Refactor telegram handlers. Fix linting (#609)

* Refactor telegram handlers. Fix linting

3 files changed, 306 insertions, 278 deletions

diff --git a/bridge/telegram/handlers.go b/bridge/telegram/handlers.go
new file mode 100644
index 00000000..810043b5
--- /dev/null
+++ b/bridge/telegram/handlers.go
@@ -0,0 +1,302 @@
+package btelegram
+
+import (
+	"regexp"
+	"strconv"
+	"strings"
+
+	"github.com/42wim/matterbridge/bridge/config"
+	"github.com/42wim/matterbridge/bridge/helper"
+	"github.com/go-telegram-bot-api/telegram-bot-api"
+)
+
+func (b *Btelegram) handleUpdate(rmsg *config.Message, message, posted, edited *tgbotapi.Message) *tgbotapi.Message {
+	// handle channels
+	if posted != nil {
+		message = posted
+		rmsg.Text = message.Text
+	}
+
+	// edited channel message
+	if edited != nil && !b.GetBool("EditDisable") {
+		message = edited
+		rmsg.Text = rmsg.Text + message.Text + b.GetString("EditSuffix")
+	}
+	return message
+}
+
+// handleChannels checks if it's a channel message and if the message is a new or edited messages
+func (b *Btelegram) handleChannels(rmsg *config.Message, message *tgbotapi.Message, update tgbotapi.Update) *tgbotapi.Message {
+	return b.handleUpdate(rmsg, message, update.ChannelPost, update.EditedChannelPost)
+}
+
+// handleGroups checks if it's a group message and if the message is a new or edited messages
+func (b *Btelegram) handleGroups(rmsg *config.Message, message *tgbotapi.Message, update tgbotapi.Update) *tgbotapi.Message {
+	return b.handleUpdate(rmsg, message, update.Message, update.EditedMessage)
+}
+
+// handleForwarded handles forwarded messages
+func (b *Btelegram) handleForwarded(rmsg *config.Message, message *tgbotapi.Message) {
+	if message.ForwardFrom != nil {
+		usernameForward := ""
+		if b.GetBool("UseFirstName") {
+			usernameForward = message.ForwardFrom.FirstName
+		}
+		if usernameForward == "" {
+			usernameForward = message.ForwardFrom.UserName
+			if usernameForward == "" {
+				usernameForward = message.ForwardFrom.FirstName
+			}
+		}
+		if usernameForward == "" {
+			usernameForward = unknownUser
+		}
+		rmsg.Text = "Forwarded from " + usernameForward + ": " + rmsg.Text
+	}
+}
+
+// handleQuoting handles quoting of previous messages
+func (b *Btelegram) handleQuoting(rmsg *config.Message, message *tgbotapi.Message) {
+	if message.ReplyToMessage != nil {
+		usernameReply := ""
+		if message.ReplyToMessage.From != nil {
+			if b.GetBool("UseFirstName") {
+				usernameReply = message.ReplyToMessage.From.FirstName
+			}
+			if usernameReply == "" {
+				usernameReply = message.ReplyToMessage.From.UserName
+				if usernameReply == "" {
+					usernameReply = message.ReplyToMessage.From.FirstName
+				}
+			}
+		}
+		if usernameReply == "" {
+			usernameReply = unknownUser
+		}
+		if !b.GetBool("QuoteDisable") {
+			rmsg.Text = b.handleQuote(rmsg.Text, usernameReply, message.ReplyToMessage.Text)
+		}
+	}
+}
+
+// handleUsername handles the correct setting of the username
+func (b *Btelegram) handleUsername(rmsg *config.Message, message *tgbotapi.Message) {
+	if message.From != nil {
+		rmsg.UserID = strconv.Itoa(message.From.ID)
+		if b.GetBool("UseFirstName") {
+			rmsg.Username = message.From.FirstName
+		}
+		if rmsg.Username == "" {
+			rmsg.Username = message.From.UserName
+			if rmsg.Username == "" {
+				rmsg.Username = message.From.FirstName
+			}
+		}
+		// only download avatars if we have a place to upload them (configured mediaserver)
+		if b.General.MediaServerUpload != "" {
+			b.handleDownloadAvatar(message.From.ID, rmsg.Channel)
+		}
+	}
+
+	// if we really didn't find a username, set it to unknown
+	if rmsg.Username == "" {
+		rmsg.Username = unknownUser
+	}
+}
+
+func (b *Btelegram) handleRecv(updates <-chan tgbotapi.Update) {
+	for update := range updates {
+		b.Log.Debugf("== Receiving event: %#v", update.Message)
+
+		if update.Message == nil && update.ChannelPost == nil &&
+			update.EditedMessage == nil && update.EditedChannelPost == nil {
+			b.Log.Error("Getting nil messages, this shouldn't happen.")
