refactor: shared calendar date formatting, markdown preview slot and cached place names

- CalendarTimeFormat moves to commonsUI on DateSkeletonFormatter, LocalClock and calendarYearAndDay; range and time-of-day formatting take the composable's rememberTimeOfDayFormatter instead of a Context. - LongFormPostScreen previews through LocalRichTextPlatform.Markdown. - AppServices.cachedPlaceName replaces SearchScreen's direct read of the reverse-geocoding cache. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01S7FuNBSKiyVecARSoE4B9P
2026-10-05 11:18:24 +00:00 · 2026-09-30 04:03:27 +00:00
parent 05bbe21f87
commit a6e6e8d290
13 changed files with 134 additions and 165 deletions
@@ -34,7 +34,6 @@ import androidx.compose.runtime.remember
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.layout.ContentScale
-import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.tooling.preview.Preview
 import androidx.compose.ui.unit.dp
 import com.vitorpamplona.amethyst.commons.model.AddressableNote
@@ -47,13 +46,14 @@ import com.vitorpamplona.amethyst.commons.ui.navigation.navs.INav
 import com.vitorpamplona.amethyst.commons.ui.note.CalendarRsvpCard
 import com.vitorpamplona.amethyst.commons.ui.note.LoadAddressableNote
 import com.vitorpamplona.amethyst.commons.ui.note.WatchNoteEvent
+import com.vitorpamplona.amethyst.commons.ui.note.rememberTimeOfDayFormatter
+import com.vitorpamplona.amethyst.commons.ui.screen.loggedIn.calendars.formatCalendarRange
 import com.vitorpamplona.amethyst.commons.ui.theme.ThemeComparisonColumn
 import com.vitorpamplona.amethyst.commons.viewmodels.AccountViewModel
 import com.vitorpamplona.amethyst.commons.viewmodels.mockAccountViewModel
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.calendars.CalendarAppointmentLines
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.calendars.CalendarDateBadge
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.calendars.detailRouteFor
-import com.vitorpamplona.amethyst.ui.screen.loggedIn.calendars.formatCalendarRange
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.calendars.rememberRelativeTimeLabel
 import com.vitorpamplona.quartz.nip01Core.core.Address
 import com.vitorpamplona.quartz.nip01Core.core.Event
@@ -133,10 +133,9 @@ private fun RsvpWithAppointment(
        CalendarRsvpCard(event)
        return
    }
-
-    val context = LocalContext.current
+    val timeFormatter = rememberTimeOfDayFormatter()
    val appointmentEvent = appointment.event
-    val range = remember(appointmentEvent) { formatCalendarRange(appointment, context) }
+    val range = remember(appointmentEvent) { formatCalendarRange(appointment, timeFormatter) }
    val relative = rememberRelativeTimeLabel(view, appointmentEvent?.id)
    val route = remember(appointment) { detailRouteFor(appointment) }
    // Past a week the relative formatter falls back to a plain date ("October 31"), which the
@@ -33,6 +33,7 @@ import com.vitorpamplona.amethyst.commons.service.BlossomServerFinder
 import com.vitorpamplona.amethyst.commons.service.ai.AltTextSuggester
 import com.vitorpamplona.amethyst.commons.tor.TorSettingsFlow
 import com.vitorpamplona.amethyst.service.ai.MLKitImageLabelService
+import com.vitorpamplona.amethyst.service.location.CachedReversedGeoLocations
 import com.vitorpamplona.quartz.nip05DnsIdentifiers.namecoin.NamecoinNameResolver
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.map
@@ -67,6 +68,8 @@ object AndroidAppServices : AppServices {

    override val deviceLocation: DeviceLocation get() = Amethyst.instance.locationManager

+    override fun cachedPlaceName(geohash: String): String? = CachedReversedGeoLocations.cached(geohash)
+
    override fun createAltTextSuggester(): AltTextSuggester = MLKitImageLabelService(Amethyst.instance.appContext)
 }

@@ -43,7 +43,6 @@ import androidx.compose.runtime.remember
 import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
-import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.text.style.TextOverflow
 import androidx.compose.ui.unit.dp
@@ -64,6 +63,9 @@ import com.vitorpamplona.amethyst.commons.resources.calendar_nav_next_day
 import com.vitorpamplona.amethyst.commons.resources.calendar_nav_previous_day
 import com.vitorpamplona.amethyst.commons.ui.layouts.rememberFeedContentPadding
 import com.vitorpamplona.amethyst.commons.ui.navigation.navs.INav
+import com.vitorpamplona.amethyst.commons.ui.note.rememberTimeOfDayFormatter
+import com.vitorpamplona.amethyst.commons.ui.screen.loggedIn.calendars.formatLongDate
+import com.vitorpamplona.amethyst.commons.ui.screen.loggedIn.calendars.formatTimeOfDay
 import com.vitorpamplona.amethyst.commons.ui.stringRes
 import com.vitorpamplona.amethyst.commons.ui.theme.FeedPadding
 import com.vitorpamplona.amethyst.commons.viewmodels.AccountViewModel
@@ -161,7 +163,7 @@ private fun DayRow(
        }

    val startSeconds = view.startSeconds
-    val context = LocalContext.current
+    val timeFormatter = rememberTimeOfDayFormatter()
    val timeLabel =
        when {
            view.isAllDay -> stringRes(Res.string.calendar_all_day)
@@ -170,7 +172,7 @@ private fun DayRow(
                // misleading on day 2 since the event has been ongoing overnight. Show a
                // continuation marker so the user reads it as "still happening".
