feat: render inline image links as the notification big picture

When a mention/article body contains an inline `http(s)` image link, show the
image as the notification's big picture (BigPictureStyle) instead of leaving the
raw URL in the text. NotificationContent.renderNoteText() now pulls the first
image URL out of the content — scanning all lines, since images usually sit on
their own line — using the cheap RichTextParser.isImageUrl extension check, and
strips that link from the excerpt. Videos are left in the text (Coil can't load
them as a still). The Mention and Article renderers pass the extracted URL as
bigPictureUrl; Reply stays MessagingStyle (a big picture doesn't fit a chat
bubble) and keeps its text as-is.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0122uQ8BLHLeHDni81RBP26r

amethyst/src/main/java/com/vitorpamplona/amethyst/service/notifications/NotificationContent.kt

@@ -20,6 +20,7 @@
  */
 package com.vitorpamplona.amethyst.service.notifications
 
+import com.vitorpamplona.amethyst.commons.richtext.RichTextParser
 import com.vitorpamplona.amethyst.model.LocalCache
 import com.vitorpamplona.amethyst.model.Note
 import com.vitorpamplona.amethyst.model.User
@@ -114,6 +115,66 @@ object NotificationContent {
         return ResolvedText(rewritten.take(max), cited)
     }
 
+    /**
+     * The result of [renderNoteText]: [ResolvedText] plus [imageUrl], the first
+     * inline image link found anywhere in the note. When present, a renderer shows
+     * it as the notification's big picture and the link is stripped from [text] —
+     * so a mention whose body is "look at this https://…/cat.jpg" shows the photo
+     * instead of the raw URL.
+     */
+    data class RenderedText(
+        val text: String,
+        val citedUsers: List<User>,
+        val imageUrl: String?,
+    )
+
+    private val whitespace = Regex("\\s+")
+    private val trailingPunctuation = charArrayOf('.', ',', ')', '(', '!', '?', ';', ':', '"', '\'')
+
+    /**
+     * The first `http(s)` image URL in [content] (anywhere, not only the first
+     * line — images are usually on their own line), or null. Trailing sentence
+     * punctuation is trimmed so "…/cat.jpg." still resolves. Videos are ignored:
+     * Coil can't load them as a still, so their link stays in the text.
+     */
+    fun firstImageUrl(content: String?): String? {
+        if (content == null) return null
+        content.split(whitespace).forEach { raw ->
+            if (!raw.startsWith("http://", ignoreCase = true) && !raw.startsWith("https://", ignoreCase = true)) {
+                return@forEach
+            }
+            val url = raw.trimEnd(*trailingPunctuation)
+            if (RichTextParser.isImageUrl(url)) return url
+        }
+        return null
+    }
+
+    /**
+     * [resolveMentions] plus inline-image extraction: resolves `@npub` mentions,
+     * pulls the first image link out as [RenderedText.imageUrl], and removes that
+     * link from the excerpt text (collapsing the whitespace it leaves behind).
+     */
+    fun renderNoteText(
+        content: String?,
+        max: Int = 280,
+    ): RenderedText {
+        val resolved = resolveMentions(content, max = Int.MAX_VALUE)
+        val imageUrl = firstImageUrl(content)
+
+        val text =
+            if (imageUrl != null) {
+                resolved.text
+                    .replace(imageUrl, "")
+                    .replace(whitespace, " ")
+                    .trim()
+                    .take(max)
+            } else {
+                resolved.text.take(max)
+            }
+
+        return RenderedText(text, resolved.citedUsers, imageUrl)
+    }
+
     suspend fun decryptZapContentAuthor(
         event: LnZapRequestEvent,
         signer: NostrSigner,

amethyst/src/main/java/com/vitorpamplona/amethyst/service/notifications/renderers/ArticleNotification.kt

@@ -61,7 +61,7 @@ object ArticleNotification {
                 R.string.app_notification_articles_channel_message
             }
         val bodySource = if (event is HighlightEvent) event.quote() else event.content
-        val citedUsers = NotificationContent.resolveMentions(bodySource).citedUsers
+        val rendered = NotificationContent.renderNoteText(bodySource)
 
         val nm = context.notificationManager()
 