+			continue
+		}
+
+		var message *tgbotapi.Message
+
+		rmsg := config.Message{Account: b.Account, Extra: make(map[string][]interface{})}
+
+		// handle channels
+		b.handleChannels(&rmsg, message, update)
+
+		// handle groups
+		b.handleGroups(&rmsg, message, update)
+
+		// set the ID's from the channel or group message
+		rmsg.ID = strconv.Itoa(message.MessageID)
+		rmsg.Channel = strconv.FormatInt(message.Chat.ID, 10)
+
+		// handle username
+		b.handleUsername(&rmsg, message)
+
+		// handle any downloads
+		err := b.handleDownload(&rmsg, message)
+		if err != nil {
+			b.Log.Errorf("download failed: %s", err)
+		}
+
+		// handle forwarded messages
+		b.handleForwarded(&rmsg, message)
+
+		// quote the previous message
+		b.handleQuoting(&rmsg, message)
+
+		if rmsg.Text != "" || len(rmsg.Extra) > 0 {
+			rmsg.Text = helper.RemoveEmptyNewLines(rmsg.Text)
+			// channels don't have (always?) user information. see #410
+			if message.From != nil {
+				rmsg.Avatar = helper.GetAvatar(b.avatarMap, strconv.Itoa(message.From.ID), b.General)
+			}
+
+			b.Log.Debugf("<= Sending message from %s on %s to gateway", rmsg.Username, b.Account)
+			b.Log.Debugf("<= Message is %#v", rmsg)
+			b.Remote <- rmsg
+		}
+	}
+}
+
+// handleDownloadAvatar downloads the avatar of userid from channel
+// sends a EVENT_AVATAR_DOWNLOAD message to the gateway if successful.
+// logs an error message if it fails
+func (b *Btelegram) handleDownloadAvatar(userid int, channel string) {
+	rmsg := config.Message{Username: "system",
+		Text:    "avatar",
+		Channel: channel,
+		Account: b.Account,
+		UserID:  strconv.Itoa(userid),
+		Event:   config.EventAvatarDownload,
+		Extra:   make(map[string][]interface{})}
+
+	if _, ok := b.avatarMap[strconv.Itoa(userid)]; !ok {
+		photos, err := b.c.GetUserProfilePhotos(tgbotapi.UserProfilePhotosConfig{UserID: userid, Limit: 1})
+		if err != nil {
+			b.Log.Errorf("Userprofile download failed for %#v %s", userid, err)
+		}
+
+		if len(photos.Photos) > 0 {
+			photo := photos.Photos[0][0]
+			url := b.getFileDirectURL(photo.FileID)
+			name := strconv.Itoa(userid) + ".png"
+			b.Log.Debugf("trying to download %#v fileid %#v with size %#v", name, photo.FileID, photo.FileSize)
+
+			err := helper.HandleDownloadSize(b.Log, &rmsg, name, int64(photo.FileSize), b.General)
+			if err != nil {
+				b.Log.Error(err)
+				return
+			}
+			data, err := helper.DownloadFile(url)
+			if err != nil {
+				b.Log.Errorf("download %s failed %#v", url, err)
+				return
+			}
+			helper.HandleDownloadData(b.Log, &rmsg, name, rmsg.Text, "", data, b.General)
+			b.Remote <- rmsg
+		}
+	}
+}
+
+// handleDownloadFile handles file download
+func (b *Btelegram) handleDownload(rmsg *config.Message, message *tgbotapi.Message) error {
+	size := 0
+	var url, name, text string
+	switch {
+	case message.Sticker != nil:
+		text, name, url = b.getDownloadInfo(message.Sticker.FileID, ".webp", true)
+		size = message.Sticker.FileSize
+	case message.Voice != nil:
+		text, name, url = b.getDownloadInfo(message.Voice.FileID, ".ogg", true)
+		size = message.Voice.FileSize
+	case message.Video != nil:
+		text, name, url = b.getDownloadInfo(message.Video.FileID, "", true)
+		size = message.Video.FileSize
+	case message.Audio != nil:
