"""Push notifications about new mail: the server's public key, and the devices
that want them (Settings → Accounts → Notifications)."""

from __future__ import annotations

from typing import Annotated

from fastapi import APIRouter, Depends, Request
from pydantic import BaseModel, Field
from sqlalchemy.ext.asyncio import AsyncSession

from app.api.errors import raise_api_error
from app.db import get_session
from app.identity.deps import CurrentSession, CurrentUser, require_csrf
from app.push import service, webpush

router = APIRouter(prefix="/push", tags=["push"], dependencies=[Depends(require_csrf)])

DbSession = Annotated[AsyncSession, Depends(get_session)]


class PushKeyOut(BaseModel):
    public_key: str


class PushKeys(BaseModel):
    p256dh: str = Field(min_length=1, max_length=200)
    auth: str = Field(min_length=1, max_length=100)


class SubscriptionIn(BaseModel):
    """The browser's ``PushSubscription.toJSON()``."""

    endpoint: str = Field(min_length=1, max_length=2000)
    keys: PushKeys


class EndpointIn(BaseModel):
    endpoint: str = Field(min_length=1, max_length=2000)


@router.get("/key", response_model=PushKeyOut)
async def push_key(user: CurrentUser, db: DbSession) -> PushKeyOut:
    """The key a browser subscribes with (``applicationServerKey``)."""
    return PushKeyOut(public_key=(await service.vapid(db)).public_b64)


@router.post("/subscriptions")
async def add_subscription(
    body: SubscriptionIn,
    request: Request,
    user: CurrentUser,
    session: CurrentSession,
    db: DbSession,
) -> dict[str, str]:
    if not webpush.allowed_endpoint(body.endpoint):
        raise_api_error(400, "push_service", "not a known push service")
    try:
        p256dh = webpush.b64u_decode(body.keys.p256dh)
        auth = webpush.b64u_decode(body.keys.auth)
        if len(p256dh) != 65 or len(auth) != 16:
            raise ValueError
    except ValueError:
        raise_api_error(400, "push_keys", "invalid subscription keys")
    await service.subscribe(
        db,
        user_id=user.id,
        session_sid=session.sid,
        endpoint=body.endpoint,
        p256dh=body.keys.p256dh,
        auth=body.keys.auth,
        user_agent=request.headers.get("user-agent", ""),
    )
    return {"status": "ok"}


@router.post("/subscriptions/remove")
async def remove_subscription(body: EndpointIn, user: CurrentUser, db: DbSession) -> dict[str, str]:
    await service.unsubscribe(db, user_id=user.id, endpoint=body.endpoint)
    return {"status": "ok"}