"""AWS Cognito authentication middleware for Bindu server.

This middleware validates JWT tokens from AWS Cognito for M2M and user authentication.
It inherits from AuthMiddleware and implements Cognito-specific token validation.

NOTE: This is a template/placeholder for future implementation.
To use AWS Cognito, you'll need to:
1. Install: pip install boto3 python-jose[cryptography]
2. Configure Cognito User Pool and App Client
3. Implement the validation logic below
"""

from __future__ import annotations as _annotations

from typing import Any

from bindu.utils.logging import get_logger

from .base import AuthMiddleware

logger = get_logger("bindu.server.middleware.cognito")


class CognitoMiddleware(AuthMiddleware):
    """AWS Cognito authentication middleware.

    This middleware implements AWS Cognito JWT token validation.
    It validates:
    - Token signature using Cognito public keys (JWKS)
    - Token expiration (exp claim)
    - Token issuer (iss claim - Cognito User Pool)
    - Token audience (aud/client_id claim)
    - Token use (access vs id token)

    Supports both user authentication and custom scopes.

    Configuration example:
    {
        "auth": {
            "enabled": true,
            "provider": "cognito",
            "region": "us-east-1",
            "user_pool_id": "us-east-1_XXXXXXXXX",
            "app_client_id": "your-app-client-id",
            "algorithms": ["RS256"]
        }
    }
    """

    def _initialize_provider(self) -> None:
        """Initialize AWS Cognito-specific components.

        Sets up:
        - Cognito JWKS URL from region and user pool ID
        - JWT validator for Cognito tokens
        - Boto3 client (optional, for advanced features)

        TODO: Implement Cognito initialization
        """
        # Example implementation:
        # region = self.config.region
        # user_pool_id = self.config.user_pool_id
        # self.jwks_url = f"https://cognito-idp.{region}.amazonaws.com/{user_pool_id}/.well-known/jwks.json"
        # self.issuer = f"https://cognito-idp.{region}.amazonaws.com/{user_pool_id}"
        # self.validator = CognitoJWTValidator(self.config)

        raise NotImplementedError(
            "AWS Cognito authentication is not yet implemented. This is a template for future implementation."
        )

    def _validate_token(self, token: str) -> dict[str, Any]:
        """Validate AWS Cognito JWT token.

        Args:
            token: JWT access or ID token from Cognito

        Returns:
            Decoded token payload with claims

        Raises:
            Exception: If token validation fails

        TODO: Implement Cognito token validation
        """
        # Example implementation:
        # 1. Decode token header to get kid
        # 2. Fetch JWKS from Cognito
        # 3. Verify signature using public key
        # 4. Validate claims:
        #    - iss: matches Cognito User Pool
        #    - token_use: "access" or "id"
        #    - exp: not expired
        #    - aud/client_id: matches app client
        # 5. Return decoded payload

        raise NotImplementedError("Cognito token validation not implemented")

    def _extract_user_info(self, token_payload: dict[str, Any]) -> dict[str, Any]:
        """Extract user information from Cognito token.

        Args:
            token_payload: Decoded and validated JWT payload

        Returns:
            Dictionary with standardized user information:
            {
                "sub": "cognito_user_id",
                "is_m2m": False,  # Cognito primarily for users
                "username": "...",
                "email": "...",
                "email_verified": bool,
                "phone_number": "...",
                "phone_number_verified": bool,
                "cognito:groups": [...],  # User groups
                "scope": "...",  # Custom scopes
                ... other Cognito claims
            }

        TODO: Implement Cognito user info extraction
        """
        # Example implementation:
        # sub = token_payload.get("sub")
        # username = token_payload.get("username") or token_payload.get("cognito:username")
        # email = token_payload.get("email")
        # groups = token_payload.get("cognito:groups", [])
        #
        # return {
        #     "sub": sub,
        #     "is_m2m": False,
        #     "username": username,
        #     "email": email,
        #     "email_verified": token_payload.get("email_verified", False),
        #     "groups": groups,
        #     "token_use": token_payload.get("token_use"),
        #     "scope": token_payload.get("scope", ""),
        # }

        raise NotImplementedError("Cognito user info extraction not implemented")

    def _handle_validation_error(self, error: Exception, path: str) -> Any:
        """Handle Cognito-specific token validation errors.

        Args:
            error: Validation exception
            path: Request path

        Returns:
            Appropriate JSON-RPC error response

        TODO: Implement Cognito-specific error handling
        """
        # Can use base class implementation or customize for Cognito
        return super()._handle_validation_error(error, path)
