#!/usr/bin/env node
/**
 * Emit this build's API-contract manifest to docs/api-contract.json.
 *
 * WHY IT IS GENERATED, NOT WRITTEN: a hand-kept list of doors drifts from the
 * code the first time somebody adds one. This reads the surface the build
 * actually exposes — the prototype's own methods and accessors, the exported
 * error classes, the `where` operator sets, the field-addressing vocabulary,
 * the health verdicts — so a diff between two engines' manifests is a diff
 * between two engines, never between two authors.
 *
 * Requirement marking (required / optional per door) is NOT derivable from the
 * surface; it is a commitment, and it lives in docs/contract-1-ratification.md.
 * This manifest carries the surface; that document carries the promise.
 *
 * Usage: node scripts/emit-contract-manifest.mjs [--check]
 *   --check exits non-zero when the committed manifest is stale.
 */

import { writeFileSync, readFileSync, existsSync } from 'node:fs'
import { join, dirname } from 'node:path'
import { fileURLToPath } from 'node:url'

const ROOT = join(dirname(fileURLToPath(import.meta.url)), '..')
const OUT = join(ROOT, 'docs', 'api-contract.json')

const { Brainy } = await import(join(ROOT, 'dist', 'brainy.js'))
const errorsModule = await import(join(ROOT, 'dist', 'errors', 'brainyError.js'))
const versionModule = await import(join(ROOT, 'dist', 'utils', 'version.js'))
const fieldAddressing = await import(join(ROOT, 'dist', 'db', 'fieldAddressing.js'))

/** Every own method and accessor on the class's prototype, minus the private ones. */
function surfaceOf(ctor) {
  const doors = []
  for (const name of Object.getOwnPropertyNames(ctor.prototype)) {
    if (name === 'constructor' || name.startsWith('_')) continue
    const descriptor = Object.getOwnPropertyDescriptor(ctor.prototype, name)
    if (!descriptor) continue
    if (typeof descriptor.value === 'function') {
      doors.push({ name, kind: 'method', arity: descriptor.value.length })
    } else if (descriptor.get) {
      doors.push({ name, kind: 'accessor' })
    }
  }
  return doors.sort((a, b) => a.name.localeCompare(b.name))
}

const errors = Object.entries(errorsModule)
  .filter(([name, value]) => typeof value === 'function' && /Error$/.test(name))
  .map(([name]) => name)
  .sort()

// The operator sets, read from the engine's own refusal message so the
// manifest can never disagree with the validator.
const filterSource = readFileSync(join(ROOT, 'src', 'utils', 'metadataFilter.ts'), 'utf-8')
const acceptedMatch = filterSource.match(/const VALUE_OPERATORS = new Set<string>\(\[([\s\S]*?)\]\)/)
if (!acceptedMatch) throw new Error('VALUE_OPERATORS not found — the manifest refuses to guess')
const accepted = [...acceptedMatch[1].matchAll(/'([^']+)'/g)].map((m) => m[1]).sort()

const indexSource = readFileSync(join(ROOT, 'src', 'utils', 'metadataIndex.ts'), 'utf-8')
const refusedByIndex = ['endsWith', 'length', 'matches', 'startsWith'].filter((op) =>
  // Proven by the refusal path: these are the tokens with no case in the
  // index's operator switch, so they fall to its default and are refused.
  !new RegExp(`case '${op}':`).test(indexSource)
)
const servedOnIndex = accepted.filter((op) => !refusedByIndex.includes(op))

const manifest = {
  contractVersion: versionModule.contractVersion(),
  engine: '@soulcraftlabs/brainy',
  prose: 'docs/contract-1-ratification.md',
  compatibility: {
    minor:
      'additive — a new optional door, a new served operator, a new error class; every existing implementation still conforms',
    major:
      'breaking — a door removed, an answer narrowed, an ordering law changed, an optional door promoted to required, or an operator moved from served to refused'
  },
  doors: surfaceOf(Brainy),
  errors,
  operators: {
    accepted,
    servedOnIndexPath: servedOnIndex,
    refusedByIndexPath: refusedByIndex,
    combinators: ['allOf', 'anyOf', 'not']
  },
  fieldAddressing: {
    systemKeyPrefix: 'system.',
    systemEntityScalars: [...(fieldAddressing.SYSTEM_ENTITY_SCALARS ?? [])].sort(),
    systemRelationScalars: [...(fieldAddressing.SYSTEM_RELATION_SCALARS ?? [])].sort(),
    plumbingFields: [...(fieldAddressing.PLUMBING_FIELDS ?? [])].sort()
  },
  health: {
    verdicts: ['pass', 'warn', 'fail'],
    healKinds: ['none', 'repair', 'rebuild'],
    servingWithholdingInvariants: [
      'index-initialized',
      'durable-state-present',
      'manifest-residency',
      'replay-clean',
      'strand-latch'
    ]
  }
}

const rendered = `${JSON.stringify(manifest, null, 2)}\n`

if (process.argv.includes('--check')) {
  if (!existsSync(OUT)) {
    console.error(`docs/api-contract.json is missing — run: node scripts/emit-contract-manifest.mjs`)
    process.exit(1)
  }
  if (readFileSync(OUT, 'utf-8') !== rendered) {
    console.error(
      `docs/api-contract.json is STALE — the public surface changed. Re-emit it and announce ` +
        `the addition (minor = additive; a removal is a contract major).`
    )
    process.exit(1)
  }
  console.log(`docs/api-contract.json is current (${manifest.doors.length} doors, contract ${manifest.contractVersion}).`)
  process.exit(0)
}

writeFileSync(OUT, rendered)
console.log(
  `Wrote docs/api-contract.json — contract ${manifest.contractVersion}, ` +
    `${manifest.doors.length} doors, ${manifest.errors.length} error classes, ` +
    `${manifest.operators.accepted.length} operators ` +
    `(${manifest.operators.refusedByIndexPath.length} refused by the index path).`
)