/*******************************************************************************
 * Copyright (c) 2000, 2011 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/

package org.eclipse.jdt.internal.ui.preferences.formatter;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.UnsupportedEncodingException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;
import javax.xml.transform.OutputKeys;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;

import org.xml.sax.Attributes;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;

import org.w3c.dom.Document;
import org.w3c.dom.Element;

import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.preferences.IEclipsePreferences;
import org.eclipse.core.runtime.preferences.IScopeContext;

import org.eclipse.jdt.ui.JavaUI;

import org.eclipse.jdt.internal.ui.JavaPlugin;
import org.eclipse.jdt.internal.ui.JavaUIException;
import org.eclipse.jdt.internal.ui.JavaUIStatus;
import org.eclipse.jdt.internal.ui.preferences.formatter.ProfileManager.CustomProfile;
import org.eclipse.jdt.internal.ui.preferences.formatter.ProfileManager.Profile;


/**
 * Can load/store profiles from/to profilesKey
 */
public class ProfileStore {

	/** The default encoding to use */
	public static final String ENCODING= "UTF-8"; //$NON-NLS-1$

	protected static final String VERSION_KEY_SUFFIX= ".version"; //$NON-NLS-1$

	/**
	 * A SAX event handler to parse the xml format for profiles.
	 */
	private final static class ProfileDefaultHandler extends DefaultHandler {

		private List<Profile> fProfiles;
		private int fVersion;

		private String fName;
		private Map<String, String> fSettings;
		private String fKind;

		@Override
		public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {

			switch (qName) {
			case XML_NODE_SETTING:
				final String key= attributes.getValue(XML_ATTRIBUTE_ID);
				final String value= attributes.getValue(XML_ATTRIBUTE_VALUE);
				fSettings.put(key, value);
				break;
			case XML_NODE_PROFILE:
				fName= attributes.getValue(XML_ATTRIBUTE_NAME);
				fKind= attributes.getValue(XML_ATTRIBUTE_PROFILE_KIND);
				if (fKind == null) //Can only be an CodeFormatterProfile created pre 3.3M2
					fKind= ProfileVersioner.CODE_FORMATTER_PROFILE_KIND;
				fSettings= new HashMap<>(200);
				break;
			case XML_NODE_ROOT:
				fProfiles= new ArrayList<>();
				try {
					fVersion= Integer.parseInt(attributes.getValue(XML_ATTRIBUTE_VERSION));
				} catch (NumberFormatException ex) {
					throw new SAXException(ex);
				}
				break;
			default:
				break;
			}
		}

		@Override
		public void endElement(String uri, String localName, String qName) {
			if (XML_NODE_PROFILE.equals(qName)) {
				fProfiles.add(new CustomProfile(fName, fSettings, fVersion, fKind));
				fName= null;
				fSettings= null;
				fKind= null;
			}
		}

		public List<Profile> getProfiles() {
			return fProfiles;
		}

	}

	/**
	 * Identifiers for the XML file.
	 */
	private final static String XML_NODE_ROOT= "profiles"; //$NON-NLS-1$
	private final static String XML_NODE_PROFILE= "profile"; //$NON-NLS-1$
	private final static String XML_NODE_SETTING= "setting"; //$NON-NLS-1$

	private final static String XML_ATTRIBUTE_VERSION= "version"; //$NON-NLS-1$
	private final static String XML_ATTRIBUTE_ID= "id"; //$NON-NLS-1$
	private final static String XML_ATTRIBUTE_NAME= "name"; //$NON-NLS-1$
	private final static String XML_ATTRIBUTE_PROFILE_KIND= "kind"; //$NON-NLS-1$
	private final static String XML_ATTRIBUTE_VALUE= "value"; //$NON-NLS-1$

	private final IProfileVersioner fProfileVersioner;
	private final String fProfilesKey;
	private final String fProfilesVersionKey;


	public ProfileStore(String profilesKey, IProfileVersioner profileVersioner) {
		fProfilesKey= profilesKey;
		fProfileVersioner= profileVersioner;
		fProfilesVersionKey= profilesKey + VERSION_KEY_SUFFIX;
	}

	/**
	 * @return Returns the collection of profiles currently stored in the preference store or
	 * <code>null</code> if the loading failed. The elements are of type {@link ProfileManager.CustomProfile}
	 * and are all updated to the latest version.
	 * @throws CoreException
	 */
	public List<Profile> readProfiles(IScopeContext scope) throws CoreException {
		return readProfilesFromString(scope.getNode(JavaUI.ID_PLUGIN).get(fProfilesKey, null));
	}

	public void writeProfiles(Collection<Profile> profiles, IScopeContext instanceScope) throws CoreException {
		ByteArrayOutputStream stream= new ByteArrayOutputStream(2000);
		try {
			writeProfilesToStream(profiles, stream, ENCODING, fProfileVersioner);
			String val;
			try {
				val= stream.toString(ENCODING);
			} catch (UnsupportedEncodingException e) {
				val= stream.toString();
			}
			IEclipsePreferences uiPreferences = instanceScope.getNode(JavaUI.ID_PLUGIN);
			uiPreferences.put(fProfilesKey, val);
			uiPreferences.putInt(fProfilesVersionKey, fProfileVersioner.getCurrentVersion());
		} finally {
			try { stream.close(); } catch (IOException e) { /* ignore */ }
		}
	}

	public List<Profile> readProfilesFromString(String profiles) throws CoreException {
	    if (profiles != null && profiles.length() > 0) {
			byte[] bytes;
			try {
				bytes= profiles.getBytes(ENCODING);
			} catch (UnsupportedEncodingException e) {
				bytes= profiles.getBytes();
			}
			InputStream is= new ByteArrayInputStream(bytes);
			try {
				List<Profile> res= readProfilesFromStream(new InputSource(is));
				if (res != null) {
					for (Profile re : res) {
						fProfileVersioner.update((CustomProfile) re);
					}
				}
				return res;
			} finally {
				try { is.close(); } catch (IOException e) { /* ignore */ }
			}
		}
		return null;
    }


