feat(ui): the new-chat dialog opens the person, and no longer starts the chat

Phase 3 of docs/npub-profile-preview.md, and the user-visible change: "Direct
message via npub" now shows who this is before anything is created. The
dialog's button reads "Find profile" and pushes ProfilePreviewRoute; the chat
is started from there.

The field keeps what it parsed rather than whether it parsed. Its check and its
decode used to be two different functions, which is how "nostr:npub1…" passed
the one and failed the other, closing the dialog with nothing to show for it;
CredentialParser.npubOrNull is the sign-in decode exposed for an address field
-- an nsec is null there, because a field asking whom to write to must never
take a secret for an answer -- and the enabled button and the route it pushes
read the same key. The nip05 branch still lands on the placeholder, and the
test says so. "Start chat" goes with its only reader.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Pulled-From: curated/curated@923b59ec32

composeApp/src/commonMain/kotlin/press/mantra/compose/identity/CredentialParser.kt

@@ -131,20 +131,39 @@ object CredentialParser {
         return Result.Recognised(SignInCredential.NostrSecret(privateKey, privateKey.nostrPublicKeyHex()))
     }
 
+    /**
+     * The x-only key under an `npub1…`, with or without a `nostr:` prefix, or null.
+     *
+     * The one shape a message address can arrive in, for the field that takes one. Hex
+     * stays a secret here for the reason [parse] gives, and an nsec is null because it is
+     * not an address -- a field asking whom to write to must never take a secret for an
+     * answer. Same decode as the sign-in branch, so the two cannot disagree.
+     */
+    fun npubOrNull(raw: String): HexKey? {
+        val token = raw.trim().removePrefix("nostr:").lowercase()
+        if (!token.startsWith("npub1")) return null
+        return decodeNpub(token)
+    }
+
+    private fun npub(token: String): Result =
+        decodeNpub(token)
+            ?.let { Result.Recognised(SignInCredential.NostrPublicKey(it)) }
+            ?: Result.Refused(CredentialProblem.InvalidKey)
+
     /**
      * Thirty-two bytes under the `npub` prefix that name a point on the curve -- the
      * counterpart of the `isValid()` a secret is checked with, since not every x
      * coordinate has a point above it.
      */
-    private fun npub(token: String): Result {
+    private fun decodeNpub(token: String): HexKey? {
         val bytes = runCatching {
             val (hrp, data) = Bech32.decodeBytes(token)
             require(hrp == "npub") { "not an npub" }
             require(data.size == 32) { "not an x-only key" }
             data
-        }.getOrNull() ?: return Result.Refused(CredentialProblem.InvalidKey)
+        }.getOrNull() ?: return null
         val xOnly = XonlyPublicKey(ByteVector32(bytes))
-        if (!xOnly.publicKey.isValid()) return Result.Refused(CredentialProblem.InvalidKey)
-        return Result.Recognised(SignInCredential.NostrPublicKey(xOnly.value.toHex()))
+        if (!xOnly.publicKey.isValid()) return null
+        return xOnly.value.toHex()
     }
 }

composeApp/src/commonMain/kotlin/press/mantra/compose/ui/composable/widgets/dialogs/StartDirectMessageToNpubOrNip05Dialog.kt

@@ -14,7 +14,7 @@ import androidx.compose.foundation.text.input.TextFieldLineLimits
 import androidx.compose.foundation.text.input.rememberTextFieldState
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.filled.Close
-import androidx.compose.material.icons.filled.Start
+import androidx.compose.material.icons.filled.PersonSearch
 import androidx.compose.material3.Card
 import androidx.compose.material3.Icon
 import androidx.compose.material3.IconButton
@@ -32,9 +32,9 @@ import androidx.compose.ui.Modifier
 import androidx.compose.ui.text.style.TextAlign
 import androidx.compose.ui.unit.dp
 import androidx.compose.ui.window.Dialog
-import press.mantra.compose.extensions.bech32ToHexOrNull
-import press.mantra.compose.ui.composable.navigation.routes.ChatRoomMessagingRoute
+import press.mantra.compose.identity.CredentialParser
 import press.mantra.compose.ui.composable.navigation.routes.ImplementationPendingRoute
+import press.mantra.compose.ui.composable.navigation.routes.ProfilePreviewRoute
 import press.mantra.compose.ui.composable.navigation.routes.Route
 import press.mantra.compose.ui.theme.MantraTheme
 import com.vitorpamplona.quartz.nip01Core.core.HexKey
@@ -47,11 +47,22 @@ import androidx.compose.ui.focus.FocusRequester
 import androidx.compose.ui.focus.focusRequester
 import mantra.composeapp.generated.resources.Res
 import org.jetbrains.compose.resources.stringResource
+import mantra.composeapp.generated.resources.find_profile
 import mantra.composeapp.generated.resources.input_npub_or_nip05
-import mantra.composeapp.generated.resources.start_chat
 import mantra.composeapp.generated.resources.start_chat_via_npub_or_nip05
+import press.mantra.compose.ui.composable.widgets.Decorative
 import press.mantra.compose.ui.theme.ConformancePreviews
 
