/**********************************************************************
 * Copyright (c) 2003 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Common Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/cpl-v10.html
 * 
 * Contributors: 
 * IBM - Initial API and implementation
 **********************************************************************/
package org.eclipse.cdt.managedbuilder.core;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.InputStream;
import java.io.OutputStreamWriter;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.ListIterator;
import java.util.Map;

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

import org.apache.xerces.dom.DocumentImpl;
import org.apache.xml.serialize.Method;
import org.apache.xml.serialize.OutputFormat;
import org.apache.xml.serialize.Serializer;
import org.apache.xml.serialize.SerializerFactory;
import org.eclipse.cdt.core.AbstractCExtension;
import org.eclipse.cdt.core.parser.*;
import org.eclipse.cdt.managedbuilder.internal.core.Configuration;
import org.eclipse.cdt.managedbuilder.internal.core.ManagedBuildInfo;
import org.eclipse.cdt.managedbuilder.internal.core.Target;
import org.eclipse.core.resources.IFile;
import org.eclipse.core.resources.IProject;
import org.eclipse.core.resources.IResource;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IConfigurationElement;
import org.eclipse.core.runtime.IExtension;
import org.eclipse.core.runtime.IExtensionPoint;
import org.eclipse.core.runtime.QualifiedName;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;

/**
 * This is the main entry point for getting at the build information
 * for the managed build system. 
 */
public class ManagedBuildManager extends AbstractCExtension implements IScannerInfoProvider {

	private static final QualifiedName buildInfoProperty = new QualifiedName(ManagedBuilderCorePlugin.getUniqueIdentifier(), "managedBuildInfo");
	private static final String ROOT_ELEM_NAME = "ManagedProjectBuildInfo";	//$NON-NLS-1$
	private static final String FILE_NAME = ".cdtbuild";	//$NON-NLS-1$
	private static final ITarget[] emptyTargets = new ITarget[0];
	public static final String INTERFACE_IDENTITY = ManagedBuilderCorePlugin.getUniqueIdentifier() + "." + "ManagedBuildManager";	//$NON-NLS-1$
	public static final String EXTENSION_POINT_ID = "ManagedBuildInfo";		//$NON-NLS-1$
	
	// Targets defined by extensions (i.e., not associated with a resource)
	private static boolean extensionTargetsLoaded = false;
	private static List extensionTargets;
	private static Map extensionTargetMap;

	// Listeners interested in build model changes
	private static Map buildModelListeners; 

	/**
	 * Returns the list of targets that are defined by this project,
	 * projects referenced by this project, and by the extensions. 
	 * 
	 * @param project
	 * @return
	 */
	public static ITarget[] getDefinedTargets(IProject project) {
		// Make sure the extensions are loaded
		loadExtensions();

		// Get the targets for this project and all referenced projects
		List definedTargets = null;
		// To Do

		// Create the array and copy the elements over
		int size = extensionTargets != null ? 
				extensionTargets.size()	+ (definedTargets != null ? definedTargets.size() : 0) :
				0;

		ITarget[] targets = new ITarget[size];
		
		int n = 0;
		for (int i = 0; i < extensionTargets.size(); ++i)
			targets[n++] = (ITarget)extensionTargets.get(i);
		
		if (definedTargets != null)
			for (int i = 0; i < definedTargets.size(); ++i)
				targets[n++] = (ITarget)definedTargets.get(i);
				
		return targets;
	}

	/**
	 * @return
	 */
	public static Map getExtensionTargetMap() {
		if (extensionTargetMap == null) {
			extensionTargetMap = new HashMap();
		}
		return extensionTargetMap;
	}

	/**
	 * Returns the targets owned by this project.  If none are owned,
	 * an empty array is returned.
	 * 
	 * @param project
	 * @return
	 */
	public static ITarget[] getTargets(IResource resource) {
		IManagedBuildInfo buildInfo = getBuildInfo(resource);
		
		if (buildInfo != null) {
			List targets = buildInfo.getTargets();
			return (ITarget[])targets.toArray(new ITarget[targets.size()]);
		} else {
			return emptyTargets;
		}
	}

	
	/**
	 * Answers the result of a best-effort search to find a target with the 
	 * specified ID, or <code>null</code> if one is not found.
	 * 
	 * @param resource
	 * @param id
	 * @return
	 */
	public static ITarget getTarget(IResource resource, String id) {
		ITarget target = null;
		// Check if the target is spec'd in the build info for the resource
		if (resource != null) {
			IManagedBuildInfo buildInfo = getBuildInfo(resource);
			if (buildInfo != null)
				target = buildInfo.getTarget(id);
		}
		// OK, check the extension map
		if (target == null) {
			target = (ITarget)getExtensionTargetMap().get(id);
		}
		return target;
	}

