@Stable
class ColorScheme(
    primary: Color,						// ... プロパティへ格納
    onPrimary: Color,	　　　　　　　　// ... プロパティへ格納
    primaryContainer: Color,
    onPrimaryContainer: Color,
    inversePrimary: Color,
    secondary: Color,
    onSecondary: Color,
    secondaryContainer: Color,
    onSecondaryContainer: Color,
    tertiary: Color,
    onTertiary: Color,
    tertiaryContainer: Color,
    onTertiaryContainer: Color,
    background: Color,
    onBackground: Color,
    surface: Color,
    onSurface: Color,
    surfaceVariant: Color,
    onSurfaceVariant: Color,
    surfaceTint: Color,
    inverseSurface: Color,
    inverseOnSurface: Color,
    error: Color,
    onError: Color,
    errorContainer: Color,
    onErrorContainer: Color,
    outline: Color,
    outlineVariant: Color,
    scrim: Color,
) {
    var primary by mutableStateOf(primary, structuralEqualityPolicy())
        internal set
    var onPrimary by mutableStateOf(onPrimary, structuralEqualityPolicy())
        internal set
    ...
}

fun darkColorScheme(
    primary: Color = ColorDarkTokens.Primary,		// デフォルト値（定数）
    onPrimary: Color = ColorDarkTokens.OnPrimary,	// デフォルト値（定数）
	...
): ColorScheme =
    ColorScheme(
        primary = primary,
        onPrimary = onPrimary,
		...
	)

private val DarkColorScheme = darkColorScheme(
    primary = Purple80,				// アプリ専用の色
    secondary = PurpleGrey80,		// 同上
	tertiary = Pink80				// 同上
)

val Purple80 = Color(0xFFD0BCFF)		// Dark用
val PurpleGrey80 = Color(0xFFCCC2DC)
val Pink80 = Color(0xFFEFB8C8)

val Purple40 = Color(0xFF6650a4)		// Light用
val PurpleGrey40 = Color(0xFF625b71)
val Pink40 = Color(0xFF7D5260)

@RequiresApi(Build.VERSION_CODES.S)
fun dynamicDarkColorScheme(context: Context): ColorScheme {
    val tonalPalette = dynamicTonalPalette(context)	// 壁紙に合わせた配色が返る
    return darkColorScheme(
        primary = tonalPalette.primary80,			// アプリ専用の色
        onPrimary = tonalPalette.primary20,			// 同上
        ...
    )
}

@Composable
fun MyApplicationTheme(
    darkTheme: Boolean = isSystemInDarkTheme(),
    // Dynamic color is available on Android 12+
    dynamicColor: Boolean = true,
    content: @Composable () -> Unit
) {
    val colorScheme = when {
        dynamicColor && Build.VERSION.SDK_INT >= Build.VERSION_CODES.S -> {
            val context = LocalContext.current
            if (darkTheme) dynamicDarkColorScheme(context) 
			else dynamicLightColorScheme(context)
        }

        darkTheme -> DarkColorScheme
        else -> LightColorScheme
    }
    val view = LocalView.current
    if (!view.isInEditMode) {
        SideEffect {
            val window = (view.context as Activity).window
            window.statusBarColor = colorScheme.primary.toArgb()
            WindowCompat.getInsetsController(window, view)
			    .isAppearanceLightStatusBars = darkTheme
        }
    }

    MaterialTheme(
        colorScheme = colorScheme,
        typography = Typography,
        content = content
    )
}

@Composable
fun MyApplicationTheme(
    darkTheme: Boolean = isSystemInDarkTheme(),
    // Dynamic color is available on Android 12+
    dynamicColor: Boolean = true,
    content: @Composable () -> Unit
) {
    val colorScheme = when {
        dynamicColor && Build.VERSION.SDK_INT >= Build.VERSION_CODES.S -> {
            val context = LocalContext.current
            if (darkTheme) dynamicDarkColorScheme(context) 
			else dynamicLightColorScheme(context)
        }

        darkTheme -> DarkColorScheme
        else -> LightColorScheme
    }
    val view = LocalView.current
    if (!view.isInEditMode) {
        SideEffect {
            val window = (view.context as Activity).window
            window.statusBarColor = colorScheme.primary.toArgb()
            WindowCompat.getInsetsController(window, view)
			    .isAppearanceLightStatusBars = darkTheme
        }
    }

    MaterialTheme(
        colorScheme = colorScheme,
        typography = Typography,
        content = content
    )
}

@Composable
fun MaterialTheme(
    colorScheme: ColorScheme = MaterialTheme.colorScheme,
    shapes: Shapes = MaterialTheme.shapes,
    typography: Typography = MaterialTheme.typography,
    content: @Composable () -> Unit
) {
    val rememberedColorScheme = remember {
        // Explicitly creating a new object here so we don't mutate the initial [colorScheme]
        // provided, and overwrite the values set in it.
        colorScheme.copy()
    }.apply {
        updateColorSchemeFrom(colorScheme)
    }
    val rippleIndication = rememberRipple()
    val selectionColors = rememberTextSelectionColors(rememberedColorScheme)
    CompositionLocalProvider(
        LocalColorScheme provides rememberedColorScheme,
        LocalIndication provides rippleIndication,
        LocalRippleTheme provides MaterialRippleTheme,
        LocalShapes provides shapes,
        LocalTextSelectionColors provides selectionColors,
        LocalTypography provides typography,
    ) {
        ProvideTextStyle(value = typography.bodyLarge, content = content)
    }
}

object MaterialTheme {
    /**
     * Retrieves the current [ColorScheme] at the call site's position in ...
     */
    val colorScheme: ColorScheme
        @Composable
        @ReadOnlyComposable
        get() = LocalColorScheme.current	// 定義を取り出す

    /**
     * Retrieves the current [Typography] at the call site's position in ...
     */
    val typography: Typography
        @Composable
        @ReadOnlyComposable
        get() = LocalTypography.current		// 定義を取り出す

    /**
     * Retrieves the current [Shapes] at the call site's position in ...
     */
    val shapes: Shapes
        @Composable
        @ReadOnlyComposable
        get() = LocalShapes.current			// 定義を取り出す
}

class MainActivity : ComponentActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContent {
            MyApplicationTheme {
                // A surface container using the 'background' color from the theme
                Surface(
                    modifier = Modifier.fillMaxSize(),
                    color = MaterialTheme.colorScheme.background
                ) {
                    Greeting("Android")
                }
            }
        }
    }
}