fix: platform base extract_images and truncate_message bugs + tests

- extract_images: only remove extracted image tags from content, preserve
  non-image markdown links (e.g. PDFs) that were previously silently lost
- truncate_message: walk only chunk_body (not prepended prefix) so the
  reopened code fence does not toggle in_code off, leaving continuation
  chunks with unclosed code blocks
- Add 49 unit tests covering MessageEvent command parsing, extract_images,
  extract_media, truncate_message code block handling, and _get_human_delay

gateway/platforms/base.py

@@ -460,10 +460,14 @@ class BasePlatformAdapter(ABC):
             url = match.group(1)
             images.append((url, ""))
         
-        # Remove matched image tags from content if we found images
+        # Remove only the matched image tags from content (not all markdown images)
         if images:
-            cleaned = re.sub(md_pattern, '', cleaned)
-            cleaned = re.sub(html_pattern, '', cleaned)
+            extracted_urls = {url for url, _ in images}
+            def _remove_if_extracted(match):
+                url = match.group(2) if match.lastindex >= 2 else match.group(1)
+                return '' if url in extracted_urls else match.group(0)
+            cleaned = re.sub(md_pattern, _remove_if_extracted, cleaned)
+            cleaned = re.sub(html_pattern, _remove_if_extracted, cleaned)
             # Clean up leftover blank lines
             cleaned = re.sub(r'\n{3,}', '\n\n', cleaned).strip()
         
@@ -798,11 +802,11 @@ class BasePlatformAdapter(ABC):
 
             full_chunk = prefix + chunk_body
 
-            # Walk the chunk line-by-line to determine whether we end
-            # inside an open code block.
+            # Walk only the chunk_body (not the prefix we prepended) to
+            # determine whether we end inside an open code block.
             in_code = carry_lang is not None
             lang = carry_lang or ""
-            for line in full_chunk.split("\n"):
+            for line in chunk_body.split("\n"):
                 stripped = line.strip()
                 if stripped.startswith("```"):
                     if in_code:

