feat(backend): add durable MAX linking and notification queue

Refs #82

app/api/max_notifications.py

@@ -0,0 +1,110 @@
+"""Server API for a future MAX connect UI; webhook processing is supplied by the channel adapter."""
+
+import hmac
+import json
+import re
+from datetime import datetime
+from typing import Annotated, Literal
+
+from fastapi import APIRouter, Depends, HTTPException, Request
+from fastapi.security import HTTPAuthorizationCredentials, HTTPBearer
+from pydantic import BaseModel, ConfigDict
+from sqlalchemy import select
+
+from app.config import get_settings
+from app.core import clock
+from app.db import repo
+from app.db.max_notifications import MaxBinding, MaxDelivery
+from app.db.session import get_clinical_session, get_identity_session
+from app.integrations import max_store
+
+router = APIRouter(tags=["max-notifications"])
+bearer = HTTPBearer(auto_error=False)
+
+
+async def patient_token(auth: Annotated[HTTPAuthorizationCredentials | None, Depends(bearer)]) -> str:
+    if auth is None or auth.scheme.lower() != "bearer" or not re.fullmatch(r"[A-Za-z0-9_-]{1,64}", auth.credentials):
+        raise HTTPException(401, "patient authentication required", headers={"WWW-Authenticate": "Bearer"})
+    async with get_clinical_session() as session:
+        if await repo.get_profile(session, auth.credentials) is None:
+            raise HTTPException(401, "patient authentication required")
+    return auth.credentials
+
+
+PatientToken = Annotated[str, Depends(patient_token)]
+
+
+class MaxStatus(BaseModel):
+    available: bool
+    connected: bool
+    last_delivery: str | None = None
+
+
+class LinkConsent(BaseModel):
+    model_config = ConfigDict(extra="forbid")
+    consent: Literal[True]
+
+
+class MaxLink(BaseModel):
+    url: str
+    expires_at: datetime
+
+
+@router.get("/me/notifications/max", response_model=MaxStatus)
+async def status(token: PatientToken) -> MaxStatus:
+    async with get_identity_session() as session:
+        binding = await session.get(MaxBinding, token)
+        last = await session.scalar(
+            select(MaxDelivery.state)
+            .where(MaxDelivery.token == token)
+            .order_by(MaxDelivery.created_at.desc(), MaxDelivery.id.desc())
+            .limit(1)
+        )
+    return MaxStatus(
+        available=get_settings().max_enabled, connected=bool(binding and binding.enabled), last_delivery=last
+    )
+
+
+@router.post("/me/notifications/max/link", response_model=MaxLink)
+async def link(body: LinkConsent, token: PatientToken) -> MaxLink:
+    settings = get_settings()
+    if not settings.max_enabled:
+        raise HTTPException(503, "MAX is not configured")
+    if not await max_store.active_patient(token):
+        raise HTTPException(403, "active consent and adult confirmation required")
+    async with get_identity_session() as session:
+        raw, expires = await max_store.issue_code(session, token, clock.now(), settings.max_link_ttl_seconds)
+    return MaxLink(url=f"https://max.ru/{settings.max_bot_username}?start={raw}", expires_at=expires)
+
+
+@router.delete("/me/notifications/max", response_model=MaxStatus)
+async def unlink(token: PatientToken) -> MaxStatus:
+    async with get_identity_session() as session:
+        await max_store.disconnect(session, token)
+    return MaxStatus(available=get_settings().max_enabled, connected=False)
+
+
+@router.post("/webhooks/max")
+async def webhook(request: Request) -> dict[str, bool]:
+    settings = get_settings()
+    if not settings.max_enabled:
+        raise HTTPException(503, "MAX is not configured")
+    expected = settings.max_webhook_secret.get_secret_value().encode()
+    supplied = request.headers.get("X-Max-Bot-Api-Secret", "").encode()
+    if not expected or not hmac.compare_digest(supplied, expected):
+        raise HTTPException(403, "invalid webhook secret")
+    raw = bytearray()
+    async for chunk in request.stream():
+        raw.extend(chunk)
+        if len(raw) > 65536:
+            raise HTTPException(413, "event is too large")
+    try:
+        event = json.loads(raw)
+    except (ValueError, UnicodeError) as exc:
+        raise HTTPException(400, "invalid JSON") from exc
+    if not isinstance(event, dict):
+        raise HTTPException(422, "event must be an object")
+    from app.channels.max_bot import handle_update
+
+    await handle_update(event)
+    return {"success": True}