from typing import Optional
from datetime import datetime, timedelta
from fastapi import APIRouter, Depends, HTTPException, status, Response
from fastapi.security import OAuth2PasswordBearer, OAuth2PasswordRequestForm
from jose import JWTError, jwt
from passlib.context import CryptContext
from pydantic import BaseModel
from core.database import fake_users_db

# JWT and Password Hashing Setup
SECRET_KEY = "09d25e094faa6ca2556c818166b7a9563b93f7099f6f0f4caa6cf63b88e8d3e7"
ALGORITHM = "HS256"
ACCESS_TOKEN_EXPIRE_MINUTES = 30

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

# JWT Helper Functions
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 authenticate_user(username: str, password: str):
    user = fake_users_db.get(username)
    if not user:
        return False
    if not verify_password(password, user["password"]):
        return False
    return user

def create_access_token(data: dict, expires_delta: Optional[timedelta] = None):
    to_encode = data.copy()
    if expires_delta:
        expire = datetime.utcnow() + expires_delta
    else:
        expire = datetime.utcnow() + timedelta(minutes=15)
    to_encode.update({"exp": expire})
    encoded_jwt = jwt.encode(to_encode, SECRET_KEY, algorithm=ALGORITHM)
    return encoded_jwt

# Data Models
class Token(BaseModel):
    access_token: str
    token_type: str

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

# Router Setup
router = APIRouter()

# Login Endpoint
@router.post("/token", response_model=Token)
async def login_for_access_token(form_data: OAuth2PasswordRequestForm = Depends()):
    """Login endpoint to get access token"""
    user = authenticate_user(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 = create_access_token(
        data={"sub": user["username"]}, expires_delta=access_token_expires
    )
    response = {"access_token": access_token, "token_type": "bearer"}
    
    # Store token in cookie
    response = Response(**response)
    response.set_cookie(key="access_token", value=access_token, httponly=True)
    return response

# Helper function to get current user from token
async def get_current_user(token: str = Depends(oauth2_scheme)):
    credentials_exception = HTTPException(
        status_code=status.HTTP_401_UNAUTHORIZED,
        detail="Could not validate credentials",
        headers={"WWW-Authenticate": "Bearer"},
    )
    try:
        payload = jwt.decode(token, SECRET_KEY, algorithms=[ALGORITHM])
        username: str = payload.get("sub")
        if username is None:
            raise credentials_exception
        token_data = TokenData(username=username)
    except JWTError:
        raise credentials_exception
    user = fake_users_db.get(token_data.username)
    if user is None:
        raise credentials_exception
    return user

# Authenticated user endpoint
@router.get("/users/me/", response_model=dict)
async def read_users_me(current_user: dict = Depends(get_current_user)):
    """Fetch current authenticated user"""
    return {
        "message": "User found",
        "data": current_user
    }
```

This code provides the following functionality:

1. **Login Endpoint**: `/token` endpoint to authenticate a user and return an access token. The token is stored in a browser cookie.
2. **User Endpoint**: `/users/me` endpoint to fetch the current authenticated user's data using the access token.
3. **JWT Implementation**: JSON Web Token (JWT) implementation for generating and verifying access tokens.
4. **Password Hashing**: Password hashing and verification using the `passlib` library.
5. **Helper Functions**: Functions for user authentication, password verification, token generation, and getting the current user from the token.
6. **Data Models**: Pydantic models for Token and TokenData.

Note: This code uses a fake user database (`fake_users_db`) for demonstration purposes. In a real application, you would replace it with an actual database implementation.