/*
 * Copyright 2015-2017 the original author or authors.
 *
 * All rights reserved. This program and the accompanying materials are
 * made available under the terms of the Eclipse Public License v1.0 which
 * accompanies this distribution and is available at
 *
 * http://www.eclipse.org/legal/epl-v10.html
 */

package org.junit.platform.engine.support.descriptor;

import static org.junit.platform.commons.meta.API.Usage.Experimental;

import java.util.Objects;
import java.util.Optional;

import org.junit.platform.commons.meta.API;
import org.junit.platform.commons.util.Preconditions;
import org.junit.platform.commons.util.ToStringBuilder;
import org.junit.platform.engine.TestSource;

/**
 * <em>Classpath resource</em> based {@link org.junit.platform.engine.TestSource}
 * with an optional {@linkplain FilePosition position}.
 *
 * @since 1.0
 * @see org.junit.platform.engine.discovery.ClasspathResourceSelector
 */
@API(Experimental)
public class ClasspathResourceSource implements TestSource {

	private static final long serialVersionUID = 1L;

	private final String classpathResourceName;
	private final FilePosition filePosition;

	/**
	 * Create a new {@code ClasspathResourceSource} using the supplied classpath
	 * resource name.
	 *
	 * <p>The name of a <em>classpath resource</em> must follow the semantics
	 * for resource paths as defined in {@link ClassLoader#getResource(String)}.
	 *
	 * <p>If the supplied classpath resource name is prefixed with a slash
	 * ({@code /}), the slash will be removed.
	 *
	 * @param classpathResourceName the name of the classpath resource; never
	 * {@code null} or blank
	 * @see ClassLoader#getResource(String)
	 * @see ClassLoader#getResourceAsStream(String)
	 * @see ClassLoader#getResources(String)
	 */
	public ClasspathResourceSource(String classpathResourceName) {
		this(classpathResourceName, null);
	}

	/**
	 * Create a new {@code ClasspathResourceSource} using the supplied classpath
	 * resource name and {@link FilePosition}.
	 *
	 * <p>The name of a <em>classpath resource</em> must follow the semantics
	 * for resource paths as defined in {@link ClassLoader#getResource(String)}.
	 *
	 * <p>If the supplied classpath resource name is prefixed with a slash
	 * ({@code /}), the slash will be removed.
	 *
	 * @param classpathResourceName the name of the classpath resource; never
	 * {@code null} or blank
	 * @param filePosition the position in the classpath resource; may be {@code null}
	 */
	public ClasspathResourceSource(String classpathResourceName, FilePosition filePosition) {
		Preconditions.notBlank(classpathResourceName, "Classpath resource name must not be null or blank");
		boolean startsWithSlash = classpathResourceName.startsWith("/");
		this.classpathResourceName = (startsWithSlash ? classpathResourceName.substring(1) : classpathResourceName);
		this.filePosition = filePosition;
	}

	/**
	 * Get the name of the source <em>classpath resource</em>.
	 *
	 * <p>The name of a <em>classpath resource</em> follows the semantics for
	 * resource paths as defined in {@link ClassLoader#getResource(String)}.
	 *
	 * @see ClassLoader#getResource(String)
	 * @see ClassLoader#getResourceAsStream(String)
	 * @see ClassLoader#getResources(String)
	 */
	public String getClasspathResourceName() {
		return this.classpathResourceName;
	}

	/**
	 * Get the {@link FilePosition}, if available.
	 */
	public final Optional<FilePosition> getPosition() {
		return Optional.ofNullable(this.filePosition);
	}

	@Override
	public boolean equals(Object o) {
		if (this == o) {
			return true;
		}
		if (o == null || getClass() != o.getClass()) {
			return false;
		}
		ClasspathResourceSource that = (ClasspathResourceSource) o;
		return Objects.equals(this.classpathResourceName, that.classpathResourceName)
				&& Objects.equals(this.filePosition, that.filePosition);
	}

	@Override
	public int hashCode() {
		return Objects.hash(this.classpathResourceName, this.filePosition);
	}

	@Override
	public String toString() {
		// @formatter:off
		return new ToStringBuilder(this)
				.append("classpathResourceName", this.classpathResourceName)
				.append("filePosition", this.filePosition)
				.toString();
		// @formatter:on
	}

}