import mysql from 'mysql2/promise'

export class MySQLClient {
    constructor(db, kal = 0) {
        this.db = db
        this.lastInsertedId = -1
        this.kalIntervalId = null
        if(kal > 0){
            this.kalIntervalId = setInterval(() => {
                this.db.query('SELECT 1')
            }, 1000 * kal);
        }
    }
    
    async close(){
        if(this.db) await this.db.end()
        if(this.kalIntervalId) clearInterval(this.kalIntervalId)
        this.db = null
    }

    escape(x) { return(mysql.escape(x)) }

    async execute(query, values = []){
        if(!this.db) return([])
        if(query.search(RegExp('(^|;) *(INSERT|REPLACE) +INTO','i'))>-1) this.lastInsertedId = -1
        const [result] = await this.db.execute(query, values)
    
        if('insertId' in result) {
            this.lastInsertedId = result.insertId
        } 
        return(result)
    }

    /* Makes a multi-line VALUES insert, with values for an array of objects { columns:value }
    */
    async InsertObjectsStatement(table, rows){
        this.lastInsertedId = -1
        if((!this.db) || (rows.length==0)) return([])
        const keys = Object.keys(rows[0]).map((key) => `\`${key}\``).join(', ')
        let valuesArr = []
        for(let row of rows){
            valuesArr.push(Object.values(row))
        }      
        const query = `INSERT INTO ${table} (${keys}) VALUES ?`
        const [result] = await this.db.query(query, [valuesArr]) //Note the wierd array in array of arrays, also, query, not execute
        if('insertId' in result) {
            this.lastInsertedId = result.insertId
        } 
        return(result)
    }

    /* Makes a multi-line VALUES insert, with values for an array of objects { columns:value }
    */
    async ReplaceObjectsStatement(table, rows){
        this.lastInsertedId = -1
        if((!this.db) || (rows.length==0)) return([])
        const keys = Object.keys(rows[0]).map((key) => `\`${key}\``).join(', ')
        let valuesArr = []
        for(let row of rows){
            valuesArr.push(Object.values(row))
        }      
        const query = `REPLACE INTO ${table} (${keys}) VALUES ?`
        const [result] = await this.db.query(query, [valuesArr])  //Note the wierd array in array of arrays, also, query, not execute
        if('insertId' in result) {
            this.lastInsertedId = result.insertId
        } 
        return(result)
    }
    
}