/*
 * Copyright 2010, 2011, 2012 mapsforge.org
 *
 * This program is free software: you can redistribute it and/or modify it under the
 * terms of the GNU Lesser General Public License as published by the Free Software
 * Foundation, either version 3 of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT ANY
 * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
 * PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License along with
 * this program. If not, see <http://www.gnu.org/licenses/>.
 */
package org.mapsforge.map.writer.model;

/**
 * Represents an OSM entity which is defined by a tag/value pair. Each OSM entity is attributed with the zoom level on
 * which it should appear first.
 * 
 * @author bross
 */
public class OSMTag {
	private static final String KEY_VALUE_SEPARATOR = "=";

	private final short id;
	private final String key;
	private final String value;
	private final byte zoomAppear;
	// TODO is the renderable attribute still needed?
	private final boolean renderable;
	private final boolean forcePolygonLine;

	/**
	 * @param id
	 *            the internal id of the tag
	 * @param key
	 *            the key of the tag
	 * @param value
	 *            the value of the tag
	 * @param zoomAppear
	 *            the minimum zoom level the tag appears first
	 * @param renderable
	 *            flag if the tag represents a renderable entity
	 * @param forcePolygonLine
	 *            flag if polygon line instead of area is forced with closed polygons
	 */
	public OSMTag(short id, String key, String value, byte zoomAppear, boolean renderable, boolean forcePolygonLine) {
		super();
		this.id = id;
		this.key = key;
		this.value = value;
		this.zoomAppear = zoomAppear;
		this.renderable = renderable;
		this.forcePolygonLine = forcePolygonLine;
	}

	/**
	 * Convenience method that constructs a new OSMTag with a new id from another OSMTag.
	 * 
	 * @param otherTag
	 *            the OSMTag to copy
	 * @param newID
	 *            the new id
	 * @return a newly constructed OSMTag with the attributes of otherTag
	 */
	public static OSMTag fromOSMTag(OSMTag otherTag, short newID) {
		return new OSMTag(newID, otherTag.getKey(), otherTag.getValue(), otherTag.getZoomAppear(),
				otherTag.isRenderable(), otherTag.isForcePolygonLine());
	}

	/**
	 * @return the id
	 */
	public final short getId() {
		return this.id;
	}

	/**
	 * @return the key
	 */
	public final String getKey() {
		return this.key;
	}

	/**
	 * @return the value
	 */
	public final String getValue() {
		return this.value;
	}

	/**
	 * @return the zoomAppear
	 */
	public final byte getZoomAppear() {
		return this.zoomAppear;
	}

	/**
	 * @return the renderable
	 */
	public final boolean isRenderable() {
		return this.renderable;
	}

	/**
	 * @return whether the tag represents a coastline
	 */
	public final boolean isCoastline() {
		return this.key.equals("natural") && this.value.equals("coastline");
	}

	/**
	 * @return the string representation of the OSMTag
	 */
	public final String tagKey() {
		return this.key + KEY_VALUE_SEPARATOR + this.value;
	}

	/**
	 * @return the forcePolygonLine
	 */
	public final boolean isForcePolygonLine() {
		return this.forcePolygonLine;
	}

	/**
	 * Convenience method for generating a string representation of a key/value pair.
	 * 
	 * @param key
	 *            the key of the tag
	 * @param value
	 *            the value of the tag
	 * @return a string representation of the key/Value pair
	 */
	public static String tagKey(String key, String value) {
		return key + KEY_VALUE_SEPARATOR + value;
	}

	@Override
	public final int hashCode() {
		final int prime = 31;
		int result = 1;
		result = prime * result + this.id;
		return result;
	}

	@Override
	public final boolean equals(Object obj) {
		if (this == obj)
			return true;
		if (obj == null)
			return false;
		if (getClass() != obj.getClass())
			return false;
		OSMTag other = (OSMTag) obj;
		if (this.id != other.id)
			return false;
		return true;
	}

	@Override
	public final String toString() {
		return "OSMTag [id=" + this.id + ", key=" + this.key + ", value=" + this.value + ", zoomAppear="
				+ this.zoomAppear + ", renderable=" + this.renderable + "]";
	}
}