#!/usr/bin/env node
// tools/scripts/lint-room-layout.mjs
// Source: 04-CONTEXT.md D-09/D-11/D-25 — structural drift guard for the
// hot-reload contract locked in docs/adr/0004-room-hot-reload.md.
//
// Walks `apps/server/rooms/`, validates every <rev>.json against the
// canonical layoutSchema's top-level keys, and verifies <rev>.sig against
// the committed public-key sibling
// (./keys/rebno-room-signing.ed25519.pub.pem).
//
// Usage: node tools/scripts/lint-room-layout.mjs
// Exit: 0 clean, 1 violation.

import { readFileSync, readdirSync, existsSync, statSync } from 'node:fs';
import { join, basename } from 'node:path';
import { createPublicKey, verify, createHash } from 'node:crypto';

const ROOMS_DIR = 'apps/server/rooms';
const PUBKEY_PATH =
  process.env.ROOM_SIGNING_PUBKEY_PATH ??
  './keys/rebno-room-signing.ed25519.pub.pem';

// Phase 4 / SRV-13 original schema (mvp-lobby and extracted-room layouts)
const REQUIRED_KEYS_LEGACY = [
  'tile_grid',
  'collision_polys',
  'spawn_points',
  'platform_defs',
  'scripted_triggers',
  'room_size',
  'tile_atlas_ref',
  'bg_atlas_ref',
];

// Plan 06-14 / D-29 extended SRV-13 schema (synthetic mvp-room + future converted rooms).
// Identified by the presence of `room_id` at the top level.
// [doc->REQ-AST-01] [doc->REQ-CLI-07]
const REQUIRED_KEYS_NEW = [
  'room_id',
  'version',
  'width_tiles',
  'height_tiles',
  'tile_w',
  'tile_h',
  'viewport',
  'tiles',
  'spawn_points',
];

const ROOM_ID_RE = /^[a-z0-9-]{1,64}$/;

if (!existsSync(PUBKEY_PATH)) {
  process.stderr.write(
    `lint-room-layout: pubkey ${PUBKEY_PATH} missing — generate via dev boot or set ROOM_SIGNING_PUBKEY_PATH env\n`,
  );
  process.exit(1);
}
const pub = createPublicKey({
  key: readFileSync(PUBKEY_PATH, 'utf-8'),
  format: 'pem',
});

let violations = 0;

function fail(msg) {
  process.stderr.write(`lint-room-layout: ${msg}\n`);
  violations++;
}

if (!existsSync(ROOMS_DIR)) {
  console.log(
    'lint-room-layout: rooms dir absent — nothing to validate (acceptable for fresh checkout)',
  );
  process.exit(0);
}

for (const entry of readdirSync(ROOMS_DIR)) {
  const room_dir = join(ROOMS_DIR, entry);
  if (!statSync(room_dir).isDirectory()) continue;
  if (!ROOM_ID_RE.test(entry)) {
    fail(`invalid room_id directory: ${entry}`);
    continue;
  }

  const jsons = readdirSync(room_dir).filter((f) => f.endsWith('.json'));
  if (jsons.length === 0) {
    fail(`${entry}: no .json files`);
    continue;
  }

  for (const j of jsons) {
    const rev = basename(j, '.json');
    // BL-04 fix: rev names are AT LEAST 3 digits zero-padded; revs ≥ 1000
    // keep their natural width. Tightening to /^\d{3}$/ historically caused
    // RoomRegistry + room-converter to silently corrupt the rev counter at
    // the 1000-boundary (lex sort 1000 < 999 + filter elision).
    if (!/^\d{3,}$/.test(rev)) {
      fail(`${entry}/${j}: rev must be ≥3-digit zero-padded all-numeric (got '${rev}')`);
      continue;
    }
    const sigPath = join(room_dir, `${rev}.sig`);
    if (!existsSync(sigPath)) {
      fail(`${entry}/${j}: companion .sig missing`);
      continue;
    }

    let json;
    try {
      json = readFileSync(join(room_dir, j), 'utf-8');
    } catch (e) {
      fail(`${entry}/${j}: read failed ${e.message}`);
      continue;
    }

    let parsed;
    try {
      parsed = JSON.parse(json);
    } catch (e) {
      fail(`${entry}/${j}: JSON parse failed: ${e.message}`);
      continue;
    }

    // Choose schema based on presence of `room_id` (new SRV-13 extended shape)
    // vs. legacy `tile_grid` shape (mvp-lobby and Phase 4 extracted rooms).
    const requiredKeys = ('room_id' in parsed) ? REQUIRED_KEYS_NEW : REQUIRED_KEYS_LEGACY;
    for (const k of requiredKeys) {
      if (!(k in parsed)) fail(`${entry}/${j}: missing key '${k}'`);
    }

    const sig = readFileSync(sigPath);
    const payload = Buffer.concat([
      Buffer.from(entry, 'utf-8'),
      Buffer.from(rev, 'utf-8'),
      createHash('sha256').update(Buffer.from(json, 'utf-8')).digest(),
    ]);
    if (!verify(null, payload, pub, sig)) {
      fail(`${entry}/${j}: Ed25519 signature INVALID`);
    }
  }
}

if (violations > 0) {
  process.stderr.write(
    `lint-room-layout: ${violations} violation(s)\n`,
  );
  process.exit(1);
}
console.log('lint-room-layout: OK');
process.exit(0);