+		text, name, url = b.getDownloadInfo(message.Audio.FileID, "", true)
+		size = message.Audio.FileSize
+	case message.Document != nil:
+		_, _, url = b.getDownloadInfo(message.Document.FileID, "", false)
+		size = message.Document.FileSize
+		name = message.Document.FileName
+		text = " " + message.Document.FileName + " : " + url
+	case message.Photo != nil:
+		photos := *message.Photo
+		size = photos[len(photos)-1].FileSize
+		text, name, url = b.getDownloadInfo(photos[len(photos)-1].FileID, "", true)
+	}
+
+	// if name is empty we didn't match a thing to download
+	if name == "" {
+		return nil
+	}
+	// use the URL instead of native upload
+	if b.GetBool("UseInsecureURL") {
+		b.Log.Debugf("Setting message text to :%s", text)
+		rmsg.Text += text
+		return nil
+	}
+	// if we have a file attached, download it (in memory) and put a pointer to it in msg.Extra
+	err := helper.HandleDownloadSize(b.Log, rmsg, name, int64(size), b.General)
+	if err != nil {
+		return err
+	}
+	data, err := helper.DownloadFile(url)
+	if err != nil {
+		return err
+	}
+	helper.HandleDownloadData(b.Log, rmsg, name, message.Caption, "", data, b.General)
+	return nil
+}
+
+func (b *Btelegram) getDownloadInfo(id string, suffix string, urlpart bool) (string, string, string) {
+	url := b.getFileDirectURL(id)
+	name := ""
+	if urlpart {
+		urlPart := strings.Split(url, "/")
+		name = urlPart[len(urlPart)-1]
+	}
+	if suffix != "" && !strings.HasSuffix(name, suffix) {
+		name += suffix
+	}
+	text := " " + url
+	return text, name, url
+}
+
+// handleUploadFile handles native upload of files
+func (b *Btelegram) handleUploadFile(msg *config.Message, chatid int64) string {
+	var c tgbotapi.Chattable
+	for _, f := range msg.Extra["file"] {
+		fi := f.(config.FileInfo)
+		file := tgbotapi.FileBytes{
+			Name:  fi.Name,
+			Bytes: *fi.Data,
+		}
+		re := regexp.MustCompile(".(jpg|png)$")
+		if re.MatchString(fi.Name) {
+			c = tgbotapi.NewPhotoUpload(chatid, file)
+		} else {
+			c = tgbotapi.NewDocumentUpload(chatid, file)
+		}
+		_, err := b.c.Send(c)
+		if err != nil {
+			b.Log.Errorf("file upload failed: %#v", err)
+		}
+		if fi.Comment != "" {
+			if _, err := b.sendMessage(chatid, msg.Username, fi.Comment); err != nil {
+				b.Log.Errorf("posting file comment %s failed: %s", fi.Comment, err)
+			}
+		}
+	}
+	return ""
+}
+
+func (b *Btelegram) handleQuote(message, quoteNick, quoteMessage string) string {
+	format := b.GetString("quoteformat")
+	if format == "" {
+		format = "{MESSAGE} (re @{QUOTENICK}: {QUOTEMESSAGE})"
+	}
+	format = strings.Replace(format, "{MESSAGE}", message, -1)
+	format = strings.Replace(format, "{QUOTENICK}", quoteNick, -1)
+	format = strings.Replace(format, "{QUOTEMESSAGE}", quoteMessage, -1)
+	return format
+}
diff --git a/bridge/telegram/html.go b/bridge/telegram/html.go
index 12d6d0c6..148f42e6 100644
--- a/bridge/telegram/html.go
+++ b/bridge/telegram/html.go
@@ -34,7 +34,7 @@ func (options *customHTML) Header(out *bytes.Buffer, text func() bool, level int
 }
 
 func (options *customHTML) HRule(out io.ByteWriter) {
-	out.WriteByte('\n')
+	out.WriteByte('\n') //nolint:errcheck
 }
 
 func (options *customHTML) BlockQuote(out *bytes.Buffer, text []byte) {
diff --git a/bridge/telegram/telegram.go b/bridge/telegram/telegram.go
