/*
 * Copyright (C) 2007-2012 Argeo GmbH
 *
 * 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
 *
 *         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.argeo.slc.repo.maven;

import java.io.File;
import java.util.Properties;
import java.util.Set;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.argeo.slc.SlcException;
import org.argeo.slc.aether.AetherTemplate;
import org.eclipse.aether.artifact.Artifact;
import org.eclipse.aether.artifact.DefaultArtifact;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NodeList;

/**
 * Static utilities around Maven which are NOT using the Maven APIs (conventions
 * based).
 */
public class MavenConventionsUtils {
	private final static Log log = LogFactory
			.getLog(MavenConventionsUtils.class);

	/**
	 * Path to the file identified by this artifact <b>without</b> using Maven
	 * APIs (convention based). Default location of repository
	 * (~/.m2/repository) is used here.
	 * 
	 * @see MavenConventionsUtils#artifactToFile(String, Artifact)
	 */
	public static File artifactToFile(Artifact artifact) {
		return artifactToFile(System.getProperty("user.home") + File.separator
				+ ".m2" + File.separator + "repository", artifact);
	}

	/**
	 * Path to the file identified by this artifact <b>without</b> using Maven
	 * APIs (convention based).
	 * 
	 * @param repositoryPath
	 *            path to the related local repository location
	 * @param artifact
	 *            the artifact
	 */
	public static File artifactToFile(String repositoryPath, Artifact artifact) {
		return new File(repositoryPath + File.separator
				+ artifact.getGroupId().replace('.', File.separatorChar)
				+ File.separator + artifact.getArtifactId() + File.separator
				+ artifact.getVersion() + File.separator
				+ artifactFileName(artifact)).getAbsoluteFile();
	}

	/** The file name of this artifact when stored */
	public static String artifactFileName(Artifact artifact) {
		return artifact.getArtifactId()
				+ '-'
				+ artifact.getVersion()
				+ (artifact.getClassifier().equals("") ? "" : '-' + artifact
						.getClassifier()) + '.' + artifact.getExtension();
	}

	/** Absolute path to the file */
	public static String artifactPath(String artifactBasePath, Artifact artifact) {
		return artifactParentPath(artifactBasePath, artifact) + '/'
				+ artifactFileName(artifact);
	}

	/** Absolute path to the directories where the files will be stored */
	public static String artifactParentPath(String artifactBasePath,
			Artifact artifact) {
		return artifactBasePath + (artifactBasePath.endsWith("/") ? "" : "/")
				+ artifactParentPath(artifact);
	}

	/** Absolute path to the directory of this group */
	public static String groupPath(String artifactBasePath, String groupId) {
		return artifactBasePath + (artifactBasePath.endsWith("/") ? "" : "/")
				+ groupId.replace('.', '/');
	}

	/** Relative path to the directories where the files will be stored */
	public static String artifactParentPath(Artifact artifact) {
		return artifact.getGroupId().replace('.', '/') + '/'
				+ artifact.getArtifactId() + '/' + artifact.getBaseVersion();
	}

	public static String artifactsAsDependencyPom(Artifact pomArtifact,
			Set<Artifact> artifacts, Artifact parent) {
		StringBuffer p = new StringBuffer();

		// XML header
		p.append("<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n");
		p.append("<project xmlns=\"http://maven.apache.org/POM/4.0.0\" xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\" xsi:schemaLocation=\"http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd\">\n");
		p.append("<modelVersion>4.0.0</modelVersion>\n");

		// Artifact
		if (parent != null) {
			p.append("<parent>\n");
			p.append("<groupId>").append(parent.getGroupId())
					.append("</groupId>\n");
			p.append("<artifactId>").append(parent.getArtifactId())
					.append("</artifactId>\n");
			p.append("<version>").append(parent.getVersion())
					.append("</version>\n");
			p.append("</parent>\n");
		}
		p.append("<groupId>").append(pomArtifact.getGroupId())
				.append("</groupId>\n");
		p.append("<artifactId>").append(pomArtifact.getArtifactId())
				.append("</artifactId>\n");
		p.append("<version>").append(pomArtifact.getVersion())
				.append("</version>\n");
		p.append("<packaging>pom</packaging>\n");

