/*
 This file is part of GNU Taler
 (C) 2019-2020 Taler Systems SA

 GNU Taler is free software; you can redistribute it and/or modify it under the
 terms of the GNU General Public License as published by the Free Software
 Foundation; either version 3, or (at your option) any later version.

 GNU Taler is distributed in the hope that it will be useful, but WITHOUT ANY
 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
 A PARTICULAR PURPOSE.  See the GNU General Public License for more details.

 You should have received a copy of the GNU General Public License along with
 GNU Taler; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
 */

/**
 * Classes and helpers for error handling specific to wallet operations.
 *
 * @author Florian Dold <dold@taler.net>
 */

/**
 * Imports.
 */
import { TalerErrorCode, TalerErrorDetails } from "@gnu-taler/taler-util";

/**
 * This exception is there to let the caller know that an error happened,
 * but the error has already been reported by writing it to the database.
 */
export class OperationFailedAndReportedError extends Error {
  static fromCode(
    ec: TalerErrorCode,
    message: string,
    details: Record<string, unknown>,
  ): OperationFailedAndReportedError {
    return new OperationFailedAndReportedError(
      makeErrorDetails(ec, message, details),
    );
  }

  constructor(public operationError: TalerErrorDetails) {
    super(operationError.message);

    // Set the prototype explicitly.
    Object.setPrototypeOf(this, OperationFailedAndReportedError.prototype);
  }
}

/**
 * This exception is thrown when an error occurred and the caller is
 * responsible for recording the failure in the database.
 */
export class OperationFailedError extends Error {
  static fromCode(
    ec: TalerErrorCode,
    message: string,
    details: Record<string, unknown>,
  ): OperationFailedError {
    return new OperationFailedError(makeErrorDetails(ec, message, details));
  }

  constructor(public operationError: TalerErrorDetails) {
    super(operationError.message);

    // Set the prototype explicitly.
    Object.setPrototypeOf(this, OperationFailedError.prototype);
  }
}

export function makeErrorDetails(
  ec: TalerErrorCode,
  message: string,
  details: Record<string, unknown>,
): TalerErrorDetails {
  return {
    code: ec,
    hint: `Error: ${TalerErrorCode[ec]}`,
    details: details,
    message,
  };
}

/**
 * Run an operation and call the onOpError callback
 * when there was an exception or operation error that must be reported.
 * The cause will be re-thrown to the caller.
 */
export async function guardOperationException<T>(
  op: () => Promise<T>,
  onOpError: (e: TalerErrorDetails) => Promise<void>,
): Promise<T> {
  try {
    return await op();
  } catch (e) {
    if (e instanceof OperationFailedAndReportedError) {
      throw e;
    }
    if (e instanceof OperationFailedError) {
      await onOpError(e.operationError);
      throw new OperationFailedAndReportedError(e.operationError);
    }
    if (e instanceof Error) {
      const opErr = makeErrorDetails(
        TalerErrorCode.WALLET_UNEXPECTED_EXCEPTION,
        `unexpected exception (message: ${e.message})`,
        {
          stack: e.stack,
        },
      );
      await onOpError(opErr);
      throw new OperationFailedAndReportedError(opErr);
    }
    // Something was thrown that is not even an exception!
    // Try to stringify it.
    let excString: string;
    try {
      excString = e.toString();
    } catch (e) {
      // Something went horribly wrong.
      excString = "can't stringify exception";
    }
    const opErr = makeErrorDetails(
      TalerErrorCode.WALLET_UNEXPECTED_EXCEPTION,
      `unexpected exception (not an exception, ${excString})`,
      {},
    );
    await onOpError(opErr);
    throw new OperationFailedAndReportedError(opErr);
  }
}