feat: add PHP preprocessing for Mermaid code blocks

- Add argon_format_mermaid_code filter in functions.php
- Decode WP-Markdown escape characters in PHP
- Auto-add newlines for single-line mermaid code
- Simplify JavaScript rendering logic
- Use data-mermaid-code attribute for preprocessed code
- Remove debug console.log statements

functions.php

@@ -3607,6 +3607,52 @@ function the_content_filter($content){
 	return $content;
 }
 add_filter('the_content' , 'the_content_filter',20);
+
+// Mermaid 代码块预处理
+function argon_format_mermaid_code($content) {
+	if (!get_option('argon_mermaid_enable', 'false') == 'true') {
+		return $content;
+	}
+	
+	// 匹配 WP-Markdown 生成的 mermaid 代码块格式
+	$pattern = '/<div class="mermaid">(.*?)<\/div>/s';
+	
+	$content = preg_replace_callback($pattern, function($matches) {
+		$div_content = $matches[1];
+		
+		// 检查是否包含 script 标签（WP-Markdown 格式）
+		if (preg_match('/<script[^>]*>document\.write\("(.*)"\)<\/script>/s', $div_content, $script_match)) {
+			$mermaid_code = $script_match[1];
+			
+			// 解码转义字符
+			$mermaid_code = str_replace('\\n', "\n", $mermaid_code);
+			$mermaid_code = str_replace('\\"', '"', $mermaid_code);
+			$mermaid_code = str_replace("\\'", "'", $mermaid_code);
+			$mermaid_code = html_entity_decode($mermaid_code);
+			
+			// 如果代码看起来像一行（前100个字符中换行符很少），添加换行
+			$first_100 = substr($mermaid_code, 0, 100);
+			$newline_count = substr_count($first_100, "\n");
+			
+			if ($newline_count < 2) {
+				// 在箭头前添加换行
+				$mermaid_code = preg_replace('/\s*-->\s*/', "\n    --> ", $mermaid_code);
+				// 在 style 语句前添加换行
+				$mermaid_code = preg_replace('/\s*style\s+/', "\nstyle ", $mermaid_code);
+			}
+			
+			// 返回带 data 属性的 div
+			return '<div class="mermaid" data-mermaid-code="' . esc_attr($mermaid_code) . '">' . $div_content . '</div>';
+		}
+		
+		// 不是 WP-Markdown 格式，保持原样
+		return $matches[0];
+	}, $content);
+	
+	return $content;
+}
+add_filter('the_content', 'argon_format_mermaid_code', 25);
+
 //使用 CDN 加速 gravatar
 function gravatar_cdn($url){
 	$cdn = get_option('argon_gravatar_cdn', 'gravatar.pho.ink/avatar/');