refactor: wallet, filename, language and local-time seams for more screens

- WalletAppLauncher opens any payment URI; payInvoice and payBolt12Offer are
  extensions, so Bolt12OffersDialog stops launching intents itself.
- MediaUploader.displayName replaces MarmotFileUploader's content-resolver
  query; it no longer takes a Context.
- LanguageOption/availableLanguages/languageDisplayName expects in commons
  replace java.util.Locale in the language settings.
- RequestToVanishScreen uses LocalClock and rememberIs24HourClock.
- Toasts in MarmotInviteDeviceBanner and Bolt12OffersDialog go through
  the shared notices; PodcastTopSupporters uses the KMP BigDecimal.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01S7FuNBSKiyVecARSoE4B9P

amethyst/src/main/java/com/vitorpamplona/amethyst/service/uploads/AndroidMediaUploader.kt

@@ -22,6 +22,7 @@ package com.vitorpamplona.amethyst.service.uploads
 
 import android.content.Context
 import android.net.Uri
+import android.provider.OpenableColumns
 import android.webkit.MimeTypeMap
 import com.vitorpamplona.amethyst.Amethyst
 import com.vitorpamplona.amethyst.commons.model.Account
@@ -605,4 +606,10 @@ class AndroidMediaUploader(
             val mimeType = MimeTypeMap.getSingleton().getMimeTypeFromExtension(fileExtension.lowercase(Locale.getDefault()))
             FileHeader.prepare(url, mimeType, null) { httpClients.okHttpClientForImage(it) }.getOrNull()
         }
+
+    override fun displayName(uri: MediaUri): String? =
+        appContext.contentResolver.query(uri, null, null, null, null)?.use {
+            val idx = it.getColumnIndex(OpenableColumns.DISPLAY_NAME)
+            if (idx >= 0 && it.moveToFirst()) it.getString(idx) else null
+        }
 }

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/chats/marmotGroup/MarmotGroupChatView.kt

@@ -45,7 +45,6 @@ import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.graphics.Color
-import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.text.style.TextAlign
 import androidx.compose.ui.unit.dp
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
@@ -232,7 +231,6 @@ fun MarmotGroupMessageComposer(
 ) {
     val scope = rememberCoroutineScope()
     val canPost by remember { derivedStateOf { newMessageModel.canPost() } }
-    val context = LocalContext.current
     val shortNotice = rememberShortNotice()
 
     var isUploading by remember { mutableStateOf(false) }
@@ -350,7 +348,6 @@ private fun MarmotGroupFileUploadDialog(
     onUpload: suspend () -> Unit,
     onCancel: () -> Unit,
 ) {
-    val context = LocalContext.current
     val shortNotice = rememberShortNotice()
     val longNotice = rememberLongNotice()
     val scope = rememberCoroutineScope()
@@ -382,7 +379,6 @@ private fun MarmotGroupFileUploadDialog(
                             longNotice.show("$title: $message")
                         }
                     },
-                    context = context,
                     uploader = accountViewModel.host.mediaUploader,
                     onceUploaded = { uploads ->
                         MarmotFileSender(nostrGroupId, accountViewModel).send(uploads)

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/chats/marmotGroup/MarmotInviteDeviceBanner.kt

@@ -20,7 +20,6 @@
  */
 package com.vitorpamplona.amethyst.ui.screen.loggedIn.chats.marmotGroup
 