index 7097644e..e16e2bef 100644
--- a/bridge/telegram/telegram.go
+++ b/bridge/telegram/telegram.go
@@ -2,7 +2,6 @@ package btelegram
 
 import (
 	"html"
-	"regexp"
 	"strconv"
 	"strings"
 
@@ -90,7 +89,9 @@ func (b *Btelegram) Send(msg config.Message) (string, error) {
 	// Upload a file if it exists
 	if msg.Extra != nil {
 		for _, rmsg := range helper.HandleExtra(&msg, b.General) {
-			b.sendMessage(chatid, rmsg.Username, rmsg.Text)
+			if _, err := b.sendMessage(chatid, rmsg.Username, rmsg.Text); err != nil {
+				b.Log.Errorf("sendMessage failed: %s", err)
+			}
 		}
 		// check if we have files to upload (from slack, telegram or mattermost)
 		if len(msg.Extra["file"]) > 0 {
@@ -132,130 +133,6 @@ func (b *Btelegram) Send(msg config.Message) (string, error) {
 	return b.sendMessage(chatid, msg.Username, msg.Text)
 }
 
-func (b *Btelegram) handleRecv(updates <-chan tgbotapi.Update) {
-	for update := range updates {
-		b.Log.Debugf("== Receiving event: %#v", update.Message)
-
-		if update.Message == nil && update.ChannelPost == nil && update.EditedMessage == nil && update.EditedChannelPost == nil {
-			b.Log.Error("Getting nil messages, this shouldn't happen.")
-			continue
-		}
-
-		var message *tgbotapi.Message
-
-		rmsg := config.Message{Account: b.Account, Extra: make(map[string][]interface{})}
-
-		// handle channels
-		if update.ChannelPost != nil {
-			message = update.ChannelPost
-			rmsg.Text = message.Text
-		}
-
-		// edited channel message
-		if update.EditedChannelPost != nil && !b.GetBool("EditDisable") {
-			message = update.EditedChannelPost
-			rmsg.Text = rmsg.Text + message.Text + b.GetString("EditSuffix")
-		}
-
-		// handle groups
-		if update.Message != nil {
-			message = update.Message
-			rmsg.Text = message.Text
-		}
-
-		// edited group message
-		if update.EditedMessage != nil && !b.GetBool("EditDisable") {
-			message = update.EditedMessage
-			rmsg.Text = rmsg.Text + message.Text + b.GetString("EditSuffix")
-		}
-
-		// set the ID's from the channel or group message
-		rmsg.ID = strconv.Itoa(message.MessageID)
-		rmsg.Channel = strconv.FormatInt(message.Chat.ID, 10)
-
-		// handle username
-		if message.From != nil {
-			rmsg.UserID = strconv.Itoa(message.From.ID)
-			if b.GetBool("UseFirstName") {
-				rmsg.Username = message.From.FirstName
-			}
-			if rmsg.Username == "" {
-				rmsg.Username = message.From.UserName
-				if rmsg.Username == "" {
-					rmsg.Username = message.From.FirstName
-				}
-			}
-			// only download avatars if we have a place to upload them (configured mediaserver)
-			if b.General.MediaServerUpload != "" {
-				b.handleDownloadAvatar(message.From.ID, rmsg.Channel)
-			}
-		}
-
-		// if we really didn't find a username, set it to unknown
-		if rmsg.Username == "" {
-			rmsg.Username = unknownUser
-		}
-
-		// handle any downloads
-		err := b.handleDownload(message, &rmsg)
-		if err != nil {
-			b.Log.Errorf("download failed: %s", err)
-		}
-
-		// handle forwarded messages
-		if message.ForwardFrom != nil {
-			usernameForward := ""
-			if b.GetBool("UseFirstName") {
-				usernameForward = message.ForwardFrom.FirstName
-			}
-			if usernameForward == "" {
-				usernameForward = message.ForwardFrom.UserName
-				if usernameForward == "" {
