from fastapi import FastAPI, Depends, HTTPException
from sqlalchemy.orm import Session
from typing import List, Optional

from models import Todo, SessionLocal
from schemas import TodoCreate, TodoResponse

app = FastAPI()

# Dependency to get database session
def get_db():
    db = SessionLocal()
    try:
        yield db
    finally:
        db.close()

@app.post("/todos", response_model=TodoResponse, status_code=201)
def create_todo(todo: TodoCreate, db: Session = Depends(get_db)):
    db_todo = Todo(**todo.model_dump())
    db.add(db_todo)
    db.commit()
    db.refresh(db_todo)
    return db_todo

@app.get("/todos", response_model=List[TodoResponse])
def read_todos(status: Optional[str] = None, db: Session = Depends(get_db)):
    if status:
        todos = db.query(Todo).filter(Todo.status == status).all()
    else:
        todos = db.query(Todo).all()
    return todos

@app.get("/todos/{todo_id}", response_model=TodoResponse)
def read_todo(todo_id: int, db: Session = Depends(get_db)):
    todo = db.query(Todo).filter(Todo.id == todo_id).first()
    if not todo:
        raise HTTPException(status_code=404, detail="Todo not found")
    return todo

@app.put("/todos/{todo_id}", response_model=TodoResponse)
def update_todo(todo_id: int, todo: TodoCreate, db: Session = Depends(get_db)):
    db_todo = db.query(Todo).filter(Todo.id == todo_id).first()
    if not db_todo:
        raise HTTPException(status_code=404, detail="Todo not found")
    for key, value in todo.model_dump().items():
        setattr(db_todo, key, value)
    db.commit()
    db.refresh(db_todo)
    return db_todo

@app.delete("/todos/{todo_id}", status_code=204)
def delete_todo(todo_id: int, db: Session = Depends(get_db)):
    db_todo = db.query(Todo).filter(Todo.id == todo_id).first()
    if not db_todo:
        raise HTTPException(status_code=404, detail="Todo not found")
    db.delete(db_todo)
    db.commit()