is.go

package godash

import (
	"encoding/base64"
	"encoding/json"
	"math"
	"net"
	"net/url"
	"regexp"
	"strconv"
	"strings"
	"unicode"
	"unicode/utf8"
)

// IsInRange returns true if value lies between left and right border
func IsInRange(value, left, right float64) bool {
	if left > right {
		left, right = right, left
	}
	return value >= left && value <= right
}

// IsEmail is a constraint to do a simple validation for email addresses, it only check if the string contains "@"
// and that it is not in the first or last character of the string
// https://en.wikipedia.org/wiki/Email_address#Valid_email_addresses
func IsEmail(s string) bool {
	if !strings.Contains(s, "@") || string(s[0]) == "@" || string(s[len(s)-1]) == "@" {
		return false
	}
	return true
}

// IsURL check if the string is an URL.
func IsURL(str string) bool {
	if str == "" || len(str) >= 2083 || len(str) <= 3 || strings.HasPrefix(str, ".") {
		return false
	}
	u, err := url.Parse(str)
	if err != nil {
		return false
	}
	if strings.HasPrefix(u.Host, ".") {
		return false
	}
	if u.Host == "" && (u.Path != "" && !strings.Contains(u.Path, ".")) {
		return false
	}
	return rxURL.MatchString(str)

}

// IsRequestURL check if the string rawurl, assuming
// it was recieved in an HTTP request, is a valid
// URL confirm to RFC 3986
func IsRequestURL(rawurl string) bool {
	url, err := url.ParseRequestURI(rawurl)
	if err != nil {
		return false //Couldn't even parse the rawurl
	}
	if len(url.Scheme) == 0 {
		return false //No Scheme found
	}
	return true
}

// IsRequestURI check if the string rawurl, assuming
// it was recieved in an HTTP request, is an
// absolute URI or an absolute path.
func IsRequestURI(rawurl string) bool {
	_, err := url.ParseRequestURI(rawurl)
	return err == nil
}

// IsAlpha check if the string contains only letters (a-zA-Z). Empty string is valid.
func IsAlpha(s string) bool {
	for _, v := range s {
		if ('Z' < v || v < 'A') && ('z' < v || v < 'a') {
			return false
		}
	}
	return true
}

//IsUTFLetter check if the string contains only unicode letter characters.
//Similar to IsAlpha but for all languages. Empty string is valid.
func IsUTFLetter(str string) bool {
	for _, v := range str {
		if !unicode.IsLetter(v) {
			return false
		}
	}
	return true

}

// IsAlphanumeric check if the string contains only letters and numbers. Empty string is valid.
func IsAlphanumeric(s string) bool {
	for _, v := range s {
		if ('Z' < v || v < 'A') && ('z' < v || v < 'a') && ('9' < v || v < '0') {
			return false
		}
	}
	return true
}

// IsUTFLetterNumeric check if the string contains only unicode letters and numbers. Empty string is valid.
func IsUTFLetterNumeric(s string) bool {
	for _, v := range s {
		if !unicode.IsLetter(v) && !unicode.IsNumber(v) { //letters && numbers are ok
			return false
		}
	}
	return true
}

// IsNumeric check if the string contains only numbers. Empty string is valid.
func IsNumeric(s string) bool {
	for _, v := range s {
		if '9' < v || v < '0' {
			return false
		}
	}
	return true
}

// IsUTFNumeric check if the string contains only unicode numbers of any kind.
// Numbers can be 0-9 but also Fractions ¾,Roman Ⅸ and Hangzhou 〩. Empty string is valid.
func IsUTFNumeric(s string) bool {
	for _, v := range s {
		if unicode.IsNumber(v) == false {
			return false
		}
	}
	return true
}

// IsNegative returns true if value < 0
func IsNegative(value float64) bool {
	return value < 0
}

// IsPositive returns true if value > 0
func IsPositive(value float64) bool {
	return value > 0
}

// IsNonNegative returns true if value >= 0
func IsNonNegative(value float64) bool {
	return value >= 0
}

