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package com.google.auth.oauth2;

import com.google.api.client.http.HttpStatusCodes;
import com.google.api.client.http.LowLevelHttpRequest;
import com.google.api.client.http.LowLevelHttpResponse;
import com.google.api.client.json.GenericJson;
import com.google.api.client.json.Json;
import com.google.api.client.testing.http.MockHttpTransport;
import com.google.api.client.testing.http.MockLowLevelHttpRequest;
import com.google.api.client.testing.http.MockLowLevelHttpResponse;
import com.google.auth.TestUtils;
import com.google.common.io.BaseEncoding;
import java.io.IOException;

/** Transport that simulates the IAMCredentials server for access tokens. */
public class MockIAMCredentialsServiceTransport extends MockHttpTransport {

  private static final String DEFAULT_IAM_ACCESS_TOKEN_ENDPOINT =
      "https://iamcredentials.googleapis.com/v1/projects/-/serviceAccounts/%s:generateAccessToken";
  private static final String IAM_ID_TOKEN_ENDPOINT =
      "https://iamcredentials.googleapis.com/v1/projects/-/serviceAccounts/%s:generateIdToken";
  private static final String IAM_SIGN_ENDPOINT =
      "https://iamcredentials.googleapis.com/v1/projects/-/serviceAccounts/%s:signBlob";
  private Integer tokenResponseErrorCode;
  private String tokenResponseErrorContent;
  private String targetPrincipal;
  private byte[] signedBlob;
  private int responseCode = HttpStatusCodes.STATUS_CODE_OK;
  private String errorMessage;
  private String iamAccessTokenEndpoint;

  private String accessToken;
  private String expireTime;

  private String idToken;

  private MockLowLevelHttpRequest request;

  public MockIAMCredentialsServiceTransport() {}

  public void setTokenResponseErrorCode(Integer tokenResponseErrorCode) {
    this.tokenResponseErrorCode = tokenResponseErrorCode;
  }

  public void setTokenResponseErrorContent(String tokenResponseErrorContent) {
    this.tokenResponseErrorContent = tokenResponseErrorContent;
  }

  public void setTargetPrincipal(String targetPrincipal) {
    this.targetPrincipal = targetPrincipal;
  }

  public void setAccessToken(String accessToken) {
    this.accessToken = accessToken;
  }

  public void setExpireTime(String expireTime) {
    this.expireTime = expireTime;
  }

  public void setSignedBlob(byte[] signedBlob) {
    this.signedBlob = signedBlob;
  }

  public void setErrorResponseCodeAndMessage(int responseCode, String errorMessage) {
    this.responseCode = responseCode;
    this.errorMessage = errorMessage;
  }

  public void setIdToken(String idToken) {
    this.idToken = idToken;
  }

  public void setAccessTokenEndpoint(String accessTokenEndpoint) {
    this.iamAccessTokenEndpoint = accessTokenEndpoint;
  }

  public MockLowLevelHttpRequest getRequest() {
    return request;
  }

  @Override
  public LowLevelHttpRequest buildRequest(String method, String url) throws IOException {

    String iamAccesssTokenformattedUrl =
        iamAccessTokenEndpoint != null
            ? iamAccessTokenEndpoint
            : String.format(DEFAULT_IAM_ACCESS_TOKEN_ENDPOINT, this.targetPrincipal);
    String iamSignBlobformattedUrl = String.format(IAM_SIGN_ENDPOINT, this.targetPrincipal);
    String iamIdTokenformattedUrl = String.format(IAM_ID_TOKEN_ENDPOINT, this.targetPrincipal);
    if (url.equals(iamAccesssTokenformattedUrl)) {
      this.request =
          new MockLowLevelHttpRequest(url) {
            @Override
            public LowLevelHttpResponse execute() throws IOException {

              if (tokenResponseErrorCode != null) {
                return new MockLowLevelHttpResponse()
                    .setStatusCode(tokenResponseErrorCode)
                    .setContentType(Json.MEDIA_TYPE)
                    .setContent(tokenResponseErrorContent);
              }

              // Create the JSON response
              GenericJson refreshContents = new GenericJson();
              refreshContents.setFactory(OAuth2Utils.JSON_FACTORY);
              refreshContents.put("accessToken", accessToken);
              refreshContents.put("expireTime", expireTime);
              String refreshText = refreshContents.toPrettyString();
              return new MockLowLevelHttpResponse()
                  .setContentType(Json.MEDIA_TYPE)
                  .setContent(refreshText);
            }
          };
    } else if (url.equals(iamSignBlobformattedUrl)
        && responseCode != HttpStatusCodes.STATUS_CODE_OK) {
      this.request =
          new MockLowLevelHttpRequest(url) {
            @Override
            public LowLevelHttpResponse execute() throws IOException {

              if (tokenResponseErrorCode != null) {
                return new MockLowLevelHttpResponse()
                    .setStatusCode(tokenResponseErrorCode)
                    .setContentType(Json.MEDIA_TYPE)
                    .setContent(tokenResponseErrorContent);
              }

              BaseEncoding base64 = BaseEncoding.base64();
              GenericJson refreshContents = new GenericJson();
              refreshContents.setFactory(OAuth2Utils.JSON_FACTORY);
              refreshContents.put("signedBlob", base64.encode(signedBlob));
              return new MockLowLevelHttpResponse()
                  .setStatusCode(responseCode)
                  .setContent(TestUtils.errorJson(errorMessage));
            }
          };
    } else if (url.equals(iamSignBlobformattedUrl)) {
      this.request =
          new MockLowLevelHttpRequest(url) {
            @Override
            public LowLevelHttpResponse execute() throws IOException {

              if (tokenResponseErrorCode != null) {
                return new MockLowLevelHttpResponse()
                    .setStatusCode(tokenResponseErrorCode)
                    .setContentType(Json.MEDIA_TYPE)
                    .setContent(tokenResponseErrorContent);
              }

              BaseEncoding base64 = BaseEncoding.base64();
              GenericJson refreshContents = new GenericJson();
              refreshContents.setFactory(OAuth2Utils.JSON_FACTORY);
              refreshContents.put("signedBlob", base64.encode(signedBlob));
              String refreshText = refreshContents.toPrettyString();
              return new MockLowLevelHttpResponse()
                  .setContentType(Json.MEDIA_TYPE)
                  .setContent(refreshText);
            }
          };
    } else if (url.equals(iamIdTokenformattedUrl)) {
      this.request =
          new MockLowLevelHttpRequest(url) {
            @Override
            public LowLevelHttpResponse execute() throws IOException {

              if (responseCode != HttpStatusCodes.STATUS_CODE_OK) {
                return new MockLowLevelHttpResponse()
                    .setStatusCode(responseCode)
                    .setContentType(Json.MEDIA_TYPE)
                    .setContent(errorMessage);
              }

              GenericJson refreshContents = new GenericJson();
              refreshContents.setFactory(OAuth2Utils.JSON_FACTORY);
              refreshContents.put("token", idToken);
              String tokenContent = refreshContents.toPrettyString();
              return new MockLowLevelHttpResponse()
                  .setContentType(Json.MEDIA_TYPE)
                  .setContent(tokenContent);
            }
          };
    } else {
      return super.buildRequest(method, url);
    }

    return this.request;
  }
}