1 files changed, 100 insertions, 0 deletions
diff --git a/vendor/maunium.net/go/mautrix/event/reply.go b/vendor/maunium.net/go/mautrix/event/reply.go
new file mode 100644
index 00000000..e1844a4a
--- /dev/null
+++ b/vendor/maunium.net/go/mautrix/event/reply.go
@@ -0,0 +1,100 @@
+// Copyright (c) 2020 Tulir Asokan
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+package event
+
+import (
+	"fmt"
+	"regexp"
+	"strings"
+
+	"golang.org/x/net/html"
+
+	"maunium.net/go/mautrix/id"
+)
+
+var HTMLReplyFallbackRegex = regexp.MustCompile(`^<mx-reply>[\s\S]+?</mx-reply>`)
+
+func TrimReplyFallbackHTML(html string) string {
+	return HTMLReplyFallbackRegex.ReplaceAllString(html, "")
+}
+
+func TrimReplyFallbackText(text string) string {
+	if !strings.HasPrefix(text, "> ") || !strings.Contains(text, "\n") {
+		return text
+	}
+
+	lines := strings.Split(text, "\n")
+	for len(lines) > 0 && strings.HasPrefix(lines[0], "> ") {
+		lines = lines[1:]
+	}
+	return strings.TrimSpace(strings.Join(lines, "\n"))
+}
+
+func (content *MessageEventContent) RemoveReplyFallback() {
+	if len(content.RelatesTo.GetReplyTo()) > 0 && !content.replyFallbackRemoved {
+		if content.Format == FormatHTML {
+			content.FormattedBody = TrimReplyFallbackHTML(content.FormattedBody)
+		}
+		content.Body = TrimReplyFallbackText(content.Body)
+		content.replyFallbackRemoved = true
+	}
+}
+
+// Deprecated: RelatesTo methods are nil-safe, so RelatesTo.GetReplyTo can be used directly
+func (content *MessageEventContent) GetReplyTo() id.EventID {
+	return content.RelatesTo.GetReplyTo()
+}
+
+const ReplyFormat = `<mx-reply><blockquote><a href="https://matrix.to/#/%s/%s">In reply to</a> <a href="https://matrix.to/#/%s">%s</a><br>%s</blockquote></mx-reply>`
+
+func (evt *Event) GenerateReplyFallbackHTML() string {
+	parsedContent, ok := evt.Content.Parsed.(*MessageEventContent)
+	if !ok {
+		return ""
+	}
+	parsedContent.RemoveReplyFallback()
+	body := parsedContent.FormattedBody
+	if len(body) == 0 {
+		body = strings.ReplaceAll(html.EscapeString(parsedContent.Body), "\n", "<br/>")
+	}
+
+	senderDisplayName := evt.Sender
+
+	return fmt.Sprintf(ReplyFormat, evt.RoomID, evt.ID, evt.Sender, senderDisplayName, body)
+}
+
+func (evt *Event) GenerateReplyFallbackText() string {
+	parsedContent, ok := evt.Content.Parsed.(*MessageEventContent)
+	if !ok {
+		return ""
+	}
+	parsedContent.RemoveReplyFallback()
+	body := parsedContent.Body
+	lines := strings.Split(strings.TrimSpace(body), "\n")
+	firstLine, lines := lines[0], lines[1:]
+
+	senderDisplayName := evt.Sender
+
+	var fallbackText strings.Builder
+	_, _ = fmt.Fprintf(&fallbackText, "> <%s> %s", senderDisplayName, firstLine)
+	for _, line := range lines {
+		_, _ = fmt.Fprintf(&fallbackText, "\n> %s", line)
+	}
+	fallbackText.WriteString("\n\n")
+	return fallbackText.String()
+}
+
+func (content *MessageEventContent) SetReply(inReplyTo *Event) {
+	content.RelatesTo = (&RelatesTo{}).SetReplyTo(inReplyTo.ID)
+
+	if content.MsgType == MsgText || content.MsgType == MsgNotice {
+		content.EnsureHasHTML()
+		content.FormattedBody = inReplyTo.GenerateReplyFallbackHTML() + content.FormattedBody
+		content.Body = inReplyTo.GenerateReplyFallbackText() + content.Body
+		content.replyFallbackRemoved = false
+	}
+}