import { Config } from "./builder";
import { DeepPartial, Dependencies, Effects, ExpectedExports } from "../types";
import { InputSpec } from "./configTypes";
import { Utils, nullIfEmpty, once, utils } from "../util";
import { TypeFromProps } from "../util/propertiesMatcher";

declare const dependencyProof: unique symbol;
export type DependenciesReceipt = void & {
  [dependencyProof]: never;
};

export type Save<WD, A> = (options: {
  effects: Effects;
  input: A;
  utils: Utils<WD>;
}) => Promise<DependenciesReceipt>;
export type Read<WD, A> = (options: {
  effects: Effects;
  utils: Utils<WD>;
}) => Promise<null | DeepPartial<A>>;
/**
 * We want to setup a config export with a get and set, this
 * is going to be the default helper to setup config, because it will help
 * enforce that we have a spec, write, and reading.
 * @param options
 * @returns
 */
export function setupConfig<WD, A extends Config<InputSpec>>(
  spec: A,
  write: Save<WD, TypeFromProps<A>>,
  read: Read<WD, TypeFromProps<A>>,
) {
  const validator = once(() => spec.validator());
  return {
    setConfig: (async ({ effects, input }) => {
      if (!validator().test(input)) {
        await effects.error(String(validator().errorMessage(input)));
        return { error: "Set config type error for config" };
      }
      await write({
        input: JSON.parse(JSON.stringify(input)),
        effects,
        utils: utils<WD>(effects),
      });
    }) as ExpectedExports.setConfig,
    getConfig: (async ({ effects, config }) => {
      return {
        spec: spec.build(),
        config: nullIfEmpty(await read({ effects, utils: utils<WD>(effects) })),
      };
    }) as ExpectedExports.getConfig,
  };
}

export default setupConfig;