// Copyright GoFrame Author(https://goframe.org). All Rights Reserved.
//
// This Source Code Form is subject to the terms of the MIT License.
// If a copy of the MIT was not distributed with this file,
// You can obtain one at https://github.com/gogf/gf.

package gstr

import "strings"

// Str returns part of `haystack` string starting from and including
// the first occurrence of `needle` to the end of `haystack`.
// See http://php.net/manual/en/function.strstr.php.
func Str(haystack string, needle string) string {
	if needle == "" {
		return ""
	}
	pos := strings.Index(haystack, needle)
	if pos == NotFoundIndex {
		return ""
	}
	return haystack[pos+len([]byte(needle))-1:]
}

// StrEx returns part of `haystack` string starting from and excluding
// the first occurrence of `needle` to the end of `haystack`.
func StrEx(haystack string, needle string) string {
	if s := Str(haystack, needle); s != "" {
		return s[1:]
	}
	return ""
}

// StrTill returns part of `haystack` string ending to and including
// the first occurrence of `needle` from the start of `haystack`.
func StrTill(haystack string, needle string) string {
	pos := strings.Index(haystack, needle)
	if pos == NotFoundIndex || pos == 0 {
		return ""
	}
	return haystack[:pos+1]
}

// StrTillEx returns part of `haystack` string ending to and excluding
// the first occurrence of `needle` from the start of `haystack`.
func StrTillEx(haystack string, needle string) string {
	pos := strings.Index(haystack, needle)
	if pos == NotFoundIndex || pos == 0 {
		return ""
	}
	return haystack[:pos]
}