-import android.widget.Toast
 import androidx.compose.animation.AnimatedVisibility
 import androidx.compose.foundation.background
 import androidx.compose.foundation.layout.Arrangement
@@ -45,7 +44,6 @@ import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.draw.clip
-import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.unit.dp
 import com.vitorpamplona.amethyst.commons.icons.symbols.Icon
 import com.vitorpamplona.amethyst.commons.icons.symbols.MaterialSymbols
@@ -57,6 +55,8 @@ import com.vitorpamplona.amethyst.commons.resources.marmot_invite_device_failure
 import com.vitorpamplona.amethyst.commons.resources.marmot_invite_device_publish
 import com.vitorpamplona.amethyst.commons.resources.marmot_invite_device_rejected
 import com.vitorpamplona.amethyst.commons.resources.marmot_invite_device_success
+import com.vitorpamplona.amethyst.commons.ui.components.rememberLongNotice
+import com.vitorpamplona.amethyst.commons.ui.components.rememberShortNotice
 import com.vitorpamplona.amethyst.commons.ui.loadStringRes
 import com.vitorpamplona.amethyst.commons.ui.stringRes
 import com.vitorpamplona.amethyst.commons.viewmodels.AccountViewModel
@@ -96,7 +96,8 @@ fun MarmotInviteDeviceBanner(
     // has already read and waved away.
     var dismissed by rememberSaveable { mutableStateOf(false) }
     val scope = rememberCoroutineScope()
-    val context = LocalContext.current
+    val shortNotice = rememberShortNotice()
+    val longNotice = rememberLongNotice()
     // A read-only login cannot publish at all, so the only action this banner
     // offers is impossible for it. Better to say nothing than to offer a button
     // that silently does nothing.
@@ -178,9 +179,9 @@ fun MarmotInviteDeviceBanner(
                                 val accepted = accountViewModel.republishKeyPackage()
                                 launch(Dispatchers.Main) {
                                     if (accepted) {
-                                        Toast.makeText(context, successMessage, Toast.LENGTH_SHORT).show()
+                                        shortNotice.show(successMessage)
                                     } else {
-                                        Toast.makeText(context, rejectedMessage, Toast.LENGTH_LONG).show()
+                                        longNotice.show(rejectedMessage)
                                         owner = LatestKeyPackageOwner.OTHER_DEVICE
                                     }
                                 }
@@ -194,7 +195,7 @@ fun MarmotInviteDeviceBanner(
                                 val failureMessage =
                                     loadStringRes(Res.string.marmot_invite_device_failure, e.message ?: "")
                                 launch(Dispatchers.Main) {
-                                    Toast.makeText(context, failureMessage, Toast.LENGTH_LONG).show()
+                                    longNotice.show(failureMessage)
                                     // The warning was right after all, so put it back.
                                     owner = LatestKeyPackageOwner.OTHER_DEVICE
                                 }

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/chats/marmotGroup/send/MarmotFileUploader.kt

@@ -20,8 +20,6 @@
  */
 package com.vitorpamplona.amethyst.ui.screen.loggedIn.chats.marmotGroup.send
 
-import android.content.Context
-import android.net.Uri
 import com.vitorpamplona.amethyst.commons.model.Account
 import com.vitorpamplona.amethyst.commons.resources.Res
 import com.vitorpamplona.amethyst.commons.resources.failed_to_upload_media_no_details
@@ -79,7 +77,6 @@ class MarmotFileUploader(
         viewState: ChatFileUploadState,
         exporterSecret: ByteArray,
         onError: (title: String, message: String) -> Unit,
-        context: Context,
         uploader: MediaUploader,
         /**
          * Produce `encrypted-media-v2` references instead of MIP-04 ones.
@@ -98,7 +95,7 @@ class MarmotFileUploader(
             val item = multiOrchestrator.get(i)
             val media = item.media
             val mimeType = media.mimeType ?: "application/octet-stream"
-            val filename = resolveFilename(context, media.uri, mimeType)
+            val filename = uploader.displayName(media.uri) ?: fallbackFilename(mimeType)
 
             // v2 puts `m` inside both the key derivation and the AEAD
             // associated data, so it has to be the canonical form and not
@@ -197,19 +194,7 @@ class MarmotFileUploader(
         viewState.mediaUploadTracker.finishUpload()
     }
 
-    private fun resolveFilename(
-        context: Context,
-        uri: Uri,
-        mimeType: String,
-    ): String {
-        val cursor = context.contentResolver.query(uri, null, null, null, null)
-        val name =
-            cursor?.use {
-                val idx = it.getColumnIndex(android.provider.OpenableColumns.DISPLAY_NAME)
-                if (idx >= 0 && it.moveToFirst()) it.getString(idx) else null
-            }
-        if (name != null) return name
-
+    private fun fallbackFilename(mimeType: String): String {
         val ext =
             when {
                 mimeType.startsWith("image/jpeg") -> "jpg"

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/podcasts/PodcastTopSupporters.kt

