import type { Precondition } from './flow.js';

export type MaterialiserMetadata =
  | { readonly kind: 'exact'; readonly amount: bigint }
  | { readonly kind: 'exact-native'; readonly amount: bigint }
  | { readonly kind: 'runtime' };

export interface MaterialiserResolution {
  readonly meta: MaterialiserMetadata;
  readonly preconditions: readonly Precondition[];
}

export const foldMaterialiserMetadata = <R>(
  meta: MaterialiserMetadata,
  cases: {
    readonly exact: (amount: bigint) => R;
    readonly exactNative: (amount: bigint) => R;
    readonly runtime: () => R;
  }
): R => {
  if (meta.kind === 'exact') return cases.exact(meta.amount);
  if (meta.kind === 'exact-native') return cases.exactNative(meta.amount);
  return cases.runtime();
};