from fastapi import APIRouter, Depends, HTTPException, status, Query
from sqlalchemy.orm import Session
from typing import List, Optional

from app.db.database import get_db
from app.models.todo import Todo as TodoModel
from app.schemas.todo import Todo, TodoCreate, TodoUpdate

router = APIRouter(
    prefix="/todos",
    tags=["todos"]
)

@router.post("/", response_model=Todo, status_code=status.HTTP_201_CREATED)
def create_todo(todo: TodoCreate, db: Session = Depends(get_db)):
    db_todo = TodoModel(**todo.dict())
    db.add(db_todo)
    db.commit()
    db.refresh(db_todo)
    return db_todo

@router.get("/", response_model=List[Todo])
def read_todos(
    skip: int = 0,
    limit: int = 100,
    priority: Optional[int] = Query(None, ge=1, le=3, description="Filter by priority (1=Low, 2=Medium, 3=High)"),
    db: Session = Depends(get_db)
):
    query = db.query(TodoModel)

    if priority is not None:
        query = query.filter(TodoModel.priority == priority)

    todos = query.offset(skip).limit(limit).all()
    return todos

@router.get("/{todo_id}", response_model=Todo)
def read_todo(todo_id: int, db: Session = Depends(get_db)):
    db_todo = db.query(TodoModel).filter(TodoModel.id == todo_id).first()
    if db_todo is None:
        raise HTTPException(status_code=404, detail="Todo not found")
    return db_todo

@router.put("/{todo_id}", response_model=Todo)
def update_todo(todo_id: int, todo: TodoUpdate, db: Session = Depends(get_db)):
    db_todo = db.query(TodoModel).filter(TodoModel.id == todo_id).first()
    if db_todo is None:
        raise HTTPException(status_code=404, detail="Todo not found")
    
    update_data = todo.dict(exclude_unset=True)
    for key, value in update_data.items():
        setattr(db_todo, key, value)
    
    db.commit()
    db.refresh(db_todo)
    return db_todo

@router.delete("/{todo_id}", status_code=status.HTTP_204_NO_CONTENT)
def delete_todo(todo_id: int, db: Session = Depends(get_db)):
    db_todo = db.query(TodoModel).filter(TodoModel.id == todo_id).first()
    if db_todo is None:
        raise HTTPException(status_code=404, detail="Todo not found")
    
    db.delete(db_todo)
    db.commit()
    return None