fix: add newline rules to separate multiple images in markdown

lib/src/plugins/markdown/decoder/document_markdown_decoder.dart

@@ -63,26 +63,48 @@ class DocumentMarkdownDecoder extends Converter<String, Document> {
     return nodes;
   }
 
-  String _formatMarkdown(String markdown) {
-    // Rule 1: single '\n' between text and image, add double '\n'
-    String result = markdown.replaceAllMapped(
-      RegExp(r'([^\n])\n!\[([^\]]*)\]\(([^)]+)\)', multiLine: true),
+String _formatMarkdown(String markdown) {
+    String result = markdown;
+
+    // 1. Ensure every image is *preceded* by two newlines
+    //    Handles:
+    //    - Inline images after text (e.g., "text ![img](url)")
+    //    - List items before images
+    //    - Consecutive images
+    //    - Images directly at line start
+    //
+    //    We apply two separate rules:
+    //    a) Images directly after non-newline characters
+    result = result.replaceAllMapped(
+      RegExp(r'([^\n])\s*!\[([^\]]*)\]\(([^)]+)\)'),
       (match) {
-        final text = match[1] ?? '';
-        final altText = match[2] ?? '';
-        final url = match[3] ?? '';
-        return '$text\n\n![$altText]($url)';
+        final before = match[1];
+        final alt = match[2];
+        final url = match[3];
+        return '$before\n\n![$alt]($url)';
       },
     );
 
-    // Rule 2: without '\n' between text and image, add double '\n'
+    //    b) Images not preceded by a blank line
+    result = result.replaceAllMapped(
+      RegExp(r'(?<!\n)\s*!\[([^\]]*)\]\(([^)]+)\)'),
+      (match) {
+        final alt = match[1];
+        final url = match[2];
+        return '\n\n![$alt]($url)';
+      },
+    );
+
+    // 2. Ensure every image is *followed* by two newlines
+    //    So that next content is not inline with the image
     result = result.replaceAllMapped(
-      RegExp(r'([^\n])!\[([^\]]*)\]\(([^)]+)\)'),
-      (match) => '${match[1]}\n\n![${match[2]}](${match[3]})',
+      RegExp(r'!\[[^\]]*\]\([^)]+\)(?!\n\n)'),
+      (match) => '${match[0]}\n\n',
     );
 
-    // Add another rules here.
+    // 3. Clean up excessive newlines (e.g., \n\n\n)
+    result = result.replaceAll(RegExp(r'\n{3,}'), '\n\n');
 
-    return result;
+    return result.trim();
   }
 }

test/plugins/markdown/document_markdown_test.dart

@@ -27,37 +27,53 @@ void main() {
       expect(markdown, markdownDocumentEncoded);
     });
 
-    test('paragraph + image with single \n', () {
-      const markdown = '''This is the first line
-![image](https://example.com/image.png)''';
-      final document = markdownToDocument(markdown);
-      final nodes = document.root.children;
-      expect(nodes.length, 2);
-      expect(nodes[0].delta?.toPlainText(), 'This is the first line');
-      expect(nodes[1].attributes['url'], 'https://example.com/image.png');
-    });
+test('image inside paragraph (no spacing)', () {
+  const markdown = 'Text before![img](https://example.com/image.png)text after.';
+  final document = markdownToDocument(markdown);
+  final nodes = document.root.children;
+  expect(nodes.length, 3);
+  expect(nodes[0].delta?.toPlainText(), 'Text before');
+  expect(nodes[1].attributes['url'], 'https://example.com/image.png');
+  expect(nodes[2].delta?.toPlainText(), 'text after.');
+});
 
-    test('paragraph + image with double \n', () {
-      const markdown = '''This is the first line
+test('image between two paragraphs (no blank lines)', () {
+  const markdown = 'First paragraph.\n![img](https://example.com/image.png)\nSecond paragraph.';
+  final document = markdownToDocument(markdown);
+  final nodes = document.root.children;
+  expect(nodes.length, 3);
+  expect(nodes[0].delta?.toPlainText(), 'First paragraph.');
+  expect(nodes[1].attributes['url'], 'https://example.com/image.png');
+  expect(nodes[2].delta?.toPlainText(), 'Second paragraph.');
+});
 
-![image](https://example.com/image.png)''';
-      final document = markdownToDocument(markdown);
-      final nodes = document.root.children;
-      expect(nodes.length, 2);
-      expect(nodes[0].delta?.toPlainText(), 'This is the first line');
-      expect(nodes[1].attributes['url'], 'https://example.com/image.png');
-    });
+test('multiple images on same line (inline)', () {
+  const markdown = '![img1](https://example.com/image.png) ![img2](https://example.com/image.png)![img3](https://example.com/image.png)';
+  final document = markdownToDocument(markdown);
+  final nodes = document.root.children;
+  expect(nodes.length, 3);
+  expect(nodes[0].attributes['url'], 'https://example.com/image.png');
+  expect(nodes[1].attributes['url'], 'https://example.com/image.png');
+  expect(nodes[2].attributes['url'], 'https://example.com/image.png');
+});
 
-    test('paragraph + image without \n', () {
-      const markdown =
-          '''This is the first line![image](https://example.com/image.png)''';
-      final document = markdownToDocument(markdown);
-      final nodes = document.root.children;
-      expect(nodes.length, 2);
-      expect(nodes[0].delta?.toPlainText(), 'This is the first line');
-      expect(nodes[1].attributes['url'], 'https://example.com/image.png');
-    });
-  });
+test('image attached directly to previous content (no newline or space)', () {
+  const markdown = 'Paragraph![img](https://example.com/image.png)';
+  final document = markdownToDocument(markdown);
+  final nodes = document.root.children;
+  expect(nodes.length, 2);
+  expect(nodes[0].delta?.toPlainText(), 'Paragraph');
+  expect(nodes[1].attributes['url'], 'https://example.com/image.png');
+});
+
+test('image attached directly to next content (no newline)', () {
+  const markdown = '![img](https://example.com/image.png)This is a sentence.';
+  final document = markdownToDocument(markdown);
+  final nodes = document.root.children;
+  expect(nodes.length, 2);
+  expect(nodes[0].attributes['url'], 'https://example.com/image.png');
+  expect(nodes[1].delta?.toPlainText(), 'This is a sentence.');
+});
 }
 
 const testDocument = '''{