/**
 * Copyright 2008-2009 DRIVER PROJECT (ICM UW)
 * Original author: Marek Horst
 *
 * Licensed 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.
 */
// $Id: CQLProxNode.java 5239 2008-03-17 09:00:00Z icmdriver $

package org.z3950.zing.cql;


/**
 * Represents a proximity node in a CQL parse-tree.
 * The left- and right-hand-sides must be satisfied by parts of the
 * candidate records which are sufficiently close to each other, as
 * specified by a set of proximity parameters.
 *
 * @version	$Id: CQLProxNode.java 5239 2008-03-17 09:00:00Z icmdriver $
 */
public class CQLProxNode extends CQLBooleanNode {
    /**
     * Creates a new PROX node with the specified left- and right-hand
     * sides and modifiers.
     */
    public CQLProxNode(CQLNode left, CQLNode right, ModifierSet ms) {
	super(left, right, ms);
    }

    /*
     * proximity ::= exclusion distance ordered relation which-code unit-code.
     * exclusion ::= '1' | '0' | 'void'.
     * distance ::= integer.
     * ordered ::= '1' | '0'.
     * relation ::= integer.
     * which-code ::= 'known' | 'private' | integer.
     * unit-code ::= integer.
     */
    String opPQF() {
	int relCode = getRelCode();
	int unitCode = getProxUnitCode();

	String res = "prox " +
	    "0 " +
	    ms.modifier("distance") + " " +
	    (ms.modifier("ordering").equals("ordered") ? 1 : 0) + " " +
	    relCode + " " +
	    "1 " +
	    unitCode;

	return res;
    }

    private int getRelCode() {
	String rel = ms.modifier("relation");
	if (rel.equals("<")) {
	    return 1;
	} else if (rel.equals("<=")) {
	    return 2;
	} else if (rel.equals("=")) {
	    return 3;
	} else if (rel.equals(">=")) {
	    return 4;
	} else if (rel.equals(">")) {
	    return 5;
	} else if (rel.equals("<>")) {
	    return 6;
	}
	return 0;
    }

    private int getProxUnitCode() {
	String unit = ms.modifier("unit");
	if (unit.equals("word")) {
	    return 2;
	} else if (unit.equals("sentence")) {
	    return 3;
	} else if (unit.equals("paragraph")) {
	    return 4;
	} else if (unit.equals("element")) {
	    return 8;
	}
	return 0;
    }


    byte[] opType1() {
	byte[] op = new byte[100];
	int offset, value;
	offset = putTag(CONTEXT, 46, CONSTRUCTED, op, 0); // Operator
	op[offset++] = (byte)(0x80&0xff); // indefinite length

	offset = putTag(CONTEXT, 3, CONSTRUCTED, op, offset); // prox
	op[offset++] = (byte)(0x80&0xff); // indefinite length

	offset = putTag(CONTEXT, 1, PRIMITIVE, op, offset); // exclusion
	value = 0; // false
	offset = putLen(numLen(value), op, offset);
	offset = putNum(value, op, offset);

	offset = putTag(CONTEXT, 2, PRIMITIVE, op, offset); // distance
	value = Integer.parseInt(ms.modifier("distance"));
	offset = putLen(numLen(value), op, offset);
	offset = putNum(value, op, offset);

	offset = putTag(CONTEXT, 3, PRIMITIVE, op, offset); // ordered
	value = ms.modifier("ordering").equals("ordered") ? 1 : 0;
	offset = putLen(numLen(value), op, offset);
	offset = putNum(value, op, offset);

	offset = putTag(CONTEXT, 4, PRIMITIVE, op, offset); // relationType
	value = getRelCode();
	offset = putLen(numLen(value), op, offset);
	offset = putNum(value, op, offset);

	offset = putTag(CONTEXT, 5, CONSTRUCTED, op, offset); // proximityUnitCode
	op[offset++] = (byte)(0x80&0xff); // indefinite length
	offset = putTag(CONTEXT, 1, PRIMITIVE, op, offset); // known
	value = getProxUnitCode();
	offset = putLen(numLen(value), op, offset);
	offset = putNum(value, op, offset);
	op[offset++] = 0x00; // end of proximityUnitCode
	op[offset++] = 0x00;

	op[offset++] = 0x00; // end of prox
	op[offset++] = 0x00;
	op[offset++] = 0x00; // end of Operator
	op[offset++] = 0x00;

	byte[] o = new byte[offset];
	System.arraycopy(op, 0, o, 0, offset);
	return o;
    }
}