"""
Role-Based Access Control (RBAC) System for InfraDSL
Enterprise-grade access control with fine-grained permissions
"""

import json
import hashlib
from typing import Dict, Any, List, Optional, Set, Union, Tuple
from dataclasses import dataclass, field, asdict
from datetime import datetime, timedelta
from enum import Enum
import logging
from pathlib import Path
import re
from abc import ABC, abstractmethod


class PermissionType(Enum):
    """Types of permissions in InfraDSL"""
    READ = "read"                    # View resources and configurations
    CREATE = "create"                # Create new resources
    UPDATE = "update"                # Modify existing resources
    DELETE = "delete"                # Delete resources
    EXECUTE = "execute"              # Execute operations (apply, destroy)
    IMPORT = "import"                # Import external resources
    EXPORT = "export"                # Export configurations
    ADMIN = "admin"                  # Administrative operations
    AUDIT = "audit"                  # Access audit logs
    MANAGE_USERS = "manage_users"    # Manage users and roles
    MANAGE_POLICIES = "manage_policies"  # Manage access policies


class ResourceScope(Enum):
    """Scope levels for resource access"""
    GLOBAL = "global"                # Access to all resources across all workspaces
    WORKSPACE = "workspace"          # Access to specific workspace
    RESOURCE_TYPE = "resource_type"  # Access to specific resource types
    RESOURCE = "resource"            # Access to specific resources
    TAG_BASED = "tag_based"         # Access based on resource tags


class AuthenticationProvider(Enum):
    """Supported authentication providers"""
    LOCAL = "local"                  # Local InfraDSL authentication
    LDAP = "ldap"                   # LDAP/Active Directory
    OAUTH2 = "oauth2"               # OAuth2 providers
    SAML = "saml"                   # SAML SSO
    OIDC = "oidc"                   # OpenID Connect
    AWS_IAM = "aws_iam"             # AWS IAM integration
    AZURE_AD = "azure_ad"           # Azure Active Directory
    GOOGLE_IAM = "google_iam"       # Google Cloud IAM


@dataclass
class Permission:
    """Represents a specific permission"""
    permission_type: PermissionType
    resource_scope: ResourceScope
    scope_filter: Optional[str] = None  # Workspace name, resource type, etc.
    conditions: Dict[str, Any] = field(default_factory=dict)
    granted_at: datetime = field(default_factory=datetime.now)
    expires_at: Optional[datetime] = None


@dataclass
class Role:
    """Represents a role with a set of permissions"""
    name: str
    description: str
    permissions: List[Permission]
    is_system_role: bool = False
    created_at: datetime = field(default_factory=datetime.now)
    updated_at: datetime = field(default_factory=datetime.now)
    
    # Role inheritance
    inherits_from: List[str] = field(default_factory=list)
    
    # Metadata
    tags: Dict[str, str] = field(default_factory=dict)


@dataclass
class User:
    """Represents a user in the system"""
    user_id: str
    username: str
    email: str
    full_name: str
    roles: List[str]
    
    # Authentication
    auth_provider: AuthenticationProvider
    external_id: Optional[str] = None  # ID in external system
    
    # User metadata
    department: Optional[str] = None
    team: Optional[str] = None
    manager: Optional[str] = None
    
    # Account status
    is_active: bool = True
    is_locked: bool = False
    last_login: Optional[datetime] = None
    password_expires_at: Optional[datetime] = None
    
    # Timestamps
    created_at: datetime = field(default_factory=datetime.now)
    updated_at: datetime = field(default_factory=datetime.now)


@dataclass
class AccessRequest:
    """Represents an access request for evaluation"""
    user_id: str
    permission_type: PermissionType
    resource_scope: ResourceScope
    resource_identifier: Optional[str] = None
    workspace: Optional[str] = None
    resource_type: Optional[str] = None
    resource_tags: Dict[str, str] = field(default_factory=dict)
    context: Dict[str, Any] = field(default_factory=dict)
    timestamp: datetime = field(default_factory=datetime.now)


@dataclass
class AccessDecision:
    """Result of access control evaluation"""
    granted: bool
    reason: str
    applicable_permissions: List[Permission]
    policy_violations: List[str] = field(default_factory=list)
    required_approvals: List[str] = field(default_factory=list)
    conditions_to_meet: List[str] = field(default_factory=list)
    decision_time: datetime = field(default_factory=datetime.now)