@@ -62,7 +62,7 @@ import com.vitorpamplona.amethyst.commons.ui.theme.grayText
 import com.vitorpamplona.amethyst.commons.util.showAmountInteger
 import com.vitorpamplona.amethyst.commons.viewmodels.AccountViewModel
 import com.vitorpamplona.quartz.nip57Zaps.ZapReceiptEvent
-import java.math.BigDecimal
+import com.vitorpamplona.quartz.utils.BigDecimal
 
 private val Gold = Color(0xFFFFC300)
 private val Silver = Color(0xFFB0B7C0)
@@ -151,7 +151,7 @@ private fun SupporterRow(
 
         ZapIcon(Size16Modifier, BitcoinOrange)
         Text(
-            text = showAmountInteger(BigDecimal.valueOf(entry.totalSats)),
+            text = showAmountInteger(BigDecimal(entry.totalSats)),
             style = MaterialTheme.typography.bodyMedium,
             fontWeight = FontWeight.Bold,
         )

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/profile/header/Bolt12OffersDialog.kt

@@ -20,7 +20,6 @@
  */
 package com.vitorpamplona.amethyst.ui.screen.loggedIn.profile.header
 
-import android.widget.Toast
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.Row
@@ -45,7 +44,6 @@ import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.platform.LocalClipboard
-import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.text.font.FontFamily
 import androidx.compose.ui.text.input.KeyboardType
 import androidx.compose.ui.text.style.TextOverflow
@@ -62,13 +60,15 @@ import com.vitorpamplona.amethyst.commons.resources.copy_to_clipboard
 import com.vitorpamplona.amethyst.commons.resources.no_wallet_found
 import com.vitorpamplona.amethyst.commons.ui.components.M3ActionDialog
 import com.vitorpamplona.amethyst.commons.ui.components.M3ActionSection
+import com.vitorpamplona.amethyst.commons.ui.components.rememberShortNotice
 import com.vitorpamplona.amethyst.commons.ui.components.util.setText
 import com.vitorpamplona.amethyst.commons.ui.loadStringRes
 import com.vitorpamplona.amethyst.commons.ui.stringRes
 import com.vitorpamplona.amethyst.commons.ui.theme.ButtonBorder
 import com.vitorpamplona.amethyst.commons.ui.theme.Size20Modifier
+import com.vitorpamplona.amethyst.commons.ui.wallet.payBolt12Offer
+import com.vitorpamplona.amethyst.commons.ui.wallet.rememberWalletAppLauncher
 import com.vitorpamplona.amethyst.commons.viewmodels.AccountViewModel
-import com.vitorpamplona.amethyst.ui.note.payViaBolt12Intent
 import kotlinx.coroutines.launch
 
 @Composable
@@ -78,7 +78,8 @@ fun Bolt12OffersDialog(
     onDismiss: () -> Unit,
 ) {
     val noWalletFoundStr = stringRes(Res.string.no_wallet_found)
-    val context = LocalContext.current
+    val walletApp = rememberWalletAppLauncher()
+    val shortNotice = rememberShortNotice()
     val clipboardManager = LocalClipboard.current
     val scope = rememberCoroutineScope()
 
@@ -101,22 +102,16 @@ fun Bolt12OffersDialog(
                     onCopy = {
                         scope.launch {
                             clipboardManager.setText(offer)
-                            Toast
-                                .makeText(
-                                    context,
-                                    loadStringRes(Res.string.copied_to_clipboard),
-                                    Toast.LENGTH_SHORT,
-                                ).show()
+                            shortNotice.show(loadStringRes(Res.string.copied_to_clipboard))
                         }
                     },
                     onPayViaIntent = {
-                        payViaBolt12Intent(
+                        walletApp.payBolt12Offer(
                             offer = offer,
-                            context = context,
-                            noWalletFoundStr,
+                            noWalletFound = noWalletFoundStr,
                             onPaid = { onDismiss() },
                             onError = { msg ->
-                                Toast.makeText(context, msg, Toast.LENGTH_SHORT).show()
+                                shortNotice.show(msg)
                             },
                         )
                     },

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/relays/vanish/RequestToVanishScreen.kt

