package org.apache.lucene.xmlparser.builders;

/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import java.io.IOException;

import org.apache.lucene.index.IndexReader;
import org.apache.lucene.search.DocIdSet;
import org.apache.lucene.search.Filter;
import org.apache.lucene.search.NumericRangeFilter;
import org.apache.lucene.util.NumericUtils;
import org.apache.lucene.xmlparser.DOMUtils;
import org.apache.lucene.xmlparser.FilterBuilder;
import org.apache.lucene.xmlparser.ParserException;
import org.w3c.dom.Element;

/**
 * Creates a {@link NumericRangeFilter}. The table below specifies the required
 * attributes and the defaults if optional attributes are omitted. For more
 * detail on what each of the attributes actually do, consult the documentation
 * for {@link NumericRangeFilter}:
 * <table>
 * <tr>
 * <th>Attribute name</th>
 * <th>Values</th>
 * <th>Required</th>
 * <th>Default</th>
 * </tr>
 * <tr>
 * <td>fieldName</td>
 * <td>String</td>
 * <td>Yes</td>
 * <td>N/A</td>
 * </tr>
 * <tr>
 * <td>lowerTerm</td>
 * <td>Specified by <tt>type</tt></td>
 * <td>Yes</td>
 * <td>N/A</td>
 * </tr>
 * <tr>
 * <td>upperTerm</td>
 * <td>Specified by <tt>type</tt></td>
 * <td>Yes</td>
 * <td>N/A</td>
 * </tr>
 * <tr>
 * <td>type</td>
 * <td>int, long, float, double</td>
 * <td>No</td>
 * <td>int</td>
 * </tr>
 * <tr>
 * <td>includeLower</td>
 * <td>true, false</td>
 * <td>No</td>
 * <td>true</td>
 * </tr>
 * <tr>
 * <td>includeUpper</td>
 * <td>true, false</td>
 * <td>No</td>
 * <td>true</td>
 * </tr>
 * <tr>
 * <td>precisionStep</td>
 * <td>Integer</td>
 * <td>No</td>
 * <td>4</td>
 * </tr>
 * </table>
 * <p>
 * If an error occurs parsing the supplied <tt>lowerTerm</tt> or
 * <tt>upperTerm</tt> into the numeric type specified by <tt>type</tt>, then the
 * error will be silently ignored and the resulting filter will not match any
 * documents.
 */
public class NumericRangeFilterBuilder implements FilterBuilder {
	private static final NoMatchFilter NO_MATCH_FILTER = new NoMatchFilter();

	private boolean strictMode = false;

	/**
	 * Specifies how this {@link NumericRangeFilterBuilder} will handle errors.
	 * <p>
	 * If this is set to true, {@link #getFilter(Element)} will throw a
	 * {@link ParserException} if it is unable to parse the lowerTerm or upperTerm
	 * into the appropriate numeric type. If this is set to false, then this
	 * exception will be silently ignored and the resulting filter will not match
	 * any documents.
	 * <p>
	 * Defaults to false.
	 * 
	 * @param strictMode
	 */
	public void setStrictMode(boolean strictMode) {
		this.strictMode = strictMode;
	}

	public Filter getFilter(Element e) throws ParserException {
		String field = DOMUtils.getAttributeWithInheritanceOrFail(e, "fieldName");
		String lowerTerm = DOMUtils.getAttributeOrFail(e, "lowerTerm");
		String upperTerm = DOMUtils.getAttributeOrFail(e, "upperTerm");
		boolean lowerInclusive = DOMUtils.getAttribute(e, "includeLower", true);
		boolean upperInclusive = DOMUtils.getAttribute(e, "includeUpper", true);
		int precisionStep = DOMUtils.getAttribute(e, "precisionStep",  NumericUtils.PRECISION_STEP_DEFAULT);

		String type = DOMUtils.getAttribute(e, "type", "int");
		try {
			Filter filter;
			if (type.equalsIgnoreCase("int")) {
				filter = NumericRangeFilter.newIntRange(field, precisionStep, Integer
						.valueOf(lowerTerm), Integer.valueOf(upperTerm), lowerInclusive,
						upperInclusive);
			} else if (type.equalsIgnoreCase("long")) {
				filter = NumericRangeFilter.newLongRange(field, precisionStep, Long
						.valueOf(lowerTerm), Long.valueOf(upperTerm), lowerInclusive,
						upperInclusive);
			} else if (type.equalsIgnoreCase("double")) {
				filter = NumericRangeFilter.newDoubleRange(field, precisionStep, Double
						.valueOf(lowerTerm), Double.valueOf(upperTerm), lowerInclusive,
						upperInclusive);
			} else if (type.equalsIgnoreCase("float")) {
				filter = NumericRangeFilter.newFloatRange(field, precisionStep, Float
						.valueOf(lowerTerm), Float.valueOf(upperTerm), lowerInclusive,
						upperInclusive);
			} else {
				throw new ParserException(
						"type attribute must be one of: [long, int, double, float]");
			}
			return filter;
		} catch (NumberFormatException nfe) {
			if (strictMode) {
				throw new ParserException(
						"Could not parse lowerTerm or upperTerm into a number", nfe);
			}
			return NO_MATCH_FILTER;
		}
	}

	static class NoMatchFilter extends Filter {
		private static final long serialVersionUID = 1L;

		@Override
		public DocIdSet getDocIdSet(IndexReader reader) throws IOException {
			return null;
		}

	}
}