feat: Initial clean release of CHM

packages/lib/services/style/cssToTheme.ts

@@ -0,0 +1,53 @@
+import { Theme } from '../../themes/type';
+
+// Need to include it that way due to a bug in the lib:
+// https://github.com/reworkcss/css/pull/146#issuecomment-740412799
+import { CssRuleAST, CssTypes, parse as cssParse } from '@adobe/css-tools';
+
+function formatCssToThemeVariable(cssVariable: string): string {
+	const elements = cssVariable.substr(2).split('-');
+	if (elements[0] !== 'joplin') throw new Error(`CSS variable name must start with "--joplin": ${cssVariable}`);
+
+	elements.splice(0, 1);
+
+	return elements.map((e, i) => {
+		const c = i === 0 ? e[0] : e[0].toUpperCase();
+		return c + e.substr(1);
+	}).join('');
+}
+
+// function unquoteValue(v:string):string {
+// 	if (v.startsWith("'") && v.endsWith("'") || v.startsWith('"') && v.endsWith('"')) return v.substr(1, v.length - 2);
+// 	return v;
+// }
+
+export default function cssToTheme(css: string, sourceFilePath: string): Theme {
+	const o = cssParse(css, {
+		silent: false,
+		source: sourceFilePath,
+	});
+
+	const rules = o?.stylesheet?.rules;
+
+	if (!rules?.length) throw new Error(`Invalid CSS color file: ${sourceFilePath}`);
+
+	let rootRule: CssRuleAST|null = null;
+	for (const rule of rules) {
+		if (rule.type === CssTypes.rule) {
+			rootRule = rule;
+			break;
+		}
+	}
+
+	if (!rootRule || !rootRule.selectors.includes(':root')) throw new Error('`:root` rule not found');
+
+	const declarations = rootRule.declarations;
+
+	const output: Record<string, string> = {};
+	for (const declaration of declarations) {
+		if (declaration.type !== 'declaration') continue; // Skip comment lines
+		output[formatCssToThemeVariable(declaration.property)] = declaration.value;
+	}
+
+	return output as unknown as Theme;
+}