package util

import (
	"net/url"
)

// MaskURLQuery masks specific url query string values
func MaskURLQuery(originalURL string, keysToMask ...string) (string, error) {
	parsedURL, err := url.Parse(originalURL)
	if err != nil {
		return "", err
	}

	queryParams := parsedURL.Query()
	for _, key := range keysToMask {
		if value, exists := queryParams[key]; exists {
			for i := range value {
				queryParams[key][i] = maskValue(value[i])
			}
		}
	}

	parsedURL.RawQuery = queryParams.Encode()

	return parsedURL.String(), nil
}

func maskValue(value string) string {
	const defaultMask = "xxxxx" // using `x` because `*` will be encoded

	if len(value) < 5 {
		return defaultMask
	}

	maskLength := len(value) - 5
	return defaultMask + value[maskLength:]
}