Use full date format for day dividers in timeline (#3057)

* Use full date format for day dividers in timeline

* Use AM/PM for `DefaultLastMessageTimestampFormatter` when the locale needs it

changelog.d/2916.misc

@@ -0,0 +1 @@
+Use a more natural date format for day dividers in the timeline. Also improve the time format for last messages in the room list.

libraries/dateformatter/impl/src/main/kotlin/io/element/android/libraries/dateformatter/impl/DateFormatters.kt

@@ -26,19 +26,18 @@ import kotlinx.datetime.toJavaLocalDate
 import kotlinx.datetime.toJavaLocalDateTime
 import java.time.Period
 import java.time.format.DateTimeFormatter
+import java.time.format.FormatStyle
 import java.util.Locale
 import javax.inject.Inject
 import kotlin.math.absoluteValue
 
-// TODO rework this date formatting
 class DateFormatters @Inject constructor(
     private val locale: Locale,
     private val clock: Clock,
     private val timeZone: TimeZone,
 ) {
     private val onlyTimeFormatter: DateTimeFormatter by lazy {
-        val pattern = DateFormat.getBestDateTimePattern(locale, "HH:mm") ?: "HH:mm"
-        DateTimeFormatter.ofPattern(pattern, locale)
+        DateTimeFormatter.ofLocalizedTime(FormatStyle.SHORT).withLocale(locale)
     }
 
     private val dateWithMonthFormatter: DateTimeFormatter by lazy {
@@ -51,6 +50,10 @@ class DateFormatters @Inject constructor(
         DateTimeFormatter.ofPattern(pattern, locale)
     }
 
+    private val dateWithFullFormatFormatter: DateTimeFormatter by lazy {
+        DateTimeFormatter.ofLocalizedDate(FormatStyle.FULL).withLocale(locale)
+    }
+
     internal fun formatTime(localDateTime: LocalDateTime): String {
         return onlyTimeFormatter.format(localDateTime.toJavaLocalDateTime())
     }
@@ -63,6 +66,10 @@ class DateFormatters @Inject constructor(
         return dateWithYearFormatter.format(localDateTime.toJavaLocalDateTime())
     }
 
+    internal fun formatDateWithFullFormat(localDateTime: LocalDateTime): String {
+        return dateWithFullFormatFormatter.format(localDateTime.toJavaLocalDateTime())
+    }
+
     internal fun formatDate(
         dateToFormat: LocalDateTime,
         currentDate: LocalDateTime,

libraries/dateformatter/impl/src/main/kotlin/io/element/android/libraries/dateformatter/impl/DefaultDaySeparatorFormatter.kt

@@ -28,6 +28,7 @@ class DefaultDaySeparatorFormatter @Inject constructor(
 ) : DaySeparatorFormatter {
     override fun format(timestamp: Long): String {
         val dateToFormat = localDateTimeProvider.providesFromTimestamp(timestamp)
-        return dateFormatters.formatDateWithYear(dateToFormat)
+        // TODO use relative formatting once iOS uses it too
+        return dateFormatters.formatDateWithFullFormat(dateToFormat)
     }
 }

libraries/dateformatter/impl/src/test/kotlin/io/element/android/libraries/dateformatter/impl/DefaultLastMessageTimestampFormatterTest.kt

@@ -21,6 +21,7 @@ import io.element.android.libraries.dateformatter.api.LastMessageTimestampFormat
 import io.element.android.libraries.dateformatter.test.FakeClock
 import kotlinx.datetime.Instant
 import kotlinx.datetime.TimeZone
+import kotlinx.datetime.toLocalDateTime
 import org.junit.Test
 import java.util.Locale
 
@@ -44,7 +45,7 @@ class DefaultLastMessageTimestampFormatterTest {
         val now = "1980-04-06T18:35:24.00Z"
         val dat = "1980-04-06T18:35:24.00Z"
         val formatter = createFormatter(now)
-        assertThat(formatter.format(Instant.parse(dat).toEpochMilliseconds())).isEqualTo("18:35")
+        assertThat(formatter.format(Instant.parse(dat).toEpochMilliseconds())).isEqualTo("6:35 PM")
     }
 
     @Test
@@ -52,7 +53,7 @@ class DefaultLastMessageTimestampFormatterTest {
         val now = "1980-04-06T18:35:24.00Z"
         val dat = "1980-04-06T18:35:23.00Z"
         val formatter = createFormatter(now)
-        assertThat(formatter.format(Instant.parse(dat).toEpochMilliseconds())).isEqualTo("18:35")
+        assertThat(formatter.format(Instant.parse(dat).toEpochMilliseconds())).isEqualTo("6:35 PM")
     }
 
     @Test
@@ -60,7 +61,7 @@ class DefaultLastMessageTimestampFormatterTest {
         val now = "1980-04-06T18:35:24.00Z"
         val dat = "1980-04-06T18:34:24.00Z"
         val formatter = createFormatter(now)
-        assertThat(formatter.format(Instant.parse(dat).toEpochMilliseconds())).isEqualTo("18:34")
+        assertThat(formatter.format(Instant.parse(dat).toEpochMilliseconds())).isEqualTo("6:34 PM")
     }
 
     @Test
@@ -68,7 +69,7 @@ class DefaultLastMessageTimestampFormatterTest {
         val now = "1980-04-06T18:35:24.00Z"
         val dat = "1980-04-06T17:35:24.00Z"
         val formatter = createFormatter(now)
-        assertThat(formatter.format(Instant.parse(dat).toEpochMilliseconds())).isEqualTo("17:35")
+        assertThat(formatter.format(Instant.parse(dat).toEpochMilliseconds())).isEqualTo("5:35 PM")
     }
 
     @Test
@@ -96,6 +97,15 @@ class DefaultLastMessageTimestampFormatterTest {
         assertThat(formatter.format(Instant.parse(dat).toEpochMilliseconds())).isEqualTo("06.04.1979")
     }
 
+    @Test
+    fun `test full format`() {
+        val now = "1980-04-06T18:35:24.00Z"
+        val dat = "1979-04-06T18:35:24.00Z"
+        val clock = FakeClock().apply { givenInstant(Instant.parse(now)) }
+        val dateFormatters = DateFormatters(Locale.US, clock, TimeZone.UTC)
+        assertThat(dateFormatters.formatDateWithFullFormat(Instant.parse(dat).toLocalDateTime(TimeZone.UTC))).isEqualTo("Friday, April 6, 1979")
+    }
+
     /**
      * Create DefaultLastMessageFormatter and set current time to the provided date.
      */