import fs from 'fs';
import selectorParser from 'postcss-selector-parser';

export default function extractTailwindClasses(opts = {}) {
    const classSet = new Set();

    return {
        postcssPlugin: 'extract-tailwind-classes',
        Rule(rule) {
            selectorParser(selectors => {
                selectors.walkClasses(node => {
                    classSet.add(node.value);
                });
            }).processSync(rule.selector);
        },
        OnceExit() {
            const classArray = Array.from(classSet).sort();
            fs.mkdirSync('../../../Moonlight.Frontend/Styles', { recursive: true });
            fs.writeFileSync('../../../Moonlight.Frontend/Styles/Moonlight.Frontend.map', classArray.join('\n'));
            console.log(`Extracted classes ${classArray.length}`);
        }
    };
}

extractTailwindClasses.postcss = true;