@@ -20,7 +20,6 @@
  */
 package com.vitorpamplona.amethyst.ui.screen.loggedIn.relays.vanish
 
-import android.text.format.DateFormat
 import androidx.compose.foundation.border
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.Row
@@ -59,7 +58,6 @@ 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.TextAlign
 import androidx.compose.ui.tooling.preview.Preview
@@ -89,12 +87,14 @@ import com.vitorpamplona.amethyst.commons.resources.vanish_select_date
 import com.vitorpamplona.amethyst.commons.resources.vanish_select_time
 import com.vitorpamplona.amethyst.commons.resources.vanish_send_request
 import com.vitorpamplona.amethyst.commons.resources.vanish_target_relay
+import com.vitorpamplona.amethyst.commons.search.calendar.LocalClock
 import com.vitorpamplona.amethyst.commons.ui.components.TitleExplainer
 import com.vitorpamplona.amethyst.commons.ui.navigation.navs.EmptyNav
 import com.vitorpamplona.amethyst.commons.ui.navigation.navs.INav
 import com.vitorpamplona.amethyst.commons.ui.navigation.topbars.TopBarWithBackButton
 import com.vitorpamplona.amethyst.commons.ui.note.DateTimeStyle
 import com.vitorpamplona.amethyst.commons.ui.note.formatDateTime
+import com.vitorpamplona.amethyst.commons.ui.note.rememberIs24HourClock
 import com.vitorpamplona.amethyst.commons.ui.screen.loggedIn.relays.common.BasicRelaySetupInfoDialog
 import com.vitorpamplona.amethyst.commons.ui.screen.loggedIn.relays.common.RelayUrlEditField
 import com.vitorpamplona.amethyst.commons.ui.screen.loggedIn.relays.common.relaySetupInfoBuilder
@@ -108,9 +108,6 @@ import com.vitorpamplona.quartz.nip01Core.relay.normalizer.NormalizedRelayUrl
 import com.vitorpamplona.quartz.nip01Core.relay.normalizer.displayUrl
 import com.vitorpamplona.quartz.utils.TimeUtils
 import kotlinx.collections.immutable.toImmutableList
-import java.time.Instant
-import java.time.ZoneId
-import java.time.ZoneOffset
 
 @OptIn(ExperimentalMaterial3Api::class)
 @Composable
@@ -149,14 +146,13 @@ fun RequestToVanishScreen(
             initialSelectedDateMillis = vanishDate * 1000,
         )
 
-    val currentTime = Instant.ofEpochMilli(vanishDate * 1000).atZone(ZoneId.systemDefault()).toLocalDateTime()
-
-    val context = LocalContext.current
+    // The vanish time as a local wall-clock time: seconds since the epoch shifted by this zone's offset.
+    val localSecondOfDay = (vanishDate + LocalClock.utcOffsetSeconds(vanishDate)).mod(TimeUtils.ONE_DAY)
     val timePickerState =
         rememberTimePickerState(
-            initialHour = currentTime.hour,
-            initialMinute = currentTime.minute,
-            is24Hour = DateFormat.is24HourFormat(context),
+            initialHour = localSecondOfDay / TimeUtils.ONE_HOUR,
+            initialMinute = (localSecondOfDay % TimeUtils.ONE_HOUR) / TimeUtils.ONE_MINUTE,
+            is24Hour = rememberIs24HourClock(),
         )
 
     val relayOptions =
@@ -387,9 +383,7 @@ fun RequestToVanishScreen(
                                     (timePickerState.minute * TimeUtils.ONE_MINUTE)
                             } ?: TimeUtils.now()
 
-                        val offset: ZoneOffset = ZoneId.systemDefault().rules.getOffset(Instant.now())
-
-                        vanishDate = datetimeLocalTimeZone - offset.totalSeconds
+                        vanishDate = datetimeLocalTimeZone - LocalClock.utcOffsetSeconds(TimeUtils.now())
 
                         showTimePicker = false
                     },

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/settings/UserSettingsScreen.kt