	/**
	 * Read the available profiles from the internal XML file and return them
	 * as collection or <code>null</code> if the file is not a profile file.
	 * @param file The file to read from
	 * @return returns a list of <code>CustomProfile</code> or <code>null</code>
	 * @throws CoreException
	 */
	public List<Profile> readProfilesFromFile(File file) throws CoreException {
		try {
			final FileInputStream reader= new FileInputStream(file);
			try {
				return readProfilesFromStream(new InputSource(reader));
			} finally {
				try { reader.close(); } catch (IOException e) { /* ignore */ }
			}
		} catch (IOException e) {
			throw createException(e, FormatterMessages.CodingStyleConfigurationBlock_error_reading_xml_message);
		}
	}

	/**
	 * Load profiles from a XML stream and add them to a map or <code>null</code> if the source is not a profile store.
	 * @param inputSource The input stream
	 * @return returns a list of <code>CustomProfile</code> or <code>null</code>
	 * @throws CoreException
	 */
	public static List<Profile> readProfilesFromStream(InputSource inputSource) throws CoreException {

		final ProfileDefaultHandler handler= new ProfileDefaultHandler();
		try {
		    final SAXParserFactory factory= SAXParserFactory.newInstance();
			final SAXParser parser= factory.newSAXParser();
			parser.parse(inputSource, handler);
		} catch (SAXException | IOException | ParserConfigurationException e) {
			throw createException(e, FormatterMessages.CodingStyleConfigurationBlock_error_reading_xml_message);
		}
		return handler.getProfiles();
	}

	/**
	 * Write the available profiles to the internal XML file.
	 * @param profiles List of <code>CustomProfile</code>
	 * @param file File to write
	 * @param encoding the encoding to use
	 * @throws CoreException
	 */
	public void writeProfilesToFile(Collection<Profile> profiles, File file, String encoding) throws CoreException {
		final OutputStream stream;
		try {
			stream= new FileOutputStream(file);
			try {
				writeProfilesToStream(profiles, stream, encoding, fProfileVersioner);
			} finally {
				try { stream.close(); } catch (IOException e) { /* ignore */ }
			}
		} catch (IOException e) {
			throw createException(e, FormatterMessages.CodingStyleConfigurationBlock_error_serializing_xml_message);
		}
	}

	/**
	 * Save profiles to an XML stream
	 * @param profiles the list of <code>CustomProfile</code>
	 * @param stream the stream to write to
	 * @param encoding the encoding to use
	 * @throws CoreException
	 */
	public static void writeProfilesToStream(Collection<Profile> profiles, OutputStream stream, String encoding, IProfileVersioner profileVersioner) throws CoreException {

		try {
			final DocumentBuilderFactory factory= DocumentBuilderFactory.newInstance();
			final DocumentBuilder builder= factory.newDocumentBuilder();
			final Document document= builder.newDocument();

			final Element rootElement = document.createElement(XML_NODE_ROOT);
			rootElement.setAttribute(XML_ATTRIBUTE_VERSION, Integer.toString(profileVersioner.getCurrentVersion()));

			document.appendChild(rootElement);

			for (Profile profile : profiles) {
				if (profile.isProfileToSave()) {
					final Element profileElement= createProfileElement(profile, document, profileVersioner);
					rootElement.appendChild(profileElement);
				}
			}

			Transformer transformer=TransformerFactory.newInstance().newTransformer();
			transformer.setOutputProperty(OutputKeys.METHOD, "xml"); //$NON-NLS-1$
			transformer.setOutputProperty(OutputKeys.ENCODING, encoding);
			transformer.setOutputProperty(OutputKeys.INDENT, "yes"); //$NON-NLS-1$
			transformer.transform(new DOMSource(document), new StreamResult(stream));
		} catch (TransformerException | ParserConfigurationException e) {
			throw createException(e, FormatterMessages.CodingStyleConfigurationBlock_error_serializing_xml_message);
		}
	}


	/*
	 * Create a new profile element in the specified document. The profile is not added
	 * to the document by this method.
	 */
	private static Element createProfileElement(Profile profile, Document document, IProfileVersioner profileVersioner) {
		final Element element= document.createElement(XML_NODE_PROFILE);
		element.setAttribute(XML_ATTRIBUTE_NAME, profile.getName());
		element.setAttribute(XML_ATTRIBUTE_VERSION, Integer.toString(profile.getVersion()));
		element.setAttribute(XML_ATTRIBUTE_PROFILE_KIND, profileVersioner.getProfileKind());

		final Iterator<String> keyIter= profile.getSettings().keySet().iterator();

		while (keyIter.hasNext()) {
			final String key= keyIter.next();
			final String value= profile.getSettings().get(key);
			if (value != null) {
				final Element setting= document.createElement(XML_NODE_SETTING);
				setting.setAttribute(XML_ATTRIBUTE_ID, key);
				setting.setAttribute(XML_ATTRIBUTE_VALUE, value);
				element.appendChild(setting);
			} else {
				JavaPlugin.logErrorMessage("ProfileStore: Profile does not contain value for key " + key); //$NON-NLS-1$
			}
		}
		return element;
	}


	/*
	 * Creates a UI exception for logging purposes
	 */
	private static JavaUIException createException(Throwable t, String message) {
		return new JavaUIException(JavaUIStatus.createError(IStatus.ERROR, message, t));
	}
}
