import hashlib
import uuid
import time

class UserAuth:
    def __init__(self):
        self.users = {}  # Store users as {username: {password_hash, salt}}
        self.sessions = {}  # Store sessions as {session_id: {username, expiry}}
        self.session_duration = 3600  # 1 hour

    def hash_password(self, password, salt=None):
        if salt is None:
            salt = uuid.uuid4().hex
        return hashlib.sha256((password + salt).encode()).hexdigest(), salt

    def register_user(self, username, password):
        if username in self.users:
            return False, "User already exists"
        password_hash, salt = self.hash_password(password)
        self.users[username] = {"password_hash": password_hash, "salt": salt}
        return True, "User registered successfully"

    def authenticate(self, username, password):
        if username not in self.users:
            return False, "User not found"
        user = self.users[username]
        password_hash, _ = self.hash_password(password, user["salt"])
        if password_hash == user["password_hash"]:
            session_id = uuid.uuid4().hex
            expiry = time.time() + self.session_duration
            self.sessions[session_id] = {"username": username, "expiry": expiry}
            return True, session_id
        return False, "Invalid password"

def authenticate_request(self, session_id, action):
    if action in ['register', 'login']:  # These actions don't require authentication
        return True, None
    
    success, result = self.validate_session(session_id)
    if not success:
        return False, "Authentication required"
    return True, result  # result here is the username

    def validate_session(self, session_id):
        if session_id not in self.sessions:
            return False, "Invalid session"
        session = self.sessions[session_id]
        if time.time() > session["expiry"]:
            del self.sessions[session_id]
            return False, "Session expired"
        return True, session["username"]

    def logout(self, session_id):
        if session_id in self.sessions:
            del self.sessions[session_id]
            return True, "Logged out successfully"
        return False, "Invalid session"

user_auth = UserAuth()

def do_register(args):
    """Register a new user: register <username> <password>"""
    try:
        username, password = args.split()
        success, message = user_auth.register_user(username, password)
        return message
    except ValueError:
        return "Invalid arguments. Usage: register <username> <password>"

def do_login(args):
    """Login a user: login <username> <password>"""
    try:
        username, password = args.split()
        success, result = user_auth.authenticate(username, password)
        if success:
            return f"Login successful. Session ID: {result}"
        return result
    except ValueError:
        return "Invalid arguments. Usage: login <username> <password>"

def do_validate(args):
    """Validate a session: validate <session_id>"""
    success, result = user_auth.validate_session(args)
    if success:
        return f"Valid session for user: {result}"
    return result

def do_logout(args):
    """Logout a user: logout <session_id>"""
    success, message = user_auth.logout(args)
    return message

def auth_pre_command_hook(command):
    action = command.get('action')
    session_id = command.get('session_id')
    
    if action in ['register', 'login']:
        return True
    
    success, result = user_auth.validate_session(session_id)
    if not success:
        return False
    return True

commands = {
    'register': do_register,
    'login': do_login,
    'validate': do_validate,
    'logout': do_logout,
}

def get_commands():
    return commands

def initialize():
    print("User authentication module initialized")

def shutdown():
    print("User authentication module shut down")

def register_hooks(hook_manager):
    hook_manager.register_hook('pre_command', auth_pre_command_hook)

def unregister_hooks(hook_manager):
    hook_manager.unregister_hook('pre_command', auth_pre_command_hook)