tests/gateway/test_platform_base.py

@@ -0,0 +1,347 @@
+"""Tests for gateway/platforms/base.py — MessageEvent, media extraction, message truncation."""
+
+import os
+from unittest.mock import patch
+
+from gateway.platforms.base import (
+    BasePlatformAdapter,
+    MessageEvent,
+    MessageType,
+)
+
+
+# ---------------------------------------------------------------------------
+# MessageEvent — command parsing
+# ---------------------------------------------------------------------------
+
+
+class TestMessageEventIsCommand:
+    def test_slash_command(self):
+        event = MessageEvent(text="/new")
+        assert event.is_command() is True
+
+    def test_regular_text(self):
+        event = MessageEvent(text="hello world")
+        assert event.is_command() is False
+
+    def test_empty_text(self):
+        event = MessageEvent(text="")
+        assert event.is_command() is False
+
+    def test_slash_only(self):
+        event = MessageEvent(text="/")
+        assert event.is_command() is True
+
+
+class TestMessageEventGetCommand:
+    def test_simple_command(self):
+        event = MessageEvent(text="/new")
+        assert event.get_command() == "new"
+
+    def test_command_with_args(self):
+        event = MessageEvent(text="/reset session")
+        assert event.get_command() == "reset"
+
+    def test_not_a_command(self):
+        event = MessageEvent(text="hello")
+        assert event.get_command() is None
+
+    def test_command_is_lowercased(self):
+        event = MessageEvent(text="/HELP")
+        assert event.get_command() == "help"
+
+    def test_slash_only_returns_empty(self):
+        event = MessageEvent(text="/")
+        assert event.get_command() == ""
+
+
+class TestMessageEventGetCommandArgs:
+    def test_command_with_args(self):
+        event = MessageEvent(text="/new session id 123")
+        assert event.get_command_args() == "session id 123"
+
+    def test_command_without_args(self):
+        event = MessageEvent(text="/new")
+        assert event.get_command_args() == ""
+
+    def test_not_a_command_returns_full_text(self):
+        event = MessageEvent(text="hello world")
+        assert event.get_command_args() == "hello world"
+
+
+# ---------------------------------------------------------------------------
+# extract_images
+# ---------------------------------------------------------------------------
+
+
+class TestExtractImages:
+    def test_no_images(self):
+        images, cleaned = BasePlatformAdapter.extract_images("Just regular text.")
+        assert images == []
+        assert cleaned == "Just regular text."
+
+    def test_markdown_image_with_image_ext(self):
+        content = "Here is a photo: ![cat](https://example.com/cat.png)"
+        images, cleaned = BasePlatformAdapter.extract_images(content)
+        assert len(images) == 1
+        assert images[0][0] == "https://example.com/cat.png"
+        assert images[0][1] == "cat"
+        assert "![cat]" not in cleaned
+
+    def test_markdown_image_jpg(self):
+        content = "![photo](https://example.com/photo.jpg)"
+        images, _ = BasePlatformAdapter.extract_images(content)
+        assert len(images) == 1
+
+    def test_markdown_image_jpeg(self):
+        content = "![](https://example.com/photo.jpeg)"
+        images, _ = BasePlatformAdapter.extract_images(content)
+        assert len(images) == 1
+
+    def test_markdown_image_gif(self):
+        content = "![anim](https://example.com/anim.gif)"
+        images, _ = BasePlatformAdapter.extract_images(content)
+        assert len(images) == 1
+
+    def test_markdown_image_webp(self):
+        content = "![](https://example.com/img.webp)"
+        images, _ = BasePlatformAdapter.extract_images(content)
+        assert len(images) == 1
+
+    def test_fal_media_cdn(self):
+        content = "![gen](https://fal.media/files/abc123/output.png)"
+        images, _ = BasePlatformAdapter.extract_images(content)
+        assert len(images) == 1
+
+    def test_fal_cdn_url(self):
+        content = "![](https://fal-cdn.example.com/result)"
+        images, _ = BasePlatformAdapter.extract_images(content)
+        assert len(images) == 1
+
+    def test_replicate_delivery(self):
+        content = "![](https://replicate.delivery/pbxt/abc/output)"
+        images, _ = BasePlatformAdapter.extract_images(content)
+        assert len(images) == 1
+
+    def test_non_image_ext_not_extracted(self):
+        """Markdown image with non-image extension should not be extracted."""
+        content = "![doc](https://example.com/report.pdf)"
+        images, cleaned = BasePlatformAdapter.extract_images(content)
