package com.thespeechcorporation.plugin.maven;

import java.io.File;
import java.util.List;

import org.apache.maven.plugin.AbstractMojo;
import org.apache.maven.plugin.MojoExecutionException;
import org.apache.maven.plugin.MojoFailureException;
import org.xmldb.api.DatabaseManager;
import org.xmldb.api.base.Collection;
import org.xmldb.api.base.Database;
import org.xmldb.api.base.Resource;
import org.xmldb.api.base.XMLDBException;
import org.xmldb.api.modules.CollectionManagementService;

/**
 * This plugin communicates with the eXist database. This plugin is considered a replacement of the
 * existing possibility to communicate with the database from maven, namely the Ant plugin. The root
 * of the database is initialized as follow:
 * <pre>
 * Collection root = DatabaseManager.getCollection("xmldb:exist://localhost:8080/exist/xmlrpc/db", "username", "password");
 * </pre>
 * @goal execute
 * @phase install
 */
public class ExistPlugin extends AbstractMojo {
	// Constants
	private final String CLASSNAME = this.getClass().getName();
	private final String XML = "XMLResource";								// According to XM:DB API specification
	private final String BINARY = "BinaryResource";							// According to XM:DB API specification
	private final String COLLECTION_MANAGEMENT_SERVICE = "CollectionManagementService";
	private final String COLLECTION_MANAGEMENT_SERVICE_VERSION = "1.0";
	private final String DELIMITER = "/";
	// Globals
	private Collection root = null;
	private CollectionManagementService service = null;
	private Database database = null;
	
	/**
	 * The url, the database is running under
	 * @parameter default-value=""
	 * @required
	 */
	private String url = null;
	
	/**
	 * The username associated with the eXist user.
	 * @parameter default-value=""
	 * @required
	 */
	private String username = null;
	
	/**
	 * The password associated with the eXist user.
	 * @parameter default-value=""
	 */
	private String password = null;
	
	/**
	 * The List of collections to be created
	 * @parameter
	 */
	private List<String> createCollections = null;
	
	/**
	 * The List of collections to be deleted
	 * @parameter
	 */
	private List<String> deleteCollections = null;
	
	/**
	 * The List of resources to be created
	 * @parameter
	 */
	private List<Data> createData = null;
	
	/**
	 * The list of resources to be deleted
	 * @parameter
	 */
	private List<String> deleteData = null;
	
	/**
	 * An auxiliary to initialize the maven plugin.
	 * @throws MojoExecutionException When intialization failed.
	 */
	private void init() throws MojoExecutionException {
		try {
			Class<?> driver = Class.forName("org.exist.xmldb.DatabaseImpl");
			this.database = (Database) driver.newInstance();
			this.database.setProperty("create-database", "true");
			DatabaseManager.registerDatabase(this.database);
			this.root = DatabaseManager.getCollection(this.url, this.username, this.password);
			this.service = (CollectionManagementService) root.getService(COLLECTION_MANAGEMENT_SERVICE, COLLECTION_MANAGEMENT_SERVICE_VERSION);
		} catch (Exception e) {
			if(super.getLog().isErrorEnabled()) {
				super.getLog().error(e.getMessage(), e);
			}
			throw new MojoExecutionException(e.getMessage(), e);
		}
	}
	
	/**
	 * The method to execute the maven plugin.
	 * @throws MojoExecutionException When execution failed.
	 */
	public void execute() throws MojoExecutionException, MojoFailureException {
		this.init();
		if(super.getLog().isInfoEnabled()) {
			super.getLog().info("[" + CLASSNAME + "] executing...");
			super.getLog().info("\tUsing url: " + this.url);
			super.getLog().info("\tUsing username: " + this.username);
			super.getLog().info("\tUsing password: " + this.password);
		}
		// Delete collections
		this.deleteCollections();
		// Create collections
		this.createCollections();
		// Create files
		this.createFiles();
		// Delete files
		this.deleteFiles();
		if(super.getLog().isInfoEnabled()) {
			super.getLog().info("[" + CLASSNAME + "] executing... done!");
		}
	}
	
	/**
	 * An auxiliary method to delete collections. Note that subdirectories are deleted as well.
	 */
	private void deleteCollections() throws MojoExecutionException {
		if(this.deleteCollections == null || this.deleteCollections.size() == 0) {
			if(super.getLog().isInfoEnabled()) {
				super.getLog().info("No collections to delete");
			}
			return;
		}
		try {
			for(String collection : this.deleteCollections) {
				if(super.getLog().isInfoEnabled()) {
					super.getLog().info("Deleted collection: " + collection);
				}
				this.service.removeCollection(collection);
			}
		} catch (Exception e) {
			if(super.getLog().isErrorEnabled()) {
				super.getLog().error(e.getMessage(), e);
			}
			throw new MojoExecutionException(e.getMessage(), e);
		}
	}
	
