package db

import (
	"database/sql"
	"os"
	"strconv"
	"time"
)

func ApplyPoolFromEnv(d *sql.DB, prefix string) {
	if d == nil {
		return
	}
	if v := os.Getenv(prefix + "MAX_OPEN_CONNS"); v != "" {
		if n, err := strconv.Atoi(v); err == nil && n > 0 {
			d.SetMaxOpenConns(n)
		}
	}
	if v := os.Getenv(prefix + "MAX_IDLE_CONNS"); v != "" {
		if n, err := strconv.Atoi(v); err == nil && n >= 0 {
			d.SetMaxIdleConns(n)
		}
	}
	if v := os.Getenv(prefix + "CONN_MAX_LIFETIME"); v != "" {
		if dur, err := time.ParseDuration(v); err == nil {
			d.SetConnMaxLifetime(dur)
		}
	}
	if v := os.Getenv(prefix + "CONN_MAX_IDLE_TIME"); v != "" {
		if dur, err := time.ParseDuration(v); err == nil {
			d.SetConnMaxIdleTime(dur)
		}
	}
}