/*
 * ============LICENSE_START==========================================
 * ONAP Portal
 * ===================================================================
 * Copyright (C) 2019 AT&T Intellectual Property. All rights reserved.
 * ===================================================================
 * Modifications Copyright (c) 2019 Samsung
 * ===================================================================
 *
 * Unless otherwise specified, all software contained herein is licensed
 * under the Apache License, Version 2.0 (the "License");
 * you may not use this software 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.
 *
 * Unless otherwise specified, all documentation contained herein is licensed
 * under the Creative Commons License, Attribution 4.0 Intl. (the "License");
 * you may not use this documentation except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *             https://creativecommons.org/licenses/by/4.0/
 *
 * Unless required by applicable law or agreed to in writing, documentation
 * 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.
 *
 * ============LICENSE_END============================================
 *
 *
 */

package org.onap.portal.service;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;
import javax.annotation.PostConstruct;
import org.onap.portal.domain.db.fn.FnApp;
import org.onap.portal.domain.dto.transport.OnboardingApp;
import org.onap.portal.service.fn.FnAppService;
import org.onap.portalsdk.core.logging.logic.EELFLoggerDelegate;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

@Service
public class AppsCacheService {


  private final FnAppService appsService;

  private final EELFLoggerDelegate logger = EELFLoggerDelegate.getLogger(AppsCacheService.class);

  @Autowired
  public AppsCacheService(FnAppService appsService) {
    this.appsService = appsService;
  }

  final class CacheConfiguration {

    private long updateTime;
    private final int updateInterval;

    CacheConfiguration(long updateTime, int updateInterval) {
      this.updateTime = updateTime;
      this.updateInterval = updateInterval;
    }
  }

  private CacheConfiguration quickRefreshCacheConf = null;
  private CacheConfiguration slowRefreshCacheConf = null;


  private static volatile Map<Long, FnApp> appsMap;
  private static volatile Map<String, FnApp> uebAppsMap;

  @PostConstruct
  public void init() {
    quickRefreshCacheConf = new CacheConfiguration(0, 120);
    slowRefreshCacheConf = new CacheConfiguration(0, 3600);

    this.refreshAppsMap(quickRefreshCacheConf);
  }

  private void refreshAppsMap(CacheConfiguration conf) {
    long now = System.currentTimeMillis();

    if (noNeedToUpdate(now, conf)) {
      return;
    }

    synchronized (this) {
      if (noNeedToUpdate(now, conf)) {
        return;
      }
      List<FnApp> allApps = appsService.getAppsFullList();
      Map<Long, FnApp> newAppsMap = new HashMap<>();
      for (FnApp app : allApps) {
        newAppsMap.put(app.getId(), app);
      }

      Map<String, FnApp> newUebAppsMap = new HashMap<>();
      for (FnApp app : allApps) {
        newUebAppsMap.put(app.getUebKey(), app);
      }
      // Switch cache with the new one.
      appsMap = newAppsMap;
      uebAppsMap = newUebAppsMap;
      conf.updateTime = now;
    }

  }

  private boolean noNeedToUpdate(long now, CacheConfiguration conf) {
    long secondsPassed = (now - conf.updateTime) / 1000;
    if (secondsPassed < conf.updateInterval) {
      logger.debug(EELFLoggerDelegate.debugLogger,
          "no need to refresh yet, seconds since last refresh: " + secondsPassed + ", refresh interval (sec) = "
              + conf.updateInterval);
      return true; // no need to update cache
    }
    return false; // its time to update
  }

  public String getAppEndpoint(Long appId) {
    refreshAppsMap(quickRefreshCacheConf);
    FnApp app = appsMap.get(appId);
    if (app != null) {
      return app.getAppRestEndpoint();
    }
    return null;
  }

  public List<OnboardingApp> getAppsFullList() {
    refreshAppsMap(quickRefreshCacheConf);
    List<FnApp> appList = new ArrayList<>(appsMap.values());
    appList.removeIf(app -> app.getId() == 1);
    List<FnApp> appsFinalList = appList.stream()
        .filter(app -> app.getEnabled() && !app.getOpen()).collect(Collectors.toList());

    List<OnboardingApp> onboardingAppsList = new ArrayList<>();
    for (FnApp app : appsFinalList) {
      OnboardingApp onboardingApp = new OnboardingApp();
      appsService.createOnboardingFromApp(app, onboardingApp);
      onboardingAppsList.add(onboardingApp);
    }
    return onboardingAppsList;
  }

  public FnApp getApp(Long appId) {
    refreshAppsMap(quickRefreshCacheConf);
    return appsMap.get(appId);
  }

  public FnApp getAppFromUeb(String appKey) {
    return getAppFromUeb(appKey, 0);
  }

  public FnApp getAppFromUeb(String appKey, Integer quickCacheRefresh) {
    refreshAppsMap(quickCacheRefresh == 1 ? quickRefreshCacheConf : slowRefreshCacheConf);
    return uebAppsMap.get(appKey);
  }

}