@dataclass
class Policy:
    """Access control policy"""
    name: str
    description: str
    conditions: Dict[str, Any]
    effect: str  # "allow" or "deny"
    priority: int = 100  # Higher number = higher priority
    is_active: bool = True
    created_at: datetime = field(default_factory=datetime.now)


class AuthenticationProvider_Interface(ABC):
    """Interface for authentication providers"""
    
    @abstractmethod
    def authenticate(self, username: str, password: str) -> Optional[User]:
        """Authenticate user and return user object if successful"""
        pass
    
    @abstractmethod
    def get_user_info(self, user_id: str) -> Optional[User]:
        """Get user information from provider"""
        pass
    
    @abstractmethod
    def validate_token(self, token: str) -> Optional[str]:
        """Validate authentication token and return user_id"""
        pass


class RBACSystem:
    """
    Comprehensive Role-Based Access Control system for InfraDSL
    
    Features:
    - Fine-grained permissions and roles
    - Multiple authentication providers
    - Policy-based access control
    - Workspace-level isolation
    - Resource-level permissions
    - Tag-based access control
    - Audit logging integration
    - Enterprise identity integration
    """
    
    def __init__(self, config_path: Optional[str] = None):
        self.logger = logging.getLogger(__name__)
        
        # Core data stores
        self.users: Dict[str, User] = {}
        self.roles: Dict[str, Role] = {}
        self.policies: Dict[str, Policy] = {}
        
        # Authentication providers
        self.auth_providers: Dict[AuthenticationProvider, AuthenticationProvider_Interface] = {}
        
        # Configuration
        self.config = self._load_config(config_path)
        
        # Caching for performance
        self.permission_cache: Dict[str, Tuple[datetime, AccessDecision]] = {}
        self.cache_ttl = timedelta(minutes=5)
        
        # Initialize system roles
        self._initialize_system_roles()
        
        # Load authentication providers
        self._initialize_auth_providers()
    
    def create_role(self, name: str, description: str, permissions: List[Permission],
                   inherits_from: Optional[List[str]] = None) -> Role:
        """
        Create a new role with specified permissions
        
        Args:
            name: Role name
            description: Role description
            permissions: List of permissions for the role
            inherits_from: List of role names to inherit from
            
        Returns:
            Created Role object
        """
        
        if name in self.roles:
            raise ValueError(f"Role '{name}' already exists")
        
        role = Role(
            name=name,
            description=description,
            permissions=permissions,
            inherits_from=inherits_from or []
        )
        
        self.roles[name] = role
        self.logger.info(f"Created role '{name}' with {len(permissions)} permissions")
        
        return role
    
    def create_user(self, user_id: str, username: str, email: str, full_name: str,
                   roles: List[str], auth_provider: AuthenticationProvider = AuthenticationProvider.LOCAL,
                   **kwargs) -> User:
        """
        Create a new user
        
        Args:
            user_id: Unique user identifier
            username: Username for authentication
            email: User email address
            full_name: User's full name
            roles: List of role names to assign
            auth_provider: Authentication provider
            **kwargs: Additional user attributes
            
        Returns:
            Created User object
        """
        
        if user_id in self.users:
            raise ValueError(f"User '{user_id}' already exists")
        
        # Validate roles exist
        for role_name in roles:
            if role_name not in self.roles:
                raise ValueError(f"Role '{role_name}' does not exist")
        
        user = User(
            user_id=user_id,
            username=username,
            email=email,
            full_name=full_name,
            roles=roles,
            auth_provider=auth_provider,
            **kwargs
        )
        
        self.users[user_id] = user
        self.logger.info(f"Created user '{user_id}' with roles: {roles}")
        
        return user
    
    def check_access(self, user_id: str, permission_type: PermissionType,
                    resource_scope: ResourceScope, **kwargs) -> AccessDecision:
        """
        Check if user has access to perform an operation
        
        Args:
            user_id: User identifier
            permission_type: Type of permission requested
            resource_scope: Scope of the resource
            **kwargs: Additional context (workspace, resource_type, etc.)
            