		// Dependencies
		p.append("<dependencies>\n");
		for (Artifact a : artifacts) {
			p.append("\t<dependency>");
			p.append("<artifactId>").append(a.getArtifactId())
					.append("</artifactId>");
			p.append("<groupId>").append(a.getGroupId()).append("</groupId>");
			if (!a.getExtension().equals("jar"))
				p.append("<type>").append(a.getExtension()).append("</type>");
			p.append("</dependency>\n");
		}
		p.append("</dependencies>\n");

		// Dependency management
		p.append("<dependencyManagement>\n");
		p.append("<dependencies>\n");
		for (Artifact a : artifacts) {
			p.append("\t<dependency>");
			p.append("<artifactId>").append(a.getArtifactId())
					.append("</artifactId>");
			p.append("<version>").append(a.getVersion()).append("</version>");
			p.append("<groupId>").append(a.getGroupId()).append("</groupId>");
			if (a.getExtension().equals("pom")) {
				p.append("<type>").append(a.getExtension()).append("</type>");
				p.append("<scope>import</scope>");
			}
			p.append("</dependency>\n");
		}
		p.append("</dependencies>\n");
		p.append("</dependencyManagement>\n");

		// Repositories
		// p.append("<repositories>\n");
		// p.append("<repository><id>argeo</id><url>http://maven.argeo.org/argeo</url></repository>\n");
		// p.append("</repositories>\n");

		p.append("</project>\n");
		return p.toString();
	}

	/**
	 * Directly parses Maven POM XML format in order to find all artifacts
	 * references under the dependency and dependencyManagement tags. This is
	 * meant to migrate existing pom registering a lot of artifacts, not to
	 * replace Maven resolving.
	 */
	public static void gatherPomDependencies(AetherTemplate aetherTemplate,
			Set<Artifact> artifacts, Artifact pomArtifact) {
		if (log.isDebugEnabled())
			log.debug("Gather dependencies for " + pomArtifact);

		try {
			File file = aetherTemplate.getResolvedFile(pomArtifact);
			DocumentBuilder documentBuilder = DocumentBuilderFactory
					.newInstance().newDocumentBuilder();
			Document doc = documentBuilder.parse(file);

			// properties
			Properties props = new Properties();
			props.setProperty("project.version", pomArtifact.getBaseVersion());
			NodeList properties = doc.getElementsByTagName("properties");
			if (properties.getLength() > 0) {
				NodeList propertiesElems = properties.item(0).getChildNodes();
				for (int i = 0; i < propertiesElems.getLength(); i++) {
					if (propertiesElems.item(i) instanceof Element) {
						Element property = (Element) propertiesElems.item(i);
						props.put(property.getNodeName(),
								property.getTextContent());
					}
				}
			}

			// dependencies (direct and dependencyManagement)
			NodeList dependencies = doc.getElementsByTagName("dependency");
			for (int i = 0; i < dependencies.getLength(); i++) {
				Element dependency = (Element) dependencies.item(i);
				String groupId = dependency.getElementsByTagName("groupId")
						.item(0).getTextContent().trim();
				String artifactId = dependency
						.getElementsByTagName("artifactId").item(0)
						.getTextContent().trim();
				String version = dependency.getElementsByTagName("version")
						.item(0).getTextContent().trim();
				if (version.startsWith("${")) {
					String versionKey = version.substring(0,
							version.length() - 1).substring(2);
					if (!props.containsKey(versionKey))
						throw new SlcException("Cannot interpret version "
								+ version);
					version = props.getProperty(versionKey);
				}
				NodeList scopes = dependency.getElementsByTagName("scope");
				if (scopes.getLength() > 0
						&& scopes.item(0).getTextContent().equals("import")) {
					// recurse
					gatherPomDependencies(aetherTemplate, artifacts,
							new DefaultArtifact(groupId, artifactId, "pom",
									version));
				} else {
					// TODO: deal with scope?
					// TODO: deal with type
					String type = "jar";
					Artifact artifact = new DefaultArtifact(groupId,
							artifactId, type, version);
					artifacts.add(artifact);
				}
			}
		} catch (Exception e) {
			throw new SlcException("Cannot process " + pomArtifact, e);
		}
	}

	/** Prevent instantiation */
	private MavenConventionsUtils() {
	}
}