#!/usr/bin/env node
/**
 * T5 focus and size codemod (spec 4.5, 4.6 and 10.8 step 5). Pure and idempotent:
 *
 * - One focus style: the base rule `:where(:focus-visible)` in globals.css draws it. Component
 *   classes that remove the outline or draw an own ring go: `outline-none` (also behind
 *   `focus:`/`focus-visible:`), `focus-visible:ring-3`, `focus-visible:ring-ring/50`,
 *   `focus-visible:border-ring`, own outline rings (`focus-visible:outline-2 …-ring`, the hive
 *   glass edge ring, which `.holo-stage` now provides) and variant focus colours.
 * - A row whose focus target sits inside (label with its input) keeps one ring on the row:
 *   `has-[:focus-visible]:outline-*`/`ring-*` become the utility `focus-ring-within`.
 * - Compact sizes follow the pointer, not the viewport: `sm:h-*`/`sm:min-h-*`/`sm:size-*` (also
 *   behind a further variant) become `pointer-fine:…`.
 * - `focus:outline-2 focus:outline-ring` stays: it marks elements focused by script after a
 *   click, where :focus-visible does not match (guarded with an allow-list).
 * - A class string that held nothing but focus classes is dropped together with its line.
 *
 * Selection outlines (`outline-2 outline-foreground`) and menu items' `outline-hidden` stay.
 *
 * CLI: node scripts/codemod-t5-focus.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 or ends inside one). */
const TOKEN_CHAR = String.raw`[\w:/\[\]().%-]`;

const escape = (text) => text.replace(/[.*+?^${}()|[\]\\/]/g, "\\$&");

/** Classes removed outright. */
const REMOVED = [
  "outline-none",
  "focus:outline-none",
  "focus-visible:outline-none",
  "focus-visible:ring-3",
  "focus-visible:ring-[3px]",
  "focus-visible:ring-ring/50",
  "focus-visible:border-ring",
  "focus:ring-3",
  "focus:ring-ring/50",
  "focus-visible:outline-1",
  "focus-visible:outline-2",
  "focus-visible:outline-ring",
  "focus-visible:outline-offset-2",
  "focus-visible:outline-holo-edge-strong",
  "focus-visible:ring-destructive/20",
  "focus-visible:border-destructive/40",
  "focus-visible:ring-warning/30",
];

/** Own rings on a row with an inner focus target; replaced by one `focus-ring-within`. */
const WITHIN = [
  "has-[:focus-visible]:outline-2",
  "has-[:focus-visible]:outline-ring",
  "has-[:focus-visible]:ring-3",
  "has-[:focus-visible]:ring-ring/50",
  "has-focus-visible:ring-3",
  "has-focus-visible:ring-ring/50",
];
const WITHIN_UTILITY = "focus-ring-within";

function alternativesOf(classes) {
  return `(?:${classes.map(escape).join("|")})(?!${TOKEN_CHAR})`;
}

/**
 * Removes the classes so that exactly one separator stays: a class after a space goes with
 * that space, a class at the start of a string goes with the space after it.
 */
function removeClasses(line, classes) {
  const alternatives = alternativesOf(classes);
  return line
    .replace(new RegExp(` ${alternatives}`, "g"), "")
    .replace(new RegExp(`(?<!${TOKEN_CHAR})${alternatives} ?`, "g"), "");
}

const WITHIN_FIRST = new RegExp(`(?<!${TOKEN_CHAR})${alternativesOf(WITHIN)}`);
/** `sm:` plus any further variants (`sm:data-[size=default]:`) in front of `h-`/`min-h-`/`size-`. */
const SM_HEIGHT = new RegExp(String.raw`(?<!${TOKEN_CHAR})sm:((?:[^\s:"'\x60]+:)*)((?:min-)?h-|size-)`, "g");
const EMPTY_CLASS_LINE = /^\s*(["'`])\1,?\s*\r?$/;

function transformLine(line) {
  let out = removeClasses(line, REMOVED);
  if (WITHIN_FIRST.test(out)) {
    out = removeClasses(out.replace(WITHIN_FIRST, WITHIN_UTILITY), WITHIN);
  }
  return out.replace(SM_HEIGHT, "pointer-fine:$1$2");
}

/** Applies the focus and size rules to one source text; line endings are kept. */
export function transform(source) {
  const lines = source.split("\n");
  const result = [];
  for (const line of lines) {
    const out = transformLine(line);
    if (out !== line && EMPTY_CLASS_LINE.test(out)) continue;
    result.push(out);
  }
  return result.join("\n");
}

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

function main(args) {
  const check = args.includes("--check");
  const targets = args.filter((arg) => arg !== "--check");
  if (targets.length === 0) {
    console.error("usage: node scripts/codemod-t5-focus.mjs [--check] <file or directory…>");
    return 2;
  }
  const changed = targets.flatMap(sourceFiles).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);
  console.log(`${changed.length} file(s) ${check ? "to migrate" : "migrated"}`);
  return check && changed.length > 0 ? 1 : 0;
}

if (process.argv[1] && resolve(process.argv[1]) === fileURLToPath(import.meta.url)) {
  process.exitCode = main(process.argv.slice(2));
}