JodaDateConverter.groovy

import grails.plugin.jodatime.Html5DateTimeFormat

import org.grails.databinding.converters.ValueConverter
import org.joda.time.DateTime
import org.joda.time.Instant
import org.joda.time.LocalDate
import org.joda.time.LocalDateTime
import org.joda.time.LocalTime
import org.joda.time.format.DateTimeFormat
import org.joda.time.format.DateTimeFormatter
import org.springframework.context.i18n.LocaleContextHolder


class JodaDateConverter implements ValueConverter {

	static final SUPPORTED_TYPES = [LocalTime, LocalDate, LocalDateTime, DateTime, Instant].asImmutable()
	
	def grailsApplication
	
	Class<?> type
	
	@Lazy private ConfigObject config = grailsApplication.config?.jodatime?.format
	
	@Override
	public boolean canConvert(Object value) {
		println "canConvert"
		return value instanceof String
	}

	@Override
	public Object convert(Object value) {
		println "type: $type"
		println "formatter: $formatter"
		value ? formatter.parseDateTime(value)."to$type.simpleName"() : null
	}

	@Override
	public Class<?> getTargetType() {
		"targetType: $type"
		return type;
	}

	
	protected DateTimeFormatter getFormatter() {
		if (hasConfigPatternFor(type)) {
			println "Pattern ${getConfigPatternFor(type)}"
			return DateTimeFormat.forPattern(getConfigPatternFor(type))
		} else if (useISO()) {
			println "ISO: ${getISOFormatterFor(type)}"
			return getISOFormatterFor(type)
		} else {
			def style
			switch (type) {
				case LocalTime:
					style = '-S'
					break
				case LocalDate:
					style = 'S-'
					break
				default:
					style = 'SS'
			}
			Locale locale = LocaleContextHolder.locale
			return DateTimeFormat.forStyle(style).withLocale(locale)
		}
	}

	private boolean hasConfigPatternFor(Class type) {
		config?.flatten()?."$type.name"
	}

	private String getConfigPatternFor(Class type) {
		config?.flatten()?."$type.name"
	}

	private boolean useISO() {
		config?.html5
	}

	private DateTimeFormatter getISOFormatterFor(Class type) {
		switch (type) {
			case LocalTime:
				return Html5DateTimeFormat.time()
			case LocalDate:
				return Html5DateTimeFormat.date()
			case LocalDateTime:
				return Html5DateTimeFormat.datetimeLocal()
			case DateTime:
			case Instant:
				return Html5DateTimeFormat.datetime()
		}
		return null
	}
	
	
}