import composeWithMongoose from 'graphql-compose-mongoose';
import { CountryTC } from './country';

export const CitySchema = new mongoose.Schema({
  name: String,
  population: Number,
  countryCode: String, // US
  tz: String, // 'America/Los_Angeles'
  // ...
});
export const City = mongoose.model('City', CitySchema);
export const CityTC = composeWithMongoose(CityModel);

// Define some additional fields
CityTC.addFields({
  ucName: { // standard GraphQL like field definition
    type: GraphQLString,
    resolve: (source) => source.name.toUpperCase(),
  },
  localTime: { // extended GraphQL Compose field definition
    type: 'Date',
    resolve: (source) => moment().tz(source.tz).format(),
    projection: { tz: true }, // load `tz` from database, when requested only `localTime` field
  },
});

// Add relation between City and Country by `countryCode` field.
CityTC.addRelation( // GraphQL relation definition
  'country',
  () => ({
    resolver: CountryTC.getResolver('findOne'),
    args: {
      filter: source => ({ code: `${source.countryCode}` }),
    },
    projection: { countryCode: true },
  })
);

// Remove `tz` field from schema
CityTC.removeField('tz');

// Add description to field
CityTC.extendField('name', {
  description: 'City name',
});

import { GQC } from 'graphql-compose';
import { CityTC } from './city';
import { CountryTC } from './country';

GQC.rootQuery().addFields({
  city: CityTC.get('$findOne'),
  cityConnection: CityTC.get('$connection'),
  country: CountryTC.get('$findOne'),
  currentTime: {
    type: 'Date',
    resolve: () => Date.now(),
  },
});

GQC.rootMutation().addFields({
  createCity: CityTC.get('$createOne'),
  updateCity: CityTC.get('$updateById'),
  ...adminAccess({
    removeCity: CityTC.get('$removeById'),
  }),
});

function adminAccess(resolvers) {
  Object.keys(resolvers).forEach((k) => {
    resolvers[k] = resolvers[k].wrapResolve(next => (rp) => {
      // rp = resolveParams = { source, args, context, info }
      if (!rp.context.isAdmin) {
        throw new Error('You should be admin, to have access to this action.');
      }
      return next(rp);
    });
  });
  return resolvers;
}

export default GQC.buildSchema();