feat(composer): add "pick on map" location to the short-note composer

The composer could only attach the current GPS location (fixed ~5km), which
fails when GPS is denied/unavailable and can't tag a post with a different
place. Add a "pick a place on the map" action that opens the shared
GeohashLocationPickerDialog and stores the result in
ShortNotePostViewModel.pickedGeoHash, which overrides the GPS fix at build time
and round-trips through drafts. Picking a place also skips the GPS permission
prompt. The existing "use my location" GPS flow is unchanged; this is additive.

Scoped to the short-note composer for now; the other ILocationGrabber composers
(long-form, classifieds, DMs, comments, channel/nest messages) can adopt the
same pickedGeoHash override + section in a follow-up.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01YU8YLcjH9ALr4PgdAkGPZh

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/home/ShortNotePostScreen.kt

@@ -37,6 +37,7 @@ import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.height
 import androidx.compose.foundation.layout.imePadding
 import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
 import androidx.compose.foundation.rememberScrollState
 import androidx.compose.foundation.text.input.setTextAndPlaceCursorAtEnd
 import androidx.compose.foundation.verticalScroll
@@ -106,6 +107,8 @@ import com.vitorpamplona.amethyst.ui.note.creators.expiration.ExpirationDatePick
 import com.vitorpamplona.amethyst.ui.note.creators.invoice.AddLnInvoiceButton
 import com.vitorpamplona.amethyst.ui.note.creators.invoice.InvoiceRequest
 import com.vitorpamplona.amethyst.ui.note.creators.location.AddGeoHashButton
+import com.vitorpamplona.amethyst.ui.note.creators.location.DisplayLocationInTitle
+import com.vitorpamplona.amethyst.ui.note.creators.location.GeohashLocationPickerDialog
 import com.vitorpamplona.amethyst.ui.note.creators.location.LocationAsHash
 import com.vitorpamplona.amethyst.ui.note.creators.messagefield.MessageField
 import com.vitorpamplona.amethyst.ui.note.creators.notify.Notifying
@@ -527,19 +530,7 @@ private fun NewPostScreenBody(
                 }
 
                 if (postViewModel.wantsToAddGeoHash) {
-                    Row(
-                        verticalAlignment = CenterVertically,
-                        modifier = Modifier.padding(vertical = Size10dp, horizontal = Size10dp),
-                    ) {
-                        LocationAsHash(postViewModel) {
-                            SettingsRow(
-                                R.string.geohash_exclusive,
-                                R.string.geohash_exclusive_explainer,
-                            ) {
-                                Switch(postViewModel.wantsExclusiveGeoPost, onCheckedChange = { postViewModel.wantsExclusiveGeoPost = it })
-                            }
-                        }
-                    }
+                    GeoHashPostSection(postViewModel)
                 }
 
                 if (postViewModel.wantsForwardZapTo) {
@@ -881,6 +872,85 @@ private fun BottomRowActions(
     }
 }
 
+/**
+ * The composer's location section. Defaults to the device GPS flow ([LocationAsHash]),
+ * but a "pick on map" action opens the shared [GeohashLocationPickerDialog] and stores
+ * the chosen geohash in [ShortNotePostViewModel.pickedGeoHash], which then overrides GPS
+ * at build time. Picking a place also skips the GPS permission prompt.
+ */
+@Composable
+private fun GeoHashPostSection(postViewModel: ShortNotePostViewModel) {
+    var showPicker by remember { mutableStateOf(false) }
+    val picked = postViewModel.pickedGeoHash
+
+    Column(
+        modifier = Modifier.fillMaxWidth().padding(vertical = Size10dp, horizontal = Size10dp),
+    ) {
+        if (picked != null) {
+            // A map-picked place: show it, and let the user clear back to GPS.
+            Row(verticalAlignment = CenterVertically, modifier = Modifier.fillMaxWidth()) {
+                Icon(
+                    symbol = MaterialSymbols.LocationOn,
+                    contentDescription = null,
+                    modifier = Modifier.size(20.dp),
+                    tint = MaterialTheme.colorScheme.primary,
+                )
+                Text(
+                    text = stringRes(R.string.geohash_title),
+                    style = MaterialTheme.typography.titleMedium,
+                    fontWeight = FontWeight.W500,
+                    modifier = Modifier.padding(start = 10.dp),
+                )
+                DisplayLocationInTitle(geohash = picked)
+                Spacer(modifier = Modifier.weight(1f))
+                IconButton(onClick = { postViewModel.pickedGeoHash = null }) {
+                    Icon(
+                        symbol = MaterialSymbols.Close,
+                        contentDescription = stringRes(R.string.remove_location),
+                        modifier = Modifier.size(20.dp),
+                        tint = MaterialTheme.colorScheme.onSurfaceVariant,
+                    )
+                }
+            }
+            HorizontalDivider()
+            SettingsRow(R.string.geohash_exclusive, R.string.geohash_exclusive_explainer) {
+                Switch(postViewModel.wantsExclusiveGeoPost, onCheckedChange = { postViewModel.wantsExclusiveGeoPost = it })
+            }
+        } else {
+            // GPS mode (unchanged): current device location + the exclusive-post switch.
+            LocationAsHash(postViewModel) {
+                SettingsRow(R.string.geohash_exclusive, R.string.geohash_exclusive_explainer) {
+                    Switch(postViewModel.wantsExclusiveGeoPost, onCheckedChange = { postViewModel.wantsExclusiveGeoPost = it })
+                }
+            }
+        }
+
+        TextButton(onClick = { showPicker = true }, modifier = Modifier.padding(top = 4.dp)) {
+            Icon(
+                symbol = MaterialSymbols.LocationOn,
+                contentDescription = null,
+                modifier = Modifier.size(18.dp),
+                tint = MaterialTheme.colorScheme.primary,
+            )
+            Text(
+                text = stringRes(if (picked != null) R.string.location_change_place else R.string.location_pick_on_map),
+                modifier = Modifier.padding(start = 6.dp),
+            )
+        }
+    }
+
+    if (showPicker) {
+        GeohashLocationPickerDialog(
+            initialGeohash = picked,
+            onDismiss = { showPicker = false },
+            onConfirm = { cell ->
+                postViewModel.pickedGeoHash = cell
+                showPicker = false
+            },
+        )
+    }
+}
+
 @SuppressLint("ViewModelConstructorInComposable")
 @Preview
 @Composable

