}
		val, _ := evt.Unsigned.Relations.Annotations.Map[rel.Key]
		evt.Unsigned.Relations.Annotations.Map[rel.Key] = val + 1
		origEvt = evt
		return nil
	})
	if err != nil {
		debug.Print("Failed to store reaction in history db:", err)
		return
	} else if !c.config.AuthCache.InitialSyncDone || !room.Loaded() {
		return
	}

	roomView := c.ui.MainView().GetRoom(reactEvent.RoomID)
	if roomView == nil {
		debug.Printf("Failed to handle edit event %v: No room view found.", reactEvent)
		return
	}

	roomView.AddReaction(origEvt, rel.Key)
	if c.syncer.FirstSyncDone {
		c.ui.Render()
	}
}

// HandleMessage is the event handler for the m.room.message timeline event.
func (c *Container) HandleMessage(source EventSource, mxEvent *mautrix.Event) {
	room := c.GetOrCreateRoom(mxEvent.RoomID)
	if source&EventSourceLeave != 0 {
		room.HasLeft = true
		return
	} else if source&EventSourceState != 0 {
		return
	}

	if editID := mxEvent.Content.GetRelatesTo().GetReplaceID(); len(editID) > 0 {
		c.HandleEdit(room, editID, event.Wrap(mxEvent))
		return
	} else if reactionID := mxEvent.Content.GetRelatesTo().GetAnnotationID(); mxEvent.Type == mautrix.EventReaction && len(reactionID) > 0 {
		c.HandleReaction(room, reactionID, event.Wrap(mxEvent))
		return
	}

	events, err := c.history.Append(room, []*mautrix.Event{mxEvent})
	if err != nil {
		debug.Printf("Failed to add event %s to history: %v", mxEvent.ID, err)
	}
	evt := events[0]

	if !c.config.AuthCache.InitialSyncDone {
		room.LastReceivedMessage = time.Unix(evt.Timestamp/1000, evt.Timestamp%1000*1000)
		return
	}

	mainView := c.ui.MainView()

	roomView := mainView.GetRoom(evt.RoomID)
	if roomView == nil {
		debug.Printf("Failed to handle event %v: No room view found.", evt)
		return
	}

	if !room.Loaded() {
		pushRules := c.PushRules().GetActions(room, evt.Event).Should()
		shouldNotify := pushRules.Notify || !pushRules.NotifySpecified
		if !shouldNotify {
			room.LastReceivedMessage = time.Unix(evt.Timestamp/1000, evt.Timestamp%1000*1000)
			room.AddUnread(evt.ID, shouldNotify, pushRules.Highlight)
			mainView.Bump(room)
			return
		}
	}

	message := roomView.AddEvent(evt)
	if message != nil {
		roomView.MxRoom().LastReceivedMessage = message.Time()
		if c.syncer.FirstSyncDone {
			pushRules := c.PushRules().GetActions(roomView.MxRoom(), evt.Event).Should()
			mainView.NotifyMessage(roomView.MxRoom(), message, pushRules)
			c.ui.Render()
		}
	} else {
		debug.Printf("Parsing event %s type %s %v from %s in %s failed (ParseEvent() returned nil).", evt.ID, evt.Type.String(), evt.Content.Raw, evt.Sender, evt.RoomID)
	}
}

// HandleMembership is the event handler for the m.room.member state event.
func (c *Container) HandleMembership(source EventSource, evt *mautrix.Event) {
	isLeave := source&EventSourceLeave != 0
	isTimeline := source&EventSourceTimeline != 0
	if isLeave {
		c.GetOrCreateRoom(evt.RoomID).HasLeft = true
	}
	isNonTimelineLeave := isLeave && !isTimeline
	if !c.config.AuthCache.InitialSyncDone && isNonTimelineLeave {
		return
	} else if evt.StateKey != nil && *evt.StateKey == c.config.UserID {
		c.processOwnMembershipChange(evt)
	} else if !isTimeline && (!c.config.AuthCache.InitialSyncDone || isLeave) {
		// We don't care about other users' membership events in the initial sync or chats we've left.
		return
	}