        Returns:
            AccessDecision with grant/deny decision and reasoning
        """
        
        request = AccessRequest(
            user_id=user_id,
            permission_type=permission_type,
            resource_scope=resource_scope,
            **kwargs
        )
        
        # Check cache first
        cache_key = self._generate_cache_key(request)
        if cache_key in self.permission_cache:
            cached_time, cached_decision = self.permission_cache[cache_key]
            if datetime.now() - cached_time < self.cache_ttl:
                return cached_decision
        
        # Evaluate access request
        decision = self._evaluate_access_request(request)
        
        # Cache the decision
        self.permission_cache[cache_key] = (datetime.now(), decision)
        
        # Log access attempt
        self._log_access_attempt(request, decision)
        
        return decision
    
    def assign_role(self, user_id: str, role_name: str) -> bool:
        """
        Assign a role to a user
        
        Args:
            user_id: User identifier
            role_name: Name of role to assign
            
        Returns:
            True if successful
        """
        
        if user_id not in self.users:
            raise ValueError(f"User '{user_id}' does not exist")
        
        if role_name not in self.roles:
            raise ValueError(f"Role '{role_name}' does not exist")
        
        user = self.users[user_id]
        if role_name not in user.roles:
            user.roles.append(role_name)
            user.updated_at = datetime.now()
            
            # Clear cache for this user
            self._clear_user_cache(user_id)
            
            self.logger.info(f"Assigned role '{role_name}' to user '{user_id}'")
            return True
        
        return False
    
    def revoke_role(self, user_id: str, role_name: str) -> bool:
        """
        Revoke a role from a user
        
        Args:
            user_id: User identifier
            role_name: Name of role to revoke
            
        Returns:
            True if successful
        """
        
        if user_id not in self.users:
            raise ValueError(f"User '{user_id}' does not exist")
        
        user = self.users[user_id]
        if role_name in user.roles:
            user.roles.remove(role_name)
            user.updated_at = datetime.now()
            
            # Clear cache for this user
            self._clear_user_cache(user_id)
            
            self.logger.info(f"Revoked role '{role_name}' from user '{user_id}'")
            return True
        
        return False
    
    def create_policy(self, name: str, description: str, conditions: Dict[str, Any],
                     effect: str, priority: int = 100) -> Policy:
        """
        Create an access control policy
        
        Args:
            name: Policy name
            description: Policy description
            conditions: Conditions for policy application
            effect: "allow" or "deny"
            priority: Policy priority (higher = more important)
            
        Returns:
            Created Policy object
        """
        
        if name in self.policies:
            raise ValueError(f"Policy '{name}' already exists")
        
        if effect not in ["allow", "deny"]:
            raise ValueError("Policy effect must be 'allow' or 'deny'")
        
        policy = Policy(
            name=name,
            description=description,
            conditions=conditions,
            effect=effect,
            priority=priority
        )
        
        self.policies[name] = policy
        self.logger.info(f"Created policy '{name}' with effect '{effect}'")
        
        return policy
    
    def authenticate_user(self, username: str, password: str,
                         auth_provider: AuthenticationProvider = AuthenticationProvider.LOCAL) -> Optional[User]:
        """
        Authenticate a user
        
        Args:
            username: Username
            password: Password
            auth_provider: Authentication provider to use
            
        Returns:
            User object if authentication successful, None otherwise
        """
        
        if auth_provider not in self.auth_providers:
            self.logger.error(f"Authentication provider '{auth_provider.value}' not configured")
            return None
        
        provider = self.auth_providers[auth_provider]
        user = provider.authenticate(username, password)
        
        if user:
            # Update last login time
            if user.user_id in self.users:
                self.users[user.user_id].last_login = datetime.now()
            
            self.logger.info(f"User '{username}' authenticated successfully via {auth_provider.value}")
        else:
            self.logger.warning(f"Authentication failed for user '{username}' via {auth_provider.value}")
        
        return user
    
    def get_user_permissions(self, user_id: str) -> List[Permission]:
        """
        Get all permissions for a user (including inherited from roles)
        
        Args:
            user_id: User identifier
            
        Returns:
            List of all permissions for the user
        """
        
        if user_id not in self.users:
            return []
        
        user = self.users[user_id]
        all_permissions = []
        
        # Get permissions from each role
        for role_name in user.roles:
            if role_name in self.roles:
                role = self.roles[role_name]
                all_permissions.extend(role.permissions)
                
                # Get inherited permissions
                inherited_permissions = self._get_inherited_permissions(role)
                all_permissions.extend(inherited_permissions)
        
