From 61a3586caf0729f76a10ae5c40281c2f5b4bda50 Mon Sep 17 00:00:00 2001
From: Anish Sarkar <104695310+AnishSarkar22@users.noreply.github.com>
Date: Mon, 1 Jun 2026 12:36:39 +0530
Subject: [PATCH] feat(gateway): handle Slack thread replies

---
 .../app/gateway/slack/commands.py             | 64 ++++++++++++++
 .../app/gateway/slack/translator.py           | 86 +++++++++++++++++++
 2 files changed, 150 insertions(+)
 create mode 100644 surfsense_backend/app/gateway/slack/commands.py
 create mode 100644 surfsense_backend/app/gateway/slack/translator.py

diff --git a/surfsense_backend/app/gateway/slack/commands.py b/surfsense_backend/app/gateway/slack/commands.py
new file mode 100644
index 000000000..ffbd5863b
--- /dev/null
+++ b/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}"
+            ),
+        )
diff --git a/surfsense_backend/app/gateway/slack/translator.py b/surfsense_backend/app/gateway/slack/translator.py
new file mode 100644
index 000000000..658b0cac7
--- /dev/null
+++ b/surfsense_backend/app/gateway/slack/translator.py
@@ -0,0 +1,86 @@
+"""Translate agent stream events into Slack thread replies."""
+
+from __future__ import annotations
+
+import logging
+from collections.abc import AsyncIterator
+
+from app.gateway.base.adapter import PlatformSendResult
+from app.gateway.base.formatting import split_text_message
+from app.gateway.base.translator import BaseStreamTranslator, GatewayStreamEvent
+from app.gateway.ratelimit import wait_for_token
+from app.gateway.slack.adapter import SlackAdapter
+from app.observability.metrics import (
+    record_gateway_hitl_aborted,
+    record_gateway_outbound,
+    record_gateway_rate_limit_hit,
+)
+
+logger = logging.getLogger(__name__)
+
+SLACK_MAX_MESSAGE_CHARS = 35000
+HITL_UNSUPPORTED_MESSAGE = (
+    "This action requires approval and is not yet supported from Slack. "
+    "Try again with a different request."
+)
+
+
+class SlackStreamTranslator(BaseStreamTranslator):
+    def __init__(
+        self,
+        *,
+        adapter: SlackAdapter,
+        channel_id: str,
+        thread_ts: str,
+    ) -> None:
+        self.adapter = adapter
+        self.channel_id = channel_id
+        self.thread_ts = thread_ts
+        self._buffer = ""
+
+    async def translate(self, events: AsyncIterator[GatewayStreamEvent]) -> None:
+        async for event in events:
+            if event.type in {"text-delta", "text_delta", "text"}:
+                self._buffer += str(event.data.get("text") or event.data.get("delta") or "")
+            elif event.type in {"data-interrupt-request", "interrupt"}:
+                await self._handle_hitl_interrupt()
+                return
+            elif event.type in {"finish", "done"}:
+                break
+
+        await self._flush_final()
+
+    async def _flush_final(self) -> None:
+        if not self._buffer:
+            return
+        for chunk in split_text_message(self._buffer, max_chars=SLACK_MAX_MESSAGE_CHARS):
+            await self._send_text(chunk)
+
+    async def _send_text(self, text: str) -> PlatformSendResult:
+        await self._throttle()
+        try:
+            result = await self.adapter.send_message(
+                external_peer_id=self.channel_id,
+                text=text,
+                reply_to_message_id=self.thread_ts,
+            )
+        except Exception:
+            record_gateway_outbound(platform="slack", kind="send", status="failed")
+            raise
+        record_gateway_outbound(platform="slack", kind="send", status="sent")
+        return result
+
+    async def _throttle(self) -> None:
+        chat_wait = await wait_for_token(
+            f"slack:channel:{self.channel_id}",
+            capacity=1,
+            refill_per_sec=1.0,
+        )
+        if chat_wait:
+            record_gateway_rate_limit_hit(bucket="slack:channel")
+
+    async def _handle_hitl_interrupt(self) -> None:
+        if self._buffer:
+            await self._flush_final()
+        await self._send_text(HITL_UNSUPPORTED_MESSAGE)
+        record_gateway_hitl_aborted(platform="slack")