import get from 'lodash/object/get';
import isError from 'lodash/lang/isError';
import keyMirror from 'fbjs/lib/keyMirror';

export function actionGenerator(displayName, actions) {
  if (process.env.NODE_ENV === 'development') {
    Object.keys(actions).forEach(actionName => {
      if (actions[actionName]) {
        console.assert(/regeneratorRuntime\.async/.test(actions[actionName].toString()), `${displayName}.${actionName} should be async function`);
      }
    });
  }
  return Object.assign((context, payload) => {
    return new Promise(async (resolve, reject) => {
      const actionType = get(payload, ['type']);
      try {
        const action = actions[actionType];
        if (!action) {
          reject(new Error(`No action responded to ${displayName}.`));
        } else {
          console.info(`execute ${displayName}.${actionType}`);
          resolve(await action({context, payload}));
        }
      } catch (error) {
        if (isError(error)) {
          // Normal Error
          reject(Object.assign(error, {message: `${error.message} (${displayName}.${actionType})`}));
        } else {
          // Network Error
          const message = `${error.status} ${error.statusText}`;
          reject(new Error(message));
        }
      }
    });
  }, {displayName, actionTypes: keyMirror(actions)});
}