RBAC and Permissions

def get_default_roles() -> Dict[str, Dict[str, Any]]:
    """
    Get the default role definitions for JupyterHub.
    
    Returns:
        Dictionary of default roles with their scopes and descriptions:
        - 'user': Basic user permissions  
        - 'admin': Full system administrator permissions
        - 'server': Permissions for single-user servers
        - 'token': Permissions for API tokens
    """

# Default roles structure
DEFAULT_ROLES = {
    'user': {
        'description': 'Default permissions for users',
        'scopes': [
            'self',
            'servers!user',
            'access:servers!user'
        ]
    },
    'admin': {
        'description': 'Unrestricted administrative privileges',
        'scopes': ['admin:*']
    },
    'server': {
        'description': 'Permissions for single-user servers',
        'scopes': [
            'access:servers!user',
            'read:users:activity!user',
            'read:servers!user'
        ]
    },
    'token': {
        'description': 'Default permissions for API tokens',
        'scopes': ['identify']
    }
}

# Dictionary of all available scopes with descriptions
scope_definitions: Dict[str, str] = {
    # Administrative scopes
    'admin:*': 'Full administrative privileges (all permissions)',
    'admin:users': 'Full user administration',
    'admin:groups': 'Full group administration', 
    'admin:servers': 'Full server administration',
    'admin:auth': 'Authentication administration',
    
    # User management scopes
    'users': 'Full user management (read/write)',
    'users:activity': 'Read user activity information',
    'read:users': 'Read user information',
    'read:users:name': 'Read usernames',
    'read:users:groups': 'Read user group membership',
    'read:users:activity': 'Read user activity timestamps',
    
    # Group management scopes  
    'groups': 'Full group management (read/write)',
    'read:groups': 'Read group information',
    'read:groups:name': 'Read group names',
    
    # Server management scopes
    'servers': 'Full server management (read/write/delete)',
    'read:servers': 'Read server information',
    'access:servers': 'Access servers (connect to running servers)',
    'delete:servers': 'Stop/delete servers',
    
    # Service scopes
    'services': 'Full service management',
    'read:services': 'Read service information',
    
    # Role and token scopes
    'roles': 'Full role management',
    'read:roles': 'Read role information', 
    'tokens': 'Full token management',
    'read:tokens': 'Read token information',
    
    # Proxy scopes
    'proxy': 'Full proxy management',
    'read:proxy': 'Read proxy routing information',
    
    # Hub scopes
    'read:hub': 'Read hub information',
    'shutdown': 'Shutdown the hub',
    
    # Special scopes
    'self': 'User\'s own resources (expands to user-specific scopes)',
    'identify': 'Identify the token owner',
    'inherit': 'Inherit permissions from user/service'
}

# Scope expansion functions
def expand_scopes(*scopes) -> Set[str]:
    """
    Expand scope patterns into concrete scopes.
    
    Args:
        *scopes: Variable number of scope strings
        
    Returns:
        Set of expanded concrete scopes
    """

def check_scopes(required_scopes, available_scopes) -> bool:
    """
    Check if available scopes satisfy required scopes.
    
    Args:
        required_scopes: Scopes needed for operation
        available_scopes: Scopes granted to user/token
        
    Returns:
        True if access should be granted
    """

def describe_scope(scope: str) -> str:
    """
    Get human-readable description of a scope.
    
    Args:
        scope: Scope string
        
    Returns:
        Description string
    """

class Role(Base):
    """Role database model with permission management"""
    
    name: str
    description: str
    scopes: List[str]
    
    def has_scope(self, scope: str) -> bool:
        """
        Check if role has specific scope.
        
        Args:
            scope: Scope to check
            
        Returns:
            True if role grants this scope
        """
    
    def grant_scope(self, scope: str) -> None:
        """
        Grant a scope to this role.
        
        Args:
            scope: Scope to grant
        """
    
    def revoke_scope(self, scope: str) -> None:
        """
        Revoke a scope from this role.
        
        Args:
            scope: Scope to revoke
        """

# Permission inheritance functions
def get_user_scopes(user: User) -> Set[str]:
    """
    Get all scopes for a user (direct + inherited from groups/roles).
    
    Args:
        user: User object
        
    Returns:
        Set of all scopes available to user
    """

def get_token_scopes(token: APIToken) -> Set[str]:
    """
    Get all scopes for an API token.
    
    Args:
        token: API token object
        
    Returns:
        Set of scopes granted to token
    """

from jupyterhub.orm import User, Group, Role
from jupyterhub.scopes import get_default_roles

# Create custom role
instructor_role = Role(
    name='instructor',
    description='Course instructor permissions',
    scopes=[
        'read:users',
        'read:users:activity', 
        'servers!group=students',
        'access:servers!group=students'
    ]
)
db.add(instructor_role)

# Assign role to user
instructor = db.query(User).filter(User.name == 'prof_smith').first()
instructor.roles.append(instructor_role)
db.commit()

# Create student group with role
students_group = Group(name='students')
student_role = Role(
    name='student',
    description='Student permissions',
    scopes=[
        'self',  # Own resources
        'read:groups:name!group=students'  # Read group member names
    ]
)
students_group.roles.append(student_role)

# Add users to group
alice = db.query(User).filter(User.name == 'alice').first()
students_group.users.append(alice)
db.commit()

# Create service with specific permissions  
monitoring_service = Service(
    name='monitoring',
    url='http://localhost:8002'
)

monitoring_role = Role(
    name='monitoring-service',
    description='Monitoring service permissions',
    scopes=[
        'read:users:activity',
        'read:servers',
        'read:hub'
    ]
)
monitoring_service.roles.append(monitoring_role)

