package explogin

import (
	"math"
	"sync"
)

/*
	Explogin.go
	Package to handle expotential login time
	so as to prevent someone from brute forcing your password

	Author: tobychui
*/

type UserLoginEntry struct {
	Username   string
	TargetIP   string
	Timestamp  int64
	RetryCount int64
}

type ExpLoginHandler struct {
	LoginRecord  *sync.Map //Sync map to store UserLoginEntry, username+ip as key
	BaseDelay    int       //Base delay exponent
	DelayCeiling int       //Max delay time
}

//Create a new exponential login handler object
func NewExponentialLoginHandler(baseDelay int) *ExpLoginHandler {
	recordMap := sync.Map{}

	return &ExpLoginHandler{
		LoginRecord: &recordMap,
		BaseDelay:   baseDelay,
	}
}

//Check allow access now, if false return how many seconds till next retry
func (e *ExpLoginHandler) AllowImmediateAccess(username string, ip string) (bool, int64) {

}

func (e *ExpLoginHandler) getDelayTimeFromRetryCount(retryCount int) int64 {
	delaySecs := int64(math.Floor((math.Pow(2, float64(retryCount)) - 1) * 0.5))
	if delaySecs > int64(e.DelayCeiling) {
		delaySecs = int64(e.DelayCeiling)
	}

	return delaySecs
}