package meowlib

import (
	"encoding/base64"
	"fmt"
	"time"

	"github.com/ProtonMail/gopenpgp/v2/crypto"
	"github.com/ProtonMail/gopenpgp/v2/helper"
)

type KeyPair struct {
	Public    string    `json:"public,omitempty"`
	Private   string    `json:"private,omitempty"`
	Generated time.Time `json:"generated,omitempty"`
}

type KeysArray []KeyPair

func NewKeyPair() (*KeyPair, error) { // Return error!
	var kp KeyPair
	keys, err := crypto.GenerateKey("name", "mail", "x25519", 0)
	if err != nil {
		return nil, fmt.Errorf("key generation failed: %w", err)
	}
	pub, err := keys.GetArmoredPublicKey()
	if err != nil {
		return nil, fmt.Errorf("gopenpgp: unable to get public key: %w", err)
	}
	priv, err := keys.Armor()
	if err != nil {
		return nil, fmt.Errorf("failed to armor private key: %w", err)
	}
	kp.Public = base64.StdEncoding.EncodeToString([]byte(pub))
	kp.Private = base64.StdEncoding.EncodeToString([]byte(priv))
	kp.Generated = time.Now()
	return &kp, nil
}

func (Kp *KeyPair) GetCryptoKeyObject() (*crypto.Key, error) {
	priv, err := base64.StdEncoding.DecodeString(Kp.Private)
	if err != nil {
		return nil, fmt.Errorf("failed to decode private key: %w", err)
	}
	key, err := crypto.NewKeyFromArmored(string(priv))
	if err != nil {
		return nil, fmt.Errorf("Ccreate key from armoured failed: %w", err)
	}
	return key, nil
}

func AsymEncrypt(publicKey string, data []byte) ([]byte, error) {
	pub, err := base64.StdEncoding.DecodeString(publicKey)
	if err != nil {
		return nil, fmt.Errorf("Message encryption b64 failed: %w", err)
	}
	ciphertext, err := encryptMessage(string(pub), crypto.NewPlainMessage(data))
	if err != nil {
		return nil, fmt.Errorf("Message encryption failed: %w", err)
	}

	return ciphertext.GetBinary(), err
}

func AsymDecrypt(PrivateKey string, data []byte) ([]byte, error) {
	priv, err := base64.StdEncoding.DecodeString(PrivateKey)
	if err != nil {
		return nil, fmt.Errorf("Message decryption b64 failed: %w", err)
	}
	decrypted, err := decryptMessage(string(priv), nil, crypto.NewPGPMessage(data))
	if err != nil {
		return nil, fmt.Errorf("Message decryption failed: %w", err)
	}
	return decrypted.GetBinary(), err
}

func AsymEncryptArmored(PublicKey string, data []byte) ([]byte, error) {
	pub, err := base64.StdEncoding.DecodeString(PublicKey)
	if err != nil {
		return nil, fmt.Errorf("Message encryption b64 failed: %w", err)
	}
	armor, err := helper.EncryptBinaryMessageArmored(string(pub), data)
	if err != nil {
		return nil, fmt.Errorf("Message encryption failed: %w", err)
	}
	return []byte(armor), err
}

func AsymDecryptArmored(PrivateKey string, data []byte) ([]byte, error) {
	priv, err := base64.StdEncoding.DecodeString(PrivateKey)
	if err != nil {
		return nil, fmt.Errorf("Message decryption b64 failed: %w", err)
	}
	decrypted, err := helper.DecryptBinaryMessageArmored(string(priv), nil, string(data))
	if err != nil {
		return nil, fmt.Errorf("Message decryption failed: %w", err)
	}
	return []byte(decrypted), err
}

