feat(gateway): handle Slack thread replies

surfsense_backend/app/gateway/slack/commands.py

@@ -0,0 +1,64 @@
+"""Slack command/onboarding handlers."""
+
+from __future__ import annotations
+
+from app.gateway.base.adapter import ParsedInboundEvent
+from app.gateway.base.commands import BaseGatewayCommands
+from app.gateway.ratelimit import acquire_token
+from app.gateway.slack.adapter import SlackAdapter
+
+HELP_TEXT = (
+    "SurfSense Slack commands:\n"
+    "`/new` - start a fresh SurfSense conversation in this thread\n"
+    "`/help` - show this help\n\n"
+    "Mention the SurfSense bot in a channel thread to ask your agent a question."
+)
+
+
+class SlackGatewayCommands(BaseGatewayCommands):
+    async def handle_help_command(
+        self,
+        *,
+        adapter: SlackAdapter,
+        event: ParsedInboundEvent,
+    ) -> bool:
+        channel_id = event.metadata.get("channel_id")
+        thread_ts = event.metadata.get("thread_ts")
+        if not channel_id or not thread_ts:
+            return True
+        await adapter.send_message(
+            external_peer_id=channel_id,
+            text=HELP_TEXT,
+            reply_to_message_id=thread_ts,
+        )
+        return True
+
+    async def send_unbound_onboarding(
+        self,
+        *,
+        adapter: SlackAdapter,
+        event: ParsedInboundEvent,
+        dashboard_url: str,
+    ) -> None:
+        channel_id = event.metadata.get("channel_id")
+        thread_ts = event.metadata.get("thread_ts")
+        slack_user_id = event.metadata.get("slack_user_id")
+        if not channel_id or not thread_ts:
+            return
+
+        wait_ms = await acquire_token(
+            f"slack:onboarded:{event.metadata.get('team_id')}:{slack_user_id}",
+            capacity=1,
+            refill_per_sec=1 / 3600,
+        )
+        if wait_ms > 0:
+            return
+
+        await adapter.send_message(
+            external_peer_id=channel_id,
+            reply_to_message_id=thread_ts,
+            text=(
+                "Hi! Connect your Slack user to SurfSense before using the bot here: "
+                f"{dashboard_url}"
+            ),
+        )