/**
 * Property runner input domain contracts.
 *
 * These types define how render inputs are supplied to a property run:
 * either as an explicit finite enumeration (determinate) or as a
 * generated sampled domain (sampled). The mode is always explicit.
 *
 * Invariant 6: every InputDomain carries its mode at the type level so
 * downstream code cannot silently switch from enumerated to generated.
 */

// ---------------------------------------------------------------------------
// InputDomain
// ---------------------------------------------------------------------------

export type InputDomain =
  | { mode: 'enumerated'; values: unknown[] }
  | { mode: 'generated'; arbitrary: unknown; seed?: number; numRuns?: number }

// ---------------------------------------------------------------------------
// Type Guards
// ---------------------------------------------------------------------------

export function isEnumeratedDomain(domain: InputDomain): domain is Extract<InputDomain, { mode: 'enumerated' }> {
  return domain.mode === 'enumerated'
}

export function isGeneratedDomain(domain: InputDomain): domain is Extract<InputDomain, { mode: 'generated' }> {
  return domain.mode === 'generated'
}

// ---------------------------------------------------------------------------
// Factory Helpers
// ---------------------------------------------------------------------------

export function enumeratedDomain(values: unknown[]): InputDomain {
  return { mode: 'enumerated', values }
}

export function generatedDomain(arbitrary: unknown, options?: { seed?: number; numRuns?: number }): InputDomain {
  return { mode: 'generated', arbitrary, seed: options?.seed, numRuns: options?.numRuns }
}