package util

import (
	"crypto/rand"
	"encoding/hex"
	"regexp"
	"time"
)

func Round64(input float64) int64 {
	if input < 0 {
		return int64(input - 0.5)
	}
	return int64(input + 0.5)
}

func TimeToMs(date time.Time) int64 {
	return date.UnixNano() / 1000000
}

func MsToTime(ms int64) time.Time {
	return time.Unix(0, ms*1000000)
}

func NewGuid() (string, error) {
	byteArray := make([]byte, 16)

	_, err := rand.Read(byteArray)

	if err != nil {
		return "", err
	}

	return hex.EncodeToString(byteArray), nil
}

func NewInviteId() (string, error) {
	byteArray := make([]byte, 4)

	_, err := rand.Read(byteArray)

	if err != nil {
		return "", err
	}

	return hex.EncodeToString(byteArray), nil
}

func NewUUID() string {
	guid, err := NewGuid()
	if err != nil {
		// Fallback to timestamp-based UUID if random generation fails
		return hex.EncodeToString([]byte(time.Now().Format("20060102150405")))
	}
	return guid
}

func IsValidUUID(uuid string) bool {
	// Check if the string is a valid 32-character hex string (16 bytes * 2 hex chars)
	if len(uuid) != 32 {
		return false
	}
	
	// Check if all characters are valid hex characters
	matched, _ := regexp.MatchString("^[0-9a-f]{32}$", uuid)
	return matched
}