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/***************************************************************************************************
* Copyright © All Contributors. See LICENSE and AUTHORS in the root directory for details.
**************************************************************************************************/
package at.bitfire.ical4android.util
import at.bitfire.ical4android.Ical4Android
import at.bitfire.ical4android.UsesThreadContextClassLoader
import net.fortuna.ical4j.data.CalendarBuilder
import net.fortuna.ical4j.model.Date
import net.fortuna.ical4j.model.DateTime
import net.fortuna.ical4j.model.TimeZone
import net.fortuna.ical4j.model.TimeZoneRegistryFactory
import net.fortuna.ical4j.model.component.VTimeZone
import net.fortuna.ical4j.model.property.DateProperty
import java.io.StringReader
import java.time.ZoneId
/**
* Date/time utilities
*
* Before this object is accessed the first time, the accessing thread's contextClassLoader
* must be set to an Android Context.classLoader!
*/
object DateUtils {
/**
* Global ical4j time zone registry used for event/task processing. Do not
* modify this registry or its entries!
*/
@UsesThreadContextClassLoader
private val tzRegistry = TimeZoneRegistryFactory.getInstance().createRegistry()
init {
Ical4Android.checkThreadContextClassLoader()
}
// time zones
/**
* For a given time zone ID taken from an iCalendar resource, find the matching
* Android time zone ID (if possible):
*
* 1. Use a case-insensitive match ("EUROPE/VIENNA" will return "Europe/Vienna",
* assuming "Europe/Vienna") is available in Android
* 2. Find partial matches (case-sensitive) in both directions, so both "Vienna"
* and "MyClient: Europe/Vienna" will return "Europe/Vienna". This shouldn't be
* case-sensitive, because that would (for instance) return "EST" for "Westeuropäische Sommerzeit"
* 3. If nothing can be found, use the system default time zone
*
* @param tzID time zone ID to be converted into Android time zone ID
*
* @return best matching Android time zone ID
*/
fun findAndroidTimezoneID(tzID: String?): String {
val availableTZs = ZoneId.getAvailableZoneIds()
var result: String? = null
if (tzID != null) {
// first, try to find an exact match (case insensitive)
result = availableTZs.firstOrNull { it.equals(tzID, true) }
// if that doesn't work, try to find something else that matches
if (result == null)
for (availableTZ in availableTZs)
if (availableTZ.contains(tzID) || tzID.contains(availableTZ)) {
result = availableTZ
Ical4Android.log.warning("Couldn't find system time zone \"$tzID\", assuming $result")
break
}
}
// if that doesn't work, use device default as fallback
return result ?: TimeZone.getDefault().id
}
/**
* Gets a [ZoneId] from a given ID string. In opposite to [ZoneId.of],
* this methods returns null when the zone is not available.
*
* @param id zone ID, like "Europe/Berlin" (may be null)
*
* @return ZoneId or null if the argument was null or no zone with this ID could be found
*/
fun getZoneId(id: String?): ZoneId? =
id?.let {
try {
val zone = ZoneId.of(id)
zone
} catch (e: Exception) {
null
}
}
@Suppress("DEPRECATION")
@UsesThreadContextClassLoader
fun ical4jTimeZone(id: String): TimeZone? = tzRegistry.getTimeZone(id)
/**
* Determines whether a given date represents a DATE value.
* @param date date property to check
* @return *true* if the date is a DATE value; *false* otherwise (for instance, when the argument is a DATE-TIME value or null)
*/
fun isDate(date: DateProperty?) = date != null && date.date is Date && date.date !is DateTime
/**
* Determines whether a given date represents a DATE-TIME value.
* @param date date property to check
* @return *true* if the date is a DATE-TIME value; *false* otherwise (for instance, when the argument is a DATE value or null)
*/
fun isDateTime(date: DateProperty?) = date != null && date.date is DateTime
/**
* Parses a VTIMEZONE definition to a VTimeZone object.
* @param timezoneDef VTIMEZONE definition
* @return parsed VTimeZone
* @throws IllegalArgumentException when the timezone definition can't be parsed
*/
@UsesThreadContextClassLoader
fun parseVTimeZone(timezoneDef: String): VTimeZone {
Ical4Android.checkThreadContextClassLoader()
val builder = CalendarBuilder(tzRegistry)
try {
val cal = builder.build(StringReader(timezoneDef))
return cal.getComponent(VTimeZone.VTIMEZONE) as VTimeZone
} catch (e: Exception) {
throw IllegalArgumentException("Couldn't parse timezone definition")
}
}
}
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