/**
 * @author Martin Karkowski
 * @email m.karkowski@zema.de
 * @create date 2021-02-09 11:26:58
 * @modify date 2021-08-11 10:34:04
 * @desc [description]
 */

import {
  ENopeDispatcherStatus,
  IDispatcherInfo, INopeDispatcherOptions
} from "../types/nope/nopeDispatcher.interface";
import { INopeModule, INopeModuleDescription } from "../types/nope/nopeModule.interface";
import { INopeObservable } from "../types/nope/nopeObservable.interface";
import { nopeDispatcher } from "./nopeDispatcher";

export type HostInfo = {
  cpu: string;
  cores: number;
  os: string;
  ram: number;
  name: string;
  disptachers: {
    pid: number;
    id: string;
    status: ENopeDispatcherStatus;
    timestamp: number;
  }[];
  status: ENopeDispatcherStatus;
  instances: {
    identifier: string,
    status: ENopeDispatcherStatus,
    dispatcher: string
  }[];
  timestamp: number;
};

/**
 * Create an Enhanced Class, using the
 *
 * @export
 * @class nopeDispatcherManager
 * @extends {nopeDispatcher}
 */
export class nopeDispatcherManager extends nopeDispatcher {

  public readonly onDispatcherWentOffline: INopeObservable<IDispatcherInfo[]>
  public readonly onDispatcherWentOnline: INopeObservable<IDispatcherInfo[]>
  private __knownDispatchers: Array<IDispatcherInfo>;

  constructor(options: INopeDispatcherOptions,
    _generateObservable: <T>() => INopeObservable<T>) {
    super(options, _generateObservable);

    this.onDispatcherWentOffline = _generateObservable();
    this.onDispatcherWentOnline = _generateObservable();

    this.__knownDispatchers = [];
  }

  public async _init() {
    await super._init();
    const _this = this;

    // Initally store the known Dispatchers.
    this.__knownDispatchers = this.externalDispatchers.getContent();

    // Subscribe to Changes. 
    this.externalDispatchers.subscribe(dispatchers => {
      const _newDispatchers = dispatchers.map(item => item.id);
      const _oldDispatchers = _this.__knownDispatchers.map(item => item.id);

      // Determine the newly Addded Dispatchers:
      const _added = dispatchers.filter(dispatcher => !_oldDispatchers.includes(dispatcher.id));
      // Determine the removed Dispatchers:
      const _removed = _this.__knownDispatchers.filter(dispatcher => !_newDispatchers.includes(dispatcher.id));

      _this.onDispatcherWentOnline.setContent(_added);
      _this.onDispatcherWentOffline.setContent(_removed);

      // Store the Updated Disaptchers.
      _this.__knownDispatchers = dispatchers;
    });
  }

  /**
   * Function to get all hosts.
   *
   * @return {*}  {string[]}
   * @memberof nopeDispatcherManager
   */
  public getAllHosts(): string[] {
    const hosts = new Set<string>();
    for (const info of this._externalDispatchers.values()) {
      hosts.add(info.host.name);
    }

    return Array.from(hosts);
  }

  /**
   * Return the instances of the given Type.
   *
   * @param {string} type
   * @return {*}  {INopeModuleDescription[]}
   * @memberof nopeDispatcherManager
   */
  public async getInstancesOfType<I extends INopeModule>(type: string) {
    const indentifier = this.availableInstances.getContent()
      .filter(item => item.type == type)
      .map(item => item.identifier);

    const promises: Promise<I>[] = [];

    for (const identifier of indentifier) {
      promises.push(this.generateInstance({
        identifier,
        type,
        params: []
      }));
    }

    // Wait to generate all Instances.
    const result = await Promise.all(promises);

    return result;
  }

  public getInstanceDescription(identifier: string): INopeModuleDescription | null {
    if (this._externalInstances.has(identifier)) {
      return this._externalInstances.get(identifier);
    }

    return null;
  }

  public getInstanceDescriptionForType(identifier: string): INopeModuleDescription | null {
    for (const description of this._externalInstances.values()) {
      if (description.type === identifier) {
        return description;
      }
    }
    return null;
  }

  public getHostInfos(): {
    [index: string]: HostInfo
  } {
    // Define a dataset, which contains the
    // hosts.
    const sorted: {
      [index: string]: HostInfo
    } = {};

    for (const dispatcher of this._externalDispatchers.values()) {
      // If required, define the Base Element. 
      if (sorted[dispatcher.host.name] === undefined) {
        sorted[dispatcher.host.name] = {
          cores: dispatcher.host.cores,
          cpu: dispatcher.host.cpu,
          name: dispatcher.host.name,
          os: dispatcher.host.os,
          disptachers: [],
          instances: [],
          ram: dispatcher.host.ram,
          status: ENopeDispatcherStatus.HEALTHY,
          timestamp: dispatcher.timestamp
        };
      }

      if (this._mappingOfRemoteDispatchersAndInstances.has(dispatcher.id)) {
        // Add the Instances:
        for (const instance of this._mappingOfRemoteDispatchersAndInstances.get(dispatcher.id)) {
          sorted[dispatcher.host.name].instances.push({
            identifier: instance.identifier,
            status: dispatcher.status,
            dispatcher: dispatcher.id
          });
        }
      }

      // Define the state of overall state of this node.
      sorted[dispatcher.host.name].status = Math.max(
        sorted[dispatcher.host.name].status,
        dispatcher.status
      );

      // Define the timestamp of the overall node.
      sorted[dispatcher.host.name].timestamp = Math.min(
        sorted[dispatcher.host.name].timestamp,
        dispatcher.timestamp
      );

      // Store the Dispatcher Status
      sorted[dispatcher.host.name].disptachers.push({
        id: dispatcher.id,
        status: dispatcher.status,
        timestamp: dispatcher.timestamp,
        pid: dispatcher.pid as number
      });
    }

    return sorted;
  }
}