'use strict';

const _ = require('lodash');

const CRUD = ['create', 'read', 'update', 'delete'].reverse();

// should be in format `entity:number` or `entity:action` or `entity:action1,action2,action3`
// a user that can only create has 1000 bits > 8, only delete 0001 > 1, everything 1111 > 15
module.exports = function parsePermissions(permissions) {
  if (!Array.isArray(permissions)) {
    permissions = [ permissions ];
  }

  return permissions.reduce((result, str) => {
    let [ entity, actions ] = str.split(':');
    
    let integer = actions ? +actions : 0;
    
    if (!_.isNumber(integer)) {
      actions = actions.split(',')

      integer = actions.reduce((result, action) => {
        const index = CRUD.indexOf(action);

        if (index < 0) {
          throw new Error(`Unkown action "${action}"`);
        }

        return result & 2^index;
      }, 0);
    }

    if (integer > 0) {
      result[entity] = integer;
    }

    return result;
  }, {});
};