@@ -91,9 +91,11 @@ import com.vitorpamplona.amethyst.commons.ui.theme.Size10dp
 import com.vitorpamplona.amethyst.commons.ui.theme.Size20dp
 import com.vitorpamplona.amethyst.commons.ui.theme.SpacedBy10dp
 import com.vitorpamplona.amethyst.commons.ui.theme.ThemeComparisonRow
+import com.vitorpamplona.amethyst.commons.util.LanguageOption
+import com.vitorpamplona.amethyst.commons.util.availableLanguages
+import com.vitorpamplona.amethyst.commons.util.languageDisplayName
 import com.vitorpamplona.amethyst.commons.viewmodels.AccountViewModel
 import com.vitorpamplona.amethyst.commons.viewmodels.mockAccountViewModel
-import java.util.Locale as JavaLocale
 
 @Preview(device = "spec:width=2160px,height=2340px,dpi=440")
 @Composable
@@ -134,18 +136,12 @@ fun UserSettingsScreen(
     }
 }
 
-private fun getAllLanguagesSorted(): List<JavaLocale> {
-    val seen = mutableSetOf<String>()
-    return JavaLocale
-        .getAvailableLocales()
-        .filter { it.language.isNotBlank() && it.country.isBlank() && seen.add(it.language) }
-        .sortedBy { it.displayName.lowercase() }
-}
+private fun getAllLanguagesSorted(): List<LanguageOption> = availableLanguages().sortedBy { it.displayName.lowercase() }
 
 @Composable
 private fun SearchableLanguageList(
-    languages: List<JavaLocale>,
-    onSelect: (JavaLocale) -> Unit,
+    languages: List<LanguageOption>,
+    onSelect: (LanguageOption) -> Unit,
     modifier: Modifier = Modifier,
 ) {
     var searchQuery by remember { mutableStateOf("") }
@@ -225,7 +221,7 @@ fun TranslateToSetting(accountViewModel: AccountViewModel) {
                     verticalAlignment = Alignment.CenterVertically,
                 ) {
                     Text(
-                        text = JavaLocale.forLanguageTag(currentTranslateTo).displayName,
+                        text = languageDisplayName(currentTranslateTo),
                         style = MaterialTheme.typography.bodyMedium,
                         fontWeight = FontWeight.Medium,
                     )
@@ -277,7 +273,7 @@ fun DontTranslateFromSetting(accountViewModel: AccountViewModel) {
                 InputChip(
                     selected = true,
                     onClick = { accountViewModel.removeDontTranslateFrom(languageCode) },
-                    label = { Text(JavaLocale.forLanguageTag(languageCode).displayName) },
+                    label = { Text(languageDisplayName(languageCode)) },
                     trailingIcon = {
                         Icon(
                             symbol = MaterialSymbols.Close,
@@ -379,8 +375,8 @@ private fun LanguagePreferenceCard(
     preference: String,
     accountViewModel: AccountViewModel,
 ) {
-    val sourceName = JavaLocale.forLanguageTag(source).displayName
-    val targetName = JavaLocale.forLanguageTag(target).displayName
+    val sourceName = languageDisplayName(source)
+    val targetName = languageDisplayName(target)
 
     OutlinedCard(modifier = Modifier.fillMaxWidth()) {
         Column(modifier = Modifier.padding(12.dp)) {
@@ -464,9 +460,9 @@ private fun AddLanguagePairCard(
     onDismiss: () -> Unit,
 ) {
     val allLanguages = remember { getAllLanguagesSorted() }
-    var selectedSource by remember { mutableStateOf<JavaLocale?>(null) }
-    var selectedTarget by remember { mutableStateOf<JavaLocale?>(null) }
-    var selectedPreference by remember { mutableStateOf<JavaLocale?>(null) }
+    var selectedSource by remember { mutableStateOf<LanguageOption?>(null) }
+    var selectedTarget by remember { mutableStateOf<LanguageOption?>(null) }
+    var selectedPreference by remember { mutableStateOf<LanguageOption?>(null) }
     var pickingSource by remember { mutableStateOf(false) }
     var pickingTarget by remember { mutableStateOf(false) }
 

commons/src/commonMain/kotlin/com/vitorpamplona/amethyst/commons/service/uploads/MediaUploader.kt

