mockly-hono/scripts/from-openapi.ts

/**
 * Generate mock route files from an OpenAPI 3 spec (json or yaml).
 *
 *   npm run openapi -- path/to/openapi.yaml [outDir]
 *
 * For each path × method it writes a route file whose body is the response
 * example (or a synthesized one from the schema). Non-200 success codes land
 * in the filename (e.g. users.post.201.json).
 */
import { readFileSync, mkdirSync, writeFileSync } from 'node:fs'
import { dirname, join } from 'node:path'
import { fileURLToPath } from 'node:url'
import YAML from 'yaml'

const __dirname = dirname(fileURLToPath(import.meta.url))
const specPath = process.argv[2]
const outDir = process.argv[3] ?? join(__dirname, '..', 'routes')

if (!specPath) {
  console.error('usage: npm run openapi -- <spec.yaml|json> [outDir]')
  process.exit(1)
}

const text = readFileSync(specPath, 'utf8')
const spec: any = specPath.endsWith('.json') ? JSON.parse(text) : YAML.parse(text)

function resolveRef(ref: string): any {
  // #/components/schemas/Foo
  const parts = ref.replace(/^#\//, '').split('/')
  return parts.reduce((o, k) => o?.[k], spec)
}

function example(schema: any, depth = 0): any {
  if (!schema || depth > 6) return null
  if (schema.$ref) return example(resolveRef(schema.$ref), depth + 1)
  if (schema.example !== undefined) return schema.example
  if (schema.default !== undefined) return schema.default
  if (schema.enum) return schema.enum[0]
  if (schema.allOf) return Object.assign({}, ...schema.allOf.map((s: any) => example(s, depth + 1)))
  if (schema.oneOf || schema.anyOf) return example((schema.oneOf ?? schema.anyOf)[0], depth + 1)

  switch (schema.type) {
    case 'object': {
      const out: Record<string, unknown> = {}
      for (const [k, v] of Object.entries(schema.properties ?? {})) out[k] = example(v, depth + 1)
      return out
    }
    case 'array':
      return [example(schema.items, depth + 1)]
    case 'integer':
    case 'number':
      return schema.format === 'float' ? 1.5 : 1
    case 'boolean':
      return true
    case 'string':
      if (schema.format === 'date-time') return '2026-01-01T00:00:00Z'
      if (schema.format === 'email') return 'user@example.com'
      if (schema.format === 'uuid') return '00000000-0000-0000-0000-000000000000'
      return 'string'
    default:
      return schema.properties ? example({ ...schema, type: 'object' }, depth) : null
  }
}

function pickResponse(op: any): { status: number; body: unknown } | null {
  const responses = op.responses ?? {}
  const code = Object.keys(responses).find((c) => /^2\d\d$/.test(c)) ?? Object.keys(responses)[0]
  if (!code) return null
  const r = responses[code]
  const json = r?.content?.['application/json']
  let body: unknown = {}
  if (json?.example !== undefined) body = json.example
  else if (json?.examples) body = (Object.values(json.examples)[0] as any)?.value ?? {}
  else if (json?.schema) body = example(json.schema)
  return { status: Number(code) || 200, body }
}

function fileFor(path: string, method: string, status: number): string {
  // /users/{id} -> users/[id]
  const segs = path.split('/').filter(Boolean).map((s) => s.replace(/^\{(.+)\}$/, '[$1]'))
  const base = segs.length ? segs.join('/') : 'index'
  const parts = [base]
  if (method !== 'get') parts.push(method)
  if (status !== 200 && status !== 0) parts.push(String(status))
  return join(outDir, parts.join('.') + '.json')
}

let count = 0
for (const [path, item] of Object.entries<any>(spec.paths ?? {})) {
  for (const method of ['get', 'post', 'put', 'patch', 'delete']) {
    const op = item[method]
    if (!op) continue
    const picked = pickResponse(op)
    if (!picked) continue
    const file = fileFor(path, method, picked.status)
    mkdirSync(dirname(file), { recursive: true })
    writeFileSync(file, JSON.stringify(picked.body, null, 2) + '\n')
    count++
    console.log(`+ ${method.toUpperCase().padEnd(6)} ${path}  ->  ${file.replace(outDir + '/', '')}`)
  }
}
console.log(`\n${count} route(s) generated into ${outDir}`)