stage-5: full discord-claude chat integration

Message router, typing indicator, emoji reactions, auto start/resume sessions, message splitting >2000 chars. 34 new tests (141 total).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/adapters/discord_bot.py

@@ -1,11 +1,14 @@
 """Discord bot adapter — slash commands and event handlers."""
 
+import asyncio
 import logging
 
 import discord
 from discord import app_commands
 
 from src.config import Config
+from src.claude_session import clear_session, get_active_session
+from src.router import route_message
 
 logger = logging.getLogger("echo-core.discord")
 
@@ -42,6 +45,28 @@ def is_registered_channel(channel_id: str) -> bool:
     return any(ch.get("id") == channel_id for ch in channels.values())
 
 
+# --- Message splitting helper ---
+
+
+def split_message(text: str, limit: int = 2000) -> list[str]:
+    """Split text into chunks that fit Discord's message limit."""
+    if len(text) <= limit:
+        return [text]
+
+    chunks = []
+    while text:
+        if len(text) <= limit:
+            chunks.append(text)
+            break
+        # Find last newline before limit
+        split_at = text.rfind('\n', 0, limit)
+        if split_at == -1:
+            split_at = limit
+        chunks.append(text[:split_at])
+        text = text[split_at:].lstrip('\n')
+    return chunks
+
+
 # --- Factory ---
 
 
@@ -76,6 +101,8 @@ def create_bot(config: Config) -> discord.Client:
             "`/channel add <alias>` — Register current channel (owner only)",
             "`/channels` — List registered channels",
             "`/admin add <user_id>` — Add an admin (owner only)",
+            "`/clear` — Clear the session for this channel",
+            "`/status` — Show session status for this channel",
         ]
         await interaction.response.send_message(
             "\n".join(lines), ephemeral=True
@@ -161,6 +188,39 @@ def create_bot(config: Config) -> discord.Client:
             "\n".join(lines), ephemeral=True
         )
 
+    @tree.command(name="clear", description="Clear the session for this channel")
+    async def clear(interaction: discord.Interaction) -> None:
+        channel_id = str(interaction.channel_id)
+        removed = clear_session(channel_id)
+        if removed:
+            await interaction.response.send_message(
+                "Session cleared.", ephemeral=True
+            )
+        else:
+            await interaction.response.send_message(
+                "No active session for this channel.", ephemeral=True
+            )
+
+    @tree.command(name="status", description="Show session status")
+    async def status(interaction: discord.Interaction) -> None:
+        channel_id = str(interaction.channel_id)
+        session = get_active_session(channel_id)
+        if session is None:
+            await interaction.response.send_message(
+                "No active session.", ephemeral=True
+            )
+            return
+        sid = session.get("session_id", "?")
+        truncated_sid = sid[:8] + "..." if len(sid) > 8 else sid
+        model = session.get("model", "?")
+        count = session.get("message_count", 0)
+        await interaction.response.send_message(
+            f"**Model:** {model}\n"
+            f"**Session:** `{truncated_sid}`\n"
+            f"**Messages:** {count}",
+            ephemeral=True,
+        )
+
     # --- Events ---
 
     @client.event
@@ -168,20 +228,51 @@ def create_bot(config: Config) -> discord.Client:
         await tree.sync()
         logger.info("Echo Core online as %s", client.user)
 
+    async def _handle_chat(message: discord.Message) -> None:
+        """Process a chat message through the router and send the response."""
+        channel_id = str(message.channel.id)
+        user_id = str(message.author.id)
+        text = message.content
+
+        # React to acknowledge receipt
+        await message.add_reaction("\U0001f440")
+
+        try:
+            async with message.channel.typing():
+                response = await asyncio.to_thread(
+                    route_message, channel_id, user_id, text
+                )
+
+            chunks = split_message(response)
+            for chunk in chunks:
+                await message.channel.send(chunk)
+        except Exception:
+            logger.exception("Error processing message from %s", message.author)
+            await message.channel.send(
+                "Sorry, something went wrong processing your message."
+            )
+        finally:
+            # Remove the eyes reaction
+            try:
+                await message.remove_reaction("\U0001f440", client.user)
+            except discord.HTTPException:
+                pass
+
     @client.event
     async def on_message(message: discord.Message) -> None:
         # Ignore bot's own messages
         if message.author == client.user:
             return
 
-        # DM handling: ignore if sender not admin
+        # DM handling: only process if sender is admin
         if isinstance(message.channel, discord.DMChannel):
             if not is_admin(str(message.author.id)):
                 return
             logger.info(
                 "DM from admin %s: %s", message.author, message.content[:100]
             )
-            return  # Stage 5 will add chat integration
+            await _handle_chat(message)
+            return
 
         # Guild messages: ignore if channel not registered
         if not is_registered_channel(str(message.channel.id)):
@@ -193,6 +284,6 @@ def create_bot(config: Config) -> discord.Client:
             message.author,
             message.content[:100],
         )
-        # Stage 5 will add chat integration here
+        await _handle_chat(message)
 
     return client