package utils

import (
	"crypto/md5"
	"crypto/sha256"
	"encoding/hex"
	"io"
	"os"

	"golang.org/x/crypto/bcrypt"
)

// HashPassword 使用bcrypt对密码进行哈希
func HashPassword(password string) (string, error) {
	bytes, err := bcrypt.GenerateFromPassword([]byte(password), bcrypt.DefaultCost)
	return string(bytes), err
}

// CheckPassword 验证密码是否匹配
func CheckPassword(password, hash string) bool {
	err := bcrypt.CompareHashAndPassword([]byte(hash), []byte(password))
	return err == nil
}

// MD5Hash 计算字符串的MD5值
func MD5Hash(text string) string {
	hash := md5.Sum([]byte(text))
	return hex.EncodeToString(hash[:])
}

// FileMD5 计算文件的MD5值
// 用于秒传判断: 相同MD5的文件只需存储一份
func FileMD5(filePath string) (string, error) {
	file, err := os.Open(filePath)
	if err != nil {
		return "", err
	}
	defer file.Close()

	hash := md5.New()
	if _, err := io.Copy(hash, file); err != nil {
		return "", err
	}

	return hex.EncodeToString(hash.Sum(nil)), nil
}

// FileSHA256 计算文件的SHA256值
func FileSHA256(filePath string) (string, error) {
	file, err := os.Open(filePath)
	if err != nil {
		return "", err
	}
	defer file.Close()

	hash := sha256.New()
	if _, err := io.Copy(hash, file); err != nil {
		return "", err
	}

	return hex.EncodeToString(hash.Sum(nil)), nil
}