                stringRes(Res.string.calendar_continues)
-            startSeconds != null -> formatTimeOfDay(startSeconds, context)
+            startSeconds != null -> formatTimeOfDay(startSeconds, timeFormatter)
            else -> "—"
        }

@@ -40,7 +40,6 @@ import androidx.compose.runtime.remember
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.layout.ContentScale
-import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.platform.LocalLocale
 import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.text.style.TextOverflow
@@ -53,6 +52,8 @@ import com.vitorpamplona.amethyst.commons.model.nip52Calendar.CalendarAppointmen
 import com.vitorpamplona.amethyst.commons.model.nip52Calendar.appointmentView
 import com.vitorpamplona.amethyst.commons.ui.components.MyAsyncImage
 import com.vitorpamplona.amethyst.commons.ui.navigation.navs.INav
+import com.vitorpamplona.amethyst.commons.ui.note.rememberTimeOfDayFormatter
+import com.vitorpamplona.amethyst.commons.ui.screen.loggedIn.calendars.formatCalendarRange
 import com.vitorpamplona.amethyst.commons.ui.screen.loggedIn.video.UserCardHeader
 import com.vitorpamplona.amethyst.commons.viewmodels.AccountViewModel
 import com.vitorpamplona.quartz.nip01Core.core.BaseAddressableEvent
@@ -80,8 +81,8 @@ fun CalendarEventListCard(
    footer: (@Composable () -> Unit)? = null,
 ) {
    val view = note.appointmentView() ?: return
-    val context = LocalContext.current
-    val range = remember(note.idHex) { formatCalendarRange(note, context) }
+    val timeFormatter = rememberTimeOfDayFormatter()
+    val range = remember(note.idHex) { formatCalendarRange(note, timeFormatter) }
    val relative = rememberRelativeTimeLabel(view, note.idHex)
    val event = note.event ?: return
    val detailRoute = remember(event.id) { detailRouteFor(note) }
@@ -61,6 +61,9 @@ import com.vitorpamplona.amethyst.commons.resources.calendar_nav_next_month
 import com.vitorpamplona.amethyst.commons.resources.calendar_nav_previous_month
 import com.vitorpamplona.amethyst.commons.ui.layouts.rememberFeedContentPadding
 import com.vitorpamplona.amethyst.commons.ui.navigation.navs.INav
+import com.vitorpamplona.amethyst.commons.ui.screen.loggedIn.calendars.formatLongDate
+import com.vitorpamplona.amethyst.commons.ui.screen.loggedIn.calendars.formatMonthYear
+import com.vitorpamplona.amethyst.commons.ui.screen.loggedIn.calendars.formatShortWeekday
 import com.vitorpamplona.amethyst.commons.ui.stringRes
 import com.vitorpamplona.amethyst.commons.ui.theme.FeedPadding
 import com.vitorpamplona.amethyst.commons.viewmodels.AccountViewModel
@@ -1,146 +0,0 @@
-/*
- * Copyright (c) 2025 Vitor Pamplona
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy of
- * this software and associated documentation files (the "Software"), to deal in
- * the Software without restriction, including without limitation the rights to use,
- * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
- * Software, and to permit persons to whom the Software is furnished to do so,
- * subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in all
- * copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
- * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
- * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
- * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
- * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
- */
-package com.vitorpamplona.amethyst.ui.screen.loggedIn.calendars
-
-import android.content.Context
-import android.text.format.DateFormat
-import com.vitorpamplona.amethyst.commons.model.Note
-import com.vitorpamplona.amethyst.commons.model.nip52Calendar.appointmentView
-import java.text.SimpleDateFormat
-import java.util.Calendar
-import java.util.Date
-import java.util.Locale
-
-// Skeletons follow Unicode LDML — getBestDateTimePattern picks locale ordering.