// IsNonPositive returns true if value <= 0
func IsNonPositive(value float64) bool {
	return value <= 0
}

// IsWhole returns true if value is whole number
func IsWhole(value float64) bool {
	return math.Abs(math.Remainder(value, 1)) == 0
}

// IsNatural returns true if value is natural number (positive and whole)
func IsNatural(value float64) bool {
	return IsWhole(value) && IsPositive(value)
}

// IsUTFDigit check if the string contains only unicode radix-10 decimal digits. Empty string is valid.
func IsUTFDigit(s string) bool {
	for _, v := range s {
		if !unicode.IsDigit(v) {
			return false
		}
	}
	return true
}

// IsHexadecimal check if the string is a hexadecimal number.
func IsHexadecimal(str string) bool {
	return rxHexadecimal.MatchString(str)
}

// IsHexcolor check if the string is a hexadecimal color.
func IsHexcolor(str string) bool {
	return rxHexcolor.MatchString(str)
}

// IsRGBcolor check if the string is a valid RGB color in form rgb(RRR, GGG, BBB).
func IsRGBcolor(str string) bool {
	return rxRGBcolor.MatchString(str)
}

// IsLowerCase check if the string is lowercase. Empty string is valid.
func IsLowerCase(str string) bool {
	if IsNull(str) {
		return true
	}
	return str == strings.ToLower(str)
}

// IsUpperCase check if the string is uppercase. Empty string is valid.
func IsUpperCase(str string) bool {
	if IsNull(str) {
		return true
	}
	return str == strings.ToUpper(str)
}

// IsInt check if the string is an integer. Empty string is valid.
func IsInt(str string) bool {
	if IsNull(str) {
		return true
	}
	return rxInt.MatchString(str)
}

// IsFloat check if the string is a float.
func IsFloat(str string) bool {
	return str != "" && rxFloat.MatchString(str)
}

// IsDivisibleBy check if the string is a number that's divisible by another.
// If second argument is not valid integer or zero, it's return false.
// Otherwise, if first argument is not valid integer or zero, it's return true (Invalid string converts to zero).
func IsDivisibleBy(str, num string) bool {
	f, _ := ToFloat(str)
	p := int64(f)
	q, _ := ToInt(num)
	if q == 0 {
		return false
	}
	return (p == 0) || (p%q == 0)
}

// IsNull check if the string is null.
func IsNull(str string) bool {
	return len(str) == 0
}

// IsByteLength check if the string's length (in bytes) falls in a range.
func IsByteLength(str string, min, max int) bool {
	return len(str) >= min && len(str) <= max
}

// IsUUIDv3 check if the string is a UUID version 3.
func IsUUIDv3(str string) bool {
	return rxUUID3.MatchString(str)
}

// IsUUIDv4 check if the string is a UUID version 4.
func IsUUIDv4(str string) bool {
	return rxUUID4.MatchString(str)
}

// IsUUIDv5 check if the string is a UUID version 5.
func IsUUIDv5(str string) bool {
	return rxUUID5.MatchString(str)
}

// IsUUID check if the string is a UUID (version 3, 4 or 5).
func IsUUID(str string) bool {
	return rxUUID.MatchString(str)
}

// IsCreditCard check if the string is a credit card.
func IsCreditCard(str string) bool {
	r, _ := regexp.Compile("[^0-9]+")
	sanitized := r.ReplaceAll([]byte(str), []byte(""))
	if !rxCreditCard.MatchString(string(sanitized)) {
		return false
	}
	var sum int64
	var digit string
	var tmpNum int64
	var shouldDouble bool
	for i := len(sanitized) - 1; i >= 0; i-- {
		digit = string(sanitized[i:(i + 1)])
		tmpNum, _ = ToInt(digit)
		if shouldDouble {
			tmpNum *= 2
			if tmpNum >= 10 {
				sum += ((tmpNum % 10) + 1)
			} else {
				sum += tmpNum
			}
		} else {
			sum += tmpNum
		}
		shouldDouble = !shouldDouble
	}

	if sum%10 == 0 {
		return true
	}
	return false
}

// IsISBN10 check if the string is an ISBN version 10.
func IsISBN10(str string) bool {
	return IsISBN(str, 10)
}

