from datetime import datetime, timedelta
from typing import Optional
from jose import JWTError, jwt
from passlib.context import CryptContext
from fastapi import Depends, HTTPException, status
from fastapi.security import OAuth2PasswordBearer
from sqlalchemy.orm import Session
from pydantic import BaseModel, EmailStr

from config import get_settings
from database import get_db
from models import User

settings = get_settings()

pwd_context = CryptContext(schemes=["bcrypt"], deprecated="auto")
oauth2_scheme = OAuth2PasswordBearer(tokenUrl="auth/login")


# Pydantic models
class UserCreate(BaseModel):
    email: EmailStr
    password: str
    full_name: str
    phone: Optional[str] = None
    default_location: Optional[str] = None


class UserUpdate(BaseModel):
    full_name: Optional[str] = None
    phone: Optional[str] = None
    default_location: Optional[str] = None
    notify_price_alerts: Optional[bool] = None
    notify_new_dispensaries: Optional[bool] = None
    notify_weekly_digest: Optional[bool] = None
    notify_promotions: Optional[bool] = None


class UserResponse(BaseModel):
    id: int
    email: str
    full_name: Optional[str]
    phone: Optional[str]
    default_location: Optional[str]
    is_active: bool
    is_verified: bool
    notify_price_alerts: bool
    notify_new_dispensaries: bool
    notify_weekly_digest: bool
    notify_promotions: bool

    class Config:
        from_attributes = True


class Token(BaseModel):
    access_token: str
    token_type: str


class TokenData(BaseModel):
    email: Optional[str] = None


def verify_password(plain_password: str, hashed_password: str) -> bool:
    return pwd_context.verify(plain_password, hashed_password)


def get_password_hash(password: str) -> str:
    return pwd_context.hash(password)


def create_access_token(data: dict, expires_delta: Optional[timedelta] = None) -> str:
    to_encode = data.copy()
    if expires_delta:
        expire = datetime.utcnow() + expires_delta
    else:
        expire = datetime.utcnow() + timedelta(minutes=settings.access_token_expire_minutes)
    to_encode.update({"exp": expire})
    encoded_jwt = jwt.encode(to_encode, settings.secret_key, algorithm=settings.algorithm)
    return encoded_jwt


def get_user_by_email(db: Session, email: str) -> Optional[User]:
    return db.query(User).filter(User.email == email).first()


def authenticate_user(db: Session, email: str, password: str) -> Optional[User]:
    user = get_user_by_email(db, email)
    if not user:
        return None
    if not verify_password(password, user.hashed_password):
        return None
    return user


def create_user(db: Session, user_data: UserCreate) -> User:
    hashed_password = get_password_hash(user_data.password)
    db_user = User(
        email=user_data.email,
        hashed_password=hashed_password,
        full_name=user_data.full_name,
        phone=user_data.phone,
        default_location=user_data.default_location,
    )
    db.add(db_user)
    db.commit()
    db.refresh(db_user)
    return db_user


async def get_current_user(
    token: str = Depends(oauth2_scheme),
    db: Session = Depends(get_db)
) -> User:
    credentials_exception = HTTPException(
        status_code=status.HTTP_401_UNAUTHORIZED,
        detail="Could not validate credentials",
        headers={"WWW-Authenticate": "Bearer"},
    )
    try:
        payload = jwt.decode(token, settings.secret_key, algorithms=[settings.algorithm])
        email: str = payload.get("sub")
        if email is None:
            raise credentials_exception
        token_data = TokenData(email=email)
    except JWTError:
        raise credentials_exception

    user = get_user_by_email(db, email=token_data.email)
    if user is None:
        raise credentials_exception
    return user


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