-private const val DAY_MONTH_SKELETON = "EEEMMMd" // "Mon, May 28" / "Mon 28 May"
-private const val FULL_DATE_SKELETON = "EEEEMMMMdy" // "Monday, May 28, 2026" / "Monday, 28 May 2026"
-private const val MONTH_YEAR_SKELETON = "MMMMy" // "May 2026" / "Mai 2026"
-private const val WEEKDAY_SHORT_SKELETON = "EEE" // "Mon" — order doesn't matter
-
-/**
- * Per-thread cached [SimpleDateFormat] keyed off the current default [Locale].
- *
- * Cached because these run per cell in the calendar grid (≈42 cells per month,
- * 7 per weekday header) — allocating a fresh SimpleDateFormat each call
- * showed up as scroll-time GC churn. Per-thread because SimpleDateFormat
- * isn't thread-safe; calendars today are read on the UI thread but future
- * callers could differ. ThreadLocal gives both — no locks, no contention,
- * lazy rebuild on locale change.
- */
-private class LocaleAwareFormatter(
-    private val skeleton: String,
-) {
-    private val cache = ThreadLocal<Pair<Locale, SimpleDateFormat>>()
-
-    fun get(): SimpleDateFormat {
-        val current = Locale.getDefault()
-        val cached = cache.get()
-        if (cached != null && cached.first == current) return cached.second
-        val fresh = SimpleDateFormat(DateFormat.getBestDateTimePattern(current, skeleton), current)
-        cache.set(current to fresh)
-        return fresh
-    }
-}
-
-private val dayMonthFormat = LocaleAwareFormatter(DAY_MONTH_SKELETON)
-private val fullDateFormat = LocaleAwareFormatter(FULL_DATE_SKELETON)
-private val monthYearFormat = LocaleAwareFormatter(MONTH_YEAR_SKELETON)
-private val weekdayShortFormat = LocaleAwareFormatter(WEEKDAY_SHORT_SKELETON)
-
-// Time format respects the user's Android 12/24-hour system setting.
-private fun timeFormat(context: Context): java.text.DateFormat = DateFormat.getTimeFormat(context)
-
-fun formatCalendarRange(
-    note: Note,
-    context: Context,
-): String? {
-    val view = note.appointmentView() ?: return null
-    val start = view.startSeconds ?: return null
-    return if (view.isAllDay) {
-        formatDateRange(start, view.endSeconds)
-    } else {
-        formatTimeRange(start, view.endSeconds, context)
-    }
-}
-
-private fun formatTimeRange(
-    start: Long,
-    end: Long?,
-    context: Context,
-): String {
-    val dayMonth = dayMonthFormat.get()
-    val time = timeFormat(context)
-    val startMs = start * 1000
-    val startStr = "${dayMonth.format(Date(startMs))} · ${time.format(Date(startMs))}"
-    if (end == null || end == start) return startStr
-    val endMs = end * 1000
-    return if (isSameDay(startMs, endMs)) {
-        "$startStr – ${time.format(Date(endMs))}"
-    } else {
-        "$startStr – ${dayMonth.format(Date(endMs))} · ${time.format(Date(endMs))}"
-    }
-}
-
-private fun formatDateRange(
-    start: Long,
-    end: Long?,
-): String {
-    val dayMonth = dayMonthFormat.get()
-    val startStr = dayMonth.format(Date(start * 1000))
-    if (end == null || end == start) return startStr
-    return "$startStr – ${dayMonth.format(Date(end * 1000))}"
-}
-
-fun formatLongDate(unixSeconds: Long): String = fullDateFormat.get().format(Date(unixSeconds * 1000))
-
-fun formatMonthYear(
-    year: Int,
-    monthZeroBased: Int,
-): String {
-    val cal = Calendar.getInstance()
-    cal.clear()
-    cal.set(year, monthZeroBased, 1)
-    return monthYearFormat.get().format(cal.time)
-}
-
-fun formatTimeOfDay(
-    unixSeconds: Long,
-    context: Context,
-): String = timeFormat(context).format(Date(unixSeconds * 1000))
-
-fun formatShortWeekday(weekdayZeroBased: Int): String {
-    val cal = Calendar.getInstance()
-    cal.clear()
