/*
 * Copyright (c) MuleSoft, Inc.  All rights reserved.  http://www.mulesoft.com
 * The software in this package is published under the terms of the CPAL v1.0
 * license, a copy of which has been included with this distribution in the
 * LICENSE.txt file.
 */
package org.mule.runtime.module.extension.internal.util;

import static org.mule.runtime.api.meta.model.parameter.ParameterGroupModel.DEFAULT_GROUP_NAME;
import static org.mule.runtime.api.util.Preconditions.checkArgument;
import static org.springframework.util.ReflectionUtils.setField;
import org.mule.runtime.api.exception.MuleException;
import org.mule.runtime.api.meta.model.EnrichableModel;
import org.mule.runtime.api.meta.model.parameter.ParameterizedModel;
import org.mule.runtime.module.extension.internal.loader.ParameterGroupDescriptor;
import org.mule.runtime.module.extension.internal.loader.java.property.ParameterGroupModelProperty;
import org.mule.runtime.module.extension.internal.runtime.objectbuilder.ParameterGroupObjectBuilder;
import org.mule.runtime.module.extension.internal.runtime.resolver.ResolverSetResult;

import com.google.common.collect.ImmutableList;

import java.lang.reflect.Field;
import java.util.List;

/**
 * An implementation of {@link ValueSetter} for parameter groups. Parameter groups are a set of parameters defined inside a Pojo
 * in order to reference them as a group and avoid code repetition. The parameter groups are defined by applying the
 * {@link org.mule.runtime.extension.api.annotation.param.ParameterGroup} annotation to a field.
 * <p/>
 * This {@link ValueSetter} knows how to map a {@link ResolverSetResult} to an object which acts as a group. Because group nesting
 * is allowed, this class is a composite with a {@link #childSetters} collection.
 *
 * @since 3.7.0
 */
public final class GroupValueSetter implements ValueSetter {

  /**
   * Returns a {@link List} containing one {@link ValueSetter} instance per each
   * {@link ParameterGroupDescriptor} defined in the
   * {@link ParameterGroupModelProperty} extracted from the given {@code model}. If {@code model} does not contain such model
   * property then an empty {@link List} is returned
   *
   * @param model a {@link EnrichableModel} instance presumed to have the {@link ParameterGroupModelProperty}
   * @return a {@link List} with {@link ValueSetter} instances. May be empty but will never be {@code null}
   */
  public static List<ValueSetter> settersFor(ParameterizedModel model) {
    ImmutableList.Builder<ValueSetter> setters = ImmutableList.builder();
    model.getParameterGroupModels().stream()
        .filter(group -> !group.isShowInDsl())
        .filter(group -> !group.getName().equals(DEFAULT_GROUP_NAME))
        .forEach(group -> group.getModelProperty(ParameterGroupModelProperty.class).ifPresent(property -> {
          if (property.getDescriptor().getContainer() instanceof Field) {
            setters.add(new GroupValueSetter(property.getDescriptor()));
          }
        }));

    return setters.build();
  }

  private final ParameterGroupDescriptor groupDescriptor;
  private final Field container;

  /**
   * Creates a new instance that can set values defined in the given {@code group}
   *
   * @param groupDescriptor a {@link ParameterGroupDescriptor}
   */
  public GroupValueSetter(ParameterGroupDescriptor groupDescriptor) {
    this.groupDescriptor = groupDescriptor;
    checkArgument(groupDescriptor.getContainer() instanceof Field, "Only field contained parameter groups are allowed");
    container = (Field) groupDescriptor.getContainer();
  }

  @Override
  public void set(Object target, ResolverSetResult result) throws MuleException {
    container.setAccessible(true);
    setField(container, target, new ParameterGroupObjectBuilder<>(groupDescriptor).build(result));
  }
}