	/**
	 * Creates a new target for the resource based on the parentTarget.
	 * 
	 * @param resource
	 * @param parentTarget
	 * @return new <code>ITarget</code> with settings based on the parent passed in the arguments
	 * @throws BuildException
	 */
	public static ITarget createTarget(IResource resource, ITarget parentTarget)
		throws BuildException
	{
		IResource owner = parentTarget.getOwner();
		
		if (owner != null && owner.equals(resource))
			// Already added
			return parentTarget; 
			
		if (resource instanceof IProject) {
			// Must be an extension target (why?)
			if (owner != null)
				throw new BuildException("addTarget: owner not null");
		} else {
			// Owner must be owned by the project containing this resource
			if (owner == null)
				throw new BuildException("addTarget: null owner");
			if (!owner.equals(resource.getProject()))
				throw new BuildException("addTarget: owner not project");
		}
		
		// Passed validation
		return new Target(resource, parentTarget);
	}
	
	/**
	 * Sets the default configuration for the project. Note that this will also
	 * update the default target if needed.
	 *  
	 * @param project
	 * @param newDefault
	 */
	public static void setDefaultConfiguration(IProject project, IConfiguration newDefault) {
		if (project == null || newDefault == null) {
			return;
		}
		// Set the default in build information for the project 
		IManagedBuildInfo info = getBuildInfo(project);
		if (info != null) {
			info.setDefaultConfiguration(newDefault);
		}
	}
	
	/**
	 * @param config
	 * @param option
	 */
	private static void setDirty(IConfiguration config, IOption option) {
		// Set the build info dirty so builder will rebuild
		IResource resource = config.getOwner();
		IManagedBuildInfo info = getBuildInfo(resource);
		info.setDirty(true);

		// Continue if change is something that effect the scanner
		if (!(option.getValueType() == IOption.INCLUDE_PATH 
			|| option.getValueType() == IOption.PREPROCESSOR_SYMBOLS)) {
			return;
		}
		// Figure out if there is a listener for this change
		List listeners = (List) getBuildModelListeners().get(resource);
		if (listeners == null) {
			return;
		}
		ListIterator iter = listeners.listIterator();
		while (iter.hasNext()) {
			((IScannerInfoChangeListener)iter.next()).changeNotification(resource, (IScannerInfo)getBuildInfo(resource, false));
		}
	}

	/**
	 * Set the string value for an option for a given config.
	 * 
	 * @param config The configuration the option belongs to.
	 * @param option The option to set the value for.
	 * @param value The boolean that the option should contain after the change.
	 */
	public static void setOption(IConfiguration config, IOption option, boolean value) {
		try {
			config.setOption(option, value);
			setDirty(config, option);
		} catch (BuildException e) {
			return;
		}
	}

	/**
	 * Set the string value for an option for a given config.
	 * 
	 * @param config The configuration the option belongs to.
	 * @param option The option to set the value for.
	 * @param value The value that the option should contain after the change.
	 */
	public static void setOption(IConfiguration config, IOption option, String value) {
		try {
			config.setOption(option, value);
			setDirty(config, option);
		} catch (BuildException e) {
			return;
		}
	}
	
	/**
	 * Set the string array value for an option for a given config.
	 * 
	 * @param config The configuration the option belongs to.
	 * @param option The option to set the value for.
	 * @param value The values the option should contain after the change.
	 */
	public static void setOption(IConfiguration config, IOption option, String[] value) {
		try {
			config.setOption(option, value);
			setDirty(config, option);
		} catch (BuildException e) {
			return;
		}
	}

	/**
	 * Saves the build information associated with a project and all resources
	 * in the project to the build info file.
	 * 
	 * @param project
	 */
	public static void saveBuildInfo(IProject project) {
		// Create document
		Document doc = new DocumentImpl();
		Element rootElement = doc.createElement(ROOT_ELEM_NAME);
		doc.appendChild(rootElement);

		// Save the build info
		ManagedBuildInfo buildInfo = (ManagedBuildInfo) getBuildInfo(project);
		if (buildInfo != null)
			buildInfo.serialize(doc, rootElement);
		
