package utils

import (
	"regexp"
	"strings"
)

// ValidateEmail 验证邮箱
func ValidateEmail(email string) bool {
	pattern := `^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$`
	matched, _ := regexp.MatchString(pattern, email)
	return matched
}

// ValidateUsername 验证用户名
func ValidateUsername(username string) bool {
	if len(username) < 3 || len(username) > 30 {
		return false
	}
	pattern := `^[a-zA-Z0-9_]+$`
	matched, _ := regexp.MatchString(pattern, username)
	return matched
}

// ValidatePassword 验证密码强度
func ValidatePassword(password string) bool {
	if len(password) < 8 || len(password) > 50 {
		return false
	}

	var hasUpper, hasLower, hasDigit bool
	for _, c := range password {
		switch {
		case 'A' <= c && c <= 'Z':
			hasUpper = true
		case 'a' <= c && c <= 'z':
			hasLower = true
		case '0' <= c && c <= '9':
			hasDigit = true
		}
	}

	return hasUpper && hasLower && hasDigit
}

// ValidatePasswordWithDetail 验证密码强度并返回详细信息
func ValidatePasswordWithDetail(password string) (bool, string) {
	if len(password) < 8 {
		return false, "密码长度至少8位"
	}
	if len(password) > 50 {
		return false, "密码长度不能超过50位"
	}

	var hasUpper, hasLower, hasDigit bool
	for _, c := range password {
		switch {
		case 'A' <= c && c <= 'Z':
			hasUpper = true
		case 'a' <= c && c <= 'z':
			hasLower = true
		case '0' <= c && c <= '9':
			hasDigit = true
		}
	}

	if !hasUpper {
		return false, "密码必须包含大写字母"
	}
	if !hasLower {
		return false, "密码必须包含小写字母"
	}
	if !hasDigit {
		return false, "密码必须包含数字"
	}

	return true, ""
}

// ValidatePhone 验证手机号
func ValidatePhone(phone string) bool {
	pattern := `^1[3-9]\d{9}$`
	matched, _ := regexp.MatchString(pattern, phone)
	return matched
}

// SanitizeHTML 清理HTML，防止XSS攻击
func SanitizeHTML(input string) string {
	input = strings.ReplaceAll(input, "&", "&amp;")
	input = strings.ReplaceAll(input, "<", "&lt;")
	input = strings.ReplaceAll(input, ">", "&gt;")
	input = strings.ReplaceAll(input, "\"", "&quot;")
	input = strings.ReplaceAll(input, "'", "&#x27;")
	input = strings.ReplaceAll(input, "/", "&#x2F;")
	return input
}