+/**
+ * Whom to write to, as an npub or a nip05.
+ *
+ * An npub no longer starts a chat from here: it opens the person's profile, and the
+ * chat is started from there once the user has seen who it is. The field keeps what
+ * it parsed rather than whether it parsed -- the enabled button and the route it
+ * pushes read the same decoded key, which is what closed the gap where `nostr:npub1…`
+ * passed the check and then failed the decode in silence. A nip05 still lands on the
+ * placeholder; resolving one is out of scope. See docs/npub-profile-preview.md.
+ */
 @Composable
 fun StartDirectMessageToNpubOrNip05Dialog(
     activeUserPublicKey: HexKey,
@@ -65,7 +76,10 @@ fun StartDirectMessageToNpubOrNip05Dialog(
 
         }
     ) {
-        val startChatButtonEnabled = remember { mutableStateOf(false) }
+        // The key under a pasted npub, or null while the field holds anything else.
+        val parsedPublicKey = remember { mutableStateOf<HexKey?>(null) }
+        // A nip05 is recognised by shape alone; nothing resolves it yet.
+        val emailLikeAddressEntered = remember { mutableStateOf(false) }
 
         Card(
             modifier = Modifier
@@ -123,63 +137,52 @@ fun StartDirectMessageToNpubOrNip05Dialog(
                     },
                     lineLimits = TextFieldLineLimits.SingleLine,
                     inputTransformation = {
-                        val input = asCharSequence().toString().lowercase()
+                        val input = asCharSequence().toString()
 
-                        if (input.startsWith("npub1") || input.startsWith("nostr:npub1")) {
-                            // Check for valid npub
-                            startChatButtonEnabled.value = true
-                        } else if (Parser.parseEmailLikeAddress(input) != null) {
-                            // Check for valid npub
-                            startChatButtonEnabled.value = true
-                        } else {
-                            startChatButtonEnabled.value = false
-                        }
+                        parsedPublicKey.value = CredentialParser.npubOrNull(input)
+                        emailLikeAddressEntered.value = parsedPublicKey.value == null &&
+                            Parser.parseEmailLikeAddress(input.lowercase()) != null
                     }
                 )
 
                 TextButton(
-                    enabled = startChatButtonEnabled.value,
+                    enabled = parsedPublicKey.value != null || emailLikeAddressEntered.value,
                     onClick = {
+                        // Read before the dialog closes: the state lives in it.
+                        val publicKey = parsedPublicKey.value
+                        val input = textFieldState.text.toString()
+
                         scope.launch {
                             toggleOpenDialogSetting.invoke(false)
                         }.invokeOnCompletion {
-                            val input = textFieldState.text.toString()
-
-                            val emailLikeAddress = Parser.parseEmailLikeAddress(input)
-
-                            if (emailLikeAddress != null) {
-                                // TODO: Get public Key from hex...
+                            if (publicKey != null) {
                                 onNavigateToRoute.invoke(
-                                    ImplementationPendingRoute(
-                                        "Direct Message to ${textFieldState.text}"
+                                    ProfilePreviewRoute(
+                                        activeUserPublicKey = activeUserPublicKey,
+                                        profilePublicKey = publicKey,
                                     )
                                 )
                             } else {
-                                val publicKey = input.bech32ToHexOrNull()
-
-                                if (publicKey != null) {
-                                    onNavigateToRoute.invoke(
-                                        ChatRoomMessagingRoute(
-                                            activeUserPublicKey = activeUserPublicKey,
-                                            chatRoomId = publicKey,
-                                            relayHint = null
-                                        )
+                                // TODO: Resolve the nip05 to a public key, then the same route.
+                                onNavigateToRoute.invoke(
+                                    ImplementationPendingRoute(
+                                        "Direct Message to $input"
                                     )
-                                }
+                                )
                             }
-
                         }
                     }
                 ) {
-                    Text(stringResource(Res.string.start_chat))
+                    Text(stringResource(Res.string.find_profile))
 
                     Spacer(
                         modifier = Modifier.width(MaterialTheme.spacing.space125)
                     )
 
                     Icon(
-                        Icons.Default.Start,
-                        contentDescription = "Start chat"
+                        Icons.Default.PersonSearch,
+                        // The label is beside it.
+                        contentDescription = Decorative
                     )
                 }
             }