/*
 * Copyright (C) 2018 StApps
 * This program is free software: you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation, version 3.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program. If not, see <https://www.gnu.org/licenses/>.
 */
import {
  SCBulkResponse,
  SCBulkRoute,
  SCLicensePlate,
  SCNamespaces,
  SCThings,
  SCThingType,
  SCThingUpdateResponse,
  SCThingUpdateRoute,
} from '@openstapps/core';
import {asyncPool} from 'async-pool-native/dist/async-pool';
import * as moment from 'moment';
import {Bulk} from './bulk';
import {Client} from './client';
import {EmptyBulkError, NamespaceNotDefinedError} from './errors';

/* tslint:disable:no-var-requires */

/**
 * The package @types/uuid unfortunately doesn't expose the browser versions of the hashing functions.
 * That's why we need to use a little trickery to get to it.
 */
const v35 = require('uuid/lib/v35');
const sha1Browser = require('uuid/lib/sha1-browser');
const v5 = v35('v5', 0x50, sha1Browser);

/* tslint:enable */

export class ConnectorClient extends Client {
  /**
   * Instance of multi search request route
   */
  private readonly bulkRoute = new SCBulkRoute();

  /**
   * Instance of multi search request route
   */
  private readonly thingUpdateRoute = new SCThingUpdateRoute();

  /**
   * Make a UUID from a UID and a namespace ID
   *
   * *Note: valid namespace IDs are license plates of StApps universities.
   * See documentation of `NAMESPACES` for valid namespace IDs.*
   *
   * @param uid UID to make UUID from
   * @param namespaceId Namespace ID to use to make UUID
   */
  static makeUUID(uid: string, namespaceId: SCLicensePlate): string {
    if (typeof SCNamespaces[namespaceId] === 'undefined') {
      throw new NamespaceNotDefinedError(namespaceId);
    }

    return v5(uid.toString(), SCNamespaces[namespaceId]);
  }

  /**
   * Request a bulk transfer to the backend
   *
   * This uses the Bulk API supplied by the backend and returns an object that can be used
   * just like the client itself, while handling the information necessary in bulk transfers.
   *
   * @param type StAppsCore thing type
   * @param source Source identifier (should be unique per actual data source)
   * @param timeout Timeout in seconds when the bulk should expire
   */
  async bulk<T extends SCThings>(type: SCThingType, source: string, timeout?: number): Promise<Bulk<T>> {
    // set default value for timeout to one hour
    if (typeof timeout !== 'number') {
      timeout = 3600;
    }

    const bulkData = await this.invokeRoute<SCBulkResponse>(this.bulkRoute, undefined, {
      expiration: moment().add(timeout, 'seconds').format(),
      source: source,
      type: type,
    });

    return new Bulk(type, this, bulkData);
  }

  /**
   * Index a list of things
   *
   * Note that source is optional but is set to `'stapps-api'` in that case.
   * This will override any previous bulk that you indexed with that source.
   *
   * @param things List of things to index
   * @param source Source of the things
   * @param timeout Timeout of the bulk in seconds
   * @see ConnectorClient.bulk
   */
  async index<T extends SCThings>(things: T[], source?: string, timeout?: number): Promise<void> {
    // check that number of things is not zero
    if (things.length === 0) {
      throw new EmptyBulkError();
    }

    // set default source if none is given
    if (typeof source === 'undefined') {
      source = 'stapps-api';
    }

    // request a new bulk
    const bulk = await this.bulk(things[0].type, source, timeout);

    // add items to the bulk - 5 concurrently
    await asyncPool(5, things, (thing) => bulk.add(thing));

    // close bulk
    await bulk.done();
  }

  /**
   * Update an existing StAppsCore thing
   *
   * @param thing StAppsCore thing to update
   */
  async update(thing: SCThings): Promise<SCThingUpdateResponse> {
    return this.invokeRoute<SCThingUpdateResponse>(this.thingUpdateRoute, {
      TYPE: encodeURIComponent(thing.type),
      UID: encodeURIComponent(thing.uid),
    }, thing);
  }
}