import mysql from 'mysql2/promise'
import fs from 'fs'

class Test { 

	vendorProperties = {
	  "multipleStatements":true
	 ,"typeCast":true
	 ,"supportBigNumbers":true
	 ,"bigNumberStrings":true
	 ,"dateStrings":true
	 ,"trace":true
	 ,"user":"root"
	 ,"password": "oracle"
	 ,"host":"yadamu-db1"
	 ,"database":"sys"
	 ,"port":3306
	 , infileStreamFactory : (path) => {return fs.createReadStream(path)}
	 }  
	 
  async createConnectionPool() {
    
    let stack, operation
	
    try {
      stack = new Error().stack;
      operation = 'mysql.createPool()'  
      this.pool = mysql.createPool(this.vendorProperties)
      console.log('Pool Created')
	} catch (e) {
      throw e
    }
    
	
  }

  async getConnectionFromPool() {

    let stack
    
    try {    
      stack = new Error().stack;
      const connection = await this.pool.getConnection()
	  console.log('Connection obtained')
      return connection
	} catch (err) {
	  throw err 
    }
  }
  
  async closeConnection(options) {


    if ((this.connection !== undefined) && (typeof this.connection.release === 'function')) {
      let stack;
      try {
        stack = new Error().stack
        await this.connection.release()
        this.connection = undefined;
      } catch (e) {
        this.connection = undefined;
        throw e
      }
    }
  };
      
  async closePool(options) {
      
      
    if ((this.pool !== undefined) && (typeof this.pool.end === 'function')) {
      let stack;
      try {
        stack = new Error().stack
        await this.pool.end()
        this.pool = undefined;
      } catch (e) {
        this.pool = undefined;
        throw e
      }
    }
  }
 
  async executeSQL(sqlStatement,args) {
    

    let stack
	let results

      try {
        stack = new Error().stack;
		const [results,fields] = await this.connection.query(sqlStatement,args)
		return results;
      } catch (e) {
        throw e
      }
  }
  

  async test() {
      const data = [[1 , -1.7976931348623157e308],[2,1.7976931348623157e308]]
	  let results
	  try {
        await this.createConnectionPool()
	    this.connection = await this.getConnectionFromPool()
		results = await this.executeSQL(`SET AUTOCOMMIT = 0, TIME_ZONE = '+00:00',SESSION INTERACTIVE_TIMEOUT = 600000, WAIT_TIMEOUT = 600000, SQL_MODE='ANSI_QUOTES,PAD_CHAR_TO_FULL_LENGTH', GROUP_CONCAT_MAX_LEN = 1024000, GLOBAL LOCAL_INFILE = 'ON'`);
        results = await this.executeSQL(`CREATE TEMPORARY table if not exists "t1"("key" smallint  ,"double_col" double); `);
		results = await this.executeSQL(`insert into "t1"("key","double_col")  values  ?`,[data]);
		results = await this.executeSQL(`select "key", "double_col", cast("double_col" as char(64)) as "cast_result" from "t1"`);
		console.log(results)
 	    await this.closeConnection();
		await this.closePool();
	  } catch (e) {
 	    await this.closeConnection();
		await this.closePool();
		console.log(e)
	  }
  }

}

const test = new Test();
test.test().then(() => console.log('Success')).catch((e) => console.log(e))