		// Save the document
		ByteArrayOutputStream s = new ByteArrayOutputStream();
		OutputFormat format = new OutputFormat();
		format.setIndenting(true);
		format.setLineSeparator(System.getProperty("line.separator")); //$NON-NLS-1$
		String xml = null;
		try {
			Serializer serializer
				= SerializerFactory.getSerializerFactory(Method.XML).makeSerializer(new OutputStreamWriter(s, "UTF8"), format);
			serializer.asDOMSerializer().serialize(doc);
			xml = s.toString("UTF8"); //$NON-NLS-1$		
			IFile rscFile = project.getFile(FILE_NAME);
			InputStream inputStream = new ByteArrayInputStream(xml.getBytes());
			// update the resource content
			if (rscFile.exists()) {
				rscFile.setContents(inputStream, IResource.FORCE, null);
			} else {
				rscFile.create(inputStream, IResource.FORCE, null);
			}
		} catch (Exception e) {
			return;
		}
	}

	/**
	 * @param resource
	 */
	public static void removeBuildInfo(IResource resource) {
		try {
			resource.setSessionProperty(buildInfoProperty, null);
		} catch (CoreException e) {
		}
	}

	/**
	 * Resets the build information for the project and configuration specified in the arguments. 
	 * The build information will contain the settings defined in the plugin manifest. 
	 * 
	 * @param project
	 * @param configuration
	 */
	public static void resetConfiguration(IProject project, IConfiguration configuration) {
		// Make sure the extensions are loaded
		loadExtensions();

		// Find out the parent of the configuration
		IConfiguration parentConfig = configuration.getParent();
		// Find the parent target the configuration 
		ITarget parentTarget = parentConfig.getTarget();

		// Get the extension point information		
		IExtensionPoint extensionPoint = ManagedBuilderCorePlugin.getDefault().getDescriptor().getExtensionPoint(EXTENSION_POINT_ID);
		IExtension[] extensions = extensionPoint.getExtensions();
		for (int i = 0; i < extensions.length; ++i) {
			IExtension extension = extensions[i];
			IConfigurationElement[] elements = extension.getConfigurationElements();
			for (int j = 0; j < elements.length; ++j) {
				IConfigurationElement element = elements[j];
				if (element.getName().equals(ITarget.TARGET_ELEMENT_NAME) && 
					element.getAttribute(ITarget.ID).equals(parentTarget.getId())) {
					// We have the parent target so get the definition for the parent config
					IConfigurationElement[] targetElements = element.getChildren();
					for (int k = 0; k < targetElements.length; ++k) {
						IConfigurationElement targetElement = targetElements[k];
						if (targetElement.getName().equals(IConfiguration.CONFIGURATION_ELEMENT_NAME) && 
							targetElement.getAttribute(IConfiguration.ID).equals(parentConfig.getId())) {
							// We now have the plugin element the target was originally based on
							((Configuration)configuration).reset(targetElement);							 
						}
					}
				}
			}
		}
	}
	
	// Private stuff

	public static void addExtensionTarget(Target target) {
		if (extensionTargets == null) {
			extensionTargets = new ArrayList();
		}
		
		extensionTargets.add(target);
		getExtensionTargetMap().put(target.getId(), target);
	}
		
	private static ManagedBuildInfo loadBuildInfo(IProject project) {
		ManagedBuildInfo buildInfo = null;
		IFile file = project.getFile(FILE_NAME);
		if (!file.exists())
			return null;
	
		try {
			InputStream stream = file.getContents();
			DocumentBuilder parser = DocumentBuilderFactory.newInstance().newDocumentBuilder();
			Document document = parser.parse(stream);
			Node rootElement = document.getFirstChild();
			if (rootElement.getNodeName().equals(ROOT_ELEM_NAME)) {
				buildInfo = new ManagedBuildInfo(project, (Element)rootElement);
				project.setSessionProperty(buildInfoProperty, buildInfo);
			}
		} catch (Exception e) {
			buildInfo = null;
		}

		return buildInfo;
	}

	private static void loadExtensions() {
		if (extensionTargetsLoaded)
			return;
		extensionTargetsLoaded = true;