@@ -86,6 +86,9 @@ interface MediaUploader {
         url: String,
         httpClients: IRoleBasedHttpClientBuilder,
     ): FileHeader?
+
+    /** The file name the picker reported for [uri] (Android's `DISPLAY_NAME`), if any. */
+    fun displayName(uri: MediaUri): String? = uri.lastPathSegmentOrNull()
 }
 
 /** No media pipeline on this front end yet: every upload fails with a clear message. */

commons/src/commonMain/kotlin/com/vitorpamplona/amethyst/commons/util/LanguageNames.kt

@@ -0,0 +1,33 @@
+/*
+ * 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.util
+
+/** A language the user can pick: its ISO code and its name in the user's own language. */
+data class LanguageOption(
+    val language: String,
+    val displayName: String,
+)
+
+/** Every language the platform can name, one entry per language code (no regional variants). */
+expect fun availableLanguages(): List<LanguageOption>
+
+/** The name of the language [tag] (a BCP-47 tag such as `pt` or `pt-BR`) in the user's language. */
+expect fun languageDisplayName(tag: String): String

commons/src/iosMain/kotlin/com/vitorpamplona/amethyst/commons/util/LanguageNames.ios.kt

@@ -0,0 +1,35 @@
+/*
+ * 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.util
+
+import platform.Foundation.NSLocale
+import platform.Foundation.availableLocaleIdentifiers
+import platform.Foundation.currentLocale
+import platform.Foundation.localizedStringForLanguageCode
+
+actual fun availableLanguages(): List<LanguageOption> =
+    NSLocale.availableLocaleIdentifiers
+        .mapNotNull { (it as? String)?.substringBefore('_')?.substringBefore('-') }
+        .filter { it.isNotBlank() }
+        .distinct()
+        .map { LanguageOption(it, languageDisplayName(it)) }
+
+actual fun languageDisplayName(tag: String): String = NSLocale.currentLocale.localizedStringForLanguageCode(tag) ?: tag

commons/src/jvmAndroid/kotlin/com/vitorpamplona/amethyst/commons/util/LanguageNames.jvmAndroid.kt

@@ -0,0 +1,33 @@
+/*
+ * 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.util
+
+import java.util.Locale
+
+actual fun availableLanguages(): List<LanguageOption> {
+    val seen = mutableSetOf<String>()
+    return Locale
+        .getAvailableLocales()
+        .filter { it.language.isNotBlank() && it.country.isBlank() && seen.add(it.language) }
+        .map { LanguageOption(it.language, it.displayName) }
+}
+
+actual fun languageDisplayName(tag: String): String = Locale.forLanguageTag(tag).displayName

commonsUI/src/androidMain/kotlin/com/vitorpamplona/amethyst/commons/ui/wallet/WalletAppLauncher.android.kt

@@ -31,9 +31,9 @@ import kotlin.coroutines.cancellation.CancellationException
 actual fun rememberWalletAppLauncher(): WalletAppLauncher {
     val context = LocalContext.current
     return remember(context) {
-        WalletAppLauncher { invoice, noWalletFound, onPaid, onError ->
+        WalletAppLauncher { uri, noWalletFound, onPaid, onError ->
             try {
-                val intent = Intent(Intent.ACTION_VIEW, "lightning:$invoice".toUri())
+                val intent = Intent(Intent.ACTION_VIEW, uri.toUri())
                 intent.flags = Intent.FLAG_ACTIVITY_NEW_TASK or Intent.FLAG_ACTIVITY_CLEAR_TASK
 
                 context.startActivity(intent)

commonsUI/src/commonMain/kotlin/com/vitorpamplona/amethyst/commons/ui/screen/loggedIn/dvms/DvmContentDiscoveryScreen.kt

@@ -87,6 +87,7 @@ import com.vitorpamplona.amethyst.commons.ui.stringRes
 import com.vitorpamplona.amethyst.commons.ui.theme.DoubleVertSpacer
 import com.vitorpamplona.amethyst.commons.ui.theme.SimpleImage75Modifier
 import com.vitorpamplona.amethyst.commons.ui.theme.Size35dp
+import com.vitorpamplona.amethyst.commons.ui.wallet.payInvoice
 import com.vitorpamplona.amethyst.commons.ui.wallet.rememberWalletAppLauncher
 import com.vitorpamplona.amethyst.commons.viewmodels.AccountViewModel
 import com.vitorpamplona.quartz.lightning.LnInvoiceUtil

commonsUI/src/commonMain/kotlin/com/vitorpamplona/amethyst/commons/ui/wallet/WalletAppLauncher.kt

