/*
 * Copyright 2012-present the original author or authors.
 *
 * Licensed 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 org.springframework.boot.devtools.classpath;

import java.util.Set;

import org.springframework.boot.devtools.filewatch.ChangedFile;
import org.springframework.boot.devtools.filewatch.ChangedFile.Type;
import org.springframework.boot.devtools.filewatch.ChangedFiles;
import org.springframework.context.ApplicationEvent;
import org.springframework.core.style.ToStringCreator;
import org.springframework.util.Assert;

/**
 * {@link ApplicationEvent} containing details of a classpath change.
 *
 * @author Phillip Webb
 * @since 1.3.0
 * @see ClassPathFileChangeListener
 */
public class ClassPathChangedEvent extends ApplicationEvent {

	private final Set<ChangedFiles> changeSet;

	private final boolean restartRequired;

	/**
	 * Create a new {@link ClassPathChangedEvent}.
	 * @param source the source of the event
	 * @param changeSet the changed files
	 * @param restartRequired if a restart is required due to the change
	 */
	public ClassPathChangedEvent(Object source, Set<ChangedFiles> changeSet, boolean restartRequired) {
		super(source);
		Assert.notNull(changeSet, "ChangeSet must not be null");
		this.changeSet = changeSet;
		this.restartRequired = restartRequired;
	}

	/**
	 * Return details of the files that changed.
	 * @return the changed files
	 */
	public Set<ChangedFiles> getChangeSet() {
		return this.changeSet;
	}

	/**
	 * Return if an application restart is required due to the change.
	 * @return if an application restart is required
	 */
	public boolean isRestartRequired() {
		return this.restartRequired;
	}

	@Override
	public String toString() {
		return new ToStringCreator(this).append("changeSet", this.changeSet)
			.append("restartRequired", this.restartRequired)
			.toString();
	}

	/**
	 * Return an overview of the changes that triggered this event.
	 * @return an overview of the changes
	 * @since 2.6.11
	 */
	public String overview() {
		int added = 0;
		int deleted = 0;
		int modified = 0;
		for (ChangedFiles changedFiles : this.changeSet) {
			for (ChangedFile changedFile : changedFiles) {
				Type type = changedFile.getType();
				if (type == Type.ADD) {
					added++;
				}
				else if (type == Type.DELETE) {
					deleted++;
				}
				else if (type == Type.MODIFY) {
					modified++;
				}
			}
		}
		int size = added + deleted + modified;
		return String.format("%s (%s, %s, %s)", quantityOfUnit(size, "class path change"),
				quantityOfUnit(added, "addition"), quantityOfUnit(deleted, "deletion"),
				quantityOfUnit(modified, "modification"));
	}

	private String quantityOfUnit(int quantity, String unit) {
		return quantity + " " + ((quantity != 1) ? unit + "s" : unit);
	}

}