-    cal.firstDayOfWeek = Calendar.SUNDAY
-    cal.set(Calendar.DAY_OF_WEEK, Calendar.SUNDAY)
-    cal.add(Calendar.DAY_OF_YEAR, weekdayZeroBased)
-    return weekdayShortFormat.get().format(cal.time)
-}
-
-private fun isSameDay(
-    aMs: Long,
-    bMs: Long,
-): Boolean {
-    val ca = Calendar.getInstance().apply { timeInMillis = aMs }
-    val cb = Calendar.getInstance().apply { timeInMillis = bMs }
-    return ca.get(Calendar.YEAR) == cb.get(Calendar.YEAR) &&
-        ca.get(Calendar.DAY_OF_YEAR) == cb.get(Calendar.DAY_OF_YEAR)
-}
@@ -61,6 +61,9 @@ import com.vitorpamplona.amethyst.commons.resources.calendar_nav_next_week
 import com.vitorpamplona.amethyst.commons.resources.calendar_nav_previous_week
 import com.vitorpamplona.amethyst.commons.ui.layouts.rememberFeedContentPadding
 import com.vitorpamplona.amethyst.commons.ui.navigation.navs.INav
+import com.vitorpamplona.amethyst.commons.ui.screen.loggedIn.calendars.formatLongDate
+import com.vitorpamplona.amethyst.commons.ui.screen.loggedIn.calendars.formatMonthYear
+import com.vitorpamplona.amethyst.commons.ui.screen.loggedIn.calendars.formatShortWeekday
 import com.vitorpamplona.amethyst.commons.ui.stringRes
 import com.vitorpamplona.amethyst.commons.ui.theme.FeedPadding
 import com.vitorpamplona.amethyst.commons.viewmodels.AccountViewModel
@@ -71,9 +71,9 @@ import com.vitorpamplona.amethyst.commons.resources.new_calendar_collection
 import com.vitorpamplona.amethyst.commons.ui.insets.imePaddingSafe
 import com.vitorpamplona.amethyst.commons.ui.navigation.navs.INav
 import com.vitorpamplona.amethyst.commons.ui.navigation.topbars.SavingTopBar
+import com.vitorpamplona.amethyst.commons.ui.screen.loggedIn.calendars.formatLongDate
 import com.vitorpamplona.amethyst.commons.ui.stringRes
 import com.vitorpamplona.amethyst.commons.viewmodels.AccountViewModel
-import com.vitorpamplona.amethyst.ui.screen.loggedIn.calendars.formatLongDate

@OptIn(ExperimentalMaterial3Api::class)
@Composable
@@ -97,16 +97,17 @@ import com.vitorpamplona.amethyst.commons.ui.note.ClickableUserPicture
 import com.vitorpamplona.amethyst.commons.ui.note.LoadUser
 import com.vitorpamplona.amethyst.commons.ui.note.UsernameDisplay
 import com.vitorpamplona.amethyst.commons.ui.note.platform.ReactionsRow
+import com.vitorpamplona.amethyst.commons.ui.note.rememberTimeOfDayFormatter
 import com.vitorpamplona.amethyst.commons.ui.note.types.CalendarRsvpRow
 import com.vitorpamplona.amethyst.commons.ui.pluralStringRes
+import com.vitorpamplona.amethyst.commons.ui.screen.loggedIn.calendars.formatCalendarRange
+import com.vitorpamplona.amethyst.commons.ui.screen.loggedIn.calendars.formatLongDate
 import com.vitorpamplona.amethyst.commons.ui.stringRes
 import com.vitorpamplona.amethyst.commons.ui.theme.Size30dp
 import com.vitorpamplona.amethyst.commons.ui.theme.Size35dp
 import com.vitorpamplona.amethyst.commons.viewmodels.AccountViewModel
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.calendars.addToPhoneCalendar
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.calendars.datasource.CalendarsFilterAssemblerSubscription
-import com.vitorpamplona.amethyst.ui.screen.loggedIn.calendars.formatCalendarRange
-import com.vitorpamplona.amethyst.ui.screen.loggedIn.calendars.formatLongDate
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.calendars.rememberRelativeTimeLabel
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.calendars.shareIcs
 import com.vitorpamplona.quartz.nip01Core.core.Address
@@ -347,7 +348,8 @@ private fun EventBody(
            )
        }
        val context = LocalContext.current
-        formatCalendarRange(note, context)?.let { range ->