/*
	func AsymEncryptAndSign_helpers(PublicEncryptionKey string, PrivateSignatureKey string, data []byte) (*EncryptedMessage, error) {
		var enc EncryptedMessage
		pub, err := base64.StdEncoding.DecodeString(PublicEncryptionKey)
		if err != nil {
			log.Error().Msg("Message encryption and sign b64 failed")
		}
		priv, err := base64.StdEncoding.DecodeString(PrivateSignatureKey)
		if err != nil {
			log.Error().Msg("Message encryption and sign b64 failed")
		}
		encrypted, signature, err := helper.EncryptSignBinaryDetached(string(pub), string(priv), nil, data)
		if err != nil {
			log.Error().Msg("Message encryption and sign failed")
		}
		enc.data = []byte(encrypted)
		enc.signature = []byte(signature)
		return &enc, err
	}

	func AsymDecryptAndCheck_helpers(MyPrivateEncryptionKey string, MyContactPublicKey string, data []byte, Signature []byte) (DecryptedMessage []byte, err error) {
		priv, err := base64.StdEncoding.DecodeString(MyPrivateEncryptionKey)
		if err != nil {
			log.Error().Msg("Message decryption and sign b64 failed")
		}
		pub, err := base64.StdEncoding.DecodeString(MyContactPublicKey)
		if err != nil {
			log.Error().Msg("Message decryption and sign b64 failed")
		}
		DecryptedMessage, err = helper.DecryptVerifyBinaryDetached(string(pub), string(priv), nil, data, string(Signature))
		if err != nil {
			log.Error().Msg("Message decryption and sign failed")
		}
		return DecryptedMessage, err
	}
*/
func encryptMessage(key string, message *crypto.PlainMessage) (*crypto.PGPMessage, error) {
	publicKeyRing, err := createPublicKeyRing(key)
	if err != nil {
		return nil, err
	}

	ciphertext, err := publicKeyRing.Encrypt(message, nil)
	if err != nil {
		return nil, fmt.Errorf("gopenpgp: unable to encrypt message: %w", err)
	}

	return ciphertext, nil
}

func decryptMessage(privateKey string, passphrase []byte, ciphertext *crypto.PGPMessage) (*crypto.PlainMessage, error) {
	privateKeyObj, err := crypto.NewKeyFromArmored(privateKey)
	if err != nil {
		return nil, fmt.Errorf("gopenpgp: unable to parse the private key: %w", err)
	}

	privateKeyUnlocked, err := privateKeyObj.Unlock(passphrase)
	if err != nil {
		return nil, fmt.Errorf("gopenpgp: unable to unlock key: %w", err)
	}

	defer privateKeyUnlocked.ClearPrivateParams()

	privateKeyRing, err := crypto.NewKeyRing(privateKeyUnlocked)
	if err != nil {
		return nil, fmt.Errorf("gopenpgp: unable to create the private key ring: %w", err)
	}

	message, err := privateKeyRing.Decrypt(ciphertext, nil, 0)
	if err != nil {
		return nil, fmt.Errorf("gopenpgp: unable to decrypt message: %w", err)
	}

	return message, nil
}

func createPublicKeyRing(publicKey string) (*crypto.KeyRing, error) {
	publicKeyObj, err := crypto.NewKeyFromArmored(publicKey)
	if err != nil {
		return nil, fmt.Errorf("gopenpgp: unable to parse public key: %w", err)
	}

	if publicKeyObj.IsPrivate() {
		publicKeyObj, err = publicKeyObj.ToPublic()
		if err != nil {
			return nil, fmt.Errorf("gopenpgp: unable to extract public key from private key: %w", err)
		}
	}

	publicKeyRing, err := crypto.NewKeyRing(publicKeyObj)
	if err != nil {
		return nil, fmt.Errorf("gopenpgp: unable to create new keyring: %w", err)
	}

	return publicKeyRing, nil
}

func AsymEncryptAndSign(PublicEncryptionKey string, PrivateSignatureKey string, data []byte) (*EncryptedMessage, error) {
	var enc EncryptedMessage
	pub, err := base64.StdEncoding.DecodeString(PublicEncryptionKey)
	if err != nil {
		return nil, fmt.Errorf("Message encryption and sign b64 failed: %w", err)
	}
	priv, err := base64.StdEncoding.DecodeString(PrivateSignatureKey)
	if err != nil {
		return nil, fmt.Errorf("Message encryption and sign b64 failed: %w", err)
	}
	ciphertext, signature, err := encryptAndSignMessage(string(pub), string(priv), crypto.NewPlainMessage(data))
	if err != nil {
		return nil, fmt.Errorf("Message encryption failed: %w", err)
	}
	enc.Data = ciphertext.GetBinary()
	enc.Signature = []byte(signature)
	return &enc, err
}