// IsISBN13 check if the string is an ISBN version 13.
func IsISBN13(str string) bool {
	return IsISBN(str, 13)
}

// IsISBN check if the string is an ISBN (version 10 or 13).
// If version value is not equal to 10 or 13, it will be check both variants.
func IsISBN(str string, version int) bool {
	r, _ := regexp.Compile("[\\s-]+")
	sanitized := r.ReplaceAll([]byte(str), []byte(""))
	var checksum int32
	var i int32
	if version == 10 {
		if !rxISBN10.MatchString(string(sanitized)) {
			return false
		}
		for i = 0; i < 9; i++ {
			checksum += (i + 1) * int32(sanitized[i]-'0')
		}
		if sanitized[9] == 'X' {
			checksum += 10 * 10
		} else {
			checksum += 10 * int32(sanitized[9]-'0')
		}
		if checksum%11 == 0 {
			return true
		}
		return false
	} else if version == 13 {
		if !rxISBN13.MatchString(string(sanitized)) {
			return false
		}
		factor := []int32{1, 3}
		for i = 0; i < 12; i++ {
			checksum += factor[i%2] * int32(sanitized[i]-'0')
		}
		if (int32(sanitized[12]-'0'))-((10-(checksum%10))%10) == 0 {
			return true
		}
		return false
	}
	return IsISBN(str, 10) || IsISBN(str, 13)
}

// IsJSON check if the string is valid JSON (note: uses json.Unmarshal).
func IsJSON(str string) bool {
	var js json.RawMessage
	return json.Unmarshal([]byte(str), &js) == nil
}

// IsMultibyte check if the string contains one or more multibyte chars. Empty string is valid.
func IsMultibyte(s string) bool {
	for _, v := range s {
		if v >= utf8.RuneSelf {
			return true
		}
	}

	return IsNull(s)
}

// IsASCII check if the string contains ASCII chars only. Empty string is valid.
func IsASCII(s string) bool {
	for _, v := range s {
		if v >= utf8.RuneSelf {
			return false
		}
	}
	return true
}

// IsPrintableASCII check if the string contains printable ASCII chars only. Empty string is valid.
func IsPrintableASCII(s string) bool {
	for _, v := range s {
		if v < ' ' || v > '~' {
			return false
		}
	}
	return true
}

// IsFullWidth check if the string contains any full-width chars. Empty string is valid.
func IsFullWidth(str string) bool {
	if IsNull(str) {
		return true
	}
	return rxFullWidth.MatchString(str)
}

// IsHalfWidth check if the string contains any half-width chars. Empty string is valid.
func IsHalfWidth(str string) bool {
	if IsNull(str) {
		return true
	}
	return rxHalfWidth.MatchString(str)
}

// IsVariableWidth check if the string contains a mixture of full and half-width chars. Empty string is valid.
func IsVariableWidth(str string) bool {
	if IsNull(str) {
		return true
	}
	return rxHalfWidth.MatchString(str) && rxFullWidth.MatchString(str)
}

// IsBase64 check if a string is base64 encoded.
func IsBase64(s string) bool {
	if IsNull(s) {
		return false
	}
	_, err := base64.StdEncoding.DecodeString(s)

	return err == nil
}

// IsFilePath check is a string is Win or Unix file path and returns it's type.
func IsFilePath(str string) (bool, int) {
	if rxWinPath.MatchString(str) {
		//check windows path limit see:
		//  http://msdn.microsoft.com/en-us/library/aa365247(VS.85).aspx#maxpath
		if len(str[3:]) > 32767 {
			return false, Win
		}
		return true, Win
	} else if rxUnixPath.MatchString(str) {
		return true, Unix
	}
	return false, Unknown
}