@@ -69,22 +69,24 @@ object ArticleNotification {
             context = context,
             account = account,
             notificationId = event.id,
-            users = listOf(author) + citedUsers,
+            users = listOf(author) + rendered.citedUsers,
             notes = listOf(note),
             isComplete = {
                 author.metadataOrNull()?.bestName() != null &&
-                    citedUsers.all { it.metadataOrNull()?.bestName() != null }
+                    rendered.citedUsers.all { it.metadataOrNull()?.bestName() != null }
             },
         ) {
+            val body = NotificationContent.renderNoteText(bodySource)
             nm.postStandard(
                 category = NotificationCategory.ARTICLE,
                 id = event.id,
                 messageTitle = stringRes(context, titleRes, author.toBestDisplayName()),
-                messageBody = NotificationContent.resolveMentions(bodySource).text,
+                messageBody = body.text,
                 time = event.createdAt,
                 pictureUrl = author.profilePicture(),
                 uri = uri,
                 applicationContext = context,
+                bigPictureUrl = body.imageUrl,
             )
         }
     }

amethyst/src/main/java/com/vitorpamplona/amethyst/service/notifications/renderers/MentionNotification.kt

@@ -59,8 +59,9 @@ object MentionNotification {
         val uri = NotificationRoutes.noteUri(note, accountNpub)
 
         // Users cited inline in the text (nostr:npub/nprofile) are observed too, so
-        // their names fill in as their kind:0 metadata arrives.
-        val citedUsers = NotificationContent.resolveMentions(event.content).citedUsers
+        // their names fill in as their kind:0 metadata arrives. An inline image link
+        // is rendered as the big picture instead of shown as a raw URL.
+        val rendered = NotificationContent.renderNoteText(event.content)
 
         val nm = context.notificationManager()
 
@@ -68,22 +69,24 @@ object MentionNotification {
             context = context,
             account = account,
             notificationId = event.id,
-            users = listOf(author) + citedUsers,
+            users = listOf(author) + rendered.citedUsers,
             notes = listOf(note),
             isComplete = {
                 author.metadataOrNull()?.bestName() != null &&
-                    citedUsers.all { it.metadataOrNull()?.bestName() != null }
+                    rendered.citedUsers.all { it.metadataOrNull()?.bestName() != null }
             },
         ) {
+            val body = NotificationContent.renderNoteText(event.content)
             nm.postStandard(
                 category = category,
                 id = event.id,
                 messageTitle = stringRes(context, titleRes, author.toBestDisplayName()),
-                messageBody = NotificationContent.resolveMentions(event.content).text,
+                messageBody = body.text,
                 time = event.createdAt,
                 pictureUrl = author.profilePicture(),
                 uri = uri,
                 applicationContext = context,
+                bigPictureUrl = body.imageUrl,
             )
         }
     }

amethyst/src/test/java/com/vitorpamplona/amethyst/service/notifications/NotificationContentMentionTest.kt

@@ -103,4 +103,38 @@ class NotificationContentMentionTest {
         assertEquals("just a normal note with no tags", resolved.text)
         assertTrue(resolved.citedUsers.isEmpty())
     }
+
+    @Test
+    fun `an inline image link is pulled out as the big picture and stripped from the body`() {
+        val rendered = NotificationContent.renderNoteText("look at this https://example.com/cat.jpg amazing")
+
+        assertEquals("https://example.com/cat.jpg", rendered.imageUrl)
+        assertEquals("look at this amazing", rendered.text)
+    }
+
+    @Test
+    fun `an image url on its own line becomes the big picture while the caption stays the body`() {
+        val rendered = NotificationContent.renderNoteText("Check out my new photo\nhttps://example.com/pic.png")
+
+        assertEquals("https://example.com/pic.png", rendered.imageUrl)
+        assertEquals("Check out my new photo", rendered.text)
+    }
+
+    @Test
+    fun `trailing punctuation after an image url is trimmed`() {
+        assertEquals("https://example.com/a.webp", NotificationContent.firstImageUrl("nice pic https://example.com/a.webp."))
+    }
+
+    @Test
+    fun `a video link is not treated as an image and stays in the text`() {
+        val rendered = NotificationContent.renderNoteText("watch https://example.com/clip.mp4 now")
+
+        assertEquals(null, rendered.imageUrl)
+        assertTrue(rendered.text.contains("https://example.com/clip.mp4"))
+    }
+
+    @Test
+    fun `a bare filename without a url scheme is not mistaken for an image`() {
+        assertEquals(null, NotificationContent.firstImageUrl("my file is called cat.jpg locally"))
+    }
 }