package libs

import (
	"crypto/md5"
	"crypto/sha256"
	"encoding/hex"
	"fmt"
	"strings"

	"github.com/gogf/gf/v2/util/grand"
)

// Md5 计算MD5哈希（仅用于向后兼容旧密码验证）
func Md5(buf []byte) string {
	return fmt.Sprintf("%x", md5.Sum(buf))
}

// HashPassword 生成密码哈希（使用 SHA-256 + 随机盐值）
// 格式: $sha256$<salt>$<hash>
func HashPassword(password string) (string, string) {
	salt := grand.S(16)
	h := sha256.Sum256([]byte(salt + password))
	hash := fmt.Sprintf("$sha256$%s$%x", salt, h)
	return hash, salt
}

// VerifyPassword 验证密码，兼容新旧两种哈希格式
func VerifyPassword(password, storedHash, salt string) bool {
	// 新格式: $sha256$<salt>$<hash>
	if strings.HasPrefix(storedHash, "$sha256$") {
		parts := strings.Split(storedHash, "$")
		if len(parts) != 4 {
			return false
		}
		h := sha256.Sum256([]byte(parts[2] + password))
		expected := fmt.Sprintf("$sha256$%s$%x", parts[2], h)
		return storedHash == expected
	}
	// 旧格式: MD5(password + salt)
	return Md5([]byte(password+salt)) == storedHash
}

// Password 生成密码和盐值（已弃用，使用 HashPassword 代替）
func Password(length int, pwdO string) (pwd string, salt string) {
	if pwdO == "" {
		pwdO = "george518"
	}
	pwd, salt = HashPassword(pwdO)
	return
}

// Sha256Hex 计算 SHA-256 十六进制字符串
func Sha256Hex(data []byte) string {
	h := sha256.Sum256(data)
	return hex.EncodeToString(h[:])
}