package keeper

import (
	"context"
	"fmt"

	"github.com/sonr-io/crypto/argon2"
	"github.com/sonr-io/crypto/mpc"
	"github.com/sonr-io/crypto/password"
	didtypes "github.com/sonr-io/sonr/x/did/types"
)

// CreateVaultForDIDSecure creates a vault with user-provided password
func (k Keeper) CreateVaultForDIDSecure(
	ctx context.Context,
	did string,
	owner string,
	vaultID string,
	keyID string,
	userPassword []byte,
	enclaveData *mpc.EnclaveData,
) (*didtypes.CreateVaultResponse, error) {
	// Validate password strength
	validator := password.NewValidator(password.DefaultPasswordConfig())
	if err := validator.Validate(userPassword); err != nil {
		return nil, fmt.Errorf("password validation failed: %w", err)
	}

	// Create Argon2id KDF with default secure parameters
	kdf := argon2.New(argon2.DefaultConfig())

	// Generate secure salt
	salt, err := kdf.GenerateSalt()
	if err != nil {
		return nil, fmt.Errorf("failed to generate salt: %w", err)
	}

	// Derive encryption key using Argon2id
	derivedKey := kdf.DeriveKey(userPassword, salt)

	// Clear password from memory
	defer password.ZeroBytes(userPassword)

	// Encrypt enclave data with derived key
	encryptedData, err := k.encryptEnclaveData(enclaveData, derivedKey)
	if err != nil {
		return nil, fmt.Errorf("failed to encrypt vault data: %w", err)
	}

	// Store vault with encrypted data and salt
	vaultState, err := k.storeSecureVault(ctx, vaultID, owner, encryptedData, salt)
	if err != nil {
		return nil, fmt.Errorf("failed to store secure vault: %w", err)
	}

	return &didtypes.CreateVaultResponse{
		VaultID: vaultState.VaultId,
	}, nil
}

// UnlockVault unlocks a vault using the user's password
func (k Keeper) UnlockVault(
	ctx context.Context,
	vaultID string,
	userPassword []byte,
) (*mpc.EnclaveData, error) {
	// Retrieve vault state with salt
	vaultState, err := k.getVaultState(ctx, vaultID)
	if err != nil {
		return nil, fmt.Errorf("failed to retrieve vault: %w", err)
	}

	if len(vaultState.Salt) == 0 {
		return nil, fmt.Errorf("vault salt not found")
	}

	// Create KDF with same config as creation
	kdf := argon2.New(argon2.DefaultConfig())

	// Derive key using stored salt
	derivedKey := kdf.DeriveKey(userPassword, vaultState.Salt)

	// Clear password from memory
	defer password.ZeroBytes(userPassword)

	// Decrypt enclave data
	enclaveData, err := k.decryptEnclaveData(vaultState.EncryptedData, derivedKey)
	if err != nil {
		return nil, fmt.Errorf("failed to decrypt vault: invalid password")
	}

	return enclaveData, nil
}

// encryptEnclaveData encrypts enclave data with AES-GCM
func (k Keeper) encryptEnclaveData(data *mpc.EnclaveData, key []byte) ([]byte, error) {
	// Implementation would use AES-GCM for authenticated encryption
	// This is a placeholder - actual implementation needs crypto/cipher

	// For now, return a placeholder
	// In production, this would:
	// 1. Serialize enclave data to JSON
	// 2. Create AES-GCM cipher with key
	// 3. Generate nonce
	// 4. Encrypt and authenticate data
	// 5. Return nonce + ciphertext

	return []byte("encrypted_placeholder"), nil
}

// decryptEnclaveData decrypts enclave data
func (k Keeper) decryptEnclaveData(encryptedData []byte, key []byte) (*mpc.EnclaveData, error) {
	// Implementation would use AES-GCM for authenticated decryption
	// This is a placeholder - actual implementation needs crypto/cipher

	// For now, return a placeholder
	// In production, this would:
	// 1. Extract nonce from encrypted data
	// 2. Create AES-GCM cipher with key
	// 3. Decrypt and verify authentication
	// 4. Deserialize JSON to enclave data
	// 5. Return decrypted enclave data

	return &mpc.EnclaveData{}, nil
}

// storeSecureVault stores encrypted vault data with salt
func (k Keeper) storeSecureVault(
	ctx context.Context,
	vaultID string,
	owner string,
	encryptedData []byte,
	salt []byte,
) (*VaultStateWithSalt, error) {
	// This would store the vault state with salt in the database
	// For now, return a placeholder

	vaultState := &VaultStateWithSalt{
		VaultId:       vaultID,
		Owner:         owner,
		EncryptedData: encryptedData,
		Salt:          salt,
	}

	// In production: k.OrmDB.VaultStateTable().Insert(ctx, vaultState)

	return vaultState, nil
}

// getVaultState retrieves vault state with salt
func (k Keeper) getVaultState(ctx context.Context, vaultID string) (*VaultStateWithSalt, error) {
	// This would retrieve the vault state from the database
	// For now, return a placeholder

	return &VaultStateWithSalt{
		VaultId: vaultID,
		Salt:    []byte("placeholder_salt"),
	}, nil
}

// VaultStateWithSalt extends vault state with salt storage
type VaultStateWithSalt struct {
	VaultId       string
	Owner         string
	EncryptedData []byte
	Salt          []byte
}