From 230923fe008e5d74a46eb6e483e16f2223657756 Mon Sep 17 00:00:00 2001
From: Alexander Zhirkevich <sasha.zhirkevich@gmail.com>
Date: Fri, 15 Mar 2024 15:56:13 +0300
Subject: [PATCH] Locale-aware date formatting for desktop (#1159)
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It's not a complete solution - just localization for default m3
skeletons. User-provided variants will still be ugly :(

Before and after:

<img width="300" alt="Снимок экрана 2024-02-29 в 21 17 28"
src="https://github.com/JetBrains/compose-multiplatform-core/assets/63979218/4560e92d-f0a4-4d0b-85bb-34756dd5a938">

<img width="300" alt="Screenshot 2024-03-04 at 17 22 51"
src="https://github.com/JetBrains/compose-multiplatform-core/assets/63979218/eef72277-8bbe-4edf-bc6b-a5b7d0085634">
---
 .../material3/PlatformDateFormat.desktop.kt   | 25 ++++++++++++++-----
 1 file changed, 19 insertions(+), 6 deletions(-)

diff --git a/compose/material3/material3/src/desktopMain/kotlin/androidx/compose/material3/PlatformDateFormat.desktop.kt b/compose/material3/material3/src/desktopMain/kotlin/androidx/compose/material3/PlatformDateFormat.desktop.kt
index 94ce9b959d313..8698011064990 100644
--- a/compose/material3/material3/src/desktopMain/kotlin/androidx/compose/material3/PlatformDateFormat.desktop.kt
+++ b/compose/material3/material3/src/desktopMain/kotlin/androidx/compose/material3/PlatformDateFormat.desktop.kt
@@ -19,9 +19,14 @@ package androidx.compose.material3
 import java.text.DateFormat
 import java.text.SimpleDateFormat
 import java.time.DayOfWeek
+import java.time.Instant
+import java.time.ZoneOffset
+import java.time.format.DateTimeFormatter
+import java.time.format.FormatStyle
 import java.time.format.TextStyle
 
 
+@OptIn(ExperimentalMaterial3Api::class)
 internal actual class PlatformDateFormat actual constructor(private val locale: CalendarLocale) {
     private val delegate = LegacyCalendarModelImpl(locale)
 
@@ -40,18 +45,26 @@ internal actual class PlatformDateFormat actual constructor(private val locale:
         skeleton: String
     ): String {
         // Note: there is no equivalent in Java for Android's DateFormat.getBestDateTimePattern.
-        // The JDK SimpleDateFormat expects a pattern, so the results will be "2023Jan7",
+        // The JDK SimpleDateFormat expects a pattern, so the results for unrecognized skeletons will be "2023Jan7",
         // "2023January", etc. in case a skeleton holds an actual ICU skeleton and not a pattern.
 
         // TODO: support ICU skeleton on JVM
         // Maybe it will be supported in kotlinx.datetime in the future.
-        // See https://github.com/Kotlin/kotlinx-datetime/pull/251
 
-        // stub: not localized but at least readable variant
         val pattern = when(skeleton){
-            DatePickerDefaults.YearMonthSkeleton -> "MMMM yyyy"
-            DatePickerDefaults.YearAbbrMonthDaySkeleton -> "MMM d, yyyy"
-            DatePickerDefaults.YearMonthWeekdayDaySkeleton -> "EEEE, MMMM d, yyyy"
+            DatePickerDefaults.YearAbbrMonthDaySkeleton -> {
+                return DateTimeFormatter
+                    .ofLocalizedDate(FormatStyle.MEDIUM)
+                    .localizedBy(locale)
+                    .format(Instant.ofEpochMilli(utcTimeMillis).atOffset(ZoneOffset.UTC))
+            }
+            DatePickerDefaults.YearMonthWeekdayDaySkeleton -> {
+                return DateTimeFormatter
+                    .ofLocalizedDate(FormatStyle.FULL)
+                    .localizedBy(locale)
+                    .format(Instant.ofEpochMilli(utcTimeMillis).atOffset(ZoneOffset.UTC))
+            }
+            DatePickerDefaults.YearMonthSkeleton -> "LLLL yyyy" // L is a pattern for standalone month (without day)
             else -> skeleton
         }
         return formatWithPattern(utcTimeMillis, pattern)