/**
    * Copyright 2011-2012 The Kuali Foundation
    *
    * Licensed under the Educational Community 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.opensource.org/licenses/ecl2.php
    *
   * 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.kuali.maven.plugins.spring;
  
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.List;
  import java.util.Properties;
  
  import org.apache.maven.plugin.AbstractMojo;
  import org.apache.maven.plugin.MojoExecutionException;
  import org.apache.maven.project.MavenProject;
  import org.kuali.common.util.PropertyUtils;
  import org.kuali.common.util.service.SpringService;
  import org.springframework.util.Assert;
  
  /**
   * <p>
   * This mojo provides the ability to load a Spring context XML file. It uses a lightweight integration technique between Spring and Maven
   * centered around <code>java.util.Properties</code>. Prior to the Spring context being loaded, it is injected with a
   * <code>java.util.Properties</code> object containing the full set of Maven properties. The <code>java.util.Properties</code> object is
   * registered in the context as a bean under the name <code>mavenProperties</code>.
   * </p>
   * <p>
   * One common use of the injected Maven properties in a Spring context is for replacing property placeholders.
   * </p>
   * <p>
   * For example:
   * </p>
   *
   * <pre>
   *  &lt;beans&gt;
   *   &lt;context:property-placeholder properties-ref="mavenProperties" /&gt;
   *   &lt;bean id="artifactId" class="java.lang.String"&gt;
   *    &lt;constructor-arg value="${project.artifactId}" /&gt;
   *   &lt;/bean&gt;
   *  &lt;/beans&gt;
   * </pre>
   *
   * @goal load
   */
  public class LoadMojo extends AbstractMojo {
  
  	/**
  	 * Maven project
  	 *
  	 * @parameter default-value="${project}"
  	 * @required
  	 * @readonly
  	 */
  	private MavenProject project;
  
  	/**
  	 * Location of a Spring context XML file. This can be a file on the local file system, or any URL Spring's Resource loading framework
  	 * understands eg {@code classpath:my-context.xml}
  	 *
  	 * @parameter expression="${spring.location}" default-value="classpath:${project.artifactId}-context.xml"
  	 * @required
  	 */
  	private String location;
  
  	/**
  	 * List of additional Spring context XML files to load (if any).
  	 *
  	 * @parameter
  	 */
  	private List<String> locations;
  
  	/**
  	 * Additional properties to supply to the Spring context.
  	 *
  	 * @parameter
  	 */
  	private Properties properties;
  
  	/**
  	 * If true, Maven properties are injected into the Spring context as a <code>java.util.Properties</code> object
  	 *
  	 * @parameter expression="${spring.injectProperties}" default-value="true"
  	 */
  	private boolean injectProperties;
  
  	/**
  	 * If true, the <code>MavenProject</code> object is injected into the Spring context
  	 *
  	 * @parameter expression="${spring.injectProject}" default-value="false"
 	 */
 	private boolean injectProject;
 
 	/**
 	 * The name to use when registering the <code>java.util.Properties</code> object containing Maven properties as a bean in the Spring
 	 * context.
 	 *
 	 * @parameter expression="${spring.propertiesBeanName}" default-value="mavenProperties"
 	 */
 	private String propertiesBeanName;
 
 	/**
 	 * The name to use when registering the <code>MavenProject</code> object as a bean in the Spring context.
 	 *
 	 * @parameter expression="${spring.projectBeanName}" default-value="project"
 	 */
 	private String projectBeanName;
 
 	/**
 	 * The implementation of {@code org.kuali.common.util.service.SpringService} to use
 	 *
 	 * @parameter expression="${spring.serviceClassname}" default-value="org.kuali.common.util.service.DefaultSpringService"
 	 * @required
 	 */
 	private String serviceClassname;
 
 	@Override
 	public void execute() throws MojoExecutionException {
 
 		// The ordering here is significant.
 		// Properties supplied directly to the mojo override properties from project.getProperties()
 		// But, internal Maven properties need to always win.
 		// ${project.artifactId} needs to always faithfully represent the correct artifactId
 		this.properties = PropertyUtils.combine(project.getProperties(), properties, MavenUtils.getInternalProperties(project));
 