+        val timeFormatter = rememberTimeOfDayFormatter()
+        formatCalendarRange(note, timeFormatter)?.let { range ->
            Text(
                text = range,
                style = MaterialTheme.typography.bodyLarge,
@@ -130,6 +130,7 @@ import com.vitorpamplona.amethyst.commons.ui.note.creators.zapraiser.AddZapraise
 import com.vitorpamplona.amethyst.commons.ui.note.creators.zapraiser.ZapRaiserRequest
 import com.vitorpamplona.amethyst.commons.ui.note.creators.zapsplits.ForwardZapTo
 import com.vitorpamplona.amethyst.commons.ui.note.creators.zapsplits.ForwardZapToButton
+import com.vitorpamplona.amethyst.commons.ui.richtext.LocalRichTextPlatform
 import com.vitorpamplona.amethyst.commons.ui.screen.loggedIn.settings.SettingsRow
 import com.vitorpamplona.amethyst.commons.ui.stringRes
 import com.vitorpamplona.amethyst.commons.ui.text.MentionPreservingInputTransformation
@@ -139,7 +140,6 @@ import com.vitorpamplona.amethyst.commons.ui.theme.Size5dp
 import com.vitorpamplona.amethyst.commons.ui.theme.SuggestionListDefaultHeightPage
 import com.vitorpamplona.amethyst.commons.ui.theme.placeholderText
 import com.vitorpamplona.amethyst.commons.viewmodels.AccountViewModel
-import com.vitorpamplona.amethyst.ui.components.markdown.RenderContentAsMarkdown
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.home.ObserveInboxRelayListAndDisplayIfNotFound
 import com.vitorpamplona.quartz.nip01Core.core.HexKey
 import kotlinx.collections.immutable.persistentListOf
@@ -387,12 +387,13 @@ private fun MarkdownPostScreenBody(
                                .fillMaxWidth()
                                .padding(Size10dp),
                    ) {
-                        RenderContentAsMarkdown(
+                        LocalRichTextPlatform.current.Markdown(
                            content = postViewModel.message.text.toString(),
                            tags = EmptyTagList,
                            canPreview = true,
                            quotesLeft = 1,
                            backgroundColor = backgroundColor,
+                            callbackUri = null,
                            accountViewModel = accountViewModel,
                            nav = nav,
                        )
@@ -146,7 +146,6 @@ import com.vitorpamplona.amethyst.commons.ui.theme.Size5dp
 import com.vitorpamplona.amethyst.commons.ui.theme.StdTopPadding
 import com.vitorpamplona.amethyst.commons.ui.theme.placeholderText
 import com.vitorpamplona.amethyst.commons.viewmodels.AccountViewModel
-import com.vitorpamplona.amethyst.service.location.CachedReversedGeoLocations
 import com.vitorpamplona.amethyst.service.relayClient.searchCommand.TextSearchDataSourceSubscription
 import com.vitorpamplona.quartz.nip01Core.relay.normalizer.displayUrl
 import kotlinx.collections.immutable.toImmutableList
@@ -584,6 +583,7 @@ private fun SearchTextField(
        // fields rather than search terms. The value stays the plain text, so a query can still
        // be copied out and pasted back.
        val fieldState = remember { SearchFieldState(searchBarViewModel.searchValue) }
+        val appServices = LocalAppServices.current

        // Reported up rather than read down: the scaffold that has to stop moving is composed
        // above this field, and it is the only thing that can keep a picker's scroll off the bars.
@@ -650,7 +650,7 @@ private fun SearchTextField(
            groupName = { groupNames[it] },
            // The same reverse-geocode cache the feed spinner and thread view already read
            // through LoadCityName; null until it resolves, which leaves the geohash showing.
