From 63e272e2700bd04c302d2be2faf9a8d55f52ab71 Mon Sep 17 00:00:00 2001
From: Jakub <jakub@cuth.sk>
Date: Thu, 29 Feb 2024 12:21:29 +0100
Subject: [PATCH] feat(GODT-3193): preserve attachment encoding.

---
 pkg/message/parser.go                         |  4 ++++
 pkg/message/parser_test.go                    | 11 ++++++++++
 .../text_plain_xml_attachment_cp1250.eml      | 22 +++++++++++++++++++
 3 files changed, 37 insertions(+)
 create mode 100644 pkg/message/testdata/text_plain_xml_attachment_cp1250.eml

diff --git a/pkg/message/parser.go b/pkg/message/parser.go
index 491d3323..f714a6fe 100644
--- a/pkg/message/parser.go
+++ b/pkg/message/parser.go
@@ -205,6 +205,10 @@ func convertForeignEncodings(p *parser.Parser) error {
 			return p.ConvertMetaCharset()
 		}).
 		RegisterContentTypeHandler("text/.*", func(p *parser.Part) error {
+			if p.IsAttachment() {
+				return nil
+			}
+
 			return p.ConvertToUTF8()
 		}).
 		Walk()
diff --git a/pkg/message/parser_test.go b/pkg/message/parser_test.go
index 6108270e..7aa9e704 100644
--- a/pkg/message/parser_test.go
+++ b/pkg/message/parser_test.go
@@ -837,6 +837,17 @@ func TestPatchNewLineWithHtmlBreaks(t *testing.T) {
 	}
 }
 
+func TestParseCp1250Attachment(t *testing.T) {
+	r := require.New(t)
+	f := getFileReader("text_plain_xml_attachment_cp1250.eml")
+
+	m, err := Parse(f)
+	r.NoError(err)
+
+	r.Len(m.Attachments, 1)
+	r.Equal("text/xml; charset=windows-1250; name=\"cp1250.xml\"", m.Attachments[0].Header.Get("Content-Type"))
+}
+
 func getFileReader(filename string) io.Reader {
 	f, err := os.Open(filepath.Join("testdata", filename))
 	if err != nil {
diff --git a/pkg/message/testdata/text_plain_xml_attachment_cp1250.eml b/pkg/message/testdata/text_plain_xml_attachment_cp1250.eml
new file mode 100644
index 00000000..3e9b916b
--- /dev/null
+++ b/pkg/message/testdata/text_plain_xml_attachment_cp1250.eml
@@ -0,0 +1,22 @@
+From: Sender <sender@pm.me>
+To: Receiver <receiver@pm.me>
+Content-Type: multipart/mixed; boundary="------------iOaeSk0jVHjMucH3kQFwS1LB"
+
+This is a multi-part message in MIME format.
+--------------iOaeSk0jVHjMucH3kQFwS1LB
+Content-Type: text/plain; charset=UTF-8; format=flowed
+Content-Transfer-Encoding: 8bit
+
+created by me 😎
+
+--------------iOaeSk0jVHjMucH3kQFwS1LB
+Content-Type: text/xml; charset=windows-1250; name="cp1250.xml"
+Content-Disposition: attachment; filename="cp1250.xml"
+Content-Transfer-Encoding: 8bit
+
+<?xml version="1.0" encoding="WINDOWS-1250" ?>
+<pvpoj xmlns="http://schemas.cssz.cz/POJ/PVPOJ2023">
+<ulice>Horní náměstí</ulice>
+<prijmeni>ŠCheckCharsá</prijmeni>
+</pvpoj>
+--------------iOaeSk0jVHjMucH3kQFwS1LB--