	c.HandleMessage(source, evt)
}

func (c *Container) processOwnMembershipChange(evt *mautrix.Event) {
	membership := evt.Content.Membership
	prevMembership := mautrix.MembershipLeave
	if evt.Unsigned.PrevContent != nil {
		prevMembership = evt.Unsigned.PrevContent.Membership
	}
	debug.Printf("Processing own membership change: %s->%s in %s", prevMembership, membership, evt.RoomID)
	if membership == prevMembership {
		return
	}
	room := c.GetRoom(evt.RoomID)
	switch membership {
	case "join":
		if c.config.AuthCache.InitialSyncDone {
			c.ui.MainView().AddRoom(room)
		}
		room.HasLeft = false
	case "leave":
		if c.config.AuthCache.InitialSyncDone {
			c.ui.MainView().RemoveRoom(room)
		}
		room.HasLeft = true
		room.Unload()
	case "invite":
		// TODO handle
		debug.Printf("%s invited the user to %s", evt.Sender, evt.RoomID)
	}
}

func (c *Container) parseReadReceipt(evt *mautrix.Event) (largestTimestampEvent string) {
	var largestTimestamp int64
	for eventID, rawContent := range evt.Content.Raw {
		content, ok := rawContent.(map[string]interface{})
		if !ok {
			continue
		}

		mRead, ok := content["m.read"].(map[string]interface{})
		if !ok {
			continue
		}

		myInfo, ok := mRead[c.config.UserID].(map[string]interface{})
		if !ok {
			continue
		}

		ts, ok := myInfo["ts"].(float64)
		if int64(ts) > largestTimestamp {
			largestTimestamp = int64(ts)
			largestTimestampEvent = eventID
		}
	}
	return
}

func (c *Container) HandleReadReceipt(source EventSource, evt *mautrix.Event) {
	if source&EventSourceLeave != 0 {
		return
	}

	lastReadEvent := c.parseReadReceipt(evt)
	if len(lastReadEvent) == 0 {
		return
	}

	room := c.GetRoom(evt.RoomID)
	if room != nil {
		room.MarkRead(lastReadEvent)
		if c.config.AuthCache.InitialSyncDone {
			c.ui.Render()
		}
	}
}

func (c *Container) parseDirectChatInfo(evt *mautrix.Event) map[*rooms.Room]bool {
	directChats := make(map[*rooms.Room]bool)
	for _, rawRoomIDList := range evt.Content.Raw {
		roomIDList, ok := rawRoomIDList.([]interface{})
		if !ok {
			continue
		}

		for _, rawRoomID := range roomIDList {
			roomID, ok := rawRoomID.(string)
			if !ok {
				continue
			}

			room := c.GetOrCreateRoom(roomID)
			if room != nil && !room.HasLeft {
				directChats[room] = true
			}
		}
	}
	return directChats
}

func (c *Container) HandleDirectChatInfo(source EventSource, evt *mautrix.Event) {
	directChats := c.parseDirectChatInfo(evt)
	for _, room := range c.config.Rooms.Map {
		shouldBeDirect := directChats[room]
		if shouldBeDirect != room.IsDirect {
			room.IsDirect = shouldBeDirect
			if c.config.AuthCache.InitialSyncDone {
				c.ui.MainView().UpdateTags(room)
			}
		}
	}
}

// HandlePushRules is the event handler for the m.push_rules account data event.
func (c *Container) HandlePushRules(source EventSource, evt *mautrix.Event) {
	debug.Print("Received updated push rules")
	var err error
	c.config.PushRules, err = pushrules.EventToPushRules(evt)
	if err != nil {
		debug.Print("Failed to convert event to push rules:", err)
		return
	}
	c.config.SavePushRules()
}

// HandleTag is the event handler for the m.tag account data event.
func (c *Container) HandleTag(source EventSource, evt *mautrix.Event) {
	room := c.GetOrCreateRoom(evt.RoomID)

	newTags := make([]rooms.RoomTag, len(evt.Content.RoomTags))
	index := 0
	for tag, info := range evt.Content.RoomTags {
		order := "0.5"
		if len(info.Order) > 0 {
			order = info.Order.String()
		}
		newTags[index] = rooms.RoomTag{
			Tag:   tag,
			Order: order,
		}
		index++
	}
	room.RawTags = newTags

	if c.config.AuthCache.InitialSyncDone {
		mainView := c.ui.MainView()
		mainView.UpdateTags(room)
	}
}

