Add user-owned IM channel connections

backend/app/channels/providers/discord_connect.py

@@ -0,0 +1,110 @@
+"""Discord OAuth helpers for user-owned channel connections."""
+
+from __future__ import annotations
+
+from dataclasses import dataclass
+from datetime import UTC, datetime, timedelta
+from typing import Any
+
+import httpx
+
+DISCORD_API_BASE_URL = "https://discord.com/api/v10"
+DISCORD_TOKEN_URL = f"{DISCORD_API_BASE_URL}/oauth2/token"
+DISCORD_CURRENT_USER_URL = f"{DISCORD_API_BASE_URL}/users/@me"
+DISCORD_CURRENT_USER_GUILDS_URL = f"{DISCORD_API_BASE_URL}/users/@me/guilds"
+
+
+class DiscordConnectError(RuntimeError):
+    """Raised when Discord OAuth fails."""
+
+
+@dataclass(frozen=True)
+class DiscordIdentity:
+    user_id: str
+    display_name: str | None
+    username: str | None
+    guilds: list[dict[str, Any]]
+    access_token: str
+    refresh_token: str | None
+    token_type: str | None
+    scopes: list[str]
+    expires_at: datetime | None
+    raw_token: dict[str, Any]
+
+
+def _split_scopes(value: str | None) -> list[str]:
+    if not value:
+        return []
+    return [scope.strip() for scope in value.replace(",", " ").split() if scope.strip()]
+
+
+def _display_name(user: dict[str, Any]) -> str | None:
+    global_name = user.get("global_name")
+    if isinstance(global_name, str) and global_name:
+        return global_name
+    username = user.get("username")
+    return str(username) if username else None
+
+
+async def complete_discord_oauth(
+    *,
+    client_id: str,
+    client_secret: str,
+    code: str,
+    redirect_uri: str,
+    http_client: httpx.AsyncClient | None = None,
+) -> DiscordIdentity:
+    async def _complete(client: httpx.AsyncClient) -> DiscordIdentity:
+        token_response = await client.post(
+            DISCORD_TOKEN_URL,
+            data={
+                "client_id": client_id,
+                "client_secret": client_secret,
+                "grant_type": "authorization_code",
+                "code": code,
+                "redirect_uri": redirect_uri,
+            },
+            headers={"Content-Type": "application/x-www-form-urlencoded"},
+            timeout=10,
+        )
+        token_response.raise_for_status()
+        token = token_response.json()
+        access_token = token.get("access_token")
+        if not access_token:
+            raise DiscordConnectError("Discord OAuth response did not include an access token")
+
+        auth_headers = {"Authorization": f"Bearer {access_token}"}
+        user_response = await client.get(DISCORD_CURRENT_USER_URL, headers=auth_headers, timeout=10)
+        user_response.raise_for_status()
+        user = user_response.json()
+        user_id = user.get("id")
+        if not user_id:
+            raise DiscordConnectError("Discord user response did not include a user id")
+
+        guilds_response = await client.get(DISCORD_CURRENT_USER_GUILDS_URL, headers=auth_headers, timeout=10)
+        guilds: list[dict[str, Any]] = []
+        if guilds_response.status_code == 200:
+            guilds = guilds_response.json()
+
+        expires_at = None
+        expires_in = token.get("expires_in")
+        if isinstance(expires_in, int | float):
+            expires_at = datetime.now(UTC) + timedelta(seconds=float(expires_in))
+
+        return DiscordIdentity(
+            user_id=str(user_id),
+            display_name=_display_name(user),
+            username=user.get("username"),
+            guilds=guilds,
+            access_token=str(access_token),
+            refresh_token=token.get("refresh_token"),
+            token_type=token.get("token_type"),
+            scopes=_split_scopes(token.get("scope")),
+            expires_at=expires_at,
+            raw_token=token,
+        )
+
+    if http_client is None:
+        async with httpx.AsyncClient() as client:
+            return await _complete(client)
+    return await _complete(http_client)