from datetime import timedelta
from fastapi import APIRouter, Depends, HTTPException, status
from fastapi.security import OAuth2PasswordBearer, OAuth2PasswordRequestForm
from sqlalchemy.orm import Session
from app.db.session import get_db
from app.models.user import User
from app.schemas.user import UserCreate, UserResponse, Token
from app.auth.security import (
    verify_password,
    get_password_hash,
    create_access_token,
    verify_token,
    ACCESS_TOKEN_EXPIRE_MINUTES,
)

router = APIRouter()
oauth2_scheme = OAuth2PasswordBearer(tokenUrl="auth/login")


def get_user_by_email(db: Session, email: str):
    return db.query(User).filter(User.email == email).first()


def get_current_user(
    token: str = Depends(oauth2_scheme), db: Session = Depends(get_db)
):
    email = verify_token(token)
    user = get_user_by_email(db, email=email)
    if user is None:
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="Could not validate credentials",
            headers={"WWW-Authenticate": "Bearer"},
        )
    return user


@router.post("/register", response_model=UserResponse)
def register_user(user: UserCreate, db: Session = Depends(get_db)):
    db_user = get_user_by_email(db, email=user.email)
    if db_user:
        raise HTTPException(status_code=400, detail="Email already registered")

    db_user = db.query(User).filter(User.username == user.username).first()
    if db_user:
        raise HTTPException(status_code=400, detail="Username already taken")

    hashed_password = get_password_hash(user.password)
    db_user = User(
        email=user.email,
        username=user.username,
        full_name=user.full_name,
        hashed_password=hashed_password,
    )
    db.add(db_user)
    db.commit()
    db.refresh(db_user)
    return db_user


@router.post("/login", response_model=Token)
def login_user(
    form_data: OAuth2PasswordRequestForm = Depends(), db: Session = Depends(get_db)
):
    user = get_user_by_email(db, email=form_data.username)
    if not user or not verify_password(form_data.password, user.hashed_password):
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="Incorrect email or password",
            headers={"WWW-Authenticate": "Bearer"},
        )
    access_token_expires = timedelta(minutes=ACCESS_TOKEN_EXPIRE_MINUTES)
    access_token = create_access_token(
        data={"sub": user.email}, expires_delta=access_token_expires
    )
    return {"access_token": access_token, "token_type": "bearer"}


@router.get("/me", response_model=UserResponse)
def read_users_me(current_user: User = Depends(get_current_user)):
    return current_user