+        assert images == []
+        assert "![doc]" in cleaned  # Should be preserved
+
+    def test_html_img_tag(self):
+        content = 'Check this: <img src="https://example.com/photo.png">'
+        images, cleaned = BasePlatformAdapter.extract_images(content)
+        assert len(images) == 1
+        assert images[0][0] == "https://example.com/photo.png"
+        assert images[0][1] == ""  # HTML images have no alt text
+        assert "<img" not in cleaned
+
+    def test_html_img_self_closing(self):
+        content = '<img src="https://example.com/photo.png"/>'
+        images, _ = BasePlatformAdapter.extract_images(content)
+        assert len(images) == 1
+
+    def test_html_img_with_closing_tag(self):
+        content = '<img src="https://example.com/photo.png"></img>'
+        images, _ = BasePlatformAdapter.extract_images(content)
+        assert len(images) == 1
+
+    def test_multiple_images(self):
+        content = "![a](https://example.com/a.png)\n![b](https://example.com/b.jpg)"
+        images, cleaned = BasePlatformAdapter.extract_images(content)
+        assert len(images) == 2
+        assert "![a]" not in cleaned
+        assert "![b]" not in cleaned
+
+    def test_mixed_markdown_and_html(self):
+        content = '![cat](https://example.com/cat.png)\n<img src="https://example.com/dog.jpg">'
+        images, _ = BasePlatformAdapter.extract_images(content)
+        assert len(images) == 2
+
+    def test_cleaned_content_trims_excess_newlines(self):
+        content = "Before\n\n![img](https://example.com/img.png)\n\n\n\nAfter"
+        _, cleaned = BasePlatformAdapter.extract_images(content)
+        assert "\n\n\n" not in cleaned
+
+    def test_non_http_url_not_matched(self):
+        content = "![file](file:///local/path.png)"
+        images, _ = BasePlatformAdapter.extract_images(content)
+        assert images == []
+
+    def test_non_image_link_preserved_when_mixed_with_images(self):
+        """Regression: non-image markdown links must not be silently removed
+        when the response also contains real images."""
+        content = (
+            "Here is the image: ![photo](https://fal.media/cat.png)\n"
+            "And a doc: ![report](https://example.com/report.pdf)"
+        )
+        images, cleaned = BasePlatformAdapter.extract_images(content)
+        assert len(images) == 1
+        assert images[0][0] == "https://fal.media/cat.png"
+        # The PDF link must survive in cleaned content
+        assert "![report](https://example.com/report.pdf)" in cleaned
+
+
+# ---------------------------------------------------------------------------
+# extract_media
+# ---------------------------------------------------------------------------
+
+
+class TestExtractMedia:
+    def test_no_media(self):
+        media, cleaned = BasePlatformAdapter.extract_media("Just text.")
+        assert media == []
+        assert cleaned == "Just text."
+
+    def test_single_media_tag(self):
+        content = "MEDIA:/path/to/audio.ogg"
+        media, cleaned = BasePlatformAdapter.extract_media(content)
+        assert len(media) == 1
+        assert media[0][0] == "/path/to/audio.ogg"
+        assert media[0][1] is False  # no voice tag
+
+    def test_media_with_voice_directive(self):
+        content = "[[audio_as_voice]]\nMEDIA:/path/to/voice.ogg"
+        media, cleaned = BasePlatformAdapter.extract_media(content)
+        assert len(media) == 1
+        assert media[0][0] == "/path/to/voice.ogg"
+        assert media[0][1] is True  # voice tag present
+
+    def test_multiple_media_tags(self):
+        content = "MEDIA:/a.ogg\nMEDIA:/b.ogg"
+        media, _ = BasePlatformAdapter.extract_media(content)
+        assert len(media) == 2
+
+    def test_voice_directive_removed_from_content(self):
+        content = "[[audio_as_voice]]\nSome text\nMEDIA:/voice.ogg"
+        _, cleaned = BasePlatformAdapter.extract_media(content)
+        assert "[[audio_as_voice]]" not in cleaned
+        assert "MEDIA:" not in cleaned
+        assert "Some text" in cleaned
+
+    def test_media_with_text_before(self):
+        content = "Here is your audio:\nMEDIA:/output.ogg"
+        media, cleaned = BasePlatformAdapter.extract_media(content)
+        assert len(media) == 1
+        assert "Here is your audio" in cleaned
+
+    def test_cleaned_content_trims_excess_newlines(self):
+        content = "Before\n\nMEDIA:/audio.ogg\n\n\n\nAfter"
+        _, cleaned = BasePlatformAdapter.extract_media(content)
+        assert "\n\n\n" not in cleaned
+
+
+# ---------------------------------------------------------------------------
+# truncate_message
