From 8eb6ed563995d48e9835693d7a0af3155571113b Mon Sep 17 00:00:00 2001
From: Wim <wim@42.be>
Date: Sun, 29 Dec 2019 23:57:41 +0100
Subject: [PATCH] Support receiving attachments from msteams

---
 bridge/msteams/handler.go | 46 +++++++++++++++++++++++++++++++++++++++
 bridge/msteams/msteams.go | 28 +++++++++++++++++++++---
 2 files changed, 71 insertions(+), 3 deletions(-)
 create mode 100644 bridge/msteams/handler.go

diff --git a/bridge/msteams/handler.go b/bridge/msteams/handler.go
new file mode 100644
index 00000000..3283588a
--- /dev/null
+++ b/bridge/msteams/handler.go
@@ -0,0 +1,46 @@
+package bmsteams
+
+import (
+	"fmt"
+
+	"github.com/42wim/matterbridge/bridge/config"
+	"github.com/42wim/matterbridge/bridge/helper"
+)
+
+func (b *Bmsteams) findFile(weburl string) (string, error) {
+	itemRB, err := b.gc.GetDriveItemByURL(b.ctx, weburl)
+	if err != nil {
+		return "", err
+	}
+	itemRB.Workbook().Worksheets()
+	b.gc.Workbooks()
+	item, err := itemRB.Request().Get(b.ctx)
+	if err != nil {
+		return "", err
+	}
+	if url, ok := item.GetAdditionalData("@microsoft.graph.downloadUrl"); ok {
+		return url.(string), nil
+	}
+	return "", nil
+}
+
+// handleDownloadFile handles file download
+func (b *Bmsteams) handleDownloadFile(rmsg *config.Message, filename, weburl string) error {
+	realURL, err := b.findFile(weburl)
+	if err != nil {
+		return err
+	}
+	// Actually download the file.
+	data, err := helper.DownloadFile(realURL)
+	if err != nil {
+		return fmt.Errorf("download %s failed %#v", weburl, err)
+	}
+
+	// If a comment is attached to the file(s) it is in the 'Text' field of the teams messge event
+	// and should be added as comment to only one of the files. We reset the 'Text' field to ensure
+	// that the comment is not duplicated.
+	comment := rmsg.Text
+	rmsg.Text = ""
+	helper.HandleDownloadData(b.Log, rmsg, filename, comment, weburl, data, b.General)
+	return nil
+}
diff --git a/bridge/msteams/msteams.go b/bridge/msteams/msteams.go
index f2f0308b..4f72bd29 100644
--- a/bridge/msteams/msteams.go
+++ b/bridge/msteams/msteams.go
@@ -1,8 +1,9 @@
-package bgitter
+package bmsteams
 
 import (
 	"context"
 	"os"
+	"regexp"
 	"strings"
 	"time"
 
@@ -96,6 +97,7 @@ func (b *Bmsteams) getMessages(channel string) ([]msgraph.ChatMessage, error) {
 }
 
 func (b *Bmsteams) poll(channelName string) {
+	re := regexp.MustCompile(`<attachment id=.*?attachment>`)
 	msgmap := make(map[string]time.Time)
 	b.Log.Debug("getting initial messages")
 	res, err := b.getMessages(channelName)
@@ -136,8 +138,28 @@ func (b *Bmsteams) poll(channelName string) {
 			}
 			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}
+			rmsg := config.Message{
+				Username: *msg.From.User.DisplayName,
+				Text:     text,
+				Channel:  channelName,
+				Account:  b.Account,
+				Avatar:   "",
+				UserID:   *msg.From.User.ID,
+				ID:       *msg.ID,
+				Extra:    make(map[string][]interface{}),
+			}
+
+			if len(msg.Attachments) > 0 {
+				for _, a := range msg.Attachments {
+					//remove the attachment tags from the text
+					rmsg.Text = re.ReplaceAllString(rmsg.Text, "")
+					//handle the download
+					err := b.handleDownloadFile(&rmsg, *a.Name, *a.ContentURL)
+					if err != nil {
+						b.Log.Errorf("download of %s failed: %s", *a.Name, err)
+					}
+				}
+			}
 			b.Log.Debugf("<= Message is %#v", rmsg)
 			b.Remote <- rmsg
 		}