		IExtensionPoint extensionPoint = ManagedBuilderCorePlugin.getDefault().getDescriptor().getExtensionPoint(EXTENSION_POINT_ID);
		IExtension[] extensions = extensionPoint.getExtensions();
		for (int i = 0; i < extensions.length; ++i) {
			IExtension extension = extensions[i];
			IConfigurationElement[] elements = extension.getConfigurationElements();
			for (int j = 0; j < elements.length; ++j) {
				IConfigurationElement element = elements[j];
				if (element.getName().equals(ITarget.TARGET_ELEMENT_NAME)) {
					new Target(element);
				}
			}
		}
	}

	/**
	 * @param project
	 * @return
	 */
	public static boolean manages(IResource resource) {
		// The managed build manager manages build information for the 
		// resource IFF it it is a project and has a build file with the proper
		// root element
		IProject project = null;
		if (resource instanceof IProject){
			project = (IProject)resource;
		} else if (resource instanceof IFile) {
			project = ((IFile)resource).getProject();
		} else {
			return false;
		}
		IFile file = project.getFile(FILE_NAME);
		if (file.exists()) {
			try {
				InputStream stream = file.getContents();
				DocumentBuilder parser = DocumentBuilderFactory.newInstance().newDocumentBuilder();
				Document document = parser.parse(stream);
				Node rootElement = document.getFirstChild();
				if (rootElement.getNodeName().equals(ROOT_ELEM_NAME)) {
					return true;
				} 
			} catch (Exception e) {
				return false;
			}
		}
		return false;
	}

	private static ManagedBuildInfo findBuildInfo(IResource resource, boolean create) {
		// Make sure the extension information is loaded first
		loadExtensions();
		ManagedBuildInfo buildInfo = null;
		try {
			buildInfo = (ManagedBuildInfo)resource.getSessionProperty(buildInfoProperty);
		} catch (CoreException e) {
			return buildInfo;
		}
		
		if (buildInfo == null && resource instanceof IProject) {
			buildInfo = loadBuildInfo((IProject)resource);
		}
		
		if (buildInfo == null && create) {
			try {
				buildInfo = new ManagedBuildInfo(resource);
				resource.setSessionProperty(buildInfoProperty, buildInfo);
			} catch (CoreException e) {
				buildInfo = null;
			}
		}
		
		return buildInfo;
	}
	
	public static IManagedBuildInfo getBuildInfo(IResource resource, boolean create) {
		return (IManagedBuildInfo) findBuildInfo(resource, create);
	}

	public static IManagedBuildInfo getBuildInfo(IResource resource) {
		return (IManagedBuildInfo) findBuildInfo(resource, false);
	}

	/*
	 * @return
	 */
	private static Map getBuildModelListeners() {
		if (buildModelListeners == null) {
			buildModelListeners = new HashMap();
		}
		return buildModelListeners;
	}

	/* (non-Javadoc)
	 * @see org.eclipse.cdt.core.parser.IScannerInfoProvider#getScannerInformation(org.eclipse.core.resources.IResource)
	 */
	public IScannerInfo getScannerInformation(IResource resource) {
		return (IScannerInfo) getBuildInfo(resource, false);
	}

	/* (non-Javadoc)
	 * @see org.eclipse.cdt.core.parser.IScannerInfoProvider#subscribe(org.eclipse.cdt.core.parser.IScannerInfoChangeListener)
	 */
	public synchronized void subscribe(IResource resource, IScannerInfoChangeListener listener) {
		IResource project = null;
		if (resource instanceof IProject) {
			project = resource;
		} else if (resource instanceof IFile) {
			project = ((IFile)resource).getProject();
		} else {
			return;
		}
		// Get listeners for this resource
		Map map = getBuildModelListeners();
		List list = (List) map.get(project);
		if (list == null) {
			// Create a new list
			list = new ArrayList();
		}
		if (!list.contains(listener)) {
			// Add the new listener for the resource
			list.add(listener);
			map.put(project, list);
		}
	}

	/* (non-Javadoc)
	 * @see org.eclipse.cdt.core.parser.IScannerInfoProvider#unsubscribe(org.eclipse.cdt.core.parser.IScannerInfoChangeListener)
	 */
	public synchronized void unsubscribe(IResource resource, IScannerInfoChangeListener listener) {
		IResource project = null;
		if (resource instanceof IProject) {
			project = resource;
		} else if (resource instanceof IFile) {
			project = ((IFile)resource).getProject();
		} else {
			return;
		}
		// Remove the listener
		Map map = getBuildModelListeners();
		List list = (List) map.get(project);
		if (list != null && !list.isEmpty()) {
			// The list is not empty so try to remove listener
			list.remove(listener);
			map.put(project, list);
		}
	}

}