From 3738198ba97250f7e48a3830aae9e71dafe08b6a Mon Sep 17 00:00:00 2001
From: Zoe Roux <zoe.roux@sdg.moe>
Date: Sat, 5 Nov 2022 18:58:44 +0900
Subject: [PATCH] Convert css to a hook useCss

---
 examples/expo-example/metro.config.js |  5 +-
 examples/expo-example/src/app.tsx     | 12 +++--
 packages/native/src/index.tsx         | 75 ++++++++++++++++++---------
 3 files changed, 61 insertions(+), 31 deletions(-)

diff --git a/examples/expo-example/metro.config.js b/examples/expo-example/metro.config.js
index ad0672d..f79958b 100644
--- a/examples/expo-example/metro.config.js
+++ b/examples/expo-example/metro.config.js
@@ -14,10 +14,7 @@ const workspaceRoot = path.resolve(projectRoot, "../..");
 const config = getDefaultConfig(projectRoot);
 
 // 1. Watch all files within the monorepo
-config.watchFolders = [
-	path.resolve(workspaceRoot, "examples/expo-example"),
-	path.resolve(workspaceRoot, "packages"),
-];
+config.watchFolders = [workspaceRoot];
 // 2. Let Metro know where to resolve packages and in what order
 config.resolver.nodeModulesPaths = [
 	path.resolve(projectRoot, "node_modules"),
diff --git a/examples/expo-example/src/app.tsx b/examples/expo-example/src/app.tsx
index 511a73d..08253d6 100644
--- a/examples/expo-example/src/app.tsx
+++ b/examples/expo-example/src/app.tsx
@@ -6,9 +6,11 @@
 import { StatusBar } from "expo-status-bar";
 import { Text, View } from "react-native";
 import { registerRootComponent } from "expo";
-import { css } from "@yoshiki/native";
+import { useCss } from "@yoshiki/native";
 
 const CustomBox = ({ color, ...props }: { color: string }) => {
+	const css = useCss();
+
 	return (
 		<View {...css({ backgroundColor: color }, props)}>
 			<Text {...css({ color: "white" })}>Text inside the custom black box.</Text>
@@ -17,14 +19,18 @@ const CustomBox = ({ color, ...props }: { color: string }) => {
 };
 
 const BoxWithoutProps = (props: object) => {
+	const css = useCss();
+
 	return (
-		<View {...css({ backgroundColor: { xs: "00ff00", md: "#ff0000"} }, props)}>
-			<Text>Text inside the box without props</Text>
+		<View {...css({ backgroundColor: { xs: "#00ff00", md: "#ff0000"} }, props)}>
+			<Text>Text inside the box without props (green on small screens, red on bigs)</Text>
 		</View>
 	);
 };
 
 function App() {
+	const css = useCss();
+
 	return (
 		<View
 			{...css({
diff --git a/packages/native/src/index.tsx b/packages/native/src/index.tsx
index bc12dc7..9f9dbf5 100644
--- a/packages/native/src/index.tsx
+++ b/packages/native/src/index.tsx
@@ -4,7 +4,7 @@
 //
 
 import { ViewStyle, TextStyle, ImageStyle, useWindowDimensions } from "react-native";
-import { breakpoints, Breakpoints, YoushikiStyle } from "@yoshiki/core";
+import { breakpoints, Breakpoints, Theme, YoushikiStyle } from "@yoshiki/core";
 
 // TODO: shorhands
 type EnhancedStyle<Properties> = {
@@ -23,31 +23,58 @@ const useBreakpoint = (): number => {
 	return idx - 1;
 };
 
-export const css = (css: CssObject, leftOvers?: { style?: Properties }) => {
-	const { style, ...leftOverProps } = leftOvers ?? {};
+export const useTheme = () => {
+	return {} as Theme;
+};
 
-	let breakpoint: number | undefined = undefined;
-	const ret: Properties = Object.fromEntries(
-		Object.entries(css)
-			.map(([key, value]) => {
-				if (typeof value === "object") {
-					if (!breakpoint) breakpoint = useBreakpoint();
+const isBreakpoints = <T,>(value: unknown): value is Breakpoints<T> => {
+	if (typeof value !== "object" || !value) return false;
+	for (const v of Object.keys(value)) {
+		if (!(v in breakpoints)) {
+			return false;
+		}
+	}
+	return true;
+};
 
-					const bpKeys = Object.keys(breakpoints);
-					for (let i = breakpoint; i >= 0; i--) {
-						if (bpKeys[i] in value) {
-							return [key, value[bpKeys[i]]];
-						}
-					}
-					return undefined;
-				}
-				return [key, value];
-			})
-			.filter((x) => x !== undefined),
-	);
+const propertyMapper = <
+	Property extends number | string | boolean | undefined | Property[] | object,
+>(
+	value: Property | Breakpoints<Property> | ((theme: Theme) => Property),
+	{ breakpoint, theme }: { breakpoint: number; theme: Theme },
+): Property | undefined => {
+	if (isBreakpoints<Property>(value)) {
+		const bpKeys = Object.keys(breakpoints) as Array<keyof Breakpoints<Property>>;
+		for (let i = breakpoint; i >= 0; i--) {
+			if (bpKeys[i] in value) {
+				return value[bpKeys[i]];
+			}
+		}
+		return undefined;
+	}
+	if (typeof value === "function") {
+		return value(theme);
+	}
+	return value;
+};
 
-	return {
-		style: { ...ret, ...style },
-		...leftOverProps,
+// TODO: do not use a hook and use a global window width.
+export const useCss = () => {
+	const breakpoint = useBreakpoint();
+	const theme = useTheme();
+
+	return (css: CssObject, leftOvers?: { style?: Properties }) => {
+		const { style, ...leftOverProps } = leftOvers ?? {};
+
+		const ret: Properties = Object.fromEntries(
+			Object.entries(css)
+				.map(([key, value]) => [key, propertyMapper(value, { breakpoint, theme })])
+				.filter(([, value]) => value !== undefined),
+		);
+
+		return {
+			style: { ...ret, ...style },
+			...leftOverProps,
+		};
 	};
 };