Minor refactor of theming when expressions (mihonapp#396)

* Minor refactor of theming when expressions

Avoids triggering detekt's CyclomaticComplexMethod warning because of
too many when branches, which would happen with one more theme being
added in these two locations.

In TachiyomiTheme, the Monet theme is separated because it requires
the current Compose context to function. The other themes do not and
are delegated to a Map.

* Implement requested changes

- moved themeResources out of the ThemingDelegate interface
- replaced single condition when with if expression

app/src/main/java/eu/kanade/presentation/theme/TachiyomiTheme.kt

@@ -8,6 +8,7 @@ import androidx.compose.runtime.ReadOnlyComposable
 import androidx.compose.ui.platform.LocalContext
 import eu.kanade.domain.ui.UiPreferences
 import eu.kanade.domain.ui.model.AppTheme
+import eu.kanade.presentation.theme.colorscheme.BaseColorScheme
 import eu.kanade.presentation.theme.colorscheme.GreenAppleColorScheme
 import eu.kanade.presentation.theme.colorscheme.LavenderColorScheme
 import eu.kanade.presentation.theme.colorscheme.MidnightDuskColorScheme
@@ -62,23 +63,27 @@ private fun getThemeColorScheme(
     appTheme: AppTheme,
     isAmoled: Boolean,
 ): ColorScheme {
-    val colorScheme = when (appTheme) {
-        AppTheme.DEFAULT -> TachiyomiColorScheme
-        AppTheme.MONET -> MonetColorScheme(LocalContext.current)
-        AppTheme.GREEN_APPLE -> GreenAppleColorScheme
-        AppTheme.LAVENDER -> LavenderColorScheme
-        AppTheme.MIDNIGHT_DUSK -> MidnightDuskColorScheme
-        AppTheme.NORD -> NordColorScheme
-        AppTheme.STRAWBERRY_DAIQUIRI -> StrawberryColorScheme
-        AppTheme.TAKO -> TakoColorScheme
-        AppTheme.TEALTURQUOISE -> TealTurqoiseColorScheme
-        AppTheme.TIDAL_WAVE -> TidalWaveColorScheme
-        AppTheme.YINYANG -> YinYangColorScheme
-        AppTheme.YOTSUBA -> YotsubaColorScheme
-        else -> TachiyomiColorScheme
+    val colorScheme = if (appTheme == AppTheme.MONET) {
+        MonetColorScheme(LocalContext.current)
+    } else {
+        colorSchemes.getOrDefault(appTheme, TachiyomiColorScheme)
     }
     return colorScheme.getColorScheme(
         isSystemInDarkTheme(),
         isAmoled,
     )
 }
+
+private val colorSchemes: Map<AppTheme, BaseColorScheme> = mapOf(
+    AppTheme.DEFAULT to TachiyomiColorScheme,
+    AppTheme.GREEN_APPLE to GreenAppleColorScheme,
+    AppTheme.LAVENDER to LavenderColorScheme,
+    AppTheme.MIDNIGHT_DUSK to MidnightDuskColorScheme,
+    AppTheme.NORD to NordColorScheme,
+    AppTheme.STRAWBERRY_DAIQUIRI to StrawberryColorScheme,
+    AppTheme.TAKO to TakoColorScheme,
+    AppTheme.TEALTURQUOISE to TealTurqoiseColorScheme,
+    AppTheme.TIDAL_WAVE to TidalWaveColorScheme,
+    AppTheme.YINYANG to YinYangColorScheme,
+    AppTheme.YOTSUBA to YotsubaColorScheme,
+)

app/src/main/java/eu/kanade/tachiyomi/ui/base/delegate/ThemingDelegate.kt

@@ -12,51 +12,10 @@ interface ThemingDelegate {
 
     companion object {
         fun getThemeResIds(appTheme: AppTheme, isAmoled: Boolean): List<Int> {
-            val resIds = mutableListOf<Int>()
-            when (appTheme) {
-                AppTheme.MONET -> {
-                    resIds += R.style.Theme_Tachiyomi_Monet
-                }
-                AppTheme.GREEN_APPLE -> {
-                    resIds += R.style.Theme_Tachiyomi_GreenApple
-                }
-                AppTheme.LAVENDER -> {
-                    resIds += R.style.Theme_Tachiyomi_Lavender
-                }
-                AppTheme.MIDNIGHT_DUSK -> {
-                    resIds += R.style.Theme_Tachiyomi_MidnightDusk
-                }
-                AppTheme.NORD -> {
-                    resIds += R.style.Theme_Tachiyomi_Nord
-                }
-                AppTheme.STRAWBERRY_DAIQUIRI -> {
-                    resIds += R.style.Theme_Tachiyomi_StrawberryDaiquiri
-                }
-                AppTheme.TAKO -> {
-                    resIds += R.style.Theme_Tachiyomi_Tako
-                }
-                AppTheme.TEALTURQUOISE -> {
-                    resIds += R.style.Theme_Tachiyomi_TealTurquoise
-                }
-                AppTheme.YINYANG -> {
-                    resIds += R.style.Theme_Tachiyomi_YinYang
-                }
-                AppTheme.YOTSUBA -> {
-                    resIds += R.style.Theme_Tachiyomi_Yotsuba
-                }
-                AppTheme.TIDAL_WAVE -> {
-                    resIds += R.style.Theme_Tachiyomi_TidalWave
-                }
-                else -> {
-                    resIds += R.style.Theme_Tachiyomi
-                }
+            return buildList(2) {
+                add(themeResources.getOrDefault(appTheme, R.style.Theme_Tachiyomi))
+                if (isAmoled) add(R.style.ThemeOverlay_Tachiyomi_Amoled)
             }
-
-            if (isAmoled) {
-                resIds += R.style.ThemeOverlay_Tachiyomi_Amoled
-            }
-
-            return resIds
         }
     }
 }
@@ -68,3 +27,17 @@ class ThemingDelegateImpl : ThemingDelegate {
             .forEach(activity::setTheme)
     }
 }
+
+private val themeResources: Map<AppTheme, Int> = mapOf(
+    AppTheme.MONET to R.style.Theme_Tachiyomi_Monet,
+    AppTheme.GREEN_APPLE to R.style.Theme_Tachiyomi_GreenApple,
+    AppTheme.LAVENDER to R.style.Theme_Tachiyomi_Lavender,
+    AppTheme.MIDNIGHT_DUSK to R.style.Theme_Tachiyomi_MidnightDusk,
+    AppTheme.NORD to R.style.Theme_Tachiyomi_Nord,
+    AppTheme.STRAWBERRY_DAIQUIRI to R.style.Theme_Tachiyomi_StrawberryDaiquiri,
+    AppTheme.TAKO to R.style.Theme_Tachiyomi_Tako,
+    AppTheme.TEALTURQUOISE to R.style.Theme_Tachiyomi_TealTurquoise,
+    AppTheme.YINYANG to R.style.Theme_Tachiyomi_YinYang,
+    AppTheme.YOTSUBA to R.style.Theme_Tachiyomi_Yotsuba,
+    AppTheme.TIDAL_WAVE to R.style.Theme_Tachiyomi_TidalWave,
+)