/*
 * Copyright 2000-2016 Vaadin Ltd.
 *
 * 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 com.vaadin.ui.declarative.converters;

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;

import com.vaadin.data.Converter;
import com.vaadin.data.Result;
import com.vaadin.data.ValueContext;
import com.vaadin.ui.declarative.DesignAttributeHandler;

/**
 * A date converter to be used by {@link DesignAttributeHandler}. Provides
 * ISO-compliant way of storing date and time.
 *
 * @since 7.4
 * @author Vaadin Ltd
 */
public class DesignDateConverter implements Converter<String, Date> {

    @Override
    public Result<Date> convertToModel(String value, ValueContext context) {
        for (String pattern : new String[] { "yyyy-MM-dd HH:mm:ssZ",
                "yyyy-MM-dd HH:mm:ss", "yyyy-MM-dd HH:mm", "yyyy-MM-dd HH",
                "yyyy-MM-dd", "yyyy-MM", "yyyy" }) {
            try {
                return Result.ok(new SimpleDateFormat(pattern).parse(value));
            } catch (ParseException e) {
                // not parseable, ignore and try another format
            }
        }
        return Result.error("Could not parse date value: " + value);
    }

    @Override
    public String convertToPresentation(Date value, ValueContext context) {
        return new SimpleDateFormat("yyyy-MM-dd HH:mm:ssZ").format(value);
    }

}