export interface WebRxReactGlobals {
  readonly DEBUG: boolean;
  readonly PRODUCTION: boolean;
  readonly TEST: boolean;
  readonly WEBPACK_DEV_SERVER: boolean;
  readonly VERSION: string;
}

declare global {
  namespace NodeJS {
    // tslint:disable-next-line:no-empty-interface
    interface Global extends WebRxReactGlobals {}
  }

  // also define our globals on the global namespace
  const PRODUCTION: typeof global.PRODUCTION;
  const TEST: typeof global.TEST;
  const WEBPACK_DEV_SERVER: typeof global.WEBPACK_DEV_SERVER;
  const VERSION: typeof global.VERSION;
}

function getValueOrDefault<T>(
  value: () => T,
  envValue: (env: any) => T,
  defaultValue: T,
) {
  try {
    const val = value();

    if (val != null) {
      return val;
    }
  } catch {
    // it's possible that the value selector uses a global variable that isn't defined
  }

  if (global.process != null && global.process.env != null) {
    const val = envValue(global.process.env);

    if (val != null) {
      return val;
    }
  }

  return defaultValue;
}

// check to see if we should override the default DEBUG mode
const debugOverride =
  window && window.location
    ? (window.location.search || '')
        .substr(1)
        .split('&')
        .map(x => x.split('='))
        .filter(x => (x[0] || '').toLowerCase() === 'debug')
        .map(x => (x[1] ? true : false))
        .pop()
    : undefined;

// we need to untype global to allow us to inject fallbacks
const g: any = global;

// if we don't have a webpack environment then we'll fallback onto defaults
g.DEBUG = getValueOrDefault(
  () => (debugOverride == null ? DEBUG : debugOverride),
  env => env.NODE_ENV === 'debug',
  false,
);
g.PRODUCTION = getValueOrDefault(
  () => PRODUCTION,
  env => env.NODE_ENV === 'production',
  true,
);
g.TEST = getValueOrDefault(() => TEST, env => env.NODE_ENV === 'test', false);
g.WEBPACK_DEV_SERVER = getValueOrDefault(
  () => WEBPACK_DEV_SERVER,
  env => env.NODE_ENV === 'webpack',
  false,
);
g.VERSION = getValueOrDefault(() => VERSION, env => env.VERSION, 'BUILD');

// export webrx-react version string
export { version } from './version';