/*
 * SonarQube
 * Copyright (C) 2009-2025 SonarSource SA
 * mailto:info AT sonarsource DOT com
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 3 of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */
package org.sonar.auth.saml;

import java.io.ByteArrayInputStream;
import java.security.cert.CertificateException;
import java.security.cert.CertificateFactory;
import java.security.cert.X509Certificate;
import java.util.Base64;
import org.sonar.api.server.ServerSide;

@ServerSide
class SamlCertificateConverter {

  public static final String SPACES = "\\s+";

  X509Certificate toX509Certificate(String certificateString) {
    String cleanedCertificateString = sanitizeCertificateString(certificateString);

    byte[] decoded = Base64.getDecoder().decode(cleanedCertificateString);
    try {
      CertificateFactory factory = CertificateFactory.getInstance("X.509");
      return (X509Certificate) factory.generateCertificate(new ByteArrayInputStream(decoded));
    } catch (CertificateException e) {
      throw new IllegalStateException("Invalid certificate", e);
    }
  }

  private static String sanitizeCertificateString(String certificateString) {
    return certificateString
      .replace("-----BEGIN CERTIFICATE-----", "")
      .replace("-----END CERTIFICATE-----", "")
      .replaceAll(SPACES, "");
  }
}