 		// Combine the list with the single value
 		this.locations = combine(location, locations);
 
 		// Log what we are up to
 		logConfiguration();
 
 		// Invoke the service to load the context
 		SpringService service = getService(serviceClassname);
 		service.load(locations, getBeanNames(), getBeans());
 	}
 
 	protected List<Object> getBeans() {
 		List<Object> beans = new ArrayList<Object>();
 		if (injectProperties) {
 			beans.add(properties);
 		}
 		if (injectProject) {
 			beans.add(project);
 		}
 		return beans;
 	}
 
 	protected List<String> getBeanNames() {
 		List<String> beanNames = new ArrayList<String>();
 		if (injectProperties) {
 			beanNames.add(propertiesBeanName);
 		}
 		if (injectProject) {
 			beanNames.add(projectBeanName);
 		}
 		return beanNames;
 	}
 
 	protected void logConfiguration() {
 		if (injectProperties) {
 			getLog().info("Injecting " + properties.size() + " Maven properties as a [" + properties.getClass().getName() + "] bean under the id [" + propertiesBeanName + "]");
 			getLog().debug("Displaying " + properties.size() + " properties\n\n" + PropertyUtils.toString(properties));
 		}
 		if (injectProject) {
 			getLog().info("Injecting the Maven project as a [" + project.getClass().getName() + "] bean under the id [" + projectBeanName + "]");
 		}
 		if (locations.size() > 1) {
 			getLog().info("Loading " + locations.size() + " Spring context files");
 		}
 	}
 
 	protected SpringService getService(String serviceClassname) {
 		try {
 			Class<?> serviceClass = Class.forName(serviceClassname);
 			return (SpringService) serviceClass.newInstance();
 		} catch (ClassNotFoundException e) {
 			throw new IllegalStateException("Unexpected error", e);
 		} catch (IllegalAccessException e) {
 			throw new IllegalStateException("Unexpected error", e);
 		} catch (InstantiationException e) {
 			throw new IllegalStateException("Unexpected error", e);
 		}
 	}
 
 	/**
 	 * Return a combined list where <code>string</code> is always the first element and the Strings in the list are unique
 	 */
 	protected List<String> combine(String required, List<String> optional) {
 		Assert.notNull(required);
 		if (optional == null) {
 			return Collections.singletonList(required);
 		} else {
 			List<String> combined = new ArrayList<String>(optional);
 			// Always insert required as the first element in the list
 			combined.add(required);
 			// Add the other strings but ensure the list does not already contain them
 			for (String element : optional) {
 				boolean doesNotContain = !combined.contains(element);
 				Assert.isTrue(doesNotContain);
 				combined.add(element);
 			}
 			return combined;
 		}
 	}
 
 	public String getLocation() {
 		return location;
 	}
 
 	public void setLocation(String location) {
 		this.location = location;
 	}
 
 	public List<String> getLocations() {
 		return locations;
 	}
 
 	public void setLocations(List<String> locations) {
 		this.locations = locations;
 	}
 
 	public Properties getProperties() {
 		return properties;
 	}
 
 	public void setProperties(Properties properties) {
 		this.properties = properties;
 	}
 
 	public String getPropertiesBeanName() {
 		return propertiesBeanName;
 	}
 
 	public void setPropertiesBeanName(String propertiesBeanName) {
 		this.propertiesBeanName = propertiesBeanName;
 	}
 
 	public String getServiceClassname() {
 		return serviceClassname;
 	}
 
 	public void setServiceClassname(String serviceClassname) {
 		this.serviceClassname = serviceClassname;
 	}
 
 	public MavenProject getProject() {
 		return project;
 	}
 
 	public boolean isInjectProperties() {
 		return injectProperties;
 	}
 
 	public void setInjectProperties(boolean injectProperties) {
 		this.injectProperties = injectProperties;
 	}
 
 	public boolean isInjectProject() {
 		return injectProject;
 	}
 
 	public void setInjectProject(boolean injectProject) {
 		this.injectProject = injectProject;
 	}
 
 	public String getProjectBeanName() {
 		return projectBeanName;
 	}
 
 	public void setProjectBeanName(String projectBeanName) {
 		this.projectBeanName = projectBeanName;
 	}
 
 }