# WopiClientManager.java

    /*
     * Copyright (C) 2000 - 2021 Silverpeas
     *
     * This program is free software: you can redistribute it and/or modify
     * it under the terms of the GNU Affero General Public License as
     * published by the Free Software Foundation, either version 3 of the
     * License, or (at your option) any later version.
     *
     * As a special exception to the terms and conditions of version 3.0 of
     * the GPL, you may redistribute this Program in connection with Free/Libre
     * Open Source Software ("FLOSS") applications as described in Silverpeas's
     * FLOSS exception.  You should have received a copy of the text describing
     * the FLOSS exception, and it is also available here:
     * "https://www.silverpeas.org/legal/floss_exception.html"
     *
     * 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 Affero General Public License for more details.
     *
     * You should have received a copy of the GNU Affero General Public License
     * along with this program.  If not, see <http://www.gnu.org/licenses/>.
     */

    package org.silverpeas.wbe.wopi;

    import org.silverpeas.core.annotation.Service;
    import org.silverpeas.core.util.security.SecuritySettings;
    import org.silverpeas.core.wbe.WbeClientManager;
    import org.silverpeas.core.wbe.WbeFile;
    import org.silverpeas.core.wbe.WbeHostManager;
    import org.silverpeas.core.wbe.WbeUser;
    import org.silverpeas.wbe.wopi.discovery.WopiDiscovery;
    import org.silverpeas.wbe.wopi.util.WopiSettings;

    import javax.ws.rs.WebApplicationException;
    import java.io.InputStream;
    import java.net.http.HttpResponse;
    import java.time.Duration;
    import java.time.LocalDateTime;
    import java.util.Map;
    import java.util.Optional;
    import java.util.concurrent.ConcurrentHashMap;
    import java.util.stream.Stream;

    import static java.net.http.HttpResponse.BodyHandlers.ofInputStream;
    import static java.text.MessageFormat.format;
    import static java.time.temporal.ChronoUnit.HOURS;
    import static java.time.temporal.ChronoUnit.SECONDS;
    import static java.util.Optional.*;
    import static javax.ws.rs.core.Response.Status.OK;
    import static org.silverpeas.core.util.HttpUtil.httpClientTrustingAnySslContext;
    import static org.silverpeas.core.util.HttpUtil.toUrl;
    import static org.silverpeas.core.wbe.WbeLogger.logger;
    import static org.silverpeas.kernel.util.StringUtil.isDefined;
    import static org.silverpeas.wbe.wopi.util.WopiSettings.*;

    /**
     * @author silveryocha
     */
    @Service
    public class WopiClientManager implements WbeClientManager {

      private final Map<String, String> baseUrlByMimeTypes = new ConcurrentHashMap<>();
      private final Map<String, String> baseUrlByExtension = new ConcurrentHashMap<>();
      private LocalDateTime lastDateTimeOfDiscoveryGet;
      private String lastDiscoveryUrl;

      @Override
      public boolean isEnabled() {
        return WopiSettings.isEnabled();
      }

      @Override
      public boolean isHandled(final WbeFile file) {
        return getClientBaseUrlFor(file).isPresent();
      }

      @SuppressWarnings("unchecked")
      @Override
      public Optional<WopiEdition> prepareEditionWith(final WbeUser user, final WbeFile file) {
        return getClientBaseUrlFor(file).map(u -> new WopiEdition(file, user, u));
      }

      @Override
      public Optional<String> getAdministrationUrl() {
        return ofNullable(getWopiClientAdministrationUrl());
      }

      @Override
      public String getName(final String language) {
        return "LibreOffice Online";
      }

      @Override
      public void clear() {
        baseUrlByMimeTypes.clear();
        baseUrlByExtension.clear();
      }

      /**
       * WOPI discovery is the process by which a WOPI host identifies Office for the web
       * capabilities and how to initialize Office for the web applications within a site. WOPI hosts
       * use the discovery XML to determine how to interact with Office for the web.
       * <p>
       *   The discovery is processed every {@link WopiSettings#getWopiClientDiscoveryTimeToLive}
       *   hours to ensures the most up-to-date capabilities.
       * </p>
       */
      private synchronized void discover() {
        final String discoveryUrl = getWopiClientDiscoveryUrl();
        if (lastDiscoveryUrl == null ||
            !lastDiscoveryUrl.equals(discoveryUrl) ||
            baseUrlByMimeTypes.isEmpty() ||
            HOURS.between(lastDateTimeOfDiscoveryGet, LocalDateTime.now()) >= getWopiClientDiscoveryTimeToLive()) {
          WbeHostManager.get().clear();
          logger().debug(() -> format("discovering WOPI client with URL {0}", discoveryUrl));
          try {
            final HttpResponse<InputStream> response = httpClientTrustingAnySslContext().send(toUrl(discoveryUrl)
                .timeout(Duration.of(2, SECONDS))
                .build(), ofInputStream());
            if (response.statusCode() != OK.getStatusCode()) {
              throw new WebApplicationException(response.statusCode());
            }
            final WopiDiscovery wopiDiscovery;
            try (final InputStream body = response.body()) {
              wopiDiscovery = WopiDiscovery.load(body);
            }
            wopiDiscovery.consumeBaseUrlMimeType((n, a) -> {
              baseUrlByMimeTypes.put(n, a.getUrlsrc());
              if (isDefined(a.getExt()) && "edit".equals(a.getName())) {
                baseUrlByExtension.put(a.getExt(), a.getUrlsrc());
              }
            });
          } catch (Exception e) {
            logger().error(e);
            if (e instanceof InterruptedException) {
              Thread.currentThread().interrupt();
            }
            throw new WebApplicationException(e);
          }
          registerSecurityDomains();
          lastDiscoveryUrl = discoveryUrl;
          lastDateTimeOfDiscoveryGet = LocalDateTime.now();
        }
      }

      private Optional<String> getClientBaseUrlFor(final WbeFile file) {
        if (isEnabled()) {
          discover();
          final String clientBaseUrl = baseUrlByMimeTypes.get(file.mimeType());
          if (isDefined(clientBaseUrl)) {
            return of(clientBaseUrl);
          }
          return ofNullable(baseUrlByExtension.get(file.ext()));
        } else if (!baseUrlByMimeTypes.isEmpty()){
          WbeHostManager.get().clear();
          logger().debug(() -> format("removing all discovered actions because of WOPI disabling"));
        }
        return empty();
      }

      private void registerSecurityDomains() {
        getWopiClientBaseUrl().stream()
            .flatMap(u -> Stream.of(u, u.replaceFirst("^http", "ws")))
            .forEach(u -> {
              final SecuritySettings.Registration registration = SecuritySettings.registration();
              registration.registerDefaultSourceInCSP(u);
              registration.registerDomainInCORS(u);
              logger().debug(() -> format("registering into security WOPI client base URL {0}", u));
            });
      }

    }