/*******************************************************************************
 * Copyright (c) 2000, 2016 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
 *     James Blackburn (Broadcom Corp.) - ongoing development
 *     Lars Vogel <Lars.Vogel@vogella.com> - Bug 473427
 *     Mickael Istria (Red Hat Inc.) - Bug 488937
 *******************************************************************************/
package org.eclipse.core.internal.resources;

import java.io.DataOutputStream;
import java.io.IOException;
import java.util.*;
import org.eclipse.core.internal.watson.IPathRequestor;

//
public class MarkerWriter {

	protected MarkerManager manager;

	// version numbers
	public static final int MARKERS_SAVE_VERSION = 3;
	public static final int MARKERS_SNAP_VERSION = 2;

	// type constants
	public static final byte INDEX = 1;
	public static final byte QNAME = 2;

	// marker attribute types
	public static final byte ATTRIBUTE_NULL = 0;
	public static final byte ATTRIBUTE_BOOLEAN = 1;
	public static final byte ATTRIBUTE_INTEGER = 2;
	public static final byte ATTRIBUTE_STRING = 3;

	public MarkerWriter(MarkerManager manager) {
		super();
		this.manager = manager;
	}

	/**
	 * Returns an Object array of length 2. The first element is an Integer which is the number
	 * of persistent markers found. The second element is an array of boolean values, with a
	 * value of true meaning that the marker at that index is to be persisted.
	 */
	private Object[] filterMarkers(IMarkerSetElement[] markers) {
		Object[] result = new Object[2];
		boolean[] isPersistent = new boolean[markers.length];
		int count = 0;
		for (int i = 0; i < markers.length; i++) {
			MarkerInfo info = (MarkerInfo) markers[i];
			if (manager.isPersistent(info)) {
				isPersistent[i] = true;
				count++;
			}
		}
		result[0] = count;
		result[1] = isPersistent;
		return result;
	}

	/**
	 * <pre> {@code
	 * SAVE_FILE -> VERSION_ID RESOURCE+
	 * VERSION_ID -> int
	 * RESOURCE -> RESOURCE_PATH MARKERS_SIZE MARKER+
	 * RESOURCE_PATH -> String
	 * MARKERS_SIZE -> int
	 * MARKER -> MARKER_ID TYPE ATTRIBUTES_SIZE ATTRIBUTE* CREATION_TIME
	 * MARKER_ID -> long
	 * TYPE -> INDEX | QNAME
	 * INDEX -> byte int
	 * QNAME -> byte String
	 * ATTRIBUTES_SIZE -> short
	 * ATTRIBUTE -> ATTRIBUTE_KEY ATTRIBUTE_VALUE
	 * ATTRIBUTE_KEY -> String
	 * ATTRIBUTE_VALUE -> INTEGER_VALUE | BOOLEAN_VALUE | STRING_VALUE | NULL_VALUE
	 * INTEGER_VALUE -> byte int
	 * BOOLEAN_VALUE -> byte boolean
	 * STRING_VALUE -> byte String
	 * NULL_VALUE -> byte
	 * CREATION_TIME -> long
	 * }</pre>
	 */
	public void save(ResourceInfo info, IPathRequestor requestor, DataOutputStream output, List<String> writtenTypes) throws IOException {
		// phantom resources don't have markers
		if (info.isSet(ICoreConstants.M_PHANTOM))
			return;
		MarkerSet markers = info.getMarkers(false);
		if (markers == null)
			return;
		IMarkerSetElement[] elements = markers.elements();
		// filter out the markers...determine if there are any persistent ones
		Object[] result = filterMarkers(elements);
		int count = ((Integer) result[0]).intValue();
		if (count == 0)
			return;
		// if this is the first set of markers that we have written, then
		// write the version id for the file.
		if (output.size() == 0)
			output.writeInt(MARKERS_SAVE_VERSION);
		boolean[] isPersistent = (boolean[]) result[1];
		output.writeUTF(requestor.requestPath().toString());
		output.writeInt(count);
		for (int i = 0; i < elements.length; i++)
			if (isPersistent[i])
				write((MarkerInfo) elements[i], output, writtenTypes);
	}

