From 15169de7e5bb851a09c5d222230d744928d4f224 Mon Sep 17 00:00:00 2001
From: Claude <noreply@anthropic.com>
Date: Mon, 27 Apr 2026 19:46:18 +0000
Subject: [PATCH] fix(nests): drop themed colors when palette is incomplete
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EGG-10 lets each `["c", hex, role]` tag stand alone, but a half-
applied palette (themed background + platform text, or themed text
+ platform background) collides with whichever system theme — light
or dark — the user is on. A room that ships ONLY `background=#FFE4B5`
ends up with platform-default white text on dark theme; unreadable.

Gate all three color overrides on having a complete bg + text pair
inside `RoomTheme.from(event)`. When either is missing the whole
palette drops to null and renderers fall through to the platform
theme. Background image (`bg`) and font tags still flow through —
they don't break contrast on their own.

Both consumers — NestThemedScope (room screen) and NestJoinCard
(lobby) — pick up the change without code edits because they read
through the same `RoomTheme` projection.

The nostrnests-style `["color", "gradient-7"]` tag was never parsed
(our `c`-tag parser ignores it), so events shipping only that don't
override anything either way; this fix targets the genuine half-
applied case (rooms that emit one EGG-10 c-tag without the matching
companion).

https://claude.ai/code/session_01RDpuki4t8StSg1CZcXnV5b
---
 .../amethyst/commons/viewmodels/RoomTheme.kt  | 25 ++++++++++++++++---
 1 file changed, 22 insertions(+), 3 deletions(-)

diff --git a/commons/src/commonMain/kotlin/com/vitorpamplona/amethyst/commons/viewmodels/RoomTheme.kt b/commons/src/commonMain/kotlin/com/vitorpamplona/amethyst/commons/viewmodels/RoomTheme.kt
index 0b0185f0f7..3604d37249 100644
--- a/commons/src/commonMain/kotlin/com/vitorpamplona/amethyst/commons/viewmodels/RoomTheme.kt
+++ b/commons/src/commonMain/kotlin/com/vitorpamplona/amethyst/commons/viewmodels/RoomTheme.kt
@@ -89,10 +89,29 @@ data class RoomTheme(
                     ?.hex
                     ?.let { hexToOpaqueArgb(it) }
 
+            val backgroundArgb = pickHex(ColorTag.Target.BACKGROUND)
+            val textArgb = pickHex(ColorTag.Target.TEXT)
+            val primaryArgb = pickHex(ColorTag.Target.PRIMARY)
+
+            // EGG-10 lets each `["c", hex, role]` tag stand alone, but
+            // a half-applied palette (themed bg + platform text, or
+            // themed text + platform bg) collides with whichever
+            // system theme — light or dark — the user is on. A room
+            // that ships ONLY `background=#FFE4B5` (a light cream)
+            // ends up with platform-default white text on dark theme;
+            // unreadable.
+            //
+            // Gate ALL three color overrides on having a complete
+            // bg + text pair. When either is missing we drop the
+            // whole palette and fall back to the platform theme;
+            // background image (`bg`) and font tags still flow
+            // through (they don't break contrast on their own).
+            val hasReadablePalette = backgroundArgb != null && textArgb != null
+
             return RoomTheme(
-                backgroundArgb = pickHex(ColorTag.Target.BACKGROUND),
-                textArgb = pickHex(ColorTag.Target.TEXT),
-                primaryArgb = pickHex(ColorTag.Target.PRIMARY),
+                backgroundArgb = if (hasReadablePalette) backgroundArgb else null,
+                textArgb = if (hasReadablePalette) textArgb else null,
+                primaryArgb = if (hasReadablePalette) primaryArgb else null,
                 backgroundImageUrl = bg?.url,
                 backgroundMode =
                     when (bg?.mode) {