import { ErrorHandlerCallback } from 'react-native/Libraries/vendor/core/ErrorUtils';
import Logger from '../core/logging/logger';
import { isError } from './helpers';
import { reportError } from './reporting';

// Internal variable to keep track of the original error handler.
let originalHandler: ErrorHandlerCallback | null = null;

// This function is only used in tests to reset the state of the module.
export const resetModuleState = () => {
  originalHandler = null;
};

/**
 * CS error handler which reports fatal errors to cs.
 */
const csErrorHandler = async (
  error: Error,
  isFatal?: boolean
): Promise<void> => {
  if (isFatal) {
    await reportError(error);
  }
};

/**
 * Adds csErrorHandler to global error handler.
 */
export const addCsErrorHandler = (): void => {
  if (!originalHandler) {
    originalHandler = ErrorUtils.getGlobalHandler(); // Capture the original handler the first time
  }

  const wrappedHandler: ErrorHandlerCallback = async (
    error: Error,
    isFatal?: boolean
  ) => {
    if (!isError(error)) {
      originalHandler?.(error, isFatal);
      return;
    }

    await csErrorHandler(error, isFatal);
    originalHandler?.(error, isFatal);
  };

  ErrorUtils.setGlobalHandler(wrappedHandler);
  Logger.info('CSErrorHandler is set as JavaScript global error handler.');
};

/**
 * Restores the original global error handler.
 */
export const removeCsErrorHandler = (): void => {
  if (originalHandler) {
    ErrorUtils.setGlobalHandler(originalHandler);
    Logger.info('Original JavaScript global error handler has been restored.');
  }
};