import SqlParse from "./SqlParse"
import {MysqlError, PoolConnection} from "mysql"
import { PojoType } from "../../../../type/type"
import {IDao} from "../../../interface"
import DataSource from "./DataSource"

export default class MysqlDao{
    private dataSource = new DataSource()
    public connection?: PoolConnection = undefined
    private keepAlive: boolean = false

    public async getConnection(): Promise<PoolConnection>{
        if(!this.connection){
            this.connection = await this.dataSource.getConnection();
        }
        return this.connection
    }

    protected async query(sql: SqlParse): Promise<Array<any>>{
        const conn: PoolConnection = await this.getConnection()
        return new Promise((resolve, reject) => {
            conn.query(sql.toString(), (err: MysqlError, data: any) => {
                if(err){
                    this.releaseConnection()
                    reject(err.message)
                }else{
                    resolve(data)
                }
                if(!this.keepAlive){
                    this.releaseConnection()
                }
            })
        })
    }

    protected async execute(sql: SqlParse): Promise<any>{
        const conn: PoolConnection = await this.getConnection()
        return new Promise((resolve, reject) => {
            conn.query(sql.toString(), (err: MysqlError, data: any) => {
                if(err){
                    this.releaseConnection()
                    reject(err.message)
                }else{
                    resolve(data)
                }
            })
            if(!this.keepAlive){
                this.releaseConnection()
            }
        })
    }

    public setAlive(): void{
        this.keepAlive = true
    }

    private releaseConnection(): void{
        this.connection && this.connection.release()
        this.connection = undefined
    }
}