#!/usr/bin/env node
/**
 * T5 motion codemod (spec 17.2, 17.4, 17.7, Task A11). Pure and idempotent:
 *
 * - `motion-safe:` only asks the system and skips the level chosen in the app. Movement behind it
 *   (translate, scale, rotate, slide-, zoom-, animate-, transition-transform, also behind further
 *   variants) moves to `motion-full:`.
 * - Colour and opacity transitions need no variant ("Aus" sets every duration to zero):
 *   `motion-safe:transition-colors`/`-opacity` lose the variant.
 * - Pulsing and spinning are full motion: a bare `animate-pulse`/`animate-spin` gets
 *   `motion-full:`, and `motion-reduce:animate-none` (the old opt-out) goes.
 *
 * Hover lifts, `transition-all` and overlay timings are changed by hand (they need a judgement).
 *
 * CLI: node scripts/codemod-t5-motion.mjs [--check] <file or directory…>
 *      --check lists the files that would change and exits 1 if there are any.
 */
import { readdirSync, readFileSync, statSync, writeFileSync } from "node:fs";
import { join, resolve } from "node:path";
import { fileURLToPath } from "node:url";

/** Characters that belong to a class token (so a match never starts inside one). */
const TOKEN_CHAR = String.raw`[\w:/\[\]().%-]`;
/** Further variants between the motion variant and the utility (`data-open:`, `group-hover:`). */
const VARIANTS = String.raw`(?:[^\s"'\`:]+:)*`;
const MOVEMENT = String.raw`-?(?:translate|scale|rotate|slide-|zoom-|animate-|transition-transform)`;

const SAFE_MOVEMENT = new RegExp(String.raw`(?<!${TOKEN_CHAR})motion-safe:(?=${VARIANTS}${MOVEMENT})`, "g");
const SAFE_FADE = new RegExp(String.raw`(?<!${TOKEN_CHAR})motion-safe:(?=transition-(?:colors|opacity)(?!${TOKEN_CHAR}))`, "g");
const REDUCE_NONE = new RegExp(String.raw` ?(?<!${TOKEN_CHAR})motion-reduce:animate-none(?!${TOKEN_CHAR})`, "g");
const BARE_PULSE_SPIN = new RegExp(String.raw`(?<!${TOKEN_CHAR})animate-(pulse|spin)(?![\w-])`, "g");

/** Rewrites the motion classes of one source text. */
export function transform(text) {
  return text
    .replace(SAFE_MOVEMENT, "motion-full:")
    .replace(SAFE_FADE, "")
    .replace(REDUCE_NONE, "")
    .replace(BARE_PULSE_SPIN, "motion-full:animate-$1");
}

function filesOf(path) {
  if (statSync(path).isDirectory()) {
    return readdirSync(path).flatMap((name) => filesOf(join(path, name)));
  }
  return /\.tsx?$/.test(path) && !/\.spec\./.test(path) ? [path] : [];
}

if (process.argv[1] && resolve(process.argv[1]) === fileURLToPath(import.meta.url)) {
  const args = process.argv.slice(2);
  const check = args.includes("--check");
  const changed = args
    .filter((arg) => arg !== "--check")
    .flatMap((arg) => filesOf(resolve(arg)))
    .filter((file) => {
      const before = readFileSync(file, "utf8");
      const after = transform(before);
      if (after === before) return false;
      if (!check) writeFileSync(file, after);
      return true;
    });
  for (const file of changed) console.log(file);
  if (check && changed.length > 0) process.exit(1);
}