from contextlib import asynccontextmanager
from typing import Annotated, Union

import starlette.status as status
from fastapi import Depends, FastAPI, Request
from fastapi.responses import RedirectResponse
from fastapi.staticfiles import StaticFiles
from fastapi.templating import Jinja2Templates
from sqlmodel import Session, SQLModel, create_engine, select

from models import Event, Household, Registration

sqlite_file_name = "database.db"
sqlite_url = f"sqlite:///{sqlite_file_name}"

connect_args = {"check_same_thread": False}
engine = create_engine(sqlite_url, connect_args=connect_args)


def get_session():
    with Session(engine) as session:
        yield session


def create_db_and_tables():
    SQLModel.metadata.create_all(engine)


@asynccontextmanager
async def on_startup(app_: FastAPI):
    create_db_and_tables()
    yield


app = FastAPI(lifespan=on_startup)
app.mount("/static", StaticFiles(directory="static"), name="static")

templates = Jinja2Templates(directory="templates")

SessionDep = Annotated[Session, Depends(get_session)]


@app.get("/")
async def read_root(request: Request, session: SessionDep):
    statement = select(Event).order_by(Event.event_time)
    events = session.exec(statement).all()
    return templates.TemplateResponse(
        request=request, name="index.html", context={"events": events}
    )


@app.get("/event/{event_id}")
async def read_event(request: Request, event_id: int, session: SessionDep):
    statement = select(Event).where(Event.id == event_id)
    event = session.exec(statement).one()

    statement = select(Household)
    households = session.exec(statement).all()
    return templates.TemplateResponse(
        request=request,
        name="event.html",
        context={"event": event, "households": households},
    )


@app.post("/event/{event_id}/register")
async def add_registration(request: Request, event_id: int, session: SessionDep):
    form_data = await request.form()

    # TODO: Make this return a nicer error message
    try:
        num_adult_meals = int(form_data["numAdults"]) if form_data["numAdults"] else 0
        num_children_meals = int(form_data["numKids"]) if form_data["numKids"] else 0
        num_small_children_meals = (
            int(form_data["numSmallKids"]) if form_data["numSmallKids"] else 0
        )
    except ValueError:
        raise ValueError("All number fields must be integers")

    registration = Registration(
        household_id=form_data["household"],
        event_id=event_id,
        num_adult_meals=num_adult_meals,
        num_children_meals=num_children_meals,
        num_small_children_meals=num_small_children_meals,
    )
    session.add(registration)
    session.commit()
    return RedirectResponse(url=f"/event/{event_id}", status_code=status.HTTP_302_FOUND)


@app.get("/event/{event_id}/registration/{household_id}/delete")
async def delete_registration(
    request: Request, event_id: int, household_id: int, session: SessionDep
):
    """
    Deletes a registration record for a specific household at a given event. This endpoint
    handles the removal of the registration, commits the change to the database, and
    redirects the user to the event page.
    """
    statement = select(Registration).where(
        Registration.household_id == household_id, Registration.event_id == event_id
    )
    session.delete(session.exec(statement).one())
    session.commit()
    return RedirectResponse(url=f"/event/{event_id}", status_code=status.HTTP_302_FOUND)