// Copyright 2015 The Goma Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef DEVTOOLS_GOMA_CLIENT_OAUTH2_H_
#define DEVTOOLS_GOMA_CLIENT_OAUTH2_H_

#include <string>

#include "absl/strings/string_view.h"

namespace devtools_goma {

struct OAuth2Config {
  std::string auth_uri;
  std::string token_uri;
  std::string scope;

  std::string client_id;
  std::string client_secret;
  std::string refresh_token;

  // "type": "authorized_user" is used in gRPC GoogleDefaultCredentials.
  // TODO: Stop to use OAuth2Config with ServiceAccountConfig.
  std::string type;

  bool enabled() const {
    return !auth_uri.empty() && !token_uri.empty() && !scope.empty() &&
        !client_id.empty() && !client_secret.empty();
  }
  bool valid() const {
    return enabled() && !refresh_token.empty();
  }
  void clear() {
    auth_uri.clear();
    token_uri.clear();
    scope.clear();
    client_id.clear();
    client_secret.clear();
    refresh_token.clear();
    type.clear();
  }
};

// ServiceAccountConfig has fields in service account json
// generated by google cloud console.
// Json file should have type field, which value must be "service_account".
struct ServiceAccountConfig {
  // required for GoogleOAuth2AccessTokenRefreshTask
  std::string private_key;  // to sign JWT.
  std::string client_email;  // claim set iss.

  // optional. goma client doesn't use these fields.
  // (some of them are used only for logging.)
  std::string project_id;
  std::string private_key_id;
  std::string client_id;
  std::string auth_uri;
  std::string token_uri;
  std::string auth_provider_x509_cert_url;
  std::string client_x509_cert_url;
};

// Parse OAuth2 Access Token in refresh token response.
// Returns true on success, and token_type is set to |token_type|,
// access_token is set to |access_token|, and expires_in filed in json is
// set to |expires_in|.
bool ParseOAuth2AccessToken(const std::string& json,
                            std::string* token_type,
                            std::string* access_token,
                            int* expires_in);

// Returns default OAuth2 config.
void DefaultOAuth2Config(OAuth2Config* config);

// Parse OAuth2 config file.
// Returns true on success and all OAuth2Config fields are ready to use.
bool ParseOAuth2Config(const std::string& str, OAuth2Config* config);


// Format OAuth2 config for OAuth2 config file.
std::string FormatOAuth2Config(const OAuth2Config& config);

bool SaveOAuth2Config(const std::string& filename, const OAuth2Config& config);

// Parse ServiceAccount JSON file.
bool ParseServiceAccountJson(const std::string& str,
                             ServiceAccountConfig* config);

const char kGoogleAuthURI[] =
    "https://accounts.google.com/o/oauth2/auth";
const char kGoogleTokenURI[] =
    "https://www.googleapis.com/oauth2/v3/token";
const char kGoogleTokenInfoURI[] =
    "https://www.googleapis.com/oauth2/v3/tokeninfo";
const char kGoogleTokenAudienceURI[] =
    "https://www.googleapis.com/oauth2/v4/token";

const char kGomaAuthScope[] = "https://www.googleapis.com/auth/userinfo.email";

}  // namespace devtools_goma

#endif  // DEVTOOLS_GOMA_CLIENT_OAUTH2_H_