# Create API token for service
token = monitoring_service.new_api_token(
    note='Monitoring service token',
    roles=['monitoring-service']
)
db.commit()

# Scoped permissions using filters
custom_scopes = [
    'servers!user=alice',  # Alice's servers only
    'read:users!group=students',  # Users in students group
    'access:servers!server=shared-*',  # Servers with shared- prefix
    'admin:users!user!=admin'  # All users except admin
]

# Create role with scoped permissions
ta_role = Role(
    name='teaching-assistant',
    description='TA permissions for specific course',
    scopes=[
        'read:users!group=cs101-students',
        'servers!group=cs101-students', 
        'read:users:activity!group=cs101-students'
    ]
)

# Create limited-scope API token
user = db.query(User).filter(User.name == 'researcher').first()
limited_token = user.new_api_token(
    note='Data analysis token',
    scopes=[
        'read:servers!user',  # Only own servers
        'access:servers!user',  # Access own servers
        'read:users:name'  # Read usernames for sharing
    ],
    expires_in=3600  # 1 hour expiration
)

# Create hierarchy of roles
roles_hierarchy = {
    'student': [
        'self',
        'read:groups:name'
    ],
    'ta': [
        'inherit:student',  # Inherit student permissions
        'read:users!group=assigned-students',
        'servers!group=assigned-students'
    ],
    'instructor': [
        'inherit:ta',  # Inherit TA permissions  
        'admin:users!group=course-students',
        'admin:servers!group=course-students'
    ],
    'admin': [
        'admin:*'  # Full admin access
    ]
}

# Apply hierarchical roles
for role_name, scopes in roles_hierarchy.items():
    role = Role(name=role_name, scopes=scopes)
    db.add(role)

class ConditionalRole(Role):
    """Role with time-based or context-based conditions"""
    
    conditions: Dict[str, Any]  # Additional conditions
    
    def check_conditions(self, context: Dict[str, Any]) -> bool:
        """
        Check if role conditions are met.
        
        Args:
            context: Current request context
            
        Returns:
            True if conditions are satisfied
        """
        # Time-based conditions
        if 'time_range' in self.conditions:
            current_time = datetime.now().time()
            start, end = self.conditions['time_range']
            if not (start <= current_time <= end):
                return False
        
        # IP-based conditions
        if 'allowed_ips' in self.conditions:
            client_ip = context.get('client_ip')
            if client_ip not in self.conditions['allowed_ips']:
                return False
        
        return True

# Usage with conditions
lab_access_role = ConditionalRole(
    name='lab-access',
    scopes=['access:servers!server=lab-*'],
    conditions={
        'time_range': (time(9, 0), time(17, 0)),  # 9 AM - 5 PM
        'allowed_ips': ['192.168.1.0/24']  # Lab network only
    }
)

async def assign_dynamic_roles(user: User, authenticator_data: Dict[str, Any]):
    """
    Dynamically assign roles based on authentication data.
    
    Args:
        user: User object
        authenticator_data: Data from authenticator (LDAP groups, OAuth claims, etc.)
    """
    
    # Clear existing dynamic roles
    user.roles = [role for role in user.roles if not role.name.startswith('dynamic-')]
    
    # Assign roles based on LDAP groups
    ldap_groups = authenticator_data.get('groups', [])
    
    role_mapping = {
        'faculty': 'instructor',
        'graduate_students': 'ta',
        'undergraduate_students': 'student'
    }
    
    for ldap_group, role_name in role_mapping.items():
        if ldap_group in ldap_groups:
            role = db.query(Role).filter(Role.name == role_name).first()
            if role:
                user.roles.append(role)
    
    db.commit()

from jupyterhub.scopes import needs_scope

class CustomAPIHandler(APIHandler):
    """API handler with scope-based permissions"""
    
    @needs_scope('read:users')
    def get(self):
        """Endpoint requiring read:users scope"""
        users = self.db.query(User).all()
        self.write({'users': [user.name for user in users]})
    
    @needs_scope('admin:users')
    def post(self):
        """Endpoint requiring admin:users scope"""
        user_data = self.get_json_body()
        user = User(**user_data)
        self.db.add(user)
        self.db.commit()

from jupyterhub.scopes import check_scopes

def check_user_permission(user: User, required_scope: str, resource: str = None) -> bool:
    """
    Check if user has permission for specific operation.
    
    Args:
        user: User object
        required_scope: Scope needed for operation
        resource: Optional resource identifier
        
    Returns:
        True if user has permission
    """
    user_scopes = get_user_scopes(user)
    
    # Add resource context if provided
    if resource:
        required_scope = f"{required_scope}!{resource}"
    
    return check_scopes([required_scope], user_scopes)

# Usage
if check_user_permission(user, 'servers', 'user=alice'):
    # User can manage Alice's servers
    pass

# jupyterhub_config.py

# Define custom roles
c.JupyterHub.custom_roles = [
    {
        'name': 'instructor',
        'description': 'Course instructor permissions',
        'scopes': [
            'read:users!group=students',
            'servers!group=students',
            'admin:users!group=students'
        ]
    },
    {
        'name': 'grader',
        'description': 'Grading assistant permissions', 
        'scopes': [
            'read:users!group=students',
            'access:servers!group=students'
        ]
    }
]

# Load balancing with role-based spawning
c.JupyterHub.load_roles = [
    {
        'name': 'instructor',
        'users': ['prof_smith', 'prof_jones'],
        'scopes': ['inherit:instructor']
    },
    {
        'name': 'grader',
        'groups': ['teaching-assistants'],
        'scopes': ['inherit:grader']
    }
]