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/home/ShortNotePostViewModel.kt

@@ -329,6 +329,12 @@ open class ShortNotePostViewModel :
     // GeoHash
     var wantsToAddGeoHash by mutableStateOf(false)
     var location: StateFlow<LocationState.LocationResult>? = null
+
+    /**
+     * A geohash the user picked on the map, which overrides the live GPS location at
+     * build time. Null means "use my current GPS location" (the default behavior).
+     */
+    var pickedGeoHash by mutableStateOf<String?>(null)
     var wantsExclusiveGeoPost by mutableStateOf(false)
 
     // ZapRaiser
@@ -753,6 +759,7 @@ open class ShortNotePostViewModel :
 
         val geohash = draftEvent.getGeoHash()
         wantsToAddGeoHash = geohash != null
+        pickedGeoHash = geohash
         if (geohash != null) {
             wantsExclusiveGeoPost = draftEvent.kind == CommentEvent.KIND
         }
@@ -858,6 +865,7 @@ open class ShortNotePostViewModel :
 
         val geohash = draftEvent.getGeoHash()
         wantsToAddGeoHash = geohash != null
+        pickedGeoHash = geohash
         if (geohash != null) {
             wantsExclusiveGeoPost = draftEvent.kind == CommentEvent.KIND
         }
@@ -931,6 +939,7 @@ open class ShortNotePostViewModel :
 
         val geohash = draftEvent.getGeoHash()
         wantsToAddGeoHash = geohash != null
+        pickedGeoHash = geohash
         if (geohash != null) {
             wantsExclusiveGeoPost = draftEvent.kind == CommentEvent.KIND
         }
@@ -1236,7 +1245,13 @@ open class ShortNotePostViewModel :
 
         val zapReceiver = if (wantsForwardZapTo) forwardZapTo.value.toZapSplitSetup() else null
 
-        val geoHash = if (wantsToAddGeoHash) (location?.value as? LocationState.LocationResult.Success)?.geoHash?.toString() else null
+        val geoHash =
+            if (wantsToAddGeoHash) {
+                // A map-picked geohash wins over the live GPS fix.
+                pickedGeoHash ?: (location?.value as? LocationState.LocationResult.Success)?.geoHash?.toString()
+            } else {
+                null
+            }
         val localZapRaiserAmount = if (wantsZapRaiser) zapRaiserAmount.value else null
 
         val emojis = account.emoji.findEmojiTags(tagger.message)
@@ -1563,6 +1578,7 @@ open class ShortNotePostViewModel :
         wantsToMarkAsSensitive = false
         contentWarningDescription = ""
         wantsToAddGeoHash = false
+        pickedGeoHash = null
         wantsExclusiveGeoPost = false
         wantsSecretEmoji = false
         wantsAnonymousPost = false

amethyst/src/main/res/values/strings.xml

@@ -2149,6 +2149,8 @@
     <string name="geohash_explainer">Adds a Geohash of your location to the post. The public will know you are within 5km (3mi) of the current location</string>
     <string name="geohash_teleport_title">Teleport</string>
     <string name="geohash_teleport_action">✈  Teleport here</string>
+    <string name="location_pick_on_map">Pick a place on the map</string>
+    <string name="location_change_place">Change place on the map</string>
 
     <string name="geohash_exclusive">Location-exclusive Post</string>
     <string name="geohash_exclusive_explainer">Only followers of the location will see it. Your general followers won\'t see it.</string>