func AsymDecryptAndCheck(MyPrivateEncryptionKey string, MyContactPublicKey string, data []byte, Signature []byte) (DecryptedMessage []byte, err error) {
	priv, err := base64.StdEncoding.DecodeString(MyPrivateEncryptionKey)
	if err != nil {
		return nil, fmt.Errorf("Message decryption and sign b64 failed: %w", err)
	}
	pub, err := base64.StdEncoding.DecodeString(MyContactPublicKey)
	if err != nil {
		return nil, fmt.Errorf("Message decryption and sign b64 failed: %w", err)
	}
	DecryptedMessage, err = decryptAndCheckMessage(string(pub), string(priv), crypto.NewPGPMessage(data), crypto.NewPGPSignature(Signature))
	if err != nil {
		return nil, fmt.Errorf("Message decryption and sign failed: %w", err)
	}
	return DecryptedMessage, err
}

func encryptAndSignMessage(pub string, priv string, message *crypto.PlainMessage) (*crypto.PGPMessage, []byte, error) {
	var privateKeyObj, unlockedKeyObj *crypto.Key
	var privateKeyRing *crypto.KeyRing
	publicKeyRing, err := createPublicKeyRing(pub)
	if err != nil {
		return nil, nil, err
	}

	if err != nil {
		return nil, nil, fmt.Errorf("gopenpgp: unable to encrypt message")
	}

	if privateKeyObj, err = crypto.NewKeyFromArmored(priv); err != nil {
		return nil, nil, fmt.Errorf("gopenpgp: unable to parse private key")
	}

	if unlockedKeyObj, err = privateKeyObj.Unlock(nil); err != nil {
		return nil, nil, fmt.Errorf("gopenpgp: unable to unlock key")
	}
	defer unlockedKeyObj.ClearPrivateParams()

	if privateKeyRing, err = crypto.NewKeyRing(unlockedKeyObj); err != nil {
		return nil, nil, fmt.Errorf("gopenpgp: unable to create private keyring")
	}

	ciphertext, err := publicKeyRing.Encrypt(message, nil)
	if err != nil {
		return nil, nil, fmt.Errorf("gopenpgp: unable to encrypt message")
	}

	signature, err := privateKeyRing.SignDetached(message)
	if err != nil {
		return nil, nil, fmt.Errorf("gopenpgp: unable to encrypt message")
	}
	return ciphertext, signature.GetBinary(), nil
}

func decryptAndCheckMessage(pub string, priv string, message *crypto.PGPMessage, signature *crypto.PGPSignature) ([]byte, error) {
	var privateKeyObj, unlockedKeyObj *crypto.Key
	var privateKeyRing *crypto.KeyRing
	publicKeyRing, err := createPublicKeyRing(pub)
	if err != nil {
		return nil, err
	}

	if err != nil {
		return nil, fmt.Errorf("gopenpgp: unable to encrypt message")
	}

	if privateKeyObj, err = crypto.NewKeyFromArmored(priv); err != nil {
		return nil, fmt.Errorf("gopenpgp: unable to parse private key")
	}

	if unlockedKeyObj, err = privateKeyObj.Unlock(nil); err != nil {
		return nil, fmt.Errorf("gopenpgp: unable to unlock key")
	}
	defer unlockedKeyObj.ClearPrivateParams()

	if privateKeyRing, err = crypto.NewKeyRing(unlockedKeyObj); err != nil {
		return nil, fmt.Errorf("gopenpgp: unable to create private keyring")
	}

	plainmessage, err := privateKeyRing.Decrypt(message, nil, 0)
	if err != nil {
		return nil, fmt.Errorf("gopenpgp: unable to decrypt message")
	}

	err = publicKeyRing.VerifyDetached(plainmessage, signature, crypto.GetUnixTime())
	if err != nil {
		return nil, fmt.Errorf("gopenpgp: unable to check message signature")
	}
	return plainmessage.GetBinary(), nil
}