-					usernameForward = message.ForwardFrom.FirstName
-				}
-			}
-			if usernameForward == "" {
-				usernameForward = unknownUser
-			}
-			rmsg.Text = "Forwarded from " + usernameForward + ": " + rmsg.Text
-		}
-
-		// quote the previous message
-		if message.ReplyToMessage != nil {
-			usernameReply := ""
-			if message.ReplyToMessage.From != nil {
-				if b.GetBool("UseFirstName") {
-					usernameReply = message.ReplyToMessage.From.FirstName
-				}
-				if usernameReply == "" {
-					usernameReply = message.ReplyToMessage.From.UserName
-					if usernameReply == "" {
-						usernameReply = message.ReplyToMessage.From.FirstName
-					}
-				}
-			}
-			if usernameReply == "" {
-				usernameReply = unknownUser
-			}
-			if !b.GetBool("QuoteDisable") {
-				rmsg.Text = b.handleQuote(rmsg.Text, usernameReply, message.ReplyToMessage.Text)
-			}
-		}
-
-		if rmsg.Text != "" || len(rmsg.Extra) > 0 {
-			rmsg.Text = helper.RemoveEmptyNewLines(rmsg.Text)
-			// channels don't have (always?) user information. see #410
-			if message.From != nil {
-				rmsg.Avatar = helper.GetAvatar(b.avatarMap, strconv.Itoa(message.From.ID), b.General)
-			}
-
-			b.Log.Debugf("<= Sending message from %s on %s to gateway", rmsg.Username, b.Account)
-			b.Log.Debugf("<= Message is %#v", rmsg)
-			b.Remote <- rmsg
-		}
-	}
-}
-
 func (b *Btelegram) getFileDirectURL(id string) string {
 	res, err := b.c.GetFileDirectURL(id)
 	if err != nil {
@@ -264,146 +141,6 @@ func (b *Btelegram) getFileDirectURL(id string) string {
 	return res
 }
 
-// handleDownloadAvatar downloads the avatar of userid from channel
-// sends a EVENT_AVATAR_DOWNLOAD message to the gateway if successful.
-// logs an error message if it fails
-func (b *Btelegram) handleDownloadAvatar(userid int, channel string) {
-	rmsg := config.Message{Username: "system", Text: "avatar", Channel: channel, Account: b.Account, UserID: strconv.Itoa(userid), Event: config.EventAvatarDownload, Extra: make(map[string][]interface{})}
-	if _, ok := b.avatarMap[strconv.Itoa(userid)]; !ok {
-		photos, err := b.c.GetUserProfilePhotos(tgbotapi.UserProfilePhotosConfig{UserID: userid, Limit: 1})
-		if err != nil {
-			b.Log.Errorf("Userprofile download failed for %#v %s", userid, err)
-		}
-
-		if len(photos.Photos) > 0 {
-			photo := photos.Photos[0][0]
-			url := b.getFileDirectURL(photo.FileID)
-			name := strconv.Itoa(userid) + ".png"
-			b.Log.Debugf("trying to download %#v fileid %#v with size %#v", name, photo.FileID, photo.FileSize)
-
-			err := helper.HandleDownloadSize(b.Log, &rmsg, name, int64(photo.FileSize), b.General)
-			if err != nil {
-				b.Log.Error(err)
-				return
-			}
-			data, err := helper.DownloadFile(url)
-			if err != nil {
-				b.Log.Errorf("download %s failed %#v", url, err)
-				return
-			}
-			helper.HandleDownloadData(b.Log, &rmsg, name, rmsg.Text, "", data, b.General)
-			b.Remote <- rmsg
-		}
-	}
-}
-
-// handleDownloadFile handles file download
-func (b *Btelegram) handleDownload(message *tgbotapi.Message, rmsg *config.Message) error {
-	size := 0
-	var url, name, text string
-
-	if message.Sticker != nil {
-		v := message.Sticker
-		size = v.FileSize
-		url = b.getFileDirectURL(v.FileID)
-		urlPart := strings.Split(url, "/")
-		name = urlPart[len(urlPart)-1]