// IsDataURI checks if a string is base64 encoded data URI such as an image
func IsDataURI(str string) bool {
	dataURI := strings.Split(str, ",")
	if !rxDataURI.MatchString(dataURI[0]) {
		return false
	}
	return IsBase64(dataURI[1])
}

// IsISO3166Alpha2 checks if a string is valid two-letter country code
func IsISO3166Alpha2(str string) bool {
	for _, entry := range ISO3166List {
		if str == entry.Alpha2Code {
			return true
		}
	}
	return false
}

// IsISO3166Alpha3 checks if a string is valid three-letter country code
func IsISO3166Alpha3(str string) bool {
	for _, entry := range ISO3166List {
		if str == entry.Alpha3Code {
			return true
		}
	}
	return false
}

// IsDNSName will validate the given string as a DNS name
func IsDNSName(str string) bool {
	if str == "" || len(strings.Replace(str, ".", "", -1)) > 255 {
		// constraints already violated
		return false
	}
	return rxDNSName.MatchString(str)
}

// IsDialString validates the given string for usage with the various Dial() functions
func IsDialString(str string) bool {

	if h, p, err := net.SplitHostPort(str); err == nil && h != "" && p != "" && (IsDNSName(h) || IsIP(h)) && IsPort(p) {
		return true
	}

	return false
}

// IsIP checks if a string is either IP version 4 or 6.
func IsIP(str string) bool {
	return net.ParseIP(str) != nil
}

// IsPort checks if a string represents a valid port
func IsPort(str string) bool {
	if i, err := strconv.Atoi(str); err == nil && i > 0 && i < 65536 {
		return true
	}
	return false
}

// IsIPv4 check if the string is an IP version 4.
func IsIPv4(str string) bool {
	ip := net.ParseIP(str)
	return ip != nil && strings.Contains(str, ".")
}

// IsIPv6 check if the string is an IP version 6.
func IsIPv6(str string) bool {
	ip := net.ParseIP(str)
	return ip != nil && strings.Contains(str, ":")
}

// IsMAC check if a string is valid MAC address.
// Possible MAC formats:
// 01:23:45:67:89:ab
// 01:23:45:67:89:ab:cd:ef
// 01-23-45-67-89-ab
// 01-23-45-67-89-ab-cd-ef
// 0123.4567.89ab
// 0123.4567.89ab.cdef
func IsMAC(str string) bool {
	_, err := net.ParseMAC(str)
	return err == nil
}

// IsMongoID check if the string is a valid hex-encoded representation of a MongoDB ObjectId.
func IsMongoID(str string) bool {
	return rxHexadecimal.MatchString(str) && (len(str) == 24)
}

// IsLatitude check if a string is valid latitude.
func IsLatitude(str string) bool {
	return rxLatitude.MatchString(str)
}

// IsLongitude check if a string is valid longitude.
func IsLongitude(str string) bool {
	return rxLongitude.MatchString(str)
}

// IsSSN will validate the given string as a U.S. Social Security Number
func IsSSN(str string) bool {
	if str == "" || len(str) != 11 {
		return false
	}
	return rxSSN.MatchString(str)
}

// IsSemver check if string is valid semantic version
func IsSemver(str string) bool {
	return rxSemver.MatchString(str)
}

// IsMatches check if string matches the pattern (pattern is regular expression)
// In case of error return false
func IsMatches(str, pattern string) bool {
	match, _ := regexp.MatchString(pattern, str)
	return match
}

// IsStringMatches checks if a string matches a given pattern.
func IsStringMatches(s string, params ...string) bool {
	if len(params) == 1 {
		pattern := params[0]
		return IsMatches(s, pattern)
	}
	return false
}

// IsStringLength check string's length (including multi byte strings)
func IsStringLength(str string, params ...string) bool {

	if len(params) == 2 {
		strLength := utf8.RuneCountInString(str)
		min, _ := ToInt(params[0])
		max, _ := ToInt(params[1])
		return strLength >= int(min) && strLength <= int(max)
	}

	return false
}