From 29305675d67e2a9c2b9bc39b1cc5995fb3d6e768 Mon Sep 17 00:00:00 2001
From: Winni Neessen <winfried.neessen@cleverbridge.com>
Date: Wed, 19 Jun 2024 10:52:09 +0200
Subject: [PATCH] Refactor EML encoding and content-type parsing to separate
 functions

The commit includes extraction of blocks of code related to EML message encoding and content-type parsing into their own separate functions. By doing so, it improves code readability and maintainability.
---
 eml.go | 50 ++++++++++++++++++++++++++++++--------------------
 1 file changed, 30 insertions(+), 20 deletions(-)

diff --git a/eml.go b/eml.go
index 9db20ab..b59a2ca 100644
--- a/eml.go
+++ b/eml.go
@@ -112,26 +112,8 @@ func parseEMLHeaders(mailHeader *netmail.Header, msg *Msg) error {
 	}
 
 	// Extract content type, charset and encoding first
-	if value := mailHeader.Get(HeaderContentTransferEnc.String()); value != "" {
-		switch {
-		case strings.EqualFold(value, EncodingQP.String()):
-			msg.SetEncoding(EncodingQP)
-		case strings.EqualFold(value, EncodingB64.String()):
-			msg.SetEncoding(EncodingB64)
-		default:
-			msg.SetEncoding(NoEncoding)
-		}
-	}
-	if value := mailHeader.Get(HeaderContentType.String()); value != "" {
-		contentType, charSet := parseContentType(value)
-		if charSet != "" {
-			msg.SetCharset(Charset(charSet))
-		}
-		msg.setEncoder()
-		if contentType != "" {
-			msg.SetGenHeader(HeaderContentType, contentType)
-		}
-	}
+	parseEMLEncoding(mailHeader, msg)
+	parseEMLContentTypeCharset(mailHeader, msg)
 
 	// Extract address headers
 	if value := mailHeader.Get(HeaderFrom.String()); value != "" {
@@ -297,6 +279,34 @@ func parseEMLMultipartAlternative(params map[string]string, bodybuf *bytes.Buffe
 	return nil
 }
 
+// parseEMLEncoding parses and determines the encoding of the message
+func parseEMLEncoding(mailHeader *netmail.Header, msg *Msg) {
+	if value := mailHeader.Get(HeaderContentTransferEnc.String()); value != "" {
+		switch {
+		case strings.EqualFold(value, EncodingQP.String()):
+			msg.SetEncoding(EncodingQP)
+		case strings.EqualFold(value, EncodingB64.String()):
+			msg.SetEncoding(EncodingB64)
+		default:
+			msg.SetEncoding(NoEncoding)
+		}
+	}
+}
+
+// parseEMLContentTypeCharset parses and determines the charset and content type of the message
+func parseEMLContentTypeCharset(mailHeader *netmail.Header, msg *Msg) {
+	if value := mailHeader.Get(HeaderContentType.String()); value != "" {
+		contentType, charSet := parseContentType(value)
+		if charSet != "" {
+			msg.SetCharset(Charset(charSet))
+		}
+		msg.setEncoder()
+		if contentType != "" {
+			msg.SetGenHeader(HeaderContentType, contentType)
+		}
+	}
+}
+
 // handleEMLMultiPartBase64Encoding sets the content body of a base64 encoded Part
 func handleEMLMultiPartBase64Encoding(multiPartData []byte, part *Part) error {
 	part.SetEncoding(EncodingB64)