package stringutil

import (
	"regexp"
	"strings"
)

// urlPattern matches scheme://... URLs up to the next whitespace or quote.
var urlPattern = regexp.MustCompile(`[a-zA-Z][a-zA-Z0-9+.-]*://[^\s"']+`)

// userInfoPattern matches the user:password@ portion following a URL scheme, up to the last @ before
// the path, so passwords containing @ are fully removed.
var userInfoPattern = regexp.MustCompile(`^([a-zA-Z][a-zA-Z0-9+.-]*://)[^/]*@`)

// secretParamPattern matches the values of well known signature and credential parameters used by
// cloud storage presigned URLs and connection strings, wherever they appear.
var secretParamPattern = regexp.MustCompile(`(?i)\b(sig|signature|x-amz-signature|x-amz-credential|x-amz-security-token|x-goog-signature|x-goog-credential|accountkey|sharedaccesssignature|access_token|token)=[^&;\s"']+`)

// RedactURLs removes query strings, fragments and user info from any URLs contained in s, and the
// values of well known signature and credential parameters anywhere in s, so that error messages
// from storage clients (which may embed presigned URLs or credentials) are safe to expose through
// logs, status endpoints and diagnostics.
func RedactURLs(s string) string {
	s = urlPattern.ReplaceAllStringFunc(s, func(u string) string {
		u = userInfoPattern.ReplaceAllString(u, "${1}REDACTED@")
		if i := strings.IndexAny(u, "?#"); i >= 0 {
			return u[:i] + "?REDACTED"
		}
		return u
	})
	return secretParamPattern.ReplaceAllString(s, "${1}=REDACTED")
}