Refactor time formatting to use 24-hour system setting

Fixes #381

app/src/main/AndroidManifest.xml

@@ -1308,6 +1308,7 @@
 
     <receiver android:name=".notifications.LocaleChangedReceiver" android:exported="false">
         <intent-filter>
+            <action android:name="android.intent.action.TIME_SET"/> <!-- MOLLY: Triggered by 12/24h format change -->
             <action android:name="android.intent.action.LOCALE_CHANGED"/>
         </intent-filter>
     </receiver>

app/src/main/java/org/thoughtcrime/securesms/notifications/LocaleChangedReceiver.java

@@ -1,16 +1,21 @@
 package org.thoughtcrime.securesms.notifications;
 
+import android.content.BroadcastReceiver;
 import android.content.Context;
 import android.content.Intent;
 
 import org.thoughtcrime.securesms.jobs.EmojiSearchIndexDownloadJob;
-import org.thoughtcrime.securesms.service.ExportedBroadcastReceiver;
+import org.thoughtcrime.securesms.service.KeyCachingService;
+import org.thoughtcrime.securesms.util.DateUtils;
 
-public class LocaleChangedReceiver extends ExportedBroadcastReceiver {
+public class LocaleChangedReceiver extends BroadcastReceiver {
 
   @Override
-  public void onReceiveUnlock(Context context, Intent intent) {
-    NotificationChannels.getInstance().onLocaleChanged();
-    EmojiSearchIndexDownloadJob.scheduleImmediately();
+  public void onReceive(Context context, Intent intent) {
+    DateUtils.updateFormat();
+    if (!KeyCachingService.isLocked()) {
+      NotificationChannels.getInstance().onLocaleChanged();
+      EmojiSearchIndexDownloadJob.scheduleImmediately();
+    }
   }
 }

app/src/main/java/org/thoughtcrime/securesms/util/DateUtils.kt

@@ -26,6 +26,8 @@ import org.thoughtcrime.securesms.conversation.v2.computed.FormattedDate
 import java.text.DateFormatSymbols
 import java.text.ParseException
 import java.text.SimpleDateFormat
+import java.time.LocalTime
+import java.time.format.DateTimeFormatter
 import java.util.Calendar
 import java.util.Date
 import java.util.Locale
@@ -36,7 +38,6 @@ import kotlin.time.Duration.Companion.days
 import kotlin.time.Duration.Companion.hours
 import kotlin.time.Duration.Companion.milliseconds
 import kotlin.time.Duration.Companion.minutes
-import kotlin.time.Duration.Companion.seconds
 import kotlin.time.DurationUnit
 
 /**
@@ -53,7 +54,12 @@ object DateUtils : android.text.format.DateUtils() {
   private val dateFormatCache: MutableMap<TemplateLocale, SimpleDateFormat> = mutableMapOf()
   private val dateFormatSymbolsCache: MutableMap<Locale, DateFormatSymbols> = mutableMapOf()
 
-  private var is24HourDateCache: Is24HourDateEntry? = null
+  private var is24HourFormatCache: Boolean? = null
+
+  @JvmStatic
+  fun updateFormat() {
+    is24HourFormatCache = null
+  }
 
   /**
    * A relative timestamp to use in space-constrained areas, like the conversation list.
@@ -153,7 +159,16 @@ object DateUtils : android.text.format.DateUtils() {
    */
   @JvmStatic
   fun getOnlyTimeString(context: Context, timestamp: Long): String {
-    return timestamp.toLocalTime().formatHours(context)
+    return getOnlyTimeString(context, timestamp.toLocalTime())
+  }
+
+  @JvmStatic
+  fun getOnlyTimeString(context: Context, localTime: LocalTime): String {
+    val locale = Locale.getDefault()
+    val skeleton = if (context.is24HourFormat()) "HHmm" else "hhmma"
+    val pattern = skeleton.localizeTemplate(locale)
+    val formatter = DateTimeFormatter.ofPattern(pattern, locale)
+    return formatter.format(localTime)
   }
 
   /**
@@ -391,15 +406,9 @@ object DateUtils : android.text.format.DateUtils() {
   }
 
   private fun Context.is24HourFormat(): Boolean {
-    is24HourDateCache?.let {
-      if (it.lastUpdated.isWithin(10.seconds)) {
-        return it.value
-      }
+    return is24HourFormatCache ?: DateFormat.is24HourFormat(this).also {
+      is24HourFormatCache = it
     }
-
-    val result = DateFormat.is24HourFormat(this)
-    is24HourDateCache = Is24HourDateEntry(result, System.currentTimeMillis())
-    return result
   }
 
   private fun Long.convertDeltaTo(unit: DurationUnit): Int {
@@ -439,6 +448,4 @@ object DateUtils : android.text.format.DateUtils() {
   }
 
   private data class TemplateLocale(val template: String, val locale: Locale)
-
-  private data class Is24HourDateEntry(val value: Boolean, val lastUpdated: Long)
 }

app/src/main/java/org/thoughtcrime/securesms/util/JavaTimeExtensions.kt

@@ -1,8 +1,6 @@
 package org.thoughtcrime.securesms.util
 
 import android.content.Context
-import android.os.Build
-import android.text.format.DateFormat
 import java.time.DayOfWeek
 import java.time.Instant
 import java.time.LocalDate
@@ -12,8 +10,6 @@ import java.time.OffsetDateTime
 import java.time.ZoneId
 import java.time.ZoneOffset
 import java.time.ZonedDateTime
-import java.time.format.DateTimeFormatter
-import java.time.format.FormatStyle
 import java.time.temporal.WeekFields
 import java.util.Locale
 import java.util.concurrent.TimeUnit
@@ -94,11 +90,7 @@ fun Long.toLocalTime(zoneId: ZoneId = ZoneId.systemDefault()): LocalTime {
  * Formats [LocalTime] as localized time. For example, "8:00 AM"
  */
 fun LocalTime.formatHours(context: Context): String {
-  return if (Build.VERSION.SDK_INT >= 26 || !DateFormat.is24HourFormat(context)) {
-    DateTimeFormatter.ofLocalizedTime(FormatStyle.SHORT).format(this)
-  } else {
-    DateTimeFormatter.ofPattern("HH:mm", Locale.getDefault()).format(this)
-  }
+  return DateUtils.getOnlyTimeString(context, localTime = this)
 }
 
 /**