/**
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 */

import { EvaluatorResult, doEval } from "./evaluator";

export type SproutResult =
  | { kind: "success"; value: string }
  | { kind: "invalid"; value: string };

function stringify(result: EvaluatorResult): string {
  return `(kind: ${result.kind}) ${result.value}${
    result.logs.length > 0 ? `\nlogs: [${result.logs.toString()}]` : ""
  }`;
}
function makeError(description: string, value: string): SproutResult {
  return {
    kind: "invalid",
    value: description + "\n" + value,
  };
}
function logsEqual(a: Array<string>, b: Array<string>) {
  if (a.length !== b.length) {
    return false;
  }
  return a.every((val, idx) => val === b[idx]);
}
export function runSprout(
  originalCode: string,
  forgetCode: string
): SproutResult {
  const forgetResult = doEval(forgetCode);
  if (forgetResult.kind === "UnexpectedError") {
    return makeError("Unexpected error in Forget runner", forgetResult.value);
  }
  if (originalCode.indexOf("@disableNonForgetInSprout") === -1) {
    const nonForgetResult = doEval(originalCode);

    if (nonForgetResult.kind === "UnexpectedError") {
      return makeError(
        "Unexpected error in non-forget runner",
        nonForgetResult.value
      );
    } else if (
      forgetResult.kind !== nonForgetResult.kind ||
      forgetResult.value !== nonForgetResult.value ||
      !logsEqual(forgetResult.logs, nonForgetResult.logs)
    ) {
      return makeError(
        "Found differences in evaluator results",
        `Non-forget (expected):
${stringify(nonForgetResult)}
Forget:
${stringify(forgetResult)}
`
      );
    }
  }
  return {
    kind: "success",
    value: stringify(forgetResult),
  };
}