<?php

namespace Aws\Crypto;

use Aws\Crypto\Cipher\CipherMethod;
use GuzzleHttp\Psr7\Stream;

/**
 * @internal
 */
abstract class AbstractCryptoClient {
	public static $supportedCiphers = [ 'cbc', 'gcm' ];

	/**
	 * Returns if the passed cipher name is supported for encryption by the SDK.
	 *
	 * @param string $cipherName The name of a cipher to verify is registered.
	 *
	 * @return bool If the cipher passed is in our supported list.
	 */
	public static function isSupportedCipher( $cipherName ) {
		return in_array( $cipherName, self::$supportedCiphers );
	}

	/**
	 * Dependency to provide an interface for building an encryption stream for
	 * data given cipher details, metadata, and materials to do so.
	 *
	 * @param Stream $plaintext Plain-text data to be encrypted using the
	 *                          materials, algorithm, and data provided.
	 * @param array $cipherOptions Options for use in determining the cipher to
	 *                             be used for encrypting data.
	 * @param MaterialsProvider $provider A provider to supply and encrypt
	 *                                    materials used in encryption.
	 * @param MetadataEnvelope $envelope A storage envelope for encryption
	 *                                   metadata to be added to.
	 *
	 * @return AesStreamInterface
	 *
	 * @internal
	 */
	abstract public function encrypt(
		Stream $plaintext,
		array $cipherOptions,
		MaterialsProvider $provider,
		MetadataEnvelope $envelope
	);

	/**
	 * Dependency to provide an interface for building a decryption stream for
	 * cipher text given metadata and materials to do so.
	 *
	 * @param string $cipherText Plain-text data to be decrypted using the
	 *                           materials, algorithm, and data provided.
	 * @param MaterialsProvider $provider A provider to supply and encrypt
	 *                                    materials used in encryption.
	 * @param MetadataEnvelope $envelope A storage envelope for encryption
	 *                                   metadata to be read from.
	 * @param array $cipherOptions Additional verification options.
	 *
	 * @return AesStreamInterface
	 *
	 * @internal
	 */
	abstract public function decrypt(
		$cipherText,
		MaterialsProvider $provider,
		MetadataEnvelope $envelope,
		array $cipherOptions = []
	);

	/**
	 * Returns an identifier recognizable by `openssl_*` functions, such as
	 * `aes-256-cbc` or `aes-128-ctr`.
	 *
	 * @param string $cipherName Name of the cipher being used for encrypting
	 *                           or decrypting.
	 * @param int $keySize Size of the encryption key, in bits, that will be
	 *                     used.
	 *
	 * @return string
	 */
	abstract protected function getCipherOpenSslName( $cipherName, $keySize );

	/**
	 * Constructs a CipherMethod for the given name, initialized with the other
	 * data passed for use in encrypting or decrypting.
	 *
	 * @param string $cipherName Name of the cipher to generate for encrypting.
	 * @param string $iv Base Initialization Vector for the cipher.
	 * @param int $keySize Size of the encryption key, in bits, that will be
	 *                     used.
	 *
	 * @return CipherMethod
	 *
	 * @internal
	 */
	abstract protected function buildCipherMethod( $cipherName, $iv, $keySize );

	/**
	 * Performs a reverse lookup to get the openssl_* cipher name from the
	 * AESName passed in from the MetadataEnvelope.
	 *
	 * @param $aesName
	 *
	 * @return string
	 *
	 * @internal
	 */
	abstract protected function getCipherFromAesName( $aesName );
}
