import hashlib
import json
import os
import gradio as gr

# File to store user credentials
USERS_FILE = "users.json"


def load_users():
    """Load users from JSON file"""
    if os.path.exists(USERS_FILE):
        with open(USERS_FILE, "r") as f:
            return json.load(f)
    return {}


def save_users(users):
    """Save users to JSON file"""
    with open(USERS_FILE, "w") as f:
        json.dump(users, f)


def hash_password(password):
    """Hash password using SHA-256"""
    return hashlib.sha256(password.encode()).hexdigest()


def register_user(username, password, confirm_password):
    """Register a new user"""
    if not username or not password:
        return "", "Username and password cannot be empty!", None

    if password != confirm_password:
        return "", "Passwords do not match!", None

    if len(password) < 6:
        return "", "Password must be at least 6 characters long!", None

    users = load_users()

    if username in users:
        return "", "Username already exists!", None

    users[username] = hash_password(password)
    save_users(users)

    return "", f"✅ Registration successful! You can now login.", None


def login_user(username, password, state):
    """Validate user login"""
    if not username or not password:
        return (
            "Please enter both username and password!",
            "",
            state,
            gr.update(visible=True),
            gr.update(visible=False),
            gr.update(visible=False),
            gr.update(open=True),
        )

    users = load_users()

    if username not in users:
        return (
            "Invalid username or password!",
            "",
            state,
            gr.update(visible=True),
            gr.update(visible=False),
            gr.update(visible=False),
            gr.update(open=True),
        )

    if users[username] != hash_password(password):
        return (
            "Invalid username or password!",
            "",
            state,
            gr.update(visible=True),
            gr.update(visible=False),
            gr.update(visible=False),
            gr.update(open=True),
        )

    # Login successful
    state = {"logged_in": True, "username": username}
    return (
        f"✅ Welcome back, {username}!",
        "",
        state,
        gr.update(visible=False),
        gr.update(visible=True),
        gr.update(visible=True),
        gr.update(open=False),
    )


def logout_user(state):
    """Logout current user"""
    state = {"logged_in": False, "username": None}
    return (
        "Logged out successfully!",
        state,
        gr.update(visible=True),
        gr.update(visible=False),
        gr.update(visible=False),
    )


def protected_content(state):
    """Content only accessible to logged-in users"""
    if state.get("logged_in"):
        return f"You are logged as {state.get('username')}\n"
    return "Please login to access this content."