import * as Mongo from 'mongodb';
import * as dotenv from 'dotenv';

dotenv.config();

const MONGO_URI = process.env.MONGO_URI;

export class LogService
{
  private static instance: LogService;
  private MongoClient: any;
  private MongoDB: any;

  private constructor()
  {
    this.MongoClient = Mongo.MongoClient;
    this.MongoClient.connect(MONGO_URI, (err: any, database: any) =>
    {
      this.MongoDB = database;
      if (err) console.log(err)
    })
  }

  public saveMessage(message: any, bot_address: string): Promise<void>
  {
    return new Promise((resolve, reject) =>
    {
      if (message.references.length === 0) {
        this.MongoDB.collection('chats').insert({
          user_address: message.to[0].address,
          bot_address: bot_address,
          parent_id: message.message_id,
          messages: [message]
        }, (err: any, result: any) =>
          {
            if (err) return reject(err);
            return resolve();
          })
      } else {
        this.MongoDB.collection('chats').update({
          parent_id: this.getParentId(message.references)
        }, { $push: { messages: message } },
          (err: any, result: any) =>
          {
            if (err) return reject(err);
            return resolve();
          })
      }
    })
  }

  public saveAccount(account: any): Promise<void>
  {
    return new Promise((resolve, reject) =>
    {
      this.MongoDB.collection('accounts').insert(account,
        (err: any, result: any) =>
        {
          if (err) return reject(err);
          return resolve();
        })
    })
  }

  public findAccount(accountAddress: string): Promise<any>
  {
    return new Promise((resolve, reject) =>
    {
      this.MongoDB.collection('accounts').findOne({ account_address: accountAddress },
        (err: any, result: any) =>
        {
          if (err) return reject(err);
          return resolve(result);
        })
    })
  }

  public getAllThreadsFromAccount(accountAddress: string): Promise<any>
  {
    return new Promise((resolve, reject) =>
    {
      this.MongoDB.collection('chats').findOne({ user_address: accountAddress },
        (err: any, result: any) =>
        {
          if (err) return reject(err);
          return resolve(result);
        })
    })
  }

  public getThread(accountAddress: string, parentMessageId: string): Promise<any>
  {
    return new Promise((resolve, reject) =>
    {
      this.MongoDB.collection('chats').findOne({ $and: [{ user_address: accountAddress }, { parent_id: parentMessageId }] },
        (err: any, result: any) =>
        {
          if (err) return reject(err);
          return resolve(result);
        })
    })
  }

  public static getInstance(): LogService
  {
    if (!this.instance) {
      this.instance = new LogService();
    }
    return this.instance;
  }

  private getParentId(references: string[]): string
  {
    let idx = references.length - 1;
    while (references[idx] === "null" || references[idx] === null || !references[idx]) {
      idx--;
    }
    return references[idx];
  }
}