feat: render nowhere links inline as branded cards

Nowhere (https://github.com/5t34k/nowhere) encodes whole mini-sites in
a URL fragment, so the OpenGraph preview path returns nothing useful and
hostednowhere.com 403s scrapers. Detect URLs on hostednowhere.com and
nowhr.xyz that carry a fragment as a NowhereLinkSegment and render them
through a NowhereLinkCard that labels the tool type (Event, Store,
Message, ...) and opens the URL in the browser on click.

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/components/NowhereLinkCard.kt

@@ -0,0 +1,87 @@
+/*
+ * 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.components
+
+import androidx.compose.foundation.clickable
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.padding
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.platform.LocalUriHandler
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.text.style.TextOverflow
+import androidx.compose.ui.unit.dp
+import com.vitorpamplona.amethyst.commons.richtext.NowhereLinkSegment
+import com.vitorpamplona.amethyst.ui.theme.innerPostModifier
+
+// Maps the first path segment of a nowhere URL to its tool. The nowhere project ships eight
+// tools (event, fundraiser, store, petition, message, drop, art, forum) and the URL path
+// uses the first letter as a discriminator (e.g. nowhr.xyz/s#... is a store). Unknown codes
+// fall through to a generic "Nowhere site" label.
+private val nowhereTools =
+    mapOf(
+        "e" to "Event",
+        "f" to "Fundraiser",
+        "s" to "Store",
+        "p" to "Petition",
+        "m" to "Message",
+        "d" to "Drop",
+        "a" to "Art",
+        "fo" to "Forum",
+    )
+
+@Composable
+fun NowhereLinkCard(segment: NowhereLinkSegment) {
+    val uri = LocalUriHandler.current
+    val toolLabel = segment.tool?.let { nowhereTools[it.lowercase()] }
+    val title = toolLabel?.let { "Nowhere $it" } ?: "Nowhere site"
+
+    Column(
+        modifier =
+            MaterialTheme.colorScheme.innerPostModifier
+                .clickable {
+                    runCatching {
+                        val target = if (segment.segmentText.contains("://")) segment.segmentText else "https://${segment.segmentText}"
+                        uri.openUri(target)
+                    }
+                }.padding(12.dp),
+    ) {
+        Text(
+            text = title,
+            style = MaterialTheme.typography.bodyMedium,
+            fontWeight = FontWeight.Bold,
+        )
+
+        Spacer(modifier = Modifier.padding(top = 2.dp))
+
+        Text(
+            text = segment.host,
+            style = MaterialTheme.typography.bodySmall,
+            color = Color.Gray,
+            maxLines = 1,
+            overflow = TextOverflow.Ellipsis,
+        )
+    }
+}

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/components/RichTextViewer.kt

@@ -80,6 +80,7 @@ import com.vitorpamplona.amethyst.commons.richtext.ImageGalleryParagraph
 import com.vitorpamplona.amethyst.commons.richtext.ImageSegment
 import com.vitorpamplona.amethyst.commons.richtext.InvoiceSegment
 import com.vitorpamplona.amethyst.commons.richtext.LinkSegment
+import com.vitorpamplona.amethyst.commons.richtext.NowhereLinkSegment
 import com.vitorpamplona.amethyst.commons.richtext.ParagraphState
 import com.vitorpamplona.amethyst.commons.richtext.PdfSegment
 import com.vitorpamplona.amethyst.commons.richtext.PhoneSegment
@@ -481,6 +482,8 @@ private fun RenderWordWithoutPreview(
 
         is LinkSegment -> ClickableUrl(word.segmentText, word.segmentText)
 
+        is NowhereLinkSegment -> ClickableUrl(word.segmentText, word.segmentText)
+
         is EmojiSegment -> RenderCustomEmoji(word.segmentText, state)
 
         // Don't offer to pay invoices
@@ -530,6 +533,7 @@ private fun RenderWordWithPreview(
         is VideoSegment -> ZoomableContentView(word.segmentText, state, accountViewModel)
         is PdfSegment -> ZoomableContentView(word.segmentText, state, accountViewModel)
         is LinkSegment -> LoadUrlPreview(word.segmentText, word.segmentText, callbackUri, accountViewModel)
+        is NowhereLinkSegment -> NowhereLinkCard(word)
         is EmojiSegment -> RenderCustomEmoji(word.segmentText, state)
         is InvoiceSegment -> MayBeInvoicePreview(word.segmentText, accountViewModel)
         is WithdrawSegment -> MayBeWithdrawal(word.segmentText, accountViewModel)

commons/src/commonMain/kotlin/com/vitorpamplona/amethyst/commons/richtext/RichTextParser.kt

