/*
 * Copyright (c) 2011-2015 EPFL DATA Laboratory
 * Copyright (c) 2014-2015 The Squall Collaboration (see NOTICE)
 *
 * All rights reserved.
 *
 * 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.
 */

package ch.epfl.data.squall.expressions;

import java.util.ArrayList;
import java.util.Calendar;
import java.util.Date;
import java.util.List;

import ch.epfl.data.squall.types.IntegerType;
import ch.epfl.data.squall.types.Type;
import ch.epfl.data.squall.visitors.ValueExpressionVisitor;

public class IntegerYearFromDate implements ValueExpression<Integer> {
    private static final long serialVersionUID = 1L;

    private final ValueExpression<Date> _veDate;
    private final Type<Integer> _wrapper = new IntegerType();

    public IntegerYearFromDate(ValueExpression<Date> veDate) {
	_veDate = veDate;
    }

    @Override
    public void accept(ValueExpressionVisitor vev) {
	vev.visit(this);
    }

    /*
     * @Override public Integer eval(List<String> firstTuple, List<String>
     * secondTuple) { Date date = _veDate.eval(firstTuple, secondTuple);
     * Calendar c = Calendar.getInstance(); c.setTime(date); int year =
     * c.get(Calendar.YEAR); // Alternative approach: //SimpleDateFormat
     * formatNowYear = new SimpleDateFormat("yyyy"); //String currentYear =
     * formatNowYear.format(date); // = '2006' return year; }
     */

    @Override
    public void changeValues(int i, ValueExpression<Integer> newExpr) {
	// nothing

    }

    @Override
    public Integer eval(List<String> tuple) {
	final Date date = _veDate.eval(tuple);

	final Calendar c = Calendar.getInstance();
	c.setTime(date);
	final int year = c.get(Calendar.YEAR);

	/*
	 * Alternative approach: SimpleDateFormat formatNowYear = new
	 * SimpleDateFormat("yyyy"); String currentYear =
	 * formatNowYear.format(date); // = '2006'
	 */

	return year;
    }

    @Override
    public String evalString(List<String> tuple) {
	final int result = eval(tuple);
	return _wrapper.toString(result);
    }

    @Override
    public List<ValueExpression> getInnerExpressions() {
	final List<ValueExpression> result = new ArrayList<ValueExpression>();
	result.add(_veDate);
	return result;
    }

    @Override
    public Type getType() {
	return _wrapper;
    }

    @Override
    public void inverseNumber() {
	// nothing

    }

    @Override
    public boolean isNegative() {
	return false;
    }

    @Override
    public String toString() {
	final StringBuilder sb = new StringBuilder();
	sb.append("IntegerYearFromDate ").append(_veDate.toString());
	return sb.toString();
    }

}