// HandleTyping is the event handler for the m.typing event.
func (c *Container) HandleTyping(source EventSource, evt *mautrix.Event) {
	if !c.config.AuthCache.InitialSyncDone {
		return
	}
	c.ui.MainView().SetTyping(evt.RoomID, evt.Content.TypingUserIDs)
}

func (c *Container) MarkRead(roomID, eventID string) {
	urlPath := c.client.BuildURL("rooms", roomID, "receipt", "m.read", eventID)
	c.client.MakeRequest("POST", urlPath, struct{}{}, nil)
}

var mentionRegex = regexp.MustCompile("\\[(.+?)]\\(https://matrix.to/#/@.+?:.+?\\)")
var roomRegex = regexp.MustCompile("\\[.+?]\\(https://matrix.to/#/(#.+?:[^/]+?)\\)")

func (c *Container) PrepareMarkdownMessage(roomID string, msgtype mautrix.MessageType, text string, edit *event.Event) *event.Event {
	content := format.RenderMarkdown(text)
	content.MsgType = msgtype

	// Remove markdown link stuff from plaintext mentions and room links
	content.Body = mentionRegex.ReplaceAllString(content.Body, "$1")
	content.Body = roomRegex.ReplaceAllString(content.Body, "$1")

	if edit != nil {
		contentCopy := content
		content.NewContent = &contentCopy
		content.Body = "* " + content.Body
		if len(content.FormattedBody) > 0 {
			content.FormattedBody = "* " + content.FormattedBody
		}
		content.RelatesTo = &mautrix.RelatesTo{
			Type:    mautrix.RelReplace,
			EventID: edit.ID,
		}
	}

	txnID := c.client.TxnID()
	localEcho := event.Wrap(&mautrix.Event{
		ID:        txnID,
		Sender:    c.config.UserID,
		Type:      mautrix.EventMessage,
		Timestamp: time.Now().UnixNano() / 1e6,
		RoomID:    roomID,
		Content:   content,
		Unsigned: mautrix.Unsigned{
			TransactionID: txnID,
		},
	})
	localEcho.Gomuks.OutgoingState = event.StateLocalEcho
	if edit != nil {
		localEcho.ID = edit.ID
		localEcho.Gomuks.Edits = []*event.Event{localEcho}
	}
	return localEcho
}

// SendMarkdownMessage sends a message with the given markdown text to the given room.
func (c *Container) SendEvent(event *event.Event) (string, error) {
	defer debug.Recover()

	c.SendTyping(event.RoomID, false)
	resp, err := c.client.SendMessageEvent(event.RoomID, event.Type, event.Content, mautrix.ReqSendEvent{TransactionID: event.Unsigned.TransactionID})
	if err != nil {
		return "", err
	}
	return resp.EventID, nil
}

// SendTyping sets whether or not the user is typing in the given room.
func (c *Container) SendTyping(roomID string, typing bool) {
	defer debug.Recover()
	ts := time.Now().Unix()
	if c.typing > ts && typing {
		return
	}

	if typing {
		c.client.UserTyping(roomID, true, 20000)
		c.typing = ts + 15
	} else {
		c.client.UserTyping(roomID, false, 0)
		c.typing = 0
	}
}

// CreateRoom attempts to create a new room and join the user.
func (c *Container) CreateRoom(req *mautrix.ReqCreateRoom) (*rooms.Room, error) {
	resp, err := c.client.CreateRoom(req)
	if err != nil {
		return nil, err
	}
	room := c.GetOrCreateRoom(resp.RoomID)
	return room, nil
}

// JoinRoom makes the current user try to join the given room.
func (c *Container) JoinRoom(roomID, server string) (*rooms.Room, error) {
	resp, err := c.client.JoinRoom(roomID, server, nil)
	if err != nil {
		return nil, err
	}

	room := c.GetOrCreateRoom(resp.RoomID)
	room.HasLeft = false
	return room, nil
}

// LeaveRoom makes the current user leave the given room.
func (c *Container) LeaveRoom(roomID string) error {
	_, err := c.client.LeaveRoom(roomID)
	if err != nil {
		return err
	}

	node := c.GetOrCreateRoom(roomID)
	node.HasLeft = true
	node.Unload()
	return nil
}

