Simplify ThemeFromPreferences by removing lambdas

app/src/main/java/org/thoughtcrime/securesms/preferences/appearance/AppearanceSettingsViewModel.kt

@@ -17,13 +17,17 @@ class AppearanceSettingsViewModel @Inject constructor(private val prefs: TextSec
     private val _uiState = MutableStateFlow(prefs.themeState())
     val uiState: StateFlow<ThemeState> = _uiState
 
+    fun invalidateComposeThemeColors() {
+        // invalidate compose theme colors
+        cachedColors = null
+    }
+
     fun setNewAccent(@StyleRes newAccentColorStyle: Int) {
         prefs.setAccentColorStyle(newAccentColorStyle)
         // update UI state
         _uiState.value = prefs.themeState()
 
-        // invalidate compose theme colors
-        cachedColors = null
+        invalidateComposeThemeColors()
     }
 
     fun setNewStyle(newThemeStyle: String) {
@@ -31,15 +35,13 @@ class AppearanceSettingsViewModel @Inject constructor(private val prefs: TextSec
         // update UI state
         _uiState.value = prefs.themeState()
 
-        // invalidate compose theme colors
-        cachedColors = null
+        invalidateComposeThemeColors()
     }
 
     fun setNewFollowSystemSettings(followSystemSettings: Boolean) {
         prefs.setFollowSystemSettings(followSystemSettings)
         _uiState.value = prefs.themeState()
 
-        // invalidate compose theme colors
-        cachedColors = null
+        invalidateComposeThemeColors()
     }
 }

app/src/main/java/org/thoughtcrime/securesms/ui/theme/MaybeFollowSystemColors.kt

@@ -0,0 +1,18 @@
+package org.thoughtcrime.securesms.ui.theme
+
+import androidx.compose.foundation.isSystemInDarkTheme
+import androidx.compose.runtime.Composable
+
+fun interface MaybeFollowSystemColors {
+    @Composable
+    fun get(): ThemeColors
+}
+
+fun FollowSystemColors(light: ThemeColors, dark: ThemeColors) = MaybeFollowSystemColors {
+    when {
+        isSystemInDarkTheme() -> dark
+        else -> light
+    }
+}
+
+fun IgnoreSystemColors(colors: ThemeColors) = MaybeFollowSystemColors { colors }

app/src/main/java/org/thoughtcrime/securesms/ui/theme/ThemeFromPreferences.kt

@@ -17,7 +17,7 @@ import org.session.libsession.utilities.TextSecurePreferences.Companion.YELLOW_A
  * Some behaviour is hardcoded to cater for legacy usage of people with themes already set
  * But future themes will be picked and set directly from the "Appearance" screen
  */
-val TextSecurePreferences.colors: @Composable () -> ThemeColors get() {
+val TextSecurePreferences.colors: MaybeFollowSystemColors get() {
     val selectedTheme = getThemeStyle()
 
     // get the chosen primary color from the preferences
@@ -28,16 +28,13 @@ val TextSecurePreferences.colors: @Composable () -> ThemeColors get() {
     val createLight = if (isOcean) ::OceanLight else ::ClassicLight
     val createDark = if (isOcean) ::OceanDark else ::ClassicDark
 
-    // create the light and dark themes outside the lambda to avoid creating them every time
-    // [SessionMaterialTheme] is called. Creating both when we don't followSystemSettings is but a
-    // minor inefficiency that increases readability.
-    val light = createLight(selectedPrimary)
-    val dark = createDark(selectedPrimary)
-
     return when {
-        getFollowSystemSettings() -> { { if (isSystemInDarkTheme()) dark else light } }
-        "light" in selectedTheme -> { { light } }
-        else -> { { dark } }
+        getFollowSystemSettings() -> FollowSystemColors(
+            light = createLight(selectedPrimary),
+            dark = createDark(selectedPrimary)
+        )
+        "light" in selectedTheme -> IgnoreSystemColors(createLight(selectedPrimary))
+        else -> IgnoreSystemColors(createDark(selectedPrimary))
     }
 }
 
@@ -50,6 +47,3 @@ fun TextSecurePreferences.primaryColor(): Color = when(getSelectedAccentColor())
     YELLOW_ACCENT -> primaryYellow
     else -> primaryGreen
 }
-
-
-

app/src/main/java/org/thoughtcrime/securesms/ui/theme/Themes.kt

@@ -1,7 +1,6 @@
 package org.thoughtcrime.securesms.ui.theme
 
 import androidx.compose.foundation.background
-import androidx.compose.foundation.isSystemInDarkTheme
 import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.shape.RoundedCornerShape
 import androidx.compose.foundation.text.selection.LocalTextSelectionColors
@@ -21,7 +20,7 @@ import org.session.libsession.utilities.AppTextSecurePreferences
 val LocalColors = compositionLocalOf <ThemeColors> { ClassicDark() }
 val LocalType = compositionLocalOf { sessionTypography }
 
-var cachedColors: (@Composable () -> ThemeColors)? = null
+var cachedColors: MaybeFollowSystemColors? = null
 
 /**
  * Apply a Material2 compose theme based on user selections in SharedPreferences.
@@ -33,10 +32,10 @@ fun SessionMaterialTheme(
     val context = LocalContext.current
     val preferences = AppTextSecurePreferences(context)
 
-    val cachedColors = cachedColors ?: preferences.colors.also { cachedColors = it }
+    val jjcachedColors = cachedColors ?: preferences.colors.also { cachedColors = it }
 
     SessionMaterialTheme(
-        colors = cachedColors(),
+        colors = cachedColors.get(),
         content = content
     )
 }
@@ -59,9 +58,8 @@ fun SessionMaterialTheme(
             LocalType provides sessionTypography,
             LocalContentColor provides colors.text,
             LocalTextSelectionColors provides colors.textSelectionColors,
-        ) {
-            content()
-        }
+            content = content
+        )
     }
 }