import * as redis from 'redis';
import { getLogger } from './loggers';

const logger = getLogger('redis');

export default class {

  private client: redis.RedisClient;
  private expireAfter: number;

  constructor(opt: IRedisConfig) {
    this.client = redis.createClient({
      host: opt.redisHost,
      port: opt.redisPort,
    });
    this.expireAfter = opt.redisExpireTime;
    logger.info(`loaded redis service at ${opt.redisHost}:${opt.redisPort}`);
  }

  private chatAsString = (chat: IChat) => `${chat.chatType}:${chat.chatID.toString()}`;

  public cacheContent = (contentId: string, content: string) =>
    new Promise<'OK'>((resolve, reject) =>
      this.client.set(`content/${contentId}`, content, 'EX', 3600 * 24, (err, res) =>
        err ? reject(err) : resolve(res)
      )
    ).then(res => {
      logger.debug(`cached content ${contentId}, result: ${res}`);
    }).catch((err: Error) => {
      logger.error(`failed to cache content ${contentId}, error: ${err}`);
    });

  public cacheForChat = (postId: string, target: IChat) => {
    const targetStr = this.chatAsString(target);
    return new Promise<'OK'>((resolve, reject) =>
      this.client.set(`sent/${targetStr}/${postId}`, 'true', 'EX', this.expireAfter, (err, res) =>
        err ? reject(err) : resolve(res)
      )
    ).then(res => {
      logger.debug(`cached post ${postId} for ${targetStr}, result: ${res}`);
    }).catch((err: Error) => {
      logger.error(`failed to cache post ${postId} for ${targetStr}, error: ${err}`);
    });
  };

  public getContent = (contentId: string) =>
    new Promise<string>((resolve, reject) =>
      this.client.get(`content/${contentId}`, (err, res) => err ? reject(err) : resolve(res))
    ).then(res => {
      logger.debug(`retrieved cached content ${contentId}, result: ${res}`);
      return res;
    }).catch((err: Error) => {
      logger.error(`failed to retrieve cached content ${contentId}, error: ${err}`);
      throw err;
    });

  public isCachedForChat = (postId: string, target: IChat) => {
    const targetStr = this.chatAsString(target);
    return new Promise<number>((resolve, reject) =>
      this.client.exists(`sent/${targetStr}/${postId}`, (err, res) => err ? reject(err) : resolve(res))
    ).then(res => {
      logger.debug(`retrieved status of post ${postId} for ${targetStr}, result: ${res}`);
      return Boolean(res);
    }).catch((err: Error) => {
      logger.error(`failed to retrieve status of post ${postId} for ${targetStr}, error: ${err}`);
      return false;
    });
  };
}