Add colors lambda

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

@@ -6,7 +6,7 @@ import dagger.hilt.android.lifecycle.HiltViewModel
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.StateFlow
 import org.session.libsession.utilities.TextSecurePreferences
-import org.thoughtcrime.securesms.ui.theme.selectedColorSet
+import org.thoughtcrime.securesms.ui.theme.cachedColors
 import org.thoughtcrime.securesms.util.ThemeState
 import org.thoughtcrime.securesms.util.themeState
 import javax.inject.Inject
@@ -22,8 +22,8 @@ class AppearanceSettingsViewModel @Inject constructor(private val prefs: TextSec
         // update UI state
         _uiState.value = prefs.themeState()
 
-        // force compose to refresh its style reference
-        selectedColorSet = null
+        // invalidate compose theme colors
+        cachedColors = null
     }
 
     fun setNewStyle(newThemeStyle: String) {
@@ -31,16 +31,15 @@ class AppearanceSettingsViewModel @Inject constructor(private val prefs: TextSec
         // update UI state
         _uiState.value = prefs.themeState()
 
-        // force compose to refresh its style reference
-        selectedColorSet = null
+        // invalidate compose theme colors
+        cachedColors = null
     }
 
     fun setNewFollowSystemSettings(followSystemSettings: Boolean) {
         prefs.setFollowSystemSettings(followSystemSettings)
         _uiState.value = prefs.themeState()
 
-        // force compose to refresh its style reference
-        selectedColorSet = null
+        // invalidate compose theme colors
+        cachedColors = null
     }
-
-}
+}

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

@@ -1,12 +0,0 @@
-package org.thoughtcrime.securesms.ui.theme
-
-/**
- * This class holds two instances of [ThemeColors], [light] representing the [ThemeColors] to use when the system is in a
- * light theme, and [dark] representing the [ThemeColors] to use when the system is in a dark theme.
- */
-data class ThemeColorSet(
-    val colorsWhenSystemInLight: ThemeColors,
-    val colorsWhenSystemInDark: ThemeColors
-) {
-    fun get(isDark: Boolean): ThemeColors = if (isDark) colorsWhenSystemInDark else colorsWhenSystemInLight
-}

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

@@ -17,27 +17,27 @@ 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
  */
-fun TextSecurePreferences.getColorSet(): ThemeColorSet {
+val TextSecurePreferences.colors: @Composable () -> ThemeColors get() {
     val selectedTheme = getThemeStyle()
 
     // get the chosen primary color from the preferences
     val selectedPrimary = primaryColor()
 
-    val createLight = if ("ocean" in selectedTheme) ::OceanLight else ::ClassicLight
-    val createDark = if ("ocean" in selectedTheme) ::OceanDark else ::ClassicDark
+    val isOcean = "ocean" in selectedTheme
 
-    val followSystemSettings = getFollowSystemSettings()
+    val createLight = if (isOcean) ::OceanLight else ::ClassicLight
+    val createDark = if (isOcean) ::OceanDark else ::ClassicDark
 
-    return if (followSystemSettings) ThemeColorSet(
-        colorsWhenSystemInLight = createLight(selectedPrimary),
-        colorsWhenSystemInDark = createDark(selectedPrimary)
-    ) else {
-        val both = if ("light" in selectedTheme) createLight(selectedPrimary) else createDark(selectedPrimary)
+    // 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)
 
-        ThemeColorSet(
-            colorsWhenSystemInLight = both,
-            colorsWhenSystemInDark = both
-        )
+    return when {
+        getFollowSystemSettings() -> { { if (isSystemInDarkTheme()) dark else light } }
+        "light" in selectedTheme -> { { light } }
+        else -> { { dark } }
     }
 }
 

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

@@ -16,13 +16,12 @@ import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.tooling.preview.PreviewParameterProvider
 import androidx.compose.ui.unit.dp
 import org.session.libsession.utilities.AppTextSecurePreferences
-import org.session.libsession.utilities.TextSecurePreferences
 
 // Globally accessible composition local objects
 val LocalColors = compositionLocalOf <ThemeColors> { ClassicDark() }
 val LocalType = compositionLocalOf { sessionTypography }
 
-var selectedColorSet: ThemeColorSet? = null
+var cachedColors: (@Composable () -> ThemeColors)? = null
 
 /**
  * Apply a Material2 compose theme based on user selections in SharedPreferences.
@@ -34,10 +33,10 @@ fun SessionMaterialTheme(
     val context = LocalContext.current
     val preferences = AppTextSecurePreferences(context)
 
-    val selectedColorSet = selectedColorSet ?: preferences.getColorSet().also { selectedColorSet = it }
+    val cachedColors = cachedColors ?: preferences.colors.also { cachedColors = it }
 
     SessionMaterialTheme(
-        colors = selectedColorSet.get(isSystemInDarkTheme()),
+        colors = cachedColors(),
         content = content
     )
 }