improve getMessageHTML signature, improve telegram message crop

Previously, the telegram message was stripped of its HTML,
which was unintended. After that change, it would be
stripped of HTML formatting only if the characters
limit is exceeded. Otherwise, we need to do sophisticated
HTML parsing to find the tag, which would be left without the
closing part when trimming the message.

app/proc/telegram.go

@@ -75,7 +75,7 @@ func (client TelegramClient) Send(channelID string, item feed.Item) (err error)
 func (client TelegramClient) sendText(channelID string, item feed.Item) (*tb.Message, error) {
 	message, err := client.Bot.Send(
 		recipient{chatID: channelID},
-		client.getMessageHTML(item, true, false),
+		client.getMessageHTML(item, htmlMessageParams{WithMp3Link: true}),
 		tb.ModeHTML,
 		tb.NoPreview,
 	)
@@ -97,7 +97,7 @@ func (client TelegramClient) sendAudio(channelID string, item feed.Item) (*tb.Me
 		File:      tb.FromReader(&httpBodyCopy),
 		FileName:  item.GetFilename(),
 		MIME:      "audio/mpeg",
-		Caption:   client.getMessageHTML(item, false, true),
+		Caption:   client.getMessageHTML(item, htmlMessageParams{TrimCaption: true}),
 		Title:     item.Title,
 		Performer: item.Author,
 		Duration:  client.duration(tee),
@@ -121,20 +121,19 @@ func (client TelegramClient) tagLinkOnlySupport(htmlText string) string {
 	return html.UnescapeString(p.Sanitize(htmlText))
 }
 
+type htmlMessageParams struct{ WithMp3Link, TrimCaption bool }
+
 // getMessageHTML generates HTML message from provided feed.Item
-func (client TelegramClient) getMessageHTML(item feed.Item, withMp3Link, trimCaption bool) string {
+func (client TelegramClient) getMessageHTML(item feed.Item, params htmlMessageParams) string {
 	var header, footer string
 	title := strings.TrimSpace(item.Title)
-	if title != "" {
-		switch {
-		case item.Link == "":
-			header = fmt.Sprintf("%s\n\n", title)
-		case item.Link != "":
-			header = fmt.Sprintf("<a href=%q>%s</a>\n\n", item.Link, title)
-		}
+	if title != "" && item.Link == "" {
+		header = fmt.Sprintf("%s\n\n", title)
+	} else if title != "" && item.Link != "" {
+		header = fmt.Sprintf("<a href=%q>%s</a>\n\n", item.Link, title)
 	}
 
-	if withMp3Link {
+	if params.WithMp3Link {
 		footer += fmt.Sprintf("\n\n%s", item.Enclosure.URL)
 	}
 
@@ -146,8 +145,8 @@ func (client TelegramClient) getMessageHTML(item feed.Item, withMp3Link, trimCap
 	description = strings.TrimSpace(description)
 
 	// https://limits.tginfo.me/en 1024 symbol limit for caption
-	if trimCaption && len(header+description+footer) > 1024 {
-		description = CleanText(description, 1020-len(header+footer))
+	if params.TrimCaption && len(header+description+footer) > 1024 {
+		description = CropText(description, 1024-len(header+footer))
 	}
 
 	return header + description + footer
@@ -181,3 +180,11 @@ func (r recipient) Recipient() string {
 
 	return r.chatID
 }
+
+// CropText shrinks the provided string, removing HTML tags in case it's exceeding the limit
+func CropText(inp string, max int) string {
+	if len([]rune(inp)) > max {
+		return CleanText(inp, max)
+	}
+	return inp
+}

app/proc/telegram_test.go

@@ -128,15 +128,21 @@ func TestFormattedMessage(t *testing.T) {
 		i := i
 		tc := tc
 		t.Run(strconv.Itoa(i), func(t *testing.T) {
-			htmlMessage := client.getMessageHTML(tc.item, false, false)
+			htmlMessage := client.getMessageHTML(tc.item, htmlMessageParams{})
 			assert.Equal(t, tc.expectedHTML, htmlMessage)
 		})
 	}
 }
 
 func TestTruncatedMessage(t *testing.T) {
 	client := TelegramClient{}
-	htmlMessage := client.getMessageHTML(feed.Item{Title: "title", Enclosure: feed.Enclosure{URL: "https://example.com/some.mp3"}, Description: template.HTML(strings.Repeat("test", 1000))}, true, true) //nolint:gosec
+	htmlMessage := client.getMessageHTML(
+		feed.Item{
+			Title:       "title",
+			Enclosure:   feed.Enclosure{URL: "https://example.com/some.mp3"},
+			Description: template.HTML(strings.Repeat("test", 1000)), //nolint:gosec // test case, no security issues
+		},
+		htmlMessageParams{WithMp3Link: true, TrimCaption: true})
 	assert.True(t, strings.HasPrefix(htmlMessage, "title\n\n"))
 	assert.True(t, strings.HasSuffix(htmlMessage, "\n\nhttps://example.com/some.mp3"))
 	assert.LessOrEqual(t, len(htmlMessage), 1024)
@@ -155,7 +161,7 @@ func TestGetMessageHTML(t *testing.T) {
 	expected := "<a href=\"https://example.com/xyz\">Podcast</a>\n\nNews <a href=\"/test\">Podcast Link</a>\n\nhttps://example.com"
 
 	client := TelegramClient{}
-	msg := client.getMessageHTML(item, true, false)
+	msg := client.getMessageHTML(item, htmlMessageParams{WithMp3Link: true})
 	assert.Equal(t, expected, msg)
 }