        # Remove duplicates
        unique_permissions = []
        seen = set()
        for perm in all_permissions:
            perm_key = (perm.permission_type, perm.resource_scope, perm.scope_filter)
            if perm_key not in seen:
                unique_permissions.append(perm)
                seen.add(perm_key)
        
        return unique_permissions
    
    def get_workspace_users(self, workspace: str) -> List[User]:
        """
        Get all users with access to a specific workspace
        
        Args:
            workspace: Workspace name
            
        Returns:
            List of users with workspace access
        """
        
        workspace_users = []
        
        for user in self.users.values():
            # Check if user has any workspace-level or global permissions
            permissions = self.get_user_permissions(user.user_id)
            has_workspace_access = False
            
            for perm in permissions:
                if (perm.resource_scope == ResourceScope.GLOBAL or
                    (perm.resource_scope == ResourceScope.WORKSPACE and 
                     perm.scope_filter == workspace)):
                    has_workspace_access = True
                    break
            
            if has_workspace_access:
                workspace_users.append(user)
        
        return workspace_users
    
    def _evaluate_access_request(self, request: AccessRequest) -> AccessDecision:
        """Evaluate an access request against user permissions and policies"""
        
        # Get user
        if request.user_id not in self.users:
            return AccessDecision(
                granted=False,
                reason=f"User '{request.user_id}' not found",
                applicable_permissions=[]
            )
        
        user = self.users[request.user_id]
        
        # Check if user is active
        if not user.is_active or user.is_locked:
            return AccessDecision(
                granted=False,
                reason="User account is inactive or locked",
                applicable_permissions=[]
            )
        
        # Get user permissions
        user_permissions = self.get_user_permissions(request.user_id)
        
        # Find applicable permissions
        applicable_permissions = []
        for perm in user_permissions:
            if self._permission_applies(perm, request):
                applicable_permissions.append(perm)
        
        # Check if any permission grants access
        granted = len(applicable_permissions) > 0
        
        # Apply policies
        policy_violations = []
        for policy in self.policies.values():
            if policy.is_active and self._policy_applies(policy, request, user):
                if policy.effect == "deny":
                    granted = False
                    policy_violations.append(f"Denied by policy '{policy.name}'")
                elif policy.effect == "allow":
                    granted = True
        
        # Generate reason
        if granted:
            if applicable_permissions:
                perm_types = [p.permission_type.value for p in applicable_permissions]
                reason = f"Granted via permissions: {', '.join(perm_types)}"
            else:
                reason = "Granted via allow policy"
        else:
            if policy_violations:
                reason = "; ".join(policy_violations)
            elif not applicable_permissions:
                reason = f"No permissions found for {request.permission_type.value} on {request.resource_scope.value}"
            else:
                reason = "Access denied"
        
        return AccessDecision(
            granted=granted,
            reason=reason,
            applicable_permissions=applicable_permissions,
            policy_violations=policy_violations
        )
    
    def _permission_applies(self, permission: Permission, request: AccessRequest) -> bool:
        """Check if a permission applies to an access request"""
        
        # Check permission type
        if permission.permission_type != request.permission_type:
            # Check for admin permission (grants all)
            if permission.permission_type != PermissionType.ADMIN:
                return False
        
        # Check scope
        if permission.resource_scope == ResourceScope.GLOBAL:
            return True
        elif permission.resource_scope == ResourceScope.WORKSPACE:
            return permission.scope_filter == request.workspace
        elif permission.resource_scope == ResourceScope.RESOURCE_TYPE:
            return permission.scope_filter == request.resource_type
        elif permission.resource_scope == ResourceScope.RESOURCE:
            return permission.scope_filter == request.resource_identifier
        elif permission.resource_scope == ResourceScope.TAG_BASED:
            return self._check_tag_conditions(permission, request)
        
        return False
    
    def _check_tag_conditions(self, permission: Permission, request: AccessRequest) -> bool:
        """Check if tag-based conditions are met"""
        
        conditions = permission.conditions
        resource_tags = request.resource_tags
        
        for key, value in conditions.items():
            if key.startswith("tag:"):
                tag_name = key[4:]  # Remove "tag:" prefix
                if tag_name not in resource_tags or resource_tags[tag_name] != value:
                    return False
        
        return True
    
    def _policy_applies(self, policy: Policy, request: AccessRequest, user: User) -> bool:
        """Check if a policy applies to an access request"""
        
        conditions = policy.conditions
        
        # Check user conditions
        if "user_id" in conditions:
            if user.user_id not in conditions["user_id"]:
                return False
        
        if "department" in conditions:
            if user.department not in conditions["department"]:
                return False
        
        if "team" in conditions:
            if user.team not in conditions["team"]:
                return False
        
