from datetime import datetime, timedelta
from typing import List, Union
from modules.database import col_users
from modules.app import app

from fastapi import Depends, HTTPException, Security, status
from starlette.status import HTTP_204_NO_CONTENT
from fastapi.security import (
    OAuth2PasswordBearer,
    SecurityScopes,
)
from jose import JWTError, jwt
from passlib.context import CryptContext
from pydantic import BaseModel, ValidationError


with open("secret_key", "r", encoding="utf-8") as f:
    SECRET_KEY = f.read()
ALGORITHM = "HS256"
ACCESS_TOKEN_EXPIRE_DAYS = 180


fake_users_db = {
    "johndoe": {
        "user": "johndoe",
        "email": "johndoe@example.com",
        "hash": "$2b$12$EixZaYVK1fsbw1ZfbX3OXePaWxn96p36WQoeG6Lruj3vjPGga31lW",
        "disabled": False,
    },
    "alice": {
        "user": "alice",
        "email": "alicechains@example.com",
        "hash": "$2b$12$gSvqqUPvlXP2tfVFaWK1Be7DlH.PKZbv5H8KnzzVgXXbVxpva.pFm",
        "disabled": True,
    },
}


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


class TokenData(BaseModel):
    user: Union[str, None] = None
    scopes: List[str] = []


class User(BaseModel):
    user: str
    email: Union[str, None] = None
    disabled: Union[bool, None] = None


class UserInDB(User):
    hash: str


pwd_context = CryptContext(schemes=["bcrypt"], deprecated="auto")

oauth2_scheme = OAuth2PasswordBearer(
    tokenUrl="token",
    scopes={
        "me": "Get current user's data.",
        "list": "List albums and images.",
        "read": "View albums and images.",
        "write": "Manage albums and images."},
)


def verify_password(plain_password, hashed_password):
    return pwd_context.verify(plain_password, hashed_password)


def get_password_hash(password):
    return pwd_context.hash(password)


def get_user(user: str):
    found_user = col_users.find_one( {"user": user} )
    return UserInDB(user=found_user["user"], email=found_user["email"], disabled=found_user["disabled"], hash=found_user["hash"])


def authenticate_user(user_name: str, password: str):
    user = get_user(user_name)
    if not user:
        return False
    if not verify_password(password, user.hash):
        return False
    return user


def create_access_token(data: dict, expires_delta: Union[timedelta, None] = None):
    to_encode = data.copy()
    if expires_delta:
        expire = datetime.utcnow() + expires_delta
    else:
        expire = datetime.utcnow() + timedelta(days=ACCESS_TOKEN_EXPIRE_DAYS)
    to_encode.update({"exp": expire})
    encoded_jwt = jwt.encode(to_encode, SECRET_KEY, algorithm=ALGORITHM)
    return encoded_jwt


async def get_current_user(
    security_scopes: SecurityScopes, token: str = Depends(oauth2_scheme)
):
    if security_scopes.scopes:
        authenticate_value = f'Bearer scope="{security_scopes.scope_str}"'
    else:
        authenticate_value = "Bearer"
    credentials_exception = HTTPException(
        status_code=status.HTTP_401_UNAUTHORIZED,
        detail="Could not validate credentials",
        headers={"WWW-Authenticate": authenticate_value},
    )
    try:
        payload = jwt.decode(token, SECRET_KEY, algorithms=[ALGORITHM])
        user: str = payload.get("sub")
        if user is None:
            raise credentials_exception
        token_scopes = payload.get("scopes", [])
        token_data = TokenData(scopes=token_scopes, user=user)
    except (JWTError, ValidationError):
        raise credentials_exception
    user = get_user(user=token_data.user)
    if user is None:
        raise credentials_exception
    for scope in security_scopes.scopes:
        if scope not in token_data.scopes:
            raise HTTPException(
                status_code=status.HTTP_401_UNAUTHORIZED,
                detail="Not enough permissions",
                headers={"WWW-Authenticate": authenticate_value},
            )
    return user


async def get_current_active_user(
    current_user: User = Security(get_current_user, scopes=["me"])
):
    if current_user.disabled:
        raise HTTPException(status_code=400, detail="Inactive user")
    return current_user