# coding: utf-8
# Copyright (c) 2016, 2024, Oracle and/or its affiliates.  All rights reserved.
# This software is dual-licensed to you under the Universal Permissive License (UPL) 1.0 as shown at https://oss.oracle.com/licenses/upl or Apache License 2.0 as shown at http://www.apache.org/licenses/LICENSE-2.0. You may choose either license.

import json
import threading

from cryptography.hazmat.primitives.serialization import Encoding, PublicFormat

import oci
import oci.signer

from .security_token_signer import SecurityTokenSigner, SECURITY_TOKEN_FORMAT_STRING
from .. import auth_utils
from ..security_token_container import SecurityTokenContainer

OPTIONAL_NESTED_PARENT_HEADER = "opc-parent-rpt-url"


class NestedResourcePrincipals(SecurityTokenSigner):

    def __init__(self, resource_principal_rpt_url=None, resource_principal_session_token_endpoint=None,
                 sub_resource_rp_signer=None, retry_strategy=None, log_requests=None, generic_headers=None,
                 current_parent_depth=0, **kwargs):

        if not sub_resource_rp_signer:
            raise ValueError("Could not initiate sub-resource principals signers please check your environment!")
        else:
            self.sub_resource_rp_signer = sub_resource_rp_signer

        # set region from sub_resource_rp_signer
        if hasattr(sub_resource_rp_signer, 'region'):
            self.region = sub_resource_rp_signer.region

        if resource_principal_session_token_endpoint:
            self.resource_principal_session_token_endpoint = resource_principal_session_token_endpoint
        else:
            raise ValueError("resource_principal_session_token_endpoint must be provided")

        if resource_principal_rpt_url is None:
            raise ValueError("resource_principal_rpt_url should be present!")

        self.resource_principal_token_endpoint = resource_principal_rpt_url
        self.resource_principal_token_path = ""
        self.current_parent_depth = current_parent_depth

        self._reset_signers_lock = threading.Lock()

        if retry_strategy:
            self.retry_strategy = retry_strategy
        else:
            self.retry_strategy = oci.retry.DEFAULT_RETRY_STRATEGY

        # Holders for the tokens needed.
        self.rpt = None
        self.spst = None

        # Set up base_client for calls to Service to get Resource Principal Token and Service Principal Session Token
        # The config is not needed but request logging could be enabled.
        config = {}
        if log_requests:
            config["log_requests"] = log_requests

        self.base_client = oci.BaseClient("",  # No service
                                          config,
                                          sub_resource_rp_signer,  # Signer composed for sub-resource
                                          {},  # No type mapping
                                          region_client=False,
                                          service_endpoint=self.resource_principal_token_endpoint)

        # Set Key Supplier
        self.session_key_supplier = self.sub_resource_rp_signer.session_key_supplier

        # Get the Resource Principal Session Token and use it to set up the signer
        self.rpst = self.get_security_token()

        if generic_headers:
            super(NestedResourcePrincipals, self).__init__(self.security_token.security_token,
                                                           self.session_key_supplier.get_key_pair()['private'],
                                                           generic_headers=generic_headers)
        else:
            super(NestedResourcePrincipals, self).__init__(self.security_token.security_token,
                                                           self.session_key_supplier.get_key_pair()['private'])

    def get_security_token(self):
        """
        Returns the security token. If it is expired, refresh the token.
        """
        if hasattr(self, 'security_token'):
            if self.security_token.valid_with_jitter():
                return self.security_token.security_token

        return self._refresh_security_token_inner()

    def refresh_security_token(self):
        """
        Refresh the security token
        """
        return self._refresh_security_token_inner()

    def _refresh_security_token_inner(self):
        self._reset_signers_lock.acquire()
        try:
            self.sub_resource_rp_signer.refresh_security_token()

            # Get RPT blob, Service Principal Session Token from service, Steps A.1 and B.1
            self.rpt, self.spst = self._get_resource_principal_token_and_service_principal_session_token()

            # Get RPST token from identity, steps A.2 and B.2
            self.security_token = SecurityTokenContainer(self.session_key_supplier,
                                                         self._get_resource_principal_session_token())
            self._reset_signers()

            return self.security_token.security_token
        finally:
            self._reset_signers_lock.release()

    def _reset_signers(self):
        self.api_key = SECURITY_TOKEN_FORMAT_STRING.format(self.security_token.security_token)
        self.private_key = self.session_key_supplier.get_key_pair()['private']

        if hasattr(self, '_basic_signer'):
            self._basic_signer.reset_signer(self.api_key, self.private_key)
        if hasattr(self, '_body_signer'):
            self._body_signer.reset_signer(self.api_key, self.private_key)

    def _get_resource_principal_token_and_service_principal_session_token(self):
        """
        Get the Resource Principal Token and the Service Principal Session Token

        This makes a call to the resource_principal_token_endpoint which is
        defined by the service.
        """
        method = "get"
        self.base_client.endpoint = self.resource_principal_token_endpoint

        response = self.make_call(method, self.resource_principal_token_path)
        if response.headers and OPTIONAL_NESTED_PARENT_HEADER in response.headers:
            self.nested_parent_rpt_url = response.headers.get(OPTIONAL_NESTED_PARENT_HEADER)
        else:
            # setting this as None to mark missing header for terminal parent.
            self.nested_parent_rpt_url = None

        parsed_response = json.loads(response.data.decode('UTF-8'))
        return parsed_response['resourcePrincipalToken'], parsed_response['servicePrincipalSessionToken']

    def _get_resource_principal_session_token(self):
        """
        Get the Resource Principal Session Token
        """
        method = "post"
        resource_path = "/v1/resourcePrincipalSessionToken"

        self.base_client.endpoint = self.resource_principal_session_token_endpoint

        public_key = self.session_key_supplier.get_key_pair()['public']
        sanitized_public_key = auth_utils.sanitize_certificate_string(
            public_key.public_bytes(Encoding.PEM, PublicFormat.SubjectPublicKeyInfo))

        request_payload = {
            'resourcePrincipalToken': self.rpt,
            'servicePrincipalSessionToken': self.spst,
            'sessionPublicKey': sanitized_public_key
        }

        # The base client will convert the payload to JSON, but won't update the content length, so we need to
        # it here.
        json_request_payload = json.dumps(request_payload)
        header_params = {'content-type': 'application/json',
                         'Content-Length': str(len(json_request_payload))}
        response = self.make_call(method, resource_path, header_params=header_params, body=request_payload)
        parsed_response = json.loads(response.data.decode('UTF-8'))

        return parsed_response['token']

    def make_call(self, method, resource_path, path_params=None, header_params=None, body=None):
        """
        make_call

        Normally this would be part of the generated client.  In this case the endpoint for the
        Resource Principal Token is not part of the generated client, so we need the same
        behavior here.
        """
        if self.retry_strategy:
            return self.retry_strategy.make_retrying_call(
                self.base_client.call_api,
                resource_path=resource_path,
                method=method,
                path_params=path_params,
                header_params=header_params,
                body=body,
                response_type=oci.base_client.BYTES_RESPONSE_TYPE)
        else:
            return self.base_client.call_api(
                resource_path=resource_path,
                method=method,
                path_params=path_params,
                header_params=header_params,
                body=body,
                response_type=oci.base_client.BYTES_RESPONSE_TYPE)