package utils

import (
	"crypto/aes"
	"crypto/cipher"
	"crypto/rand"
	"crypto/subtle"
	"encoding/base64"
	"errors"
	"io"

	"lokideploy/config"

	"golang.org/x/crypto/argon2"
)

func HashPassword(password string) (string, error) {
	salt := make([]byte, 16)
	if _, err := rand.Read(salt); err != nil {
		return "", err
	}
	hash := argon2.IDKey([]byte(password), salt, 3, 64*1024, 4, 32)
	combined := append(salt, hash...)
	return base64.StdEncoding.EncodeToString(combined), nil
}

func VerifyPassword(password, hashStr string) bool {
	combined, err := base64.StdEncoding.DecodeString(hashStr)
	if err != nil || len(combined) < 16 {
		return false
	}
	salt := combined[:16]
	hash := combined[16:]
	newHash := argon2.IDKey([]byte(password), salt, 3, 64*1024, 4, 32)
	return subtle.ConstantTimeCompare(hash, newHash) == 1
}

func Encrypt(plaintext string) (string, error) {
	key := []byte(config.GetConfig().JWTSecret)[:32]
	block, err := aes.NewCipher(key)
	if err != nil {
		return "", err
	}
	gcm, err := cipher.NewGCM(block)
	if err != nil {
		return "", err
	}
	nonce := make([]byte, gcm.NonceSize())
	if _, err = io.ReadFull(rand.Reader, nonce); err != nil {
		return "", err
	}
	ciphertext := gcm.Seal(nonce, nonce, []byte(plaintext), nil)
	return base64.StdEncoding.EncodeToString(ciphertext), nil
}

func Decrypt(ciphertext string) (string, error) {
	key := []byte(config.GetConfig().JWTSecret)[:32]
	data, err := base64.StdEncoding.DecodeString(ciphertext)
	if err != nil {
		return "", err
	}
	block, err := aes.NewCipher(key)
	if err != nil {
		return "", err
	}
	gcm, err := cipher.NewGCM(block)
	if err != nil {
		return "", err
	}
	if len(data) < gcm.NonceSize() {
		return "", errors.New("ciphertext too short")
	}
	nonce, ciphertextBytes := data[:gcm.NonceSize()], data[gcm.NonceSize():]
	plaintext, err := gcm.Open(nil, nonce, ciphertextBytes, nil)
	if err != nil {
		return "", err
	}
	return string(plaintext), nil
}