From 795a8705c3fdc5bf55e83d382e7d3ff233896a0b Mon Sep 17 00:00:00 2001
From: Wim <wim@42.be>
Date: Thu, 26 Dec 2019 23:12:28 +0100
Subject: Add initial Microsoft Teams support

Documentation on https://github.com/42wim/matterbridge/wiki/MS-Teams-setup
---
 bridge/msteams/msteams.go | 169 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 169 insertions(+)
 create mode 100644 bridge/msteams/msteams.go

(limited to 'bridge/msteams/msteams.go')

diff --git a/bridge/msteams/msteams.go b/bridge/msteams/msteams.go
new file mode 100644
index 00000000..f2f0308b
--- /dev/null
+++ b/bridge/msteams/msteams.go
@@ -0,0 +1,169 @@
+package bgitter
+
+import (
+	"context"
+	"os"
+	"strings"
+	"time"
+
+	"github.com/42wim/matterbridge/bridge"
+	"github.com/42wim/matterbridge/bridge/config"
+	"github.com/mattn/godown"
+	msgraph "github.com/yaegashi/msgraph.go/beta"
+	"github.com/yaegashi/msgraph.go/msauth"
+
+	"golang.org/x/oauth2"
+)
+
+//var defaultScopes = []string{"openid", "profile", "offline_access", "User.Read", "Files.Read", "ChannelMessage.Read.All", "Chat.ReadWrite", "User.Read.All", "User.ReadWrite.All", "Group.Read.All", "Group.ReadWrite.All"}
+var defaultScopes = []string{"openid", "profile", "offline_access", "Group.Read.All", "Group.ReadWrite.All"}
+
+type Bmsteams struct {
+	gc    *msgraph.GraphServiceRequestBuilder
+	ctx   context.Context
+	botID string
+	*bridge.Config
+}
+
+func New(cfg *bridge.Config) bridge.Bridger {
+	return &Bmsteams{Config: cfg}
+}
+
+func (b *Bmsteams) Connect() error {
+	tokenCachePath := b.GetString("sessionFile")
+	if tokenCachePath == "" {
+		tokenCachePath = "msteams_session.json"
+	}
+	ctx := context.Background()
+	m := msauth.NewManager()
+	m.LoadFile(tokenCachePath) //nolint:errcheck
+	ts, err := m.DeviceAuthorizationGrant(ctx, b.GetString("TenantID"), b.GetString("ClientID"), defaultScopes, nil)
+	if err != nil {
+		return err
+	}
+	err = m.SaveFile(tokenCachePath)
+	if err != nil {
+		b.Log.Errorf("Couldn't save sessionfile in %s: %s", tokenCachePath, err)
+	}
+	// make file readable only for matterbridge user
+	err = os.Chmod(tokenCachePath, 0600)
+	if err != nil {
+		b.Log.Errorf("Couldn't change permissions for %s: %s", tokenCachePath, err)
+	}
+	httpClient := oauth2.NewClient(ctx, ts)
+	graphClient := msgraph.NewClient(httpClient)
+	b.gc = graphClient
+	b.ctx = ctx
+
+	err = b.setBotID()
+	if err != nil {
+		return err
+	}
+	b.Log.Info("Connection succeeded")
+	return nil
+}
+
+func (b *Bmsteams) Disconnect() error {
+	return nil
+}
+
+func (b *Bmsteams) JoinChannel(channel config.ChannelInfo) error {
+	go b.poll(channel.Name)
+	return nil
+}
+
+func (b *Bmsteams) Send(msg config.Message) (string, error) {
+	b.Log.Debugf("=> Receiving %#v", msg)
+	ct := b.gc.Teams().ID(b.GetString("TeamID")).Channels().ID(msg.Channel).Messages().Request()
+	text := msg.Username + msg.Text
+	content := &msgraph.ItemBody{Content: &text}
+	rmsg := &msgraph.ChatMessage{Body: content}
+	res, err := ct.Add(b.ctx, rmsg)
+	if err != nil {
+		return "", err
+	}
+	return *res.ID, nil
+}
+
+func (b *Bmsteams) getMessages(channel string) ([]msgraph.ChatMessage, error) {
+	ct := b.gc.Teams().ID(b.GetString("TeamID")).Channels().ID(channel).Messages().Request()
+	rct, err := ct.Get(b.ctx)
+	if err != nil {
+		return nil, err
+	}
+	b.Log.Debugf("got %#v messages", len(rct))
+	return rct, nil
+}
+
+func (b *Bmsteams) poll(channelName string) {
+	msgmap := make(map[string]time.Time)
+	b.Log.Debug("getting initial messages")
+	res, err := b.getMessages(channelName)
+	if err != nil {
+		panic(err)
+	}
+	for _, msg := range res {
+		msgmap[*msg.ID] = *msg.CreatedDateTime
+		if msg.LastModifiedDateTime != nil {
+			msgmap[*msg.ID] = *msg.LastModifiedDateTime
+		}
+	}
+	time.Sleep(time.Second * 5)
+	b.Log.Debug("polling for messages")
+	for {
+		res, err := b.getMessages(channelName)
+		if err != nil {
+			panic(err)
+		}
+		for i := len(res) - 1; i >= 0; i-- {
+			msg := res[i]
+			if mtime, ok := msgmap[*msg.ID]; ok {
+				if mtime == *msg.CreatedDateTime && msg.LastModifiedDateTime == nil {
+					continue
+				}
+				if msg.LastModifiedDateTime != nil && mtime == *msg.LastModifiedDateTime {
+					continue
+				}
+			}
+			if *msg.From.User.ID == b.botID {
+				b.Log.Debug("skipping own message")
+				msgmap[*msg.ID] = *msg.CreatedDateTime
+				continue
+			}
+			msgmap[*msg.ID] = *msg.CreatedDateTime
+			if msg.LastModifiedDateTime != nil {
+				msgmap[*msg.ID] = *msg.LastModifiedDateTime
+			}
+			b.Log.Debugf("<= Sending message from %s on %s to gateway", *msg.From.User.DisplayName, b.Account)
+			text := b.convertToMD(*msg.Body.Content)
+			rmsg := config.Message{Username: *msg.From.User.DisplayName, Text: text, Channel: channelName,
+				Account: b.Account, Avatar: "", UserID: *msg.From.User.ID, ID: *msg.ID}
+			b.Log.Debugf("<= Message is %#v", rmsg)
+			b.Remote <- rmsg
+		}
+		time.Sleep(time.Second * 5)
+	}
+}
+
+func (b *Bmsteams) setBotID() error {
+	req := b.gc.Me().Request()
+	r, err := req.Get(b.ctx)
+	if err != nil {
+		return err
+	}
+	b.botID = *r.ID
+	return nil
+}
+
+func (b *Bmsteams) convertToMD(text string) string {
+	if !strings.Contains(text, "<div>") {
+		return text
+	}
+	var sb strings.Builder
+	err := godown.Convert(&sb, strings.NewReader(text), nil)
+	if err != nil {
+		b.Log.Errorf("Couldn't convert message to markdown %s", text)
+		return text
+	}
+	return sb.String()
+}
-- 
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