import { NativeModules } from 'react-native';

import { ProxyNativeModule } from './NativeModulesProxy.types';

const NativeProxy = NativeModules.NativeUnimoduleProxy;
const modulesConstantsKey = 'modulesConstants';
const exportedMethodsKey = 'exportedMethods';

const NativeModulesProxy: { [moduleName: string]: ProxyNativeModule } = {};

if (NativeProxy) {
  Object.keys(NativeProxy[exportedMethodsKey]).forEach(moduleName => {
    NativeModulesProxy[moduleName] = NativeProxy[modulesConstantsKey][moduleName] || {};
    NativeProxy[exportedMethodsKey][moduleName].forEach(methodInfo => {
      NativeModulesProxy[moduleName][methodInfo.name] = (...args: unknown[]): Promise<any> => {
        const { key, argumentsCount } = methodInfo;
        if (argumentsCount !== args.length) {
          return Promise.reject(
            new Error(
              `Native method ${moduleName}.${methodInfo.name} expects ${argumentsCount} ${
                argumentsCount === 1 ? 'argument' : 'arguments'
              } but received ${args.length}`
            )
          );
        }
        return NativeProxy.callMethod(moduleName, key, args);
      };
    });

    // These are called by EventEmitter (which is a wrapper for NativeEventEmitter)
    // only on iOS and they use iOS-specific native module, EXReactNativeEventEmitter.
    //
    // On Android only {start,stop}Observing are called on the native module
    // and these should be exported as Expo methods.
    NativeModulesProxy[moduleName].addListener = (...args) =>
      NativeModules.UMReactNativeEventEmitter.addProxiedListener(moduleName, ...args);
    NativeModulesProxy[moduleName].removeListeners = (...args) =>
      NativeModules.UMReactNativeEventEmitter.removeProxiedListeners(moduleName, ...args);
  });
} else {
  console.warn(
    `The "UMNativeModulesProxy" native module is not exported through NativeModules; verify that @unimodules/react-native-adapter's native code is linked properly`
  );
}

export default NativeModulesProxy;