/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF 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
 *
 *    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.
 *
 */

package org.apache.streampipes.export.resolver;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.apache.streampipes.commons.exceptions.ElementNotFoundException;
import org.apache.streampipes.export.utils.SerializationUtils;
import org.apache.streampipes.model.assets.AssetLink;
import org.apache.streampipes.model.export.ExportItem;
import org.apache.streampipes.storage.api.INoSqlStorage;
import org.apache.streampipes.storage.management.StorageDispatcher;
import org.lightcouch.DocumentConflictException;

import java.util.Objects;
import java.util.Set;
import java.util.stream.Collectors;

public abstract class AbstractResolver<T> {

  protected ObjectMapper spMapper;
  protected ObjectMapper defaultMapper;

  public AbstractResolver() {
    this.spMapper = SerializationUtils.getSpObjectMapper();
    this.defaultMapper = SerializationUtils.getDefaultObjectMapper();
  }

  public Set<ExportItem> resolve(Set<AssetLink> assetLinks) {
    return assetLinks
      .stream()
      .map(link -> findDocument(link.getResourceId()))
      .filter(this::existsDoc)
      .map(this::convert)
      .collect(Collectors.toSet());
  }

  protected boolean existsDoc(T doc) {
    return Objects.nonNull(doc);
  }

  public String getSerializedDocument(String resourceId) throws JsonProcessingException, ElementNotFoundException {
    var document = findDocument(resourceId);
    if (document != null) {
      return SerializationUtils.getSpObjectMapper().writeValueAsString(modifyDocumentForExport(document));
    } else {
      throw new ElementNotFoundException("Could not find element with resource id " + resourceId);
    }
  }

  protected INoSqlStorage getNoSqlStore() {
    return StorageDispatcher.INSTANCE.getNoSqlStore();
  }

  public abstract T findDocument(String resourceId);

  public abstract T modifyDocumentForExport(T doc);

  public abstract T readDocument(String serializedDoc) throws JsonProcessingException;

  public abstract ExportItem convert(T document);

  public abstract void writeDocument(String document) throws JsonProcessingException, DocumentConflictException;

  protected abstract T deserializeDocument(String document) throws JsonProcessingException;
}
