add a few helper methods

src/Message.php

@@ -87,6 +87,36 @@ public function getParts(): array
         return $this->parts;
     }
 
+    public function getHtmlPart(): ?MessagePart
+    {
+        foreach ($this->parts as $part) {
+            if ($part->isHtml()) {
+                return $part;
+            }
+        }
+
+        return null;
+    }
+
+    public function getTextPart(): ?MessagePart
+    {
+        foreach ($this->parts as $part) {
+            if ($part->isText()) {
+                return $part;
+            }
+        }
+
+        return null;
+    }
+
+    /**
+     * @return MessagePart[]
+     */
+    public function getAttachments(): array
+    {
+        return array_filter($this->parts, fn ($part) => $part->isAttachment());
+    }
+
     protected function parse()
     {
         // Parse the email message into headers and body

src/MessagePart.php

@@ -38,6 +38,21 @@ public function getContent(): string
         return $this->content;
     }
 
+    public function isHtml(): bool
+    {
+        return str_starts_with(strtolower($this->getContentType()), 'text/html');
+    }
+
+    public function isText(): bool
+    {
+        return str_starts_with(strtolower($this->getContentType()), 'text/plain');
+    }
+
+    public function isImage(): bool
+    {
+        return str_starts_with(strtolower($this->getContentType()), 'image/');
+    }
+
     public function isAttachment(): bool
     {
         return str_starts_with($this->getHeader('Content-Disposition'), 'attachment');

tests/Unit/MessageTest.php

@@ -138,6 +138,11 @@
 
     expect($parts)->toHaveCount(2);
 
+    $htmlPart = $parts[0];
+
+    expect($htmlPart->getContentType())->toBe('text/html; charset="utf-8"')
+        ->and($htmlPart->isHtml())->toBe(true);
+
     $attachmentPart = $parts[1];
 
     expect($attachmentPart->getContent())->toBe('This is a test string')