// GetHistory fetches room history.
func (c *Container) GetHistory(room *rooms.Room, limit int) ([]*event.Event, error) {
	events, err := c.history.Load(room, limit)
	if err != nil {
		return nil, err
	}
	if len(events) > 0 {
		debug.Printf("Loaded %d events for %s from local cache", len(events), room.ID)
		return events, nil
	}
	resp, err := c.client.Messages(room.ID, room.PrevBatch, "", 'b', limit)
	if err != nil {
		return nil, err
	}
	debug.Printf("Loaded %d events for %s from server from %s to %s", len(resp.Chunk), room.ID, resp.Start, resp.End)
	room.PrevBatch = resp.End
	c.config.Rooms.Put(room)
	if len(resp.Chunk) == 0 {
		return []*event.Event{}, nil
	}
	events, err = c.history.Prepend(room, resp.Chunk)
	if err != nil {
		return nil, err
	}
	return events, nil
}

func (c *Container) GetEvent(room *rooms.Room, eventID string) (*event.Event, error) {
	evt, err := c.history.Get(room, eventID)
	if err != nil && err != EventNotFoundError {
		debug.Printf("Failed to get event %s from local cache: %v", eventID, err)
	} else if evt != nil {
		debug.Printf("Found event %s in local cache", eventID)
		return evt, err
	}
	mxEvent, err := c.client.GetEvent(room.ID, eventID)
	if err != nil {
		return nil, err
	}
	evt = event.Wrap(mxEvent)
	debug.Printf("Loaded event %s from server", eventID)
	return evt, nil
}

// GetOrCreateRoom gets the room instance stored in the session.
func (c *Container) GetOrCreateRoom(roomID string) *rooms.Room {
	return c.config.Rooms.GetOrCreate(roomID)
}

// GetRoom gets the room instance stored in the session.
func (c *Container) GetRoom(roomID string) *rooms.Room {
	return c.config.Rooms.Get(roomID)
}

var mxcRegex = regexp.MustCompile("mxc://(.+)/(.+)")

// Download fetches the given Matrix content (mxc) URL and returns the data, homeserver, file ID and potential errors.
//
// The file will be either read from the media cache (if found) or downloaded from the server.
func (c *Container) Download(mxcURL string) (data []byte, hs, id string, err error) {
	parts := mxcRegex.FindStringSubmatch(mxcURL)
	if parts == nil || len(parts) != 3 {
		err = fmt.Errorf("invalid matrix content URL")
		return
	}

	hs = parts[1]
	id = parts[2]

	cacheFile := c.GetCachePath(hs, id)
	var info os.FileInfo
	if info, err = os.Stat(cacheFile); err == nil && !info.IsDir() {
		data, err = ioutil.ReadFile(cacheFile)
		if err == nil {
			return
		}
	}

	data, err = c.download(hs, id, cacheFile)
	return
}

func (c *Container) GetDownloadURL(hs, id string) string {
	dlURL, _ := url.Parse(c.client.HomeserverURL.String())
	if dlURL.Scheme == "" {
		dlURL.Scheme = "https"
	}
	dlURL.Path = path.Join(dlURL.Path, "/_matrix/media/v1/download", hs, id)
	return dlURL.String()
}

func (c *Container) download(hs, id, cacheFile string) (data []byte, err error) {
	var resp *http.Response
	resp, err = c.client.Client.Get(c.GetDownloadURL(hs, id))
	if err != nil {
		return
	}
	defer resp.Body.Close()

	var buf bytes.Buffer
	_, err = io.Copy(&buf, resp.Body)
	if err != nil {
		return
	}

	data = buf.Bytes()

	err = ioutil.WriteFile(cacheFile, data, 0600)
	return
}

// GetCachePath gets the path to the cached version of the given homeserver:fileID combination.
// The file may or may not exist, use Download() to ensure it has been cached.
func (c *Container) GetCachePath(homeserver, fileID string) string {
	dir := filepath.Join(c.config.MediaDir, homeserver)

	err := os.MkdirAll(dir, 0700)
	if err != nil {
		return ""
	}

	return filepath.Join(dir, fileID)
}