-		if !strings.HasSuffix(name, ".webp") {
-			name += ".webp"
-		}
-		text = " " + url
-	}
-	if message.Video != nil {
-		v := message.Video
-		size = v.FileSize
-		url = b.getFileDirectURL(v.FileID)
-		urlPart := strings.Split(url, "/")
-		name = urlPart[len(urlPart)-1]
-		text = " " + url
-	}
-	if message.Photo != nil {
-		photos := *message.Photo
-		size = photos[len(photos)-1].FileSize
-		url = b.getFileDirectURL(photos[len(photos)-1].FileID)
-		urlPart := strings.Split(url, "/")
-		name = urlPart[len(urlPart)-1]
-		text = " " + url
-	}
-	if message.Document != nil {
-		v := message.Document
-		size = v.FileSize
-		url = b.getFileDirectURL(v.FileID)
-		name = v.FileName
-		text = " " + v.FileName + " : " + url
-	}
-	if message.Voice != nil {
-		v := message.Voice
-		size = v.FileSize
-		url = b.getFileDirectURL(v.FileID)
-		urlPart := strings.Split(url, "/")
-		name = urlPart[len(urlPart)-1]
-		text = " " + url
-		if !strings.HasSuffix(name, ".ogg") {
-			name += ".ogg"
-		}
-	}
-	if message.Audio != nil {
-		v := message.Audio
-		size = v.FileSize
-		url = b.getFileDirectURL(v.FileID)
-		urlPart := strings.Split(url, "/")
-		name = urlPart[len(urlPart)-1]
-		text = " " + url
-	}
-	// if name is empty we didn't match a thing to download
-	if name == "" {
-		return nil
-	}
-	// use the URL instead of native upload
-	if b.GetBool("UseInsecureURL") {
-		b.Log.Debugf("Setting message text to :%s", text)
-		rmsg.Text += text
-		return nil
-	}
-	// if we have a file attached, download it (in memory) and put a pointer to it in msg.Extra
-	err := helper.HandleDownloadSize(b.Log, rmsg, name, int64(size), b.General)
-	if err != nil {
-		return err
-	}
-	data, err := helper.DownloadFile(url)
-	if err != nil {
-		return err
-	}
-	helper.HandleDownloadData(b.Log, rmsg, name, message.Caption, "", data, b.General)
-	return nil
-}
-
-// handleUploadFile handles native upload of files
-func (b *Btelegram) handleUploadFile(msg *config.Message, chatid int64) (string, error) {
-	var c tgbotapi.Chattable
-	for _, f := range msg.Extra["file"] {
-		fi := f.(config.FileInfo)
-		file := tgbotapi.FileBytes{
-			Name:  fi.Name,
-			Bytes: *fi.Data,
-		}
-		re := regexp.MustCompile(".(jpg|png)$")
-		if re.MatchString(fi.Name) {
-			c = tgbotapi.NewPhotoUpload(chatid, file)
-		} else {
-			c = tgbotapi.NewDocumentUpload(chatid, file)
-		}
-		_, err := b.c.Send(c)
-		if err != nil {
-			b.Log.Errorf("file upload failed: %#v", err)
-		}
-		if fi.Comment != "" {
-			b.sendMessage(chatid, msg.Username, fi.Comment)
-		}
-	}
-	return "", nil
-}
-
 func (b *Btelegram) sendMessage(chatid int64, username, text string) (string, error) {
 	m := tgbotapi.NewMessage(chatid, "")
 	m.Text = username + text
@@ -437,14 +174,3 @@ func (b *Btelegram) cacheAvatar(msg *config.Message) (string, error) {
 	}
 	return "", nil
 }
-
-func (b *Btelegram) handleQuote(message, quoteNick, quoteMessage string) string {
-	format := b.GetString("quoteformat")
-	if format == "" {
-		format = "{MESSAGE} (re @{QUOTENICK}: {QUOTEMESSAGE})"
-	}
-	format = strings.Replace(format, "{MESSAGE}", message, -1)
-	format = strings.Replace(format, "{QUOTENICK}", quoteNick, -1)
-	format = strings.Replace(format, "{QUOTEMESSAGE}", quoteMessage, -1)
-	return format
-}