/*
 * Copyright (C) 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 {SCThings} from '@openstapps/core';
import {readdir, readFile} from 'fs';
import {join} from 'path';
import {promisify} from 'util';
import {Bulk} from './bulk';
import {ConnectorClient} from './connectorClient';
import {HttpClientInterface} from './httpClientInterface';

/**
 * Options to set up indexing core test files to backend
 */
export interface E2EOptions {
  /**
   * File path of the directory containing core test files
   */
  samples: string;

  /**
   * URL of the backend to index to
   */
  to: string;
}

/**
 * Function to add all the SCThings that getItemsFromSamples() returns to the backend
 * 
 * @param client HTTP client
 * @param options Map of options
 */
export async function indexSamples(client: HttpClientInterface, options: E2EOptions): Promise<void> {
  const api = new ConnectorClient(client, options.to);

  const items = await getItemsFromSamples(options.samples);

  if (items.length === 0) {
    throw new Error('Could not index samples. None were retrived from the file system.');
  }

  items.sort((a, b) => (a.type.localeCompare(b.type)));

  let currentBulkType;
  let currentBulk: Bulk<SCThings> | undefined;

  try {
    // Add items depending on their type property with one type per bulk
    for (const item of items) {
      if (currentBulkType !== item.type) {
        if (typeof currentBulk !== 'undefined') {
          await currentBulk.done();
        }
        currentBulk = await api.bulk(item.type, 'stapps-core-sample-data');
        currentBulkType = item.type;
      }
      await currentBulk!.add(item);
    }
    // close the last open bulk
    if (typeof currentBulk !== 'undefined') {
      await currentBulk.done();
    }
  } catch (err) {
    throw err;
  }
}

/**
 * Get all SCThings from the predefined core test json files
 *
 * @param samplesDirectory Filepath to the directory containing to the core test json files
 * @returns an Array of all the SCThings specified for test usage
 */
export async function getItemsFromSamples<T extends SCThings>(samplesDirectory: string): Promise<T[]> {
  const readDirPromised = promisify(readdir);
  const readFilePromised = promisify(readFile);

  const things: T[] = [];
  try {
    const fileNames = await readDirPromised(samplesDirectory);
    for (const fileName of fileNames) {
      const filePath = join(samplesDirectory, fileName);
      const fileContent = await readFilePromised(filePath, {encoding: 'utf8'});
      const schemaObject = JSON.parse(fileContent);
      if (schemaObject.errorNames.length === 0 && typeof schemaObject.instance.type === 'string') {
        things.push(schemaObject.instance);
      }
    }
  } catch (error) {
    return error;
  }
  return things;
}