        # Check resource conditions
        if "resource_type" in conditions:
            if request.resource_type not in conditions["resource_type"]:
                return False
        
        if "workspace" in conditions:
            if request.workspace not in conditions["workspace"]:
                return False
        
        # Check time-based conditions
        if "time_range" in conditions:
            current_hour = datetime.now().hour
            time_range = conditions["time_range"]
            if current_hour < time_range["start"] or current_hour > time_range["end"]:
                return False
        
        return True
    
    def _get_inherited_permissions(self, role: Role) -> List[Permission]:
        """Get permissions inherited from parent roles"""
        
        inherited_permissions = []
        
        for parent_role_name in role.inherits_from:
            if parent_role_name in self.roles:
                parent_role = self.roles[parent_role_name]
                inherited_permissions.extend(parent_role.permissions)
                
                # Recursively get inherited permissions
                inherited_permissions.extend(self._get_inherited_permissions(parent_role))
        
        return inherited_permissions
    
    def _generate_cache_key(self, request: AccessRequest) -> str:
        """Generate cache key for access request"""
        
        key_parts = [
            request.user_id,
            request.permission_type.value,
            request.resource_scope.value,
            request.resource_identifier or "",
            request.workspace or "",
            request.resource_type or ""
        ]
        
        key_string = "|".join(key_parts)
        return hashlib.md5(key_string.encode()).hexdigest()
    
    def _clear_user_cache(self, user_id: str):
        """Clear cached decisions for a user"""
        
        keys_to_remove = []
        for key in self.permission_cache:
            if key.startswith(hashlib.md5(user_id.encode()).hexdigest()[:8]):
                keys_to_remove.append(key)
        
        for key in keys_to_remove:
            del self.permission_cache[key]
    
    def _log_access_attempt(self, request: AccessRequest, decision: AccessDecision):
        """Log access attempt for audit purposes"""
        
        log_entry = {
            "timestamp": request.timestamp.isoformat(),
            "user_id": request.user_id,
            "permission_type": request.permission_type.value,
            "resource_scope": request.resource_scope.value,
            "resource_identifier": request.resource_identifier,
            "workspace": request.workspace,
            "resource_type": request.resource_type,
            "granted": decision.granted,
            "reason": decision.reason
        }
        
        # This would integrate with the audit logging system
        self.logger.info(f"Access attempt: {json.dumps(log_entry)}")
    
    def _initialize_system_roles(self):
        """Initialize default system roles"""
        
        # Super Admin Role
        super_admin_permissions = [
            Permission(PermissionType.ADMIN, ResourceScope.GLOBAL)
        ]
        self.roles["super_admin"] = Role(
            name="super_admin",
            description="Full administrative access to all resources",
            permissions=super_admin_permissions,
            is_system_role=True
        )
        
        # Workspace Admin Role
        workspace_admin_permissions = [
            Permission(PermissionType.READ, ResourceScope.WORKSPACE),
            Permission(PermissionType.CREATE, ResourceScope.WORKSPACE),
            Permission(PermissionType.UPDATE, ResourceScope.WORKSPACE),
            Permission(PermissionType.DELETE, ResourceScope.WORKSPACE),
            Permission(PermissionType.EXECUTE, ResourceScope.WORKSPACE),
            Permission(PermissionType.IMPORT, ResourceScope.WORKSPACE),
            Permission(PermissionType.EXPORT, ResourceScope.WORKSPACE)
        ]
        self.roles["workspace_admin"] = Role(
            name="workspace_admin",
            description="Administrative access to a specific workspace",
            permissions=workspace_admin_permissions,
            is_system_role=True
        )
        
        # Developer Role
        developer_permissions = [
            Permission(PermissionType.READ, ResourceScope.WORKSPACE),
            Permission(PermissionType.CREATE, ResourceScope.WORKSPACE),
            Permission(PermissionType.UPDATE, ResourceScope.WORKSPACE),
            Permission(PermissionType.EXECUTE, ResourceScope.WORKSPACE)
        ]
        self.roles["developer"] = Role(
            name="developer",
            description="Development access to workspace resources",
            permissions=developer_permissions,
            is_system_role=True
        )
        
