#!/usr/bin/env node
// The kit declares exactly one contract version, in `template/module.json`'s
// `coreApi` — the same field a reader copies. This asserts it still names the
// version the pinned core actually exports.
//
// WHY EQUALITY AND NOT "SATISFIES": a range check is what CORE does at load time,
// and it is right there — a module built against 1.4.0 should keep loading into
// 1.5.0. It is the wrong question here. This kit's job is to be *current*: if core
// moved to 1.5.0, `^1.4.0` still satisfies, the build stays green, and nobody ever
// re-reads the chapters. Green would mean "the template still loads", when what we
// need it to mean is "someone has looked at this since the contract changed".
//
// So the failure is deliberate and expected on every core bump, and the fix is a
// human reading the book — not a version string.
//
// Usage: node scripts/checkCoreApi.js --core <path to a core checkout>

const fs = require('fs')
const path = require('path')

const ROOT = path.resolve(__dirname, '..')

function arg(name) {
  const i = process.argv.indexOf(name)
  return i === -1 ? null : process.argv[i + 1]
}

const corePath = arg('--core')
if (!corePath) {
  console.error('usage: node scripts/checkCoreApi.js --core <path to a core checkout>')
  process.exit(2)
}

const manifestPath = path.join(ROOT, 'template', 'module.json')
if (!fs.existsSync(manifestPath)) {
  // Slice 0 landed this check before the template it checks. Not an error: the
  // workflow guards on the same file, and this message is what a local run says.
  console.log('checkCoreApi: no template/module.json yet — nothing to check')
  process.exit(0)
}

const versionFile = path.resolve(corePath, 'server/src/modules/version.js')
if (!fs.existsSync(versionFile)) {
  console.error(`checkCoreApi: ${versionFile} does not exist.`)
  console.error('  Either --core does not point at a website checkout, or the pin in')
  console.error('  ci/core-ref.json names a ref with no module system in it (core `main`')
  console.error('  has none until the cutover — see that file).')
  process.exit(1)
}

// Core's version.js is a plain CommonJS module with no dependencies, so it can be
// required straight out of an uninstalled checkout.
const { MODULE_API_VERSION: core } = require(versionFile)

const declared = String(JSON.parse(fs.readFileSync(manifestPath, 'utf8')).coreApi || '')
// A `coreApi` is a RANGE (`^1.4.0`); the version it is built on is its base.
const base = declared.replace(/^[\^~>=<\s]+/, '').trim()

if (!base) {
  console.error(`checkCoreApi: template/module.json declares no coreApi (got ${JSON.stringify(declared)})`)
  process.exit(1)
}

if (base !== core) {
  console.error('checkCoreApi: the kit is written against a different core than it is pinned to.')
  console.error('')
  console.error(`  template/module.json  coreApi = ${declared}   (base ${base})`)
  console.error(`  pinned core           MODULE_API_VERSION = ${core}`)
  console.error('')
  console.error('  This is the anti-rot check firing, not a broken build. Someone has to:')
  console.error('    1. read MODULE_API.md §1.1 for what changed in the new version;')
  console.error('    2. read the book and the template for anything that is now untrue;')
  console.error('    3. update template/module.json and ci/core-ref.json together.')
  console.error('')
  console.error('  Bumping the two files without doing step 2 is the one way to make this')
  console.error('  check worthless.')
  process.exit(1)
}

console.log(`checkCoreApi: coreApi ${declared} matches the pinned core's ${core} — OK`)