Add methods to access week-related properties directly using Locale (#…

…110)

* Add methods to access week-related properties directly using Locale

* Fix Darwin build

core/src/commonMain/kotlin/io/islandtime/WeekDate.kt

@@ -4,7 +4,9 @@
 package io.islandtime
 
 import io.islandtime.calendar.WeekSettings
+import io.islandtime.calendar.weekSettings
 import io.islandtime.internal.lastWeekOfWeekBasedYear
+import io.islandtime.locale.Locale
 import io.islandtime.measures.days
 import io.islandtime.measures.weeks
 import kotlin.jvm.JvmMultifileClass
@@ -24,6 +26,16 @@ inline fun <T> Date.toWeekDate(settings: WeekSettings, action: (year: Int, week:
     return action(weekBasedYear(settings), weekOfWeekBasedYear(settings), dayOfWeek.number(settings))
 }
 
+/**
+ * Converts this date to a week date representation using the week definition associated with the provided [locale].
+ *
+ * Keep in mind that that the system's calendar settings may differ from that of the default locale on some platforms.
+ * To respect the system calendar settings, use [WeekSettings.systemDefault] instead.
+ */
+inline fun <T> Date.toWeekDate(locale: Locale, action: (year: Int, week: Int, day: Int) -> T): T {
+    return toWeekDate(locale.weekSettings, action)
+}
+
 /**
  * Create a [Date] from an ISO week date.
  * @param year the week-based year
@@ -77,6 +89,17 @@ fun Date.Companion.fromWeekDate(year: Int, week: Int, day: Int, settings: WeekSe
     return date + daysToAdd
 }
 
+/**
+ * Create a [Date] from a week date representation using the week definition associated with the provided [locale].
+ * @param year the week-based year
+ * @param week the week number of the week-based year
+ * @param day the day of week number, 1-7
+ * @param locale the locale providing the week definition to use when interpreting the [year], [week], and [day]
+ */
+fun Date.Companion.fromWeekDate(year: Int, week: Int, day: Int, locale: Locale): Date {
+    return fromWeekDate(year, week, day, locale.weekSettings)
+}
+
 private fun checkValidWeekOfWeekBasedYear(week: Int): Int {
     if (week !in 1..53) {
         throw DateTimeException("The week '$week' is outside the supported range of 1-53")

core/src/commonMain/kotlin/io/islandtime/calendar/WeekSettings.kt

@@ -18,8 +18,9 @@ data class WeekSettings(
 
     companion object {
         /**
-         * The definition of a week according to the current system settings. This may differ from the definition
-         * associated with the default locale on platforms that allow this to be customized, such as iOS and macOS.
+         * Returns the definition of a week according to the current system settings. This may differ from the
+         * definition associated with the default locale on platforms that allow this to be customized, such as iOS and
+         * macOS.
          */
         fun systemDefault(): WeekSettings = systemDefaultWeekSettings()
 
@@ -36,5 +37,10 @@ data class WeekSettings(
     }
 }
 
+/**
+ * The default [WeekSettings] associated with this locale.
+ */
+expect val Locale.weekSettings: WeekSettings
+
 internal expect fun systemDefaultWeekSettings(): WeekSettings
 internal expect val Locale.firstDayOfWeek: DayOfWeek

core/src/commonMain/kotlin/io/islandtime/internal/WeekNumbers.kt

@@ -8,13 +8,10 @@ import io.islandtime.measures.IntWeeks
 import io.islandtime.measures.weeks
 import io.islandtime.measures.years
 
-internal inline val Date.weekOfMonthImpl: Int get() = weekOfMonthImpl(WeekSettings.ISO)
 internal inline fun Date.weekOfMonthImpl(settings: WeekSettings): Int = weekNumber(dayOfMonth, settings)
-internal inline val Date.weekOfYearImpl: Int get() = weekOfYearImpl(WeekSettings.ISO)
 internal inline fun Date.weekOfYearImpl(settings: WeekSettings): Int = weekNumber(dayOfYear, settings)
-internal inline val Date.weekBasedYearImpl: Int get() = weekBasedYearImpl(WeekSettings.ISO)
 
-internal inline fun Date.weekBasedYearImpl(settings: WeekSettings): Int {
+internal fun Date.weekBasedYearImpl(settings: WeekSettings): Int {
     val dayOfYear = dayOfYear
     val offset = startOfWeekOffset(dayOfWeek, dayOfYear, settings)
     val week = weekNumber(dayOfYear, offset)
@@ -31,9 +28,7 @@ internal inline fun Date.weekBasedYearImpl(settings: WeekSettings): Int {
     }
 }
 
-internal inline val Date.weekOfWeekBasedYearImpl: Int get() = weekOfWeekBasedYearImpl(WeekSettings.ISO)
-
-internal inline fun Date.weekOfWeekBasedYearImpl(settings: WeekSettings): Int {
+internal fun Date.weekOfWeekBasedYearImpl(settings: WeekSettings): Int {
     val dayOfYear = dayOfYear
     val offset = startOfWeekOffset(dayOfWeek, dayOfYear, settings)
     val week = weekNumber(dayOfYear, offset)

core/src/commonTest/kotlin/io/islandtime/DatePropertiesTest.kt

@@ -123,7 +123,8 @@ class DatePropertiesTest : AbstractIslandTimeTest() {
             Date(2009, 1, 4) to 2,
             Date(2020, 5, 31) to 6
         ).forEach { (date, week) ->
-            assertEquals(week, date.weekOfMonth(SUNDAY_START), date.toString())
+            assertEquals(week, date.weekOfMonth(SUNDAY_START), message = "$date (SUNDAY_START)")
+            assertEquals(week, date.weekOfMonth(en_US), message = "$date (en-US)")
         }
     }
 