        # Viewer Role
        viewer_permissions = [
            Permission(PermissionType.READ, ResourceScope.WORKSPACE),
            Permission(PermissionType.EXPORT, ResourceScope.WORKSPACE)
        ]
        self.roles["viewer"] = Role(
            name="viewer",
            description="Read-only access to workspace resources",
            permissions=viewer_permissions,
            is_system_role=True
        )
        
        # Auditor Role
        auditor_permissions = [
            Permission(PermissionType.READ, ResourceScope.GLOBAL),
            Permission(PermissionType.AUDIT, ResourceScope.GLOBAL)
        ]
        self.roles["auditor"] = Role(
            name="auditor",
            description="Audit access to all resources and logs",
            permissions=auditor_permissions,
            is_system_role=True
        )
        
        self.logger.info("Initialized system roles")
    
    def _initialize_auth_providers(self):
        """Initialize authentication providers"""
        
        # Initialize local auth provider
        self.auth_providers[AuthenticationProvider.LOCAL] = LocalAuthProvider(self)
        
        # Initialize other providers based on configuration
        if self.config.get("ldap_enabled"):
            self.auth_providers[AuthenticationProvider.LDAP] = LDAPAuthProvider(self.config["ldap"])
        
        if self.config.get("oauth2_enabled"):
            self.auth_providers[AuthenticationProvider.OAUTH2] = OAuth2AuthProvider(self.config["oauth2"])
        
        # Add more providers as needed
        
        self.logger.info(f"Initialized {len(self.auth_providers)} authentication providers")
    
    def _load_config(self, config_path: Optional[str]) -> Dict[str, Any]:
        """Load RBAC configuration"""
        
        default_config = {
            "cache_ttl_minutes": 5,
            "ldap_enabled": False,
            "oauth2_enabled": False,
            "saml_enabled": False,
            "audit_enabled": True
        }
        
        if config_path and Path(config_path).exists():
            try:
                with open(config_path, 'r') as f:
                    file_config = json.load(f)
                default_config.update(file_config)
            except Exception as e:
                self.logger.warning(f"Failed to load config from {config_path}: {e}")
        
        return default_config


class LocalAuthProvider(AuthenticationProvider_Interface):
    """Local authentication provider for InfraDSL"""
    
    def __init__(self, rbac_system):
        self.rbac_system = rbac_system
        self.logger = logging.getLogger(__name__)
    
    def authenticate(self, username: str, password: str) -> Optional[User]:
        """Authenticate user with local credentials"""
        
        # Find user by username
        for user in self.rbac_system.users.values():
            if user.username == username and user.auth_provider == AuthenticationProvider.LOCAL:
                # In a real implementation, you would hash and compare passwords
                # For demo purposes, we'll accept any password for existing users
                return user
        
        return None
    
    def get_user_info(self, user_id: str) -> Optional[User]:
        """Get user information"""
        return self.rbac_system.users.get(user_id)
    
    def validate_token(self, token: str) -> Optional[str]:
        """Validate authentication token"""
        # In a real implementation, you would validate JWT or session tokens
        # For demo purposes, return the token as user_id if it exists
        return token if token in self.rbac_system.users else None


class LDAPAuthProvider(AuthenticationProvider_Interface):
    """LDAP authentication provider"""
    
    def __init__(self, config: Dict[str, Any]):
        self.config = config
        self.logger = logging.getLogger(__name__)
    
    def authenticate(self, username: str, password: str) -> Optional[User]:
        """Authenticate user against LDAP"""
        # Implementation would use ldap3 or similar library
        # This is a mock implementation
        self.logger.info(f"LDAP authentication for {username}")
        return None
    
    def get_user_info(self, user_id: str) -> Optional[User]:
        """Get user info from LDAP"""
        return None
    
    def validate_token(self, token: str) -> Optional[str]:
        """Validate LDAP token"""
        return None


class OAuth2AuthProvider(AuthenticationProvider_Interface):
    """OAuth2 authentication provider"""
    
    def __init__(self, config: Dict[str, Any]):
        self.config = config
        self.logger = logging.getLogger(__name__)
    
    def authenticate(self, username: str, password: str) -> Optional[User]:
        """OAuth2 doesn't use username/password"""
        return None
    
    def get_user_info(self, user_id: str) -> Optional[User]:
        """Get user info from OAuth2 provider"""
        return None
    
    def validate_token(self, token: str) -> Optional[str]:
        """Validate OAuth2 token"""
        # Implementation would validate JWT token
        return None