AppColorsTheme.kt

@Composable
private fun App() {
    val isDarkMode = isSystemInDarkTheme()
    val (darkMode, setDarkMode) = remember { mutableStateOf(isDarkMode) }
    AppTheme(darkTheme = darkMode) {
        Switch(checked = darkMode, onCheckedChange = setDarkMode)
        Text("${AppTheme.colors.onSurfaceInputBackground.toArgb()}")
    }
}

private val DarkAppColors = AppColors(
    onSurfaceInputBackground = Color.Red,
    darkColors(
        primary = Color.Black,
    )
)

private val LightAppColors = AppColors(
    onSurfaceInputBackground = Color.Blue,
    lightColors(
        primary = Color.White,
    )
)

@Composable
fun AppTheme(
    darkTheme: Boolean = isSystemInDarkTheme(),
    content: @Composable () -> Unit
) {
    val colors = if (darkTheme) DarkAppColors else LightAppColors

    ProvideAppColors(colors) {
        MaterialTheme(
            colors = colors.materialColors,
            typography = Typography,
            shapes = Shapes,
            content = content
        )
    }
}

@Stable
class AppColors(
    onSurfaceInputBackground: Color,
    materialColors: Colors
) {
    var onSurfaceInputBackground by mutableStateOf(onSurfaceInputBackground)
        private set
    var materialColors by mutableStateOf(materialColors)
        private set

    fun update(other: AppColors) {
        onSurfaceInputBackground = other.onSurfaceInputBackground
        materialColors = other.materialColors
    }

    fun copy() = AppColors(this.onSurfaceInputBackground, this.materialColors)
}

@Composable
fun ProvideAppColors(
    colors: AppColors,
    content: @Composable () -> Unit
) {
    val appColors = remember { colors.copy() }.apply { update(colors) }

    CompositionLocalProvider(
        LocalAppColors provides appColors,
        content = content
    )
}

private val LocalAppColors = staticCompositionLocalOf<AppColors> {
    error("No AppColors provided")
}

object AppTheme {
    val colors: AppColors
        @Composable
        get() = LocalAppColors.current
}