/*
 *
 * Copyright 2016 gRPC authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */

#ifndef GRPC_CORE_LIB_SECURITY_CREDENTIALS_OAUTH2_OAUTH2_CREDENTIALS_H
#define GRPC_CORE_LIB_SECURITY_CREDENTIALS_OAUTH2_OAUTH2_CREDENTIALS_H

#include "src/core/lib/json/json.h"
#include "src/core/lib/security/credentials/credentials.h"

// auth_refresh_token parsing.
typedef struct {
  const char *type;
  char *client_id;
  char *client_secret;
  char *refresh_token;
} grpc_auth_refresh_token;

/// Returns 1 if the object is valid, 0 otherwise.
int grpc_auth_refresh_token_is_valid(
    const grpc_auth_refresh_token *refresh_token);

/// Creates a refresh token object from string. Returns an invalid object if a
/// parsing error has been encountered.
grpc_auth_refresh_token grpc_auth_refresh_token_create_from_string(
    const char *json_string);

/// Creates a refresh token object from parsed json. Returns an invalid object
/// if a parsing error has been encountered.
grpc_auth_refresh_token grpc_auth_refresh_token_create_from_json(
    const grpc_json *json);

/// Destructs the object.
void grpc_auth_refresh_token_destruct(grpc_auth_refresh_token *refresh_token);

// -- Oauth2 Token Fetcher credentials --
//
//  This object is a base for credentials that need to acquire an oauth2 token
//  from an http service.

typedef void (*grpc_fetch_oauth2_func)(grpc_exec_ctx *exec_ctx,
                                       grpc_credentials_metadata_request *req,
                                       grpc_httpcli_context *http_context,
                                       grpc_polling_entity *pollent,
                                       grpc_iomgr_cb_func cb,
                                       gpr_timespec deadline);

typedef struct grpc_oauth2_pending_get_request_metadata {
  grpc_credentials_mdelem_array *md_array;
  grpc_closure *on_request_metadata;
  grpc_polling_entity *pollent;
  struct grpc_oauth2_pending_get_request_metadata *next;
} grpc_oauth2_pending_get_request_metadata;

typedef struct {
  grpc_call_credentials base;
  gpr_mu mu;
  grpc_mdelem access_token_md;
  gpr_timespec token_expiration;
  bool token_fetch_pending;
  grpc_oauth2_pending_get_request_metadata *pending_requests;
  grpc_httpcli_context httpcli_context;
  grpc_fetch_oauth2_func fetch_func;
  grpc_polling_entity pollent;
} grpc_oauth2_token_fetcher_credentials;

// Google refresh token credentials.
typedef struct {
  grpc_oauth2_token_fetcher_credentials base;
  grpc_auth_refresh_token refresh_token;
} grpc_google_refresh_token_credentials;

// Access token credentials.
typedef struct {
  grpc_call_credentials base;
  grpc_mdelem access_token_md;
} grpc_access_token_credentials;

// Private constructor for refresh token credentials from an already parsed
// refresh token. Takes ownership of the refresh token.
grpc_call_credentials *
grpc_refresh_token_credentials_create_from_auth_refresh_token(
    grpc_auth_refresh_token token);

// Exposed for testing only.
grpc_credentials_status
grpc_oauth2_token_fetcher_credentials_parse_server_response(
    grpc_exec_ctx *exec_ctx, const struct grpc_http_response *response,
    grpc_mdelem *token_md, gpr_timespec *token_lifetime);

#endif /* GRPC_CORE_LIB_SECURITY_CREDENTIALS_OAUTH2_OAUTH2_CREDENTIALS_H */