@@ -168,7 +169,8 @@ class DatePropertiesTest : AbstractIslandTimeTest() {
             Date(2009, 1, 3) to 1,
             Date(2009, 1, 4) to 2
         ).forEach { (date, week) ->
-            assertEquals(week, date.weekOfYear(SUNDAY_START), date.toString())
+            assertEquals(week, date.weekOfYear(SUNDAY_START), message = "$date (SUNDAY_START)")
+            assertEquals(week, date.weekOfYear(en_US), message = "$date (en-US)")
         }
     }
 
@@ -211,7 +213,13 @@ class DatePropertiesTest : AbstractIslandTimeTest() {
             assertEquals(
                 Pair(year, week),
                 Pair(date.weekBasedYear(SUNDAY_START), date.weekOfWeekBasedYear(SUNDAY_START)),
-                date.toString()
+                message = "$date (SUNDAY_START)"
+            )
+
+            assertEquals(
+                Pair(year, week),
+                Pair(date.weekBasedYear(en_US), date.weekOfWeekBasedYear(en_US)),
+                message = "$date (en-US)"
             )
         }
     }

core/src/commonTest/kotlin/io/islandtime/WeekDateTest.kt

@@ -1,13 +1,17 @@
 package io.islandtime
 
 import io.islandtime.calendar.WeekSettings.Companion.SUNDAY_START
+import io.islandtime.locale.localeOf
 import io.islandtime.test.AbstractIslandTimeTest
 import io.islandtime.test.TestData
 import kotlin.test.Test
 import kotlin.test.assertEquals
 import kotlin.test.assertFailsWith
 
 class WeekDateTest : AbstractIslandTimeTest() {
+    @Suppress("PrivatePropertyName")
+    private val en_US = localeOf("en-US")
+
     @Test
     fun `Date_toWeekDate() converts to ISO week date`() {
         TestData.isoWeekDates.forEach { (date, weekDate) ->
@@ -18,7 +22,8 @@ class WeekDateTest : AbstractIslandTimeTest() {
     @Test
     fun `Date_toWeekDate() converts to week date with Sunday start week definition`() {
         TestData.sundayStartWeekDates.forEach { (date, weekDate) ->
-            assertEquals(weekDate, date.toWeekDate(SUNDAY_START, ::Triple), date.toString())
+            assertEquals(weekDate, date.toWeekDate(SUNDAY_START, ::Triple), message = "$date (SUNDAY_START)")
+            assertEquals(weekDate, date.toWeekDate(en_US, ::Triple), message = "$date (en-US)")
         }
     }
 
@@ -75,7 +80,8 @@ class WeekDateTest : AbstractIslandTimeTest() {
     fun `Date_fromWeekDate() creates a Date from a Sunday start week date`() {
         TestData.sundayStartWeekDates.filter { it.first != Date.MAX }.forEach { (date, weekDate) ->
             val (year, week, day) = weekDate
-            assertEquals(date, Date.fromWeekDate(year, week, day, SUNDAY_START), date.toString())
+            assertEquals(date, Date.fromWeekDate(year, week, day, SUNDAY_START), message = "$date (SUNDAY_START)")
+            assertEquals(date, Date.fromWeekDate(year, week, day, en_US), message = "$date (en-US)")
         }
     }
 }

core/src/darwinMain/kotlin/io/islandtime/calendar/WeekSettings.kt

@@ -7,10 +7,13 @@ import kotlinx.cinterop.convert
 import platform.Foundation.NSCalendar
 import platform.Foundation.NSCalendarIdentifierGregorian
 
+actual val Locale.weekSettings: WeekSettings
+    get() = NSCalendar(NSCalendarIdentifierGregorian)
+        .also { it.locale = this }
+        .run { WeekSettings(firstDayOfWeek, minimumDaysInFirstWeek.convert()) }
+
 internal actual fun systemDefaultWeekSettings(): WeekSettings {
-    return with(NSCalendar.currentCalendar) {
-        WeekSettings(firstDayOfWeek, minimumDaysInFirstWeek().convert())
-    }
+    return with(NSCalendar.currentCalendar) { WeekSettings(firstDayOfWeek, minimumDaysInFirstWeek.convert()) }
 }
 
 internal actual val Locale.firstDayOfWeek: DayOfWeek

core/src/jvmMain/kotlin/io/islandtime/calendar/WeekSettings.kt

@@ -5,13 +5,13 @@ import io.islandtime.locale.Locale
 import io.islandtime.measures.days
 import java.util.*
 
-internal actual fun systemDefaultWeekSettings(): WeekSettings {
-    val gregorianCalendar = GregorianCalendar(Locale.getDefault().withoutVariant())
-
-    return with(gregorianCalendar) {
-        WeekSettings(firstIslandDayOfWeek, minimalDaysInFirstWeek)
+actual val Locale.weekSettings: WeekSettings
+    get() {
+        val gregorianCalendar = GregorianCalendar(this.withoutVariant())
+        return with(gregorianCalendar) { WeekSettings(firstIslandDayOfWeek, minimalDaysInFirstWeek) }
     }
-}
+
+internal actual fun systemDefaultWeekSettings(): WeekSettings = Locale.getDefault().weekSettings
 
 internal actual val Locale.firstDayOfWeek: DayOfWeek
     get() = GregorianCalendar(this.withoutVariant()).firstIslandDayOfWeek