	/**
	 * Snapshot the markers for the specified resource to the given output stream.
	 *
	 * <pre> {@code
	 * SNAP_FILE -> [VERSION_ID RESOURCE]*
	 * VERSION_ID -> int (used for backwards compatibiliy)
	 * RESOURCE -> RESOURCE_PATH MARKER_SIZE MARKER+
	 * RESOURCE_PATH -> String
	 * MARKER_SIZE -> int
	 * MARKER -> MARKER_ID TYPE ATTRIBUTES_SIZE ATTRIBUTE* CREATION_TIME
	 * MARKER_ID -> long
	 * TYPE -> INDEX | QNAME
	 * INDEX -> byte int
	 * QNAME -> byte String
	 * ATTRIBUTES_SIZE -> short
	 * ATTRIBUTE -> ATTRIBUTE_KEY ATTRIBUTE_VALUE
	 * ATTRIBUTE_KEY -> String
	 * ATTRIBUTE_VALUE -> BOOLEAN_VALUE | INTEGER_VALUE | STRING_VALUE | NULL_VALUE
	 * BOOLEAN_VALUE -> byte boolean
	 * INTEGER_VALUE -> byte int
	 * STRING_VALUE -> byte String
	 * NULL_VALUE -> byte
	 * CREATION_TIME -> long
	 * }</pre>
	 */
	public void snap(ResourceInfo info, IPathRequestor requestor, DataOutputStream output) throws IOException {
		// phantom resources don't have markers
		if (info.isSet(ICoreConstants.M_PHANTOM))
			return;
		if (!info.isSet(ICoreConstants.M_MARKERS_SNAP_DIRTY))
			return;
		MarkerSet markers = info.getMarkers(false);
		if (markers == null)
			return;
		IMarkerSetElement[] elements = markers.elements();
		// filter out the markers...determine if there are any persistent ones
		Object[] result = filterMarkers(elements);
		int count = ((Integer) result[0]).intValue();
		// write the version id for the snapshot.
		output.writeInt(MARKERS_SNAP_VERSION);
		boolean[] isPersistent = (boolean[]) result[1];
		output.writeUTF(requestor.requestPath().toString());
		// always write out the count...even if its zero. this will help
		// use pick up marker deletions from our snapshot.
		output.writeInt(count);
		List<String> writtenTypes = new ArrayList<>();
		for (int i = 0; i < elements.length; i++)
			if (isPersistent[i])
				write((MarkerInfo) elements[i], output, writtenTypes);
		info.clear(ICoreConstants.M_MARKERS_SNAP_DIRTY);
	}

	/*
	 * Write out the given marker attributes to the given output stream.
	 */
	private void write(Map<String, Object> attributes, DataOutputStream output) throws IOException {
		output.writeShort(attributes.size());
		for (Map.Entry<String, Object> e : attributes.entrySet()) {
			String key = e.getKey();
			output.writeUTF(key);
			Object value = e.getValue();
			if (value instanceof Integer) {
				output.writeByte(ATTRIBUTE_INTEGER);
				output.writeInt(((Integer) value).intValue());
				continue;
			}
			if (value instanceof Boolean) {
				output.writeByte(ATTRIBUTE_BOOLEAN);
				output.writeBoolean(((Boolean) value).booleanValue());
				continue;
			}
			if (value instanceof String) {
				output.writeByte(ATTRIBUTE_STRING);
				output.writeUTF((String) value);
				continue;
			}
			// otherwise we came across an attribute of an unknown type
			// so just write out null since we don't know how to marshal it.
			output.writeByte(ATTRIBUTE_NULL);
		}
	}

	private void write(MarkerInfo info, DataOutputStream output, List<String> writtenTypes) throws IOException {
		output.writeLong(info.getId());
		// if we have already written the type once, then write an integer
		// constant to represent it instead to remove duplication
		String type = info.getType();
		int index = writtenTypes.indexOf(type);
		if (index == -1) {
			output.writeByte(QNAME);
			output.writeUTF(type);
			writtenTypes.add(type);
		} else {
			output.writeByte(INDEX);
			output.writeInt(index);
		}

		// write out the size of the attribute table and
		// then each attribute.
		if (info.getAttributes(false) == null) {
			output.writeShort(0);
		} else
			write(info.getAttributes(false), output);

		// write out the creation time
		output.writeLong(info.getCreationTime());
	}
}