/*
    * Copyright 2018 LINE Corporation
    *
    * LINE Corporation licenses this file to you under the Apache License,
    * version 2.0 (the "License"); you may not use this file except in compliance
    * with the License. You may obtain a copy of the License at:
    *
    *   https://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.
   */
  
  package com.linecorp.centraldogma.server.internal.storage.repository.cache;
  
  import static com.google.common.base.MoreObjects.firstNonNull;
  import static com.linecorp.centraldogma.server.internal.storage.repository.RepositoryCache.logger;
  import static java.util.Objects.requireNonNull;
  
  import java.util.Objects;
  import java.util.concurrent.CompletableFuture;
  
  import com.google.common.base.MoreObjects.ToStringHelper;
  
  import com.linecorp.armeria.common.util.Exceptions;
  import com.linecorp.centraldogma.common.EntryNotFoundException;
  import com.linecorp.centraldogma.common.Revision;
  import com.linecorp.centraldogma.server.storage.repository.AbstractCacheableCall;
  import com.linecorp.centraldogma.server.storage.repository.Repository;
  
  final class CacheableFindLatestRevCall extends AbstractCacheableCall<Revision> {
  
      static final Revision EMPTY = new Revision(Integer.MIN_VALUE);
      static final Revision ENTRY_NOT_FOUND = new Revision(Integer.MIN_VALUE);
  
      private final Revision lastKnownRevision;
      private final Revision headRevision;
      private final String pathPattern;
      private final boolean errorOnEntryNotFound;
      private final int hashCode;
  
      CacheableFindLatestRevCall(Repository repo, Revision lastKnownRevision, Revision headRevision,
                                 String pathPattern, boolean errorOnEntryNotFound) {
          super(repo);
  
          this.lastKnownRevision = requireNonNull(lastKnownRevision, "lastKnownRevision");
          this.headRevision = requireNonNull(headRevision, "headRevision");
          this.pathPattern = requireNonNull(pathPattern, "pathPattern");
          this.errorOnEntryNotFound = errorOnEntryNotFound;
  
          hashCode = Objects.hash(lastKnownRevision, headRevision, pathPattern, errorOnEntryNotFound) +
                     System.identityHashCode(repo);
  
          assert !lastKnownRevision.isRelative();
      }
  
      @Override
      public int weigh(Revision value) {
          return pathPattern.length();
      }
  
      @Override
      public CompletableFuture<Revision> execute() {
          logger.debug("Cache miss: {}", this);
          return repo().findLatestRevision(lastKnownRevision, pathPattern, errorOnEntryNotFound)
                       .handle((revision, cause) -> {
                           if (cause != null) {
                               cause = Exceptions.peel(cause);
                               if (cause instanceof EntryNotFoundException) {
                                   return ENTRY_NOT_FOUND;
                               }
                               return Exceptions.throwUnsafely(cause);
                           }
                           return firstNonNull(revision, EMPTY);
                       });
      }
  
      @Override
      public int hashCode() {
          return hashCode;
      }
  
      @Override
      public boolean equals(Object o) {
          if (!super.equals(o)) {
              return false;
          }
  
          final CacheableFindLatestRevCall that = (CacheableFindLatestRevCall) o;
          return lastKnownRevision.equals(that.lastKnownRevision) &&
                 headRevision.equals(that.headRevision) &&
                 pathPattern.equals(that.pathPattern) &&
                 errorOnEntryNotFound == that.errorOnEntryNotFound;
      }
  
      @Override
     protected void toString(ToStringHelper helper) {
         helper.add("lastKnownRevision", lastKnownRevision)
               .add("headRevision", headRevision)
               .add("pathPattern", pathPattern)
               .add("errorOnEntryNotFound", errorOnEntryNotFound);
     }
 }