/*
 * Copyright (C) 2018, 2019 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 {asyncPool} from '@krlwlfrt/async-pool/lib/async-pool';
import {SCSearchRequest, SCThingType} from '@openstapps/core';
import {Bar} from 'cli-progress';
import {Client} from './client';
import {ConnectorClient} from './connector-client';
import {OutOfRangeError} from './errors';
import {HttpClientInterface} from './http-client-interface';

/**
 * Options to set up copying data from one backend to another
 */
export interface CopyOptions {
  /**
   * Batch size to copy at once
   */
  batchSize: number;

  /**
   * URL of the backend to copy from
   */
  from: string;

  /**
   * Source identifier
   */
  source: string;

  /**
   * URL of the backend to copy to
   */
  to: string;

  /**
   * StAppsCore type to copy
   */
  type: SCThingType;

  /**
   * StApps version identifier to copy data for
   */
  version: string;
}

/**
 * Copy data for a StAppsCore type from one backend to another
 *
 * @param client HTTP client
 * @param options Map of options
 */
export async function copy(client: HttpClientInterface, options: CopyOptions): Promise<void> {

  const apiIn = new Client(client, options.from, options.version);
  const apiOut = new ConnectorClient(client, options.to);

  // open a bulk
  const bulk = await apiOut.bulk(options.type, options.source);

  let searchRequest: SCSearchRequest = {
    filter: {
      arguments: {
        field: 'type',
        value: options.type,
      },
      type: 'value',
    },
    size: 0,
  };

  let searchResponse = await apiIn.search(searchRequest);

  searchRequest.size = options.batchSize;

  const progressBar = new Bar({});
  progressBar.start(searchResponse.pagination.total, 0);

  let outOfRange = false;

  do {
    try {
      ({searchRequest, searchResponse} = await apiIn.searchNext(searchRequest, searchResponse));

      await asyncPool(ConnectorClient.ITEM_CONCURRENT_LIMIT, searchResponse.data, async (item) => {
        progressBar.increment(1);

        return bulk.add(item);
      });
    } catch (e) {
      if (e instanceof OutOfRangeError) {
        outOfRange = true;
      } else {
        progressBar.stop();
        throw e;
      }
    }
  } while (!outOfRange);

  await bulk.done();

  progressBar.stop();
}