from fastapi import FastAPI, HTTPException, Depends, Query
from sqlalchemy.orm import Session
from typing import List, Optional
from pydantic.v1 import model_dump

from models import Task, User, Base, engine
from schemas import TaskCreate, TaskResponse
from sqlalchemy.exc import SQLAlchemyError

app = FastAPI()

def get_db():
    db = SessionLocal()
    try:
        yield db
    finally:
        db.close()

@app.post("/tasks/", response_model=TaskResponse, status_code=201)
async def create_task(task: TaskCreate, db: Session = Depends(get_db)):
    db_task = Task(**model_dump(task))
    db.add(db_task)
    try:
        db.commit()
        db.refresh(db_task)
    except SQLAlchemyError as e:
        raise HTTPException(status_code=400, detail=str(e))
    return db_task

@app.get("/tasks/", response_model=List[TaskResponse])
async def read_tasks(
    status: Optional[str] = Query(None),
    db: Session = Depends(get_db)
):
    query = db.query(Task)
    if status:
        query = query.filter(Task.status == status)
    tasks = query.all()
    return tasks

@app.get("/tasks/{task_id}", response_model=TaskResponse)
async def read_task(task_id: int, db: Session = Depends(get_db)):
    task = db.query(Task).filter(Task.id == task_id).first()
    if not task:
        raise HTTPException(status_code=404, detail="Task not found")
    return task

@app.put("/tasks/{task_id}", response_model=TaskResponse)
async def update_task(task_id: int, task: TaskCreate, db: Session = Depends(get_db)):
    db_task = db.query(Task).filter(Task.id == task_id).first()
    if not db_task:
        raise HTTPException(status_code=404, detail="Task not found")
    
    for key, value in model_dump(task).items():
        setattr(db_task, key, value)
    
    try:
        db.commit()
        db.refresh(db_task)
    except SQLAlchemyError as e:
        raise HTTPException(status_code=400, detail=str(e))
    return db_task

@app.delete("/tasks/{task_id}", status_code=204)
async def delete_task(task_id: int, db: Session = Depends(get_db)):
    task = db.query(Task).filter(Task.id == task_id).first()
    if not task:
        raise HTTPException(status_code=404, detail="Task not found")
    
    try:
        db.delete(task)
        db.commit()
    except SQLAlchemyError as e:
        raise HTTPException(status_code=400, detail=str(e))