import { readFile, writeFile } from "node:fs/promises";
import { createRequire } from "node:module";
import { dirname, join } from "node:path";
import { fileURLToPath } from "node:url";

import { compile } from "tailwindcss";

const directory = dirname(fileURLToPath(import.meta.url));
const appRoot = join(directory, "..");
const sourcePath = join(appRoot, "src", "preview", "Annotation.css");
const preloadPath = join(appRoot, "src", "preview", "PickPreload.ts");
const outputPath = join(appRoot, "src", "preview", "AnnotationStyles.generated.ts");
const require = createRequire(import.meta.url);
const tailwindRoot = dirname(require.resolve("tailwindcss/package.json"));

const [annotationSource, preloadSource, themeSource, preflightSource] = await Promise.all([
  readFile(sourcePath, "utf8"),
  readFile(preloadPath, "utf8"),
  readFile(join(tailwindRoot, "theme.css"), "utf8"),
  readFile(join(tailwindRoot, "preflight.css"), "utf8"),
]);

const candidates = new Set(
  Array.from(preloadSource.matchAll(/!?-?[A-Za-z0-9_:@/.[\]()%,-]+/g), (match) => match[0]),
);
const compilerInput = [
  themeSource,
  preflightSource,
  annotationSource.replace('@import "tailwindcss";', "@tailwind utilities;"),
].join("\n");
const compiler = await compile(compilerInput, { base: appRoot });
const css = compiler.build([...candidates]);
const encodedCss = `'${css
  .replaceAll("\\", "\\\\")
  .replaceAll("'", "\\'")
  .replaceAll("\r", "\\r")
  .replaceAll("\n", "\\n")}'`;
const moduleSource = `// Generated by scripts/build-preview-annotation-css.mjs. Do not edit.\nexport const previewAnnotationStyles =\n  ${encodedCss};\n`;

await writeFile(outputPath, moduleSource);