+# ---------------------------------------------------------------------------
+
+
+class TestTruncateMessage:
+    def _adapter(self):
+        """Create a minimal adapter instance for testing static/instance methods."""
+        class StubAdapter(BasePlatformAdapter):
+            async def connect(self): return True
+            async def disconnect(self): pass
+            async def send(self, *a, **kw): pass
+            async def get_chat_info(self, *a): return {}
+
+        from gateway.config import Platform, PlatformConfig
+        config = PlatformConfig(enabled=True, token="test")
+        return StubAdapter(config=config, platform=Platform.TELEGRAM)
+
+    def test_short_message_single_chunk(self):
+        adapter = self._adapter()
+        chunks = adapter.truncate_message("Hello world", max_length=100)
+        assert chunks == ["Hello world"]
+
+    def test_exact_length_single_chunk(self):
+        adapter = self._adapter()
+        msg = "x" * 100
+        chunks = adapter.truncate_message(msg, max_length=100)
+        assert chunks == [msg]
+
+    def test_long_message_splits(self):
+        adapter = self._adapter()
+        msg = "word " * 200  # ~1000 chars
+        chunks = adapter.truncate_message(msg, max_length=200)
+        assert len(chunks) > 1
+
+    def test_chunks_have_indicators(self):
+        adapter = self._adapter()
+        msg = "word " * 200
+        chunks = adapter.truncate_message(msg, max_length=200)
+        assert "(1/" in chunks[0]
+        assert f"({len(chunks)}/{len(chunks)})" in chunks[-1]
+
+    def test_code_block_first_chunk_closed(self):
+        adapter = self._adapter()
+        msg = "Before\n```python\n" + "x = 1\n" * 100 + "```\nAfter"
+        chunks = adapter.truncate_message(msg, max_length=300)
+        assert len(chunks) > 1
+        # First chunk must have a closing fence appended (code block was split)
+        first_fences = chunks[0].count("```")
+        assert first_fences == 2, "First chunk should have opening + closing fence"
+
+    def test_code_block_language_tag_carried(self):
+        adapter = self._adapter()
+        msg = "Start\n```javascript\n" + "console.log('x');\n" * 80 + "```\nEnd"
+        chunks = adapter.truncate_message(msg, max_length=300)
+        if len(chunks) > 1:
+            # At least one continuation chunk should reopen with ```javascript
+            reopened_with_lang = any(
+                "```javascript" in chunk for chunk in chunks[1:]
+            )
+            assert reopened_with_lang, "No continuation chunk reopened with language tag"
+
+    def test_continuation_chunks_have_balanced_fences(self):
+        """Regression: continuation chunks must close reopened code blocks."""
+        adapter = self._adapter()
+        msg = "Before\n```python\n" + "x = 1\n" * 100 + "```\nAfter"
+        chunks = adapter.truncate_message(msg, max_length=300)
+        assert len(chunks) > 1
+        for i, chunk in enumerate(chunks):
+            fence_count = chunk.count("```")
+            assert fence_count % 2 == 0, (
+                f"Chunk {i} has unbalanced fences ({fence_count})"
+            )
+
+    def test_each_chunk_under_max_length(self):
+        adapter = self._adapter()
+        msg = "word " * 500
+        max_len = 200
+        chunks = adapter.truncate_message(msg, max_length=max_len)
+        for i, chunk in enumerate(chunks):
+            assert len(chunk) <= max_len + 20, f"Chunk {i} too long: {len(chunk)} > {max_len}"
+
+
+# ---------------------------------------------------------------------------
+# _get_human_delay
+# ---------------------------------------------------------------------------
+
+
+class TestGetHumanDelay:
+    def test_off_mode(self):
+        with patch.dict(os.environ, {"HERMES_HUMAN_DELAY_MODE": "off"}):
+            assert BasePlatformAdapter._get_human_delay() == 0.0
+
+    def test_default_is_off(self):
+        with patch.dict(os.environ, {}, clear=False):
+            os.environ.pop("HERMES_HUMAN_DELAY_MODE", None)
+            assert BasePlatformAdapter._get_human_delay() == 0.0
+
+    def test_natural_mode_range(self):
+        with patch.dict(os.environ, {"HERMES_HUMAN_DELAY_MODE": "natural"}):
+            delay = BasePlatformAdapter._get_human_delay()
+            assert 0.8 <= delay <= 2.5
+
+    def test_custom_mode_uses_env_vars(self):
+        env = {
+            "HERMES_HUMAN_DELAY_MODE": "custom",
+            "HERMES_HUMAN_DELAY_MIN_MS": "100",
+            "HERMES_HUMAN_DELAY_MAX_MS": "200",
+        }
+        with patch.dict(os.environ, env):
+            delay = BasePlatformAdapter._get_human_delay()
+            assert 0.1 <= delay <= 0.2