/*
 * ToroDB
 * Copyright © 2014 8Kdata Technology (www.8kdata.com)
 *
 * 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.
 *
 * 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 com.torodb.mongodb.language.update;

import com.torodb.core.exceptions.user.UpdateException;
import com.torodb.core.language.AttributeReference;
import com.torodb.kvdocument.values.KvValue;

import java.util.Collection;

/**
 *
 */
public class MoveUpdateAction extends SingleFieldUpdateAction {

  private final AttributeReference newField;

  public MoveUpdateAction(
      Collection<AttributeReference> modifiedField,
      AttributeReference newField) {
    super(modifiedField);
    this.newField = newField;
  }

  public AttributeReference getNewField() {
    return newField;
  }

  @Override
  public void apply(UpdatedToroDocumentBuilder builder) throws UpdateException {
    for (AttributeReference originalKey : getModifiedField()) {
      if (move(new ObjectBuilderCallback(builder), originalKey, newField)) {
        builder.setUpdated();
        return;
      }
    }
  }

  <K> boolean move(
      BuilderCallback<K> builder,
      AttributeReference originalKey,
      AttributeReference newKeys
  ) throws UpdateException {
    Boolean result = AttributeReferenceToBuilderCallback.resolve(
        builder,
        originalKey.getKeys(),
        false,
        new OriginalKeysFound(builder, newKeys)
    );
    if (result == null) {
      return false;
    }
    return result;
  }

  private static class OriginalKeysFound implements
      ResolvedCallback<Boolean> {

    private final BuilderCallback<?> rootBuilder;
    private final AttributeReference newKeys;

    public OriginalKeysFound(
        BuilderCallback<?> rootBuilder,
        AttributeReference newKeys
    ) {
      this.rootBuilder = rootBuilder;
      this.newKeys = newKeys;
    }

    @Override
    public <K> Boolean objectReferenced(
        BuilderCallback<K> parentBuilder,
        K key,
        UpdatedToroDocumentBuilder child
    ) throws UpdateException {
      parentBuilder.unset(key);
      return AttributeReferenceToBuilderCallback.resolve(
          rootBuilder,
          newKeys.getKeys(),
          true,
          new MoveValueCallback(child.buildRoot())
      );
    }

    @Override
    public <K> Boolean arrayReferenced(
        BuilderCallback<K> parentBuilder,
        K key,
        UpdatedToroDocumentArrayBuilder child
    ) throws UpdateException {
      parentBuilder.unset(key);
      return AttributeReferenceToBuilderCallback.resolve(
          rootBuilder,
          newKeys.getKeys(),
          true,
          new MoveValueCallback(child.build())
      );
    }

    @Override
    public <K> Boolean valueReferenced(
        BuilderCallback<K> parentBuilder,
        K key,
        KvValue<?> child
    ) throws UpdateException {
      parentBuilder.unset(key);
      return AttributeReferenceToBuilderCallback.resolve(
          rootBuilder,
          newKeys.getKeys(),
          true,
          new MoveValueCallback(child)
      );
    }

    @Override
    public <K> Boolean newElementReferenced(
        BuilderCallback<K> parentBuilder,
        K key
    ) {
      return false;
    }

  }

  private static class MoveValueCallback implements
      ResolvedCallback<Boolean> {

    private final KvValue<?> newValue;

    public MoveValueCallback(KvValue<?> newValue) {
      this.newValue = newValue;
    }

    @Override
    public <K> Boolean objectReferenced(
        BuilderCallback<K> parentBuilder,
        K key,
        UpdatedToroDocumentBuilder child
    ) {
      parentBuilder.setValue(key, newValue);
      return true;
    }

    @Override
    public <K> Boolean arrayReferenced(
        BuilderCallback<K> parentBuilder,
        K key,
        UpdatedToroDocumentArrayBuilder child
    ) {
      parentBuilder.setValue(key, newValue);
      return true;
    }

    @Override
    public <K> Boolean valueReferenced(
        BuilderCallback<K> parentBuilder,
        K key,
        KvValue<?> child
    ) {
      parentBuilder.setValue(key, newValue);
      return true;
    }

    @Override
    public <K> Boolean newElementReferenced(
        BuilderCallback<K> parentBuilder,
        K key
    ) {
      parentBuilder.setValue(key, newValue);
      return true;
    }
  }

  @Override
  public <R, A> R accept(UpdateActionVisitor<R, A> visitor, A arg) {
    return visitor.visit(this, arg);
  }
}