stage-4: discord bot minimal with channel/admin management

Discord.py bot with slash commands (/ping, /help, /setup, /channel, /admin), PID file, graceful shutdown. 30 new tests (119 total).

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

src/adapters/discord_bot.py

@@ -0,0 +1,198 @@
+"""Discord bot adapter — slash commands and event handlers."""
+
+import logging
+
+import discord
+from discord import app_commands
+
+from src.config import Config
+
+logger = logging.getLogger("echo-core.discord")
+
+# Module-level config reference, set by create_bot()
+_config: Config | None = None
+
+
+def _get_config() -> Config:
+    """Return the module-level config, raising if not initialized."""
+    if _config is None:
+        raise RuntimeError("Bot not initialized — call create_bot() first")
+    return _config
+
+
+# --- Authorization helpers ---
+
+
+def is_owner(user_id: str) -> bool:
+    """Check if user_id matches config bot.owner."""
+    return _get_config().get("bot.owner") == user_id
+
+
+def is_admin(user_id: str) -> bool:
+    """Check if user_id is owner or in admins list."""
+    if is_owner(user_id):
+        return True
+    admins = _get_config().get("bot.admins", [])
+    return user_id in admins
+
+
+def is_registered_channel(channel_id: str) -> bool:
+    """Check if channel_id is in any registered channel entry."""
+    channels = _get_config().get("channels", {})
+    return any(ch.get("id") == channel_id for ch in channels.values())
+
+
+# --- Factory ---
+
+
+def create_bot(config: Config) -> discord.Client:
+    """Create and configure the Discord bot with all slash commands."""
+    global _config
+    _config = config
+
+    intents = discord.Intents.default()
+    intents.message_content = True
+
+    client = discord.Client(intents=intents)
+    tree = app_commands.CommandTree(client)
+    client.tree = tree  # type: ignore[attr-defined]
+
+    # --- Slash commands ---
+
+    @tree.command(name="ping", description="Check bot latency")
+    async def ping(interaction: discord.Interaction) -> None:
+        latency_ms = round(client.latency * 1000)
+        await interaction.response.send_message(
+            f"Pong! Latency: {latency_ms}ms", ephemeral=True
+        )
+
+    @tree.command(name="help", description="List available commands")
+    async def help_cmd(interaction: discord.Interaction) -> None:
+        lines = [
+            "**Echo Commands**",
+            "`/ping` — Check bot latency",
+            "`/help` — Show this help message",
+            "`/setup` — Claim ownership of the bot (first run only)",
+            "`/channel add <alias>` — Register current channel (owner only)",
+            "`/channels` — List registered channels",
+            "`/admin add <user_id>` — Add an admin (owner only)",
+        ]
+        await interaction.response.send_message(
+            "\n".join(lines), ephemeral=True
+        )
+
+    @tree.command(name="setup", description="Claim ownership of the bot")
+    async def setup(interaction: discord.Interaction) -> None:
+        if config.get("bot.owner") is not None:
+            await interaction.response.send_message(
+                "Owner already set.", ephemeral=True
+            )
+            return
+        config.set("bot.owner", str(interaction.user.id))
+        config.save()
+        await interaction.response.send_message(
+            "You are now the owner of Echo.", ephemeral=True
+        )
+
+    channel_group = app_commands.Group(
+        name="channel", description="Channel management"
+    )
+
+    @channel_group.command(name="add", description="Register current channel")
+    @app_commands.describe(alias="Short name for this channel")
+    async def channel_add(
+        interaction: discord.Interaction, alias: str
+    ) -> None:
+        if not is_owner(str(interaction.user.id)):
+            await interaction.response.send_message(
+                "Owner only.", ephemeral=True
+            )
+            return
+        config.set(
+            f"channels.{alias}",
+            {"id": str(interaction.channel_id), "default_model": "sonnet"},
+        )
+        config.save()
+        await interaction.response.send_message(
+            f"Channel registered as '{alias}'.", ephemeral=True
+        )
+
+    tree.add_command(channel_group)
+
+    admin_group = app_commands.Group(
+        name="admin", description="Admin management"
+    )
+
+    @admin_group.command(name="add", description="Add an admin user")
+    @app_commands.describe(user_id="Discord user ID to add as admin")
+    async def admin_add(
+        interaction: discord.Interaction, user_id: str
+    ) -> None:
+        if not is_owner(str(interaction.user.id)):
+            await interaction.response.send_message(
+                "Owner only.", ephemeral=True
+            )
+            return
+        admins = config.get("bot.admins", [])
+        if user_id not in admins:
+            admins.append(user_id)
+            config.set("bot.admins", admins)
+            config.save()
+        await interaction.response.send_message(
+            f"User {user_id} added as admin.", ephemeral=True
+        )
+
+    tree.add_command(admin_group)
+
+    @tree.command(name="channels", description="List registered channels")
+    async def channels(interaction: discord.Interaction) -> None:
+        ch_map = config.get("channels", {})
+        if not ch_map:
+            await interaction.response.send_message(
+                "No channels registered yet.", ephemeral=True
+            )
+            return
+        lines = []
+        for alias, info in ch_map.items():
+            cid = info.get("id", "?")
+            model = info.get("default_model", "?")
+            lines.append(f"\u2022 {alias} \u2192 <#{cid}> (model: {model})")
+        await interaction.response.send_message(
+            "\n".join(lines), ephemeral=True
+        )
+
+    # --- Events ---
+
+    @client.event
+    async def on_ready() -> None:
+        await tree.sync()
+        logger.info("Echo Core online as %s", client.user)
+
+    @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
+        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
+
+        # Guild messages: ignore if channel not registered
+        if not is_registered_channel(str(message.channel.id)):
+            return
+
+        logger.info(
+            "Message in registered channel %s from %s: %s",
+            message.channel,
+            message.author,
+            message.content[:100],
+        )
+        # Stage 5 will add chat integration here
+
+    return client