/*
 * 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.maven.plugin.internal;

import java.util.Collection;
import java.util.HashMap;
import java.util.Map;

import org.apache.maven.plugin.descriptor.MojoDescriptor;
import org.apache.maven.plugin.descriptor.Parameter;
import org.codehaus.plexus.component.configurator.ConfigurationListener;

/**
 * A configuration listener to help validate the plugin configuration. For instance, check for required but missing
 * parameters.
 *
 * @author Benjamin Bentmann
 */
class ValidatingConfigurationListener implements ConfigurationListener {
    private final Object mojo;

    private final ConfigurationListener delegate;

    private final Map<String, Parameter> missingParameters;

    ValidatingConfigurationListener(Object mojo, MojoDescriptor mojoDescriptor, ConfigurationListener delegate) {
        this.mojo = mojo;
        this.delegate = delegate;
        this.missingParameters = new HashMap<>();

        if (mojoDescriptor.getParameters() != null) {
            for (Parameter param : mojoDescriptor.getParameters()) {
                if (param.isRequired()) {
                    missingParameters.put(param.getName(), param);
                }
            }
        }
    }

    public Collection<Parameter> getMissingParameters() {
        return missingParameters.values();
    }

    public void notifyFieldChangeUsingSetter(String fieldName, Object value, Object target) {
        delegate.notifyFieldChangeUsingSetter(fieldName, value, target);

        if (mojo == target) {
            notify(fieldName, value);
        }
    }

    public void notifyFieldChangeUsingReflection(String fieldName, Object value, Object target) {
        delegate.notifyFieldChangeUsingReflection(fieldName, value, target);

        if (mojo == target) {
            notify(fieldName, value);
        }
    }

    private void notify(String fieldName, Object value) {
        if (value != null) {
            missingParameters.remove(fieldName);
        }
    }
}