@@ -332,6 +332,10 @@ class RichTextParser {
             }
         }
 
+        if (urls.withoutScheme.contains(word) || urls.withScheme.contains(word)) {
+            parseNowhereLink(word)?.let { return it }
+        }
+
         if (urls.withoutScheme.contains(word)) return SchemelessUrlSegment(word)
 
         if (urls.withScheme.contains(word)) return LinkSegment(word)
@@ -529,6 +533,29 @@ class RichTextParser {
         }
 
         fun isUrlWithoutScheme(url: String) = noProtocolUrlValidator.matches(url)
+
+        // Nowhere links (https://github.com/5t34k/nowhere) encode an entire mini-site in the URL
+        // fragment. Servers never see the fragment, so OpenGraph previews return nothing useful
+        // (and hostednowhere.com 403s scrapers). Detect them by host + presence of a fragment
+        // so the renderer can show a branded card instead of falling through to LoadUrlPreview.
+        private val nowhereHosts = listOf("nowhr.xyz", "hostednowhere.com")
+
+        fun parseNowhereLink(word: String): NowhereLinkSegment? {
+            val afterScheme =
+                when {
+                    word.startsWith("https://", ignoreCase = true) -> word.substring(8)
+                    word.startsWith("http://", ignoreCase = true) -> word.substring(7)
+                    else -> word
+                }
+            val slash = afterScheme.indexOf('/')
+            if (slash < 0) return null
+            val host = afterScheme.substring(0, slash).lowercase()
+            if (host !in nowhereHosts) return null
+            val hash = afterScheme.indexOf('#', slash)
+            if (hash < 0) return null
+            val pathSegment = afterScheme.substring(slash + 1, hash).substringBefore('/').takeIf { it.isNotEmpty() }
+            return NowhereLinkSegment(word, host, pathSegment)
+        }
     }
 }
 

commons/src/commonMain/kotlin/com/vitorpamplona/amethyst/commons/richtext/RichTextParserSegments.kt

@@ -158,6 +158,13 @@ class SchemelessUrlSegment(
     segment: String,
 ) : Segment(segment)
 
+@Immutable
+class NowhereLinkSegment(
+    segment: String,
+    val host: String,
+    val tool: String?,
+) : Segment(segment)
+
 @Immutable
 class RegularTextSegment(
     segment: String,

commons/src/commonTest/kotlin/com/vitorpamplona/amethyst/commons/richtext/RichTextParserTest.kt

@@ -4400,6 +4400,35 @@ class RichTextParserTest {
             }
     }
 
+    @Test
+    fun testNowhereLinkInTheMiddleOfAPost() {
+        val text = "Check out my store https://nowhr.xyz/s#bYxNC4JAEEDRX7LbpcsirR9F1MW0jRDLPsEOMZaHinJTCzOl right now"
+        val state = RichTextParser().parseText(text, EmptyTagList, null)
+        val nowhere = state.paragraphs.flatMap { it.words }.firstOrNull { it is NowhereLinkSegment } as? NowhereLinkSegment
+        assertEquals("https://nowhr.xyz/s#bYxNC4JAEEDRX7LbpcsirR9F1MW0jRDLPsEOMZaHinJTCzOl", nowhere?.segmentText)
+        assertEquals("nowhr.xyz", nowhere?.host)
+        assertEquals("s", nowhere?.tool)
+    }
+
+    @Test
+    fun testHostedNowhereSchemelessLink() {
+        val text = "see hostednowhere.com/m#bYxNAB end"
+        val state = RichTextParser().parseText(text, EmptyTagList, null)
+        val nowhere = state.paragraphs.flatMap { it.words }.firstOrNull { it is NowhereLinkSegment } as? NowhereLinkSegment
+        assertEquals("hostednowhere.com/m#bYxNAB", nowhere?.segmentText)
+        assertEquals("hostednowhere.com", nowhere?.host)
+        assertEquals("m", nowhere?.tool)
+    }
+
+    @Test
+    fun testPlainNowhereHostWithoutFragmentStaysAsLink() {
+        // No fragment => not a nowhere site, fall through to LinkSegment.
+        val text = "Visit https://hostednowhere.com/manage to manage"
+        val state = RichTextParser().parseText(text, EmptyTagList, null)
+        val nowhere = state.paragraphs.flatMap { it.words }.firstOrNull { it is NowhereLinkSegment }
+        assertEquals(null, nowhere)
+    }
+
     private fun printStateForDebug(state: RichTextViewerState) {
         state.paragraphs.forEach { paragraph ->
             paragraph.words.forEach { seg ->