package org.argeo.slc.repo.osgi;

import java.io.File;
import java.util.Map;

import org.eclipse.aether.artifact.AbstractArtifact;
import org.eclipse.aether.artifact.Artifact;

/**
 * An artifact whose identity is derived from another artifact. <em>Note:</em>
 * Instances of this class are immutable and the exposed mutators return new
 * objects rather than changing the current instance.
 */
final class SubArtifact extends AbstractArtifact {

	private final Artifact mainArtifact;

	private final String classifier;

	private final String extension;

	private final File file;

	private final Map<String, String> properties;

	/**
	 * Creates a new sub artifact. The classifier and extension specified for this
	 * artifact may use the asterisk character "*" to refer to the corresponding
	 * property of the main artifact. For instance, the classifier "*-sources" can
	 * be used to refer to the source attachment of an artifact. Likewise, the
	 * extension "*.asc" can be used to refer to the GPG signature of an artifact.
	 * 
	 * @param mainArtifact The artifact from which to derive the identity, must not
	 *                     be {@code null}.
	 * @param classifier   The classifier for this artifact, may be {@code null} if
	 *                     none.
	 * @param extension    The extension for this artifact, may be {@code null} if
	 *                     none.
	 */
	public SubArtifact(Artifact mainArtifact, String classifier, String extension) {
		this(mainArtifact, classifier, extension, (File) null);
	}

	/**
	 * Creates a new sub artifact. The classifier and extension specified for this
	 * artifact may use the asterisk character "*" to refer to the corresponding
	 * property of the main artifact. For instance, the classifier "*-sources" can
	 * be used to refer to the source attachment of an artifact. Likewise, the
	 * extension "*.asc" can be used to refer to the GPG signature of an artifact.
	 * 
	 * @param mainArtifact The artifact from which to derive the identity, must not
	 *                     be {@code null}.
	 * @param classifier   The classifier for this artifact, may be {@code null} if
	 *                     none.
	 * @param extension    The extension for this artifact, may be {@code null} if
	 *                     none.
	 * @param file         The file for this artifact, may be {@code null} if
	 *                     unresolved.
	 */
	public SubArtifact(Artifact mainArtifact, String classifier, String extension, File file) {
		this(mainArtifact, classifier, extension, null, file);
	}

	/**
	 * Creates a new sub artifact. The classifier and extension specified for this
	 * artifact may use the asterisk character "*" to refer to the corresponding
	 * property of the main artifact. For instance, the classifier "*-sources" can
	 * be used to refer to the source attachment of an artifact. Likewise, the
	 * extension "*.asc" can be used to refer to the GPG signature of an artifact.
	 * 
	 * @param mainArtifact The artifact from which to derive the identity, must not
	 *                     be {@code null}.
	 * @param classifier   The classifier for this artifact, may be {@code null} if
	 *                     none.
	 * @param extension    The extension for this artifact, may be {@code null} if
	 *                     none.
	 * @param properties   The properties of the artifact, may be {@code null}.
	 */
	public SubArtifact(Artifact mainArtifact, String classifier, String extension, Map<String, String> properties) {
		this(mainArtifact, classifier, extension, properties, null);
	}

	/**
	 * Creates a new sub artifact. The classifier and extension specified for this
	 * artifact may use the asterisk character "*" to refer to the corresponding
	 * property of the main artifact. For instance, the classifier "*-sources" can
	 * be used to refer to the source attachment of an artifact. Likewise, the
	 * extension "*.asc" can be used to refer to the GPG signature of an artifact.
	 * 
	 * @param mainArtifact The artifact from which to derive the identity, must not
	 *                     be {@code null}.
	 * @param classifier   The classifier for this artifact, may be {@code null} if
	 *                     none.
	 * @param extension    The extension for this artifact, may be {@code null} if
	 *                     none.
	 * @param properties   The properties of the artifact, may be {@code null}.
	 * @param file         The file for this artifact, may be {@code null} if
	 *                     unresolved.
	 */
	public SubArtifact(Artifact mainArtifact, String classifier, String extension, Map<String, String> properties,
			File file) {
		if (mainArtifact == null) {
			throw new IllegalArgumentException("no artifact specified");
		}
		this.mainArtifact = mainArtifact;
		this.classifier = classifier;
		this.extension = extension;
		this.file = file;
		this.properties = copyProperties(properties);
	}

	private SubArtifact(Artifact mainArtifact, String classifier, String extension, File file,
			Map<String, String> properties) {
		// NOTE: This constructor assumes immutability of the provided properties, for
		// internal use only
		this.mainArtifact = mainArtifact;
		this.classifier = classifier;
		this.extension = extension;
		this.file = file;
		this.properties = properties;
	}

	public String getGroupId() {
		return mainArtifact.getGroupId();
	}

	public String getArtifactId() {
		return mainArtifact.getArtifactId();
	}

	public String getVersion() {
		return mainArtifact.getVersion();
	}

	public String getBaseVersion() {
		return mainArtifact.getBaseVersion();
	}

	public boolean isSnapshot() {
		return mainArtifact.isSnapshot();
	}

	public String getClassifier() {
		return expand(classifier, mainArtifact.getClassifier());
	}

	public String getExtension() {
		return expand(extension, mainArtifact.getExtension());
	}

	public File getFile() {
		return file;
	}

	public Artifact setFile(File file) {
		if ((this.file == null) ? file == null : this.file.equals(file)) {
			return this;
		}
		return new SubArtifact(mainArtifact, classifier, extension, file, properties);
	}

	public Map<String, String> getProperties() {
		return properties;
	}

	public Artifact setProperties(Map<String, String> properties) {
		if (this.properties.equals(properties) || (properties == null && this.properties.isEmpty())) {
			return this;
		}
		return new SubArtifact(mainArtifact, classifier, extension, properties, file);
	}

	private static String expand(String pattern, String replacement) {
		String result = "";
		if (pattern != null) {
			result = pattern.replace("*", replacement);

			if (replacement.length() <= 0) {
				if (pattern.startsWith("*")) {
					int i = 0;
					for (; i < result.length(); i++) {
						char c = result.charAt(i);
						if (c != '-' && c != '.') {
							break;
						}
					}
					result = result.substring(i);
				}
				if (pattern.endsWith("*")) {
					int i = result.length() - 1;
					for (; i >= 0; i--) {
						char c = result.charAt(i);
						if (c != '-' && c != '.') {
							break;
						}
					}
					result = result.substring(0, i + 1);
				}
			}
		}
		return result;
	}

}