import { defineConfig } from 'vite';

// Builds two CSS entries with no plugin in the graph, isolating Vite's own bundled postcss-import,
// whose `skipDuplicates` option is the mechanism docs/plans/material-3-alignment.md's "Tailwind's
// footprint" paragraph measured and StylesheetsBundleTest.php pins: resources/css/all.css, and
// tests/Fixtures/dedup-app.css, an application-shaped entry importing per-component stylesheets
// that share button.css. A stylesheet several files import lands once per entry, at its first
// position.
//
// Not the Workbench's config: `@tailwindcss/vite` inlines the imports of any entry that uses
// Tailwind itself, without that deduplication, so a shared stylesheet repeats there. The Workbench
// keeps the package's CSS in an entry of its own (workbench/resources/css/package.css) for that
// reason, until plan step 39 removes Tailwind.
//
// DEDUP_OUT_DIR is required: the test builds into a temporary directory and deletes it, and nothing
// should land in the package's own tree, least of all workbench/public/build.
if (!process.env.DEDUP_OUT_DIR) {
    throw new Error('Set DEDUP_OUT_DIR to the directory the dedup fixture should build into.');
}

export default defineConfig({
    publicDir: false,
    build: {
        outDir: process.env.DEDUP_OUT_DIR,
        emptyOutDir: true,
        manifest: true,
        rollupOptions: {
            input: ['resources/css/all.css', 'tests/Fixtures/dedup-app.css'],
        },
    },
    logLevel: 'silent',
});