import * as plugins from './els.plugins.js';
import { Client as ElasticClient } from '@elastic/elasticsearch';

export interface IElasticKVStoreConstructorOptions {
  index: string;
  node: string;
  auth?: {
    username: string;
    password: string;
  };
}

export class ElasticKVStore {
  public client: ElasticClient;
  public index: string;
  private readyDeferred: any;

  constructor(options: IElasticKVStoreConstructorOptions) {
    this.client = new ElasticClient({
      node: options.node,
      ...(options.auth && { auth: options.auth }),
    });
    this.index = options.index;
    this.readyDeferred = plugins.smartpromise.defer();
    this.setupIndex();
  }

  private async setupIndex() {
    try {
      const indexExists = await this.client.indices.exists({ index: this.index });

      if (!indexExists) {
        await this.client.indices.create({ 
          index: this.index,
          body: {
            mappings: {
              properties: {
                key: {
                  type: 'keyword'
                },
                value: {
                  type: 'text'
                }
              }
            }
          }
        });
      }
      this.readyDeferred.resolve();
    } catch (err) {
      this.readyDeferred.reject(err);
    }
  }

  async set(key: string, value: string) {
    await this.readyDeferred.promise;
    await this.client.index({
      index: this.index,
      id: key,
      body: {
        key,
        value
      }
    });
  }

  async get(key: string): Promise<string | null> {
    await this.readyDeferred.promise;

    try {
      const response = await this.client.get({
        index: this.index,
        id: key
      });
      return response._source['value'];
    } catch (error) {
      if (error.meta && error.meta.statusCode === 404) {
        return null;
      }
      throw error;
    }
  }

  async delete(key: string) {
    await this.readyDeferred.promise;

    try {
      await this.client.delete({
        index: this.index,
        id: key
      });
    } catch (error) {
      if (error.meta && error.meta.statusCode !== 404) {
        throw error;
      }
    }
  }

  async clear() {
    await this.readyDeferred.promise;

    await this.client.deleteByQuery({
      index: this.index,
      body: {
        query: {
          match_all: {}
        }
      }
    });
  }
}