from fastapi import FastAPI, HTTPException
from fastapi.middleware.cors import CORSMiddleware
from pydantic import BaseModel
from sqlalchemy import select
from sqlalchemy.exc import SQLAlchemyError

from dependencies import SessionDep
from models import Todo

app = FastAPI()
app.add_middleware(
        CORSMiddleware,
        allow_origins=["*"],
        allow_credentials=True,
        allow_methods=["*"],
        allow_headers=["*"],
)

class todocreate(BaseModel):
    task: str

class todoupdate(BaseModel):
    completion: bool  | None = None
    task: str | None = None

class todoresponse(BaseModel):
    id: int
    task: str
    completion: bool
@app.get("/health")
def health():
    return {"status":"ok"}

@app.get("/todos", response_model=list[todoresponse])
def todos_get(session: SessionDep):
    statement = select(Todo)
    todos = session.scalars(statement).all()
    return todos

@app.post("/todos", response_model=todoresponse)
def todos_create(
    todo_data: todocreate,
    session: SessionDep,
):
    try:
        new_todo = Todo(task=todo_data.task)
        session.add(new_todo)
        session.commit()
        return new_todo
    except SQLAlchemyError:
        session.rollback()
        raise


@app.patch("/todos/{todo_id}", response_model=todoresponse)
def todos_patch(
    todo_id: int,
    update_data: todoupdate,
    session: SessionDep,
):
    try:
        todo = session.get(Todo, todo_id)
        if todo is None:
            raise HTTPException(status_code = 404, detail = "Todo not found")
        if update_data.task is not None:
            todo.task = update_data.task
        if update_data.completion is not None:
            todo.completion = update_data.completion
        session.commit()
        return todo
    except SQLAlchemyError:
        session.rollback()
        raise


@app.delete("/todos/{todo_id}", response_model=todoresponse)
def todos_delete(
    todo_id: int,
    session: SessionDep,
):
    try:
        todo = session.get(Todo, todo_id)
        if todo is None:
            raise HTTPException(status_code = 404, detail = "Todo not found")
        session.delete(todo)
        session.commit()
        return todo
    except SQLAlchemyError:
        session.rollback()
        raise