Add Slack messaging

slack.py

@@ -0,0 +1,55 @@
+import logging
+import os
+
+from langchain_core.documents import Document
+from slack_sdk import WebClient
+from slack_sdk.errors import SlackApiError
+
+
+def prepare_message_blocks(stories: list[Document]) -> list:
+    blocks = []
+    for story in stories:
+        block = [
+            {
+                "type": "header",
+                "text": {"type": "plain_text", "text": story.metadata["title"]},
+            },
+            {
+                "type": "context",
+                "elements": [
+                    {
+                        "type": "plain_text",
+                        "text": f"Categories: {', '.join(story.metadata.get('categories', []))}",
+                    },
+                ],
+            },
+            {
+                "type": "context",
+                "elements": [
+                    {
+                        "type": "plain_text",
+                        "text": f"Posted on: {story.metadata['created_at']}",
+                    }
+                ],
+            },
+            {"type": "section", "text": {"type": "mrkdwn", "text": story.page_content}},
+        ]
+
+        blocks.append(block)
+    return blocks
+
+
+def send_message(channel: str, text: str) -> None:
+    client = WebClient(token=os.environ["SLACK_BOT_TOKEN"])
+
+    try:
+        response = client.chat_postMessage(
+            channel=channel,
+            username="HN Ragandy",
+            text=text,
+            unfurl_links=False,
+        )
+        response.validate()
+        logging.info(f"Message sent successfully to channel {channel}")
+    except SlackApiError as e:
+        logging.error(f"Error sending message: {e.response['error']}")