	/**
	 * An auxiliary method to create collections. Note that subdirectories are created as well when the parent
	 * is non existent, i.e. the parent is created along.
	 * @throws MojoExecutionException When the database is non responsive.
	 */
	private void createCollections() throws MojoExecutionException {
		if(this.createCollections == null || this.createCollections.size() == 0) {
			if(super.getLog().isInfoEnabled()) {
				super.getLog().info("No collections to create");
			}
			return;
		}
		try {
			for(String collection : this.createCollections) {
				if(super.getLog().isInfoEnabled()) {
					super.getLog().info("Created collection: " + collection);
				}
				this.service.createCollection(collection);
			}
		} catch (Exception e) {
			if(super.getLog().isErrorEnabled()) {
				super.getLog().error(e.getMessage(), e);
			}
			throw new MojoExecutionException(e.getMessage(), e);
		}
	}
	
	/**
	 * An auxiliary method to create files.
	 * @throws MojoExecutionException 
	 */
	private void createFiles() throws MojoExecutionException {
		Collection target = null;
		File file = null;
		Resource resource = null;
		
		if(this.createData == null || this.createData.size() == 0) {
			if(super.getLog().isInfoEnabled()) {
				super.getLog().info("No files to create");
			}
			return;
		}
		if(super.getLog().isInfoEnabled()) {
			super.getLog().info("Total files to create: " + this.createData.size());
		}
		try {
			for(Data data : this.createData) {
				if(super.getLog().isInfoEnabled()) {
					super.getLog().info("Resource to be created:");
				}
				file = new File(data.getSource());
				if(super.getLog().isInfoEnabled()) {
					super.getLog().info("\tResource source: " + data.getSource() + ", exist: " + file.exists());
					super.getLog().info("\tResource destination: " + data.getDestination());
				}
				if(data.getType() == null || data.getType().trim().equals("") ||
					data.getType().trim().equals("xml") || data.getType().trim().equals(XML))
				{
					data.setType(XML);										// Set type default to XML
				} else {
					data.setType(BINARY);									// All other is considered binary content
				}
				if(super.getLog().isInfoEnabled()) {
					super.getLog().info("\tResource type: " + data.getType());
				}
				// Get target Collection
				target = this.navigateToCollection(data.getDestination(), this.root, false);
				if(target == null) {
					if(super.getLog().isInfoEnabled()) {
						super.getLog().info("Target collection (" + data.getDestination() + ") does not exist, aborting...");
					}
					continue;
				}
				resource = target.createResource(file.getName(), data.getType());
				resource.setContent(file);
				target.storeResource(resource);
			}
		} catch (Exception e) {
			if(super.getLog().isErrorEnabled()) {
				super.getLog().error(e.getMessage(), e);
			}
			throw new MojoExecutionException(e.getMessage(), e);
		}
	}
	
	/**
	 * An auxiliary method to delete files.
	 * @throws MojoExecutionException 
	 */
	private void deleteFiles() throws MojoExecutionException {
		Collection target = null;
		Resource resource = null;
		
		if(this.deleteData == null || this.deleteData.size() == 0) {
			if(super.getLog().isInfoEnabled()) {
				super.getLog().info("No files to delete");
			}
			return;
		}
		if(super.getLog().isInfoEnabled()) {
			super.getLog().info("Total files to delete: " + this.deleteData.size());
		}
		try {
			for(String data : this.deleteData) {
				// Get target Collection
				target = this.navigateToCollection(data, this.root, true);
				data = data.substring(data.lastIndexOf(DELIMITER) + 1, data.length());
				resource = target.getResource(data);
				if(resource != null) {
					target.removeResource(resource);
				}
			}
		} catch (Exception e) {
			if(super.getLog().isErrorEnabled()) {
				super.getLog().error(e.getMessage(), e);
			}
			throw new MojoExecutionException(e.getMessage(), e);
		}
	}
	
	/**
	 * Auxiliary method to navigate to the correct Collection. This is typically used for creation and deletion
	 * of resources in sub collections.
	 * @param path The path of the collection.
	 * @param current The current collection.
	 * @return The target collection.
	 * @throws XMLDBException When a database error occurs.
	 */
	private Collection navigateToCollection(String path, Collection current, boolean fileIncluded) throws XMLDBException {
		int index = -1;
		
		index = path.indexOf(DELIMITER);
		if(index == -1) {
			if(fileIncluded) {
				return current;
			} else {
				return current.getChildCollection(path);
			}
		} else {
			return this.navigateToCollection(path.substring(index + 1), current.getChildCollection(path.substring(0, index)), fileIncluded);
		}
	}
	
}