-            scopeName = { field, value -> if (field == "geo") CachedReversedGeoLocations.cached(value) else null },
+            scopeName = { field, value -> if (field == "geo") appServices.cachedPlaceName(value) else null },
            groups = groupCandidates,
            onPeopleQuery = { userSuggestions.processCurrentWord(it) },
            onGroupQuery = { partial -> groupQuery = partial },
@@ -70,6 +70,9 @@ interface AppServices {
    /** The device's position as geohashes. */
    val deviceLocation: DeviceLocation get() = DeviceLocation.None

+    /** The place name already reverse-geocoded for [geohash], or null when none is cached yet. */
+    fun cachedPlaceName(geohash: String): String? = null
+
    /** A new on-device alt-text suggester for image uploads, or null where the platform has none. */
    fun createAltTextSuggester(): AltTextSuggester? = null
 }
@@ -0,0 +1,98 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.amethyst.commons.ui.screen.loggedIn.calendars
+
+import com.vitorpamplona.amethyst.commons.model.Note
+import com.vitorpamplona.amethyst.commons.model.nip52Calendar.appointmentView
+import com.vitorpamplona.amethyst.commons.search.calendar.LocalClock
+import com.vitorpamplona.amethyst.commons.search.calendar.SearchDate
+import com.vitorpamplona.amethyst.commons.ui.note.DateSkeletonFormatter
+import com.vitorpamplona.amethyst.commons.ui.note.calendarYearAndDay
+
+// Skeletons follow Unicode LDML — the platform picks the locale's field order.
+private val dayMonthFormat = DateSkeletonFormatter("EEEMMMd") // "Mon, May 28" / "Mon 28 May"
+private val fullDateFormat = DateSkeletonFormatter("EEEEMMMMdy") // "Monday, May 28, 2026" / "Monday, 28 May 2026"
+private val monthYearFormat = DateSkeletonFormatter("MMMMy") // "May 2026" / "Mai 2026"
+private val weekdayShortFormat = DateSkeletonFormatter("EEE") // "Mon" — order doesn't matter
+
+/**
+ * The appointment's date or time range. [formatTime] renders a time of day under the user's
+ * 12/24-hour setting; composables get it from `rememberTimeOfDayFormatter()`.
+ */
+fun formatCalendarRange(
+    note: Note,
+    formatTime: (epochMillis: Long) -> String,
+): String? {
+    val view = note.appointmentView() ?: return null
+    val start = view.startSeconds ?: return null
+    return if (view.isAllDay) {
+        formatDateRange(start, view.endSeconds)
+    } else {
+        formatTimeRange(start, view.endSeconds, formatTime)
+    }
+}
+
+private fun formatTimeRange(
+    start: Long,
+    end: Long?,
+    formatTime: (epochMillis: Long) -> String,
+): String {
+    val startMs = start * 1000
+    val startStr = "${dayMonthFormat.format(startMs)} · ${formatTime(startMs)}"
+    if (end == null || end == start) return startStr
+    val endMs = end * 1000
+    return if (isSameDay(startMs, endMs)) {
+        "$startStr – ${formatTime(endMs)}"
+    } else {
+        "$startStr – ${dayMonthFormat.format(endMs)} · ${formatTime(endMs)}"
+    }
+}
+
+private fun formatDateRange(
+    start: Long,
+    end: Long?,
+): String {
+    val startStr = dayMonthFormat.format(start * 1000)
+    if (end == null || end == start) return startStr
+    return "$startStr – ${dayMonthFormat.format(end * 1000)}"
+}
+
+fun formatLongDate(unixSeconds: Long): String = fullDateFormat.format(unixSeconds * 1000)
+
+fun formatMonthYear(
+    year: Int,
+    monthZeroBased: Int,
+): String = monthYearFormat.format(LocalClock.startOfDay(SearchDate(year, monthZeroBased + 1, 1)) * 1000)
+
+fun formatTimeOfDay(
+    unixSeconds: Long,
+    formatTime: (epochMillis: Long) -> String,
+): String = formatTime(unixSeconds * 1000)
+
+/** The short name of a weekday, 0 = Sunday. */
+fun formatShortWeekday(weekdayZeroBased: Int): String =
+    // 2026-01-04 was a Sunday; any known Sunday works.
+    weekdayShortFormat.format(LocalClock.startOfDay(SearchDate(2026, 1, 4 + weekdayZeroBased)) * 1000)
+
+private fun isSameDay(
+    aMs: Long,
+    bMs: Long,
+): Boolean = calendarYearAndDay(aMs) == calendarYearAndDay(bMs)