import * as x from 'x-value';

import type {GeneralXBackStatesInReturn} from './back-state/index.js';
import {getXBackStatesInReturn} from './back-state/index.js';

export class ProcedureDefinition<
  TXParameter extends x.XTypeOfValue<object>,
  TXReturn extends x.XTypeOfValue<object>,
> {
  path?: string;

  private ReturnWithBackStates_:
    | x.IntersectionType<[TXReturn, GeneralXBackStatesInReturn]>
    | undefined;

  constructor(
    readonly Parameter: TXParameter,
    private Return_: TXReturn,
  ) {}

  get Return(): x.IntersectionType<[TXReturn, GeneralXBackStatesInReturn]> {
    if (!this.ReturnWithBackStates_) {
      const BackStatesInReturn = getXBackStatesInReturn();

      this.ReturnWithBackStates_ = x.intersection([
        this.Return_,
        BackStatesInReturn,
      ]);
    }

    return this.ReturnWithBackStates_;
  }
}

export function procedure<
  TXParameter extends x.XTypeOfValue<object>,
  TXReturn extends x.XTypeOfValue<object>,
>(
  Parameter: TXParameter,
  Return: TXReturn,
): ProcedureDefinition<TXParameter, TXReturn> {
  return new ProcedureDefinition(Parameter, Return);
}

export type RPCResult<T extends object> =
  | {
      return: T;
    }
  | {
      throw: {
        code: string;
        message: string;
      };
    };