from fastapi import Depends, FastAPI, HTTPException, status
from fastapi.security import OAuth2PasswordBearer, OAuth2PasswordRequestForm
from sqlalchemy.orm import Session

from . import crud, models, schemas, auth_helper
from .database import SessionLocal, engine

from typing import List
from datetime import timedelta
import jwt

models.Base.metadata.create_all(bind=engine)
#oauth2_scheme = OAuth2PasswordBearer(tokenUrl="tkn")
oauth = OAuth2PasswordBearer(tokenUrl="tkn")

app = FastAPI()


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

async def get_current_user(token: str = Depends(oauth), db: Session = Depends(get_db)):
    credentials_exception = HTTPException(
        status_code=status.HTTP_401_UNAUTHORIZED,
        detail="Could not validate credentials",
        headers={"WWW-Authenticate": "Bearer"},
    )
    try:
        payload = jwt.decode(token, auth_helper.JWT_SECRET, algorithms=[auth_helper.JWT_ALGO])
        username: str = payload.get("sub")
        if username is None:
            raise credentials_exception
        token_data = schemas.TokenData(username=username)
    except jwt.PyJWTError:
        raise credentials_exception
    user = crud.get_user_by_username(db, username=token_data.username)
    if user is None:
        raise credentials_exception
    return user

async def get_current_active_user(current_user: schemas.User = Depends(get_current_user)):
    if not current_user.is_active:
        raise HTTPException(status_code=400, detail="Inactive user")
    return current_user

@app.post("/users/reg", response_model=schemas.User, tags=['users'])
def create_user(user: schemas.UserCreate, db: Session = Depends(get_db)):
    db_user = crud.get_user_by_email(db, email=user.email)
    if db_user:
        raise HTTPException(status_code=400, detail="Email already registered")

    db_user = crud.get_user_by_username(db, username=user.username)
    if db_user:
        raise HTTPException(status_code=400, detail="Username already registerd")
        
    return crud.create_user(db=db, user=user)


@app.get("/users/", response_model=List[schemas.User])
def read_users(skip: int = 0, limit: int = 100, db: Session = Depends(get_db)):
    users = crud.get_users(db, skip=skip, limit=limit)
    return users


@app.get("/users/{user_id}", response_model=schemas.User)
def read_user(user_id: int, db: Session = Depends(get_db)):
    db_user = crud.get_user(db, user_id=user_id)
    if db_user is None:
        raise HTTPException(status_code=404, detail="User not found")
    return db_user


@app.post("/users/{user_id}/items/", response_model=schemas.IotEntity)
def create_item_for_user(
    user_id: int, item: schemas.IotEntityCreate, db: Session = Depends(get_db)
):
    return crud.create_user_item(db=db, item=item, user_id=user_id)


@app.get("/items", response_model=List[schemas.IotEntity])
def read_items(skip: int = 0, limit: int = 100, db: Session = Depends(get_db)):
    items = crud.get_items(db, skip=skip, limit=limit)
    return items

@app.post("/tkn", response_model=schemas.Token)
async def login_for_access_token(form_data: OAuth2PasswordRequestForm = Depends(), db: Session = Depends(get_db)):
    user = auth_helper.authenticate_user(db, form_data.username, form_data.password)
    if not user:
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="Incorrect username or password",
            headers={"WWW-Authenticate": "Bearer"},
        )
    #access_token_expires = timedelta(minutes=ACCESS_TOKEN_EXPIRE_MINUTES)
    access_token = auth_helper.create_access_token(
        data={"sub": form_data.username}, expires_delta=timedelta(minutes=15)
    )
    return {"access_token": access_token, "token_type": "bearer"}

@app.get("/users/me/", response_model=schemas.User)
async def read_users_me(current_user: schemas.User = Depends(get_current_active_user)):
    return current_user