@@ -25,16 +25,33 @@ import androidx.compose.runtime.Composable
 /** Hands a payment to a wallet app installed on the device. */
 fun interface WalletAppLauncher {
     /**
-     * Opens [invoice] (BOLT-11) in the wallet app. [onPaid] runs once the wallet took it, which is
-     * not a payment confirmation; [onError] gets [noWalletFound] when no wallet can open it.
+     * Opens the payment [uri] (`lightning:` or `bitcoin:`) in the wallet app. [onPaid] runs once
+     * the wallet took it, which is not a payment confirmation; [onError] gets [noWalletFound] when
+     * no wallet can open it.
      */
-    fun payInvoice(
-        invoice: String,
+    fun openPaymentUri(
+        uri: String,
         noWalletFound: String,
         onPaid: () -> Unit,
         onError: (String) -> Unit,
     )
 }
 
+/** Opens a BOLT-11 [invoice] in the wallet app; see [WalletAppLauncher.openPaymentUri]. */
+fun WalletAppLauncher.payInvoice(
+    invoice: String,
+    noWalletFound: String,
+    onPaid: () -> Unit,
+    onError: (String) -> Unit,
+) = openPaymentUri("lightning:$invoice", noWalletFound, onPaid, onError)
+
+/** Opens a BOLT-12 [offer] in the wallet app; see [WalletAppLauncher.openPaymentUri]. */
+fun WalletAppLauncher.payBolt12Offer(
+    offer: String,
+    noWalletFound: String,
+    onPaid: () -> Unit,
+    onError: (String) -> Unit,
+) = openPaymentUri("bitcoin:?lno=$offer", noWalletFound, onPaid, onError)
+
 @Composable
 expect fun rememberWalletAppLauncher(): WalletAppLauncher

commonsUI/src/iosMain/kotlin/com/vitorpamplona/amethyst/commons/ui/wallet/WalletAppLauncher.ios.kt

@@ -25,14 +25,14 @@ import androidx.compose.runtime.remember
 import androidx.compose.ui.platform.LocalUriHandler
 import kotlin.coroutines.cancellation.CancellationException
 
-/** Opens the `lightning:` link with whatever the system registered for it. */
+/** Opens the payment link with whatever the system registered for it. */
 @Composable
 actual fun rememberWalletAppLauncher(): WalletAppLauncher {
     val uriHandler = LocalUriHandler.current
     return remember(uriHandler) {
-        WalletAppLauncher { invoice, noWalletFound, onPaid, onError ->
+        WalletAppLauncher { uri, noWalletFound, onPaid, onError ->
             try {
-                uriHandler.openUri("lightning:$invoice")
+                uriHandler.openUri(uri)
                 onPaid()
             } catch (e: Exception) {
                 if (e is CancellationException) throw e

commonsUI/src/jvmMain/kotlin/com/vitorpamplona/amethyst/commons/ui/wallet/WalletAppLauncher.jvm.kt

@@ -25,14 +25,14 @@ import androidx.compose.runtime.remember
 import androidx.compose.ui.platform.LocalUriHandler
 import kotlin.coroutines.cancellation.CancellationException
 
-/** Opens the `lightning:` link with whatever the system registered for it. */
+/** Opens the payment link with whatever the system registered for it. */
 @Composable
 actual fun rememberWalletAppLauncher(): WalletAppLauncher {
     val uriHandler = LocalUriHandler.current
     return remember(uriHandler) {
-        WalletAppLauncher { invoice, noWalletFound, onPaid, onError ->
+        WalletAppLauncher { uri, noWalletFound, onPaid, onError ->
             try {
-                uriHandler.openUri("lightning:$invoice")
+                uriHandler.openUri(uri)
                 onPaid()
             } catch (e: Exception) {
                 if (e is CancellationException) throw e