/*
 * Copyright 2002-2012 the original author or authors.
 *
 * 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 org.springframework.format.datetime.standard;

import java.time.LocalDate;
import java.time.LocalDateTime;
import java.time.LocalTime;
import java.time.OffsetDateTime;
import java.time.OffsetTime;
import java.time.ZonedDateTime;
import java.time.format.DateTimeFormatter;
import java.time.temporal.TemporalAccessor;
import java.util.Collections;
import java.util.HashSet;
import java.util.Set;

import org.springframework.context.EmbeddedValueResolverAware;
import org.springframework.format.AnnotationFormatterFactory;
import org.springframework.format.Parser;
import org.springframework.format.Printer;
import org.springframework.format.annotation.DateTimeFormat;
import org.springframework.util.StringValueResolver;

/**
 * Formats fields annotated with the {@link DateTimeFormat} annotation using
 * the JSR-310 <code>java.time</code> package in JDK 8.
 *
 * @author Juergen Hoeller
 * @since 4.0
 * @see org.springframework.format.annotation.DateTimeFormat
 */
public class Jsr310DateTimeFormatAnnotationFormatterFactory
		implements AnnotationFormatterFactory<DateTimeFormat>, EmbeddedValueResolverAware {

	private static final Set<Class<?>> FIELD_TYPES;
	static {
		// Create the set of field types that may be annotated with @DateTimeFormat.
		Set<Class<?>> fieldTypes = new HashSet<Class<?>>(8);
		fieldTypes.add(LocalDate.class);
		fieldTypes.add(LocalTime.class);
		fieldTypes.add(LocalDateTime.class);
		fieldTypes.add(ZonedDateTime.class);
		fieldTypes.add(OffsetDateTime.class);
		fieldTypes.add(OffsetTime.class);
		FIELD_TYPES = Collections.unmodifiableSet(fieldTypes);
	}


	private StringValueResolver embeddedValueResolver;


	@Override
	public void setEmbeddedValueResolver(StringValueResolver resolver) {
		this.embeddedValueResolver = resolver;
	}

	protected String resolveEmbeddedValue(String value) {
		return (this.embeddedValueResolver != null ? this.embeddedValueResolver.resolveStringValue(value) : value);
	}


	@Override
	public final Set<Class<?>> getFieldTypes() {
		return FIELD_TYPES;
	}

	@Override
	public Printer<?> getPrinter(DateTimeFormat annotation, Class<?> fieldType) {
		DateTimeFormatter formatter = getFormatter(annotation, fieldType);
		return new TemporalAccessorPrinter(formatter);
	}

	@Override
	@SuppressWarnings("unchecked")
	public Parser<?> getParser(DateTimeFormat annotation, Class<?> fieldType) {
		DateTimeFormatter formatter = getFormatter(annotation, fieldType);
		return new TemporalAccessorParser((Class<? extends TemporalAccessor>) fieldType, formatter);
	}

	/**
	 * Factory method used to create a {@link org.joda.time.format.DateTimeFormatter}.
	 * @param annotation the format annotation for the field
	 * @param fieldType the type of field
	 * @return a {@link org.joda.time.format.DateTimeFormatter} instance
	 */
	protected DateTimeFormatter getFormatter(DateTimeFormat annotation, Class<?> fieldType) {
		DateTimeFormatterFactory factory = new DateTimeFormatterFactory();
		factory.setStylePattern(resolveEmbeddedValue(annotation.style()));
		factory.setIso(annotation.iso());
		factory.setPattern(resolveEmbeddedValue(annotation.pattern()));
		return factory.createDateTimeFormatter();
	}

}
