format

type BodyFrame interface {
	Serializable

	// IsFinal indicates true if the frame is final.
	IsFinal() bool

	// SequenceNumber returns the frame sequence number.
	SequenceNumber() int

	// IV returns the frame IV.
	IV() []byte

	// EncryptedContent returns the frame encrypted content.
	EncryptedContent() []byte

	// AuthenticationTag returns the frame authentication tag.
	AuthenticationTag() []byte
}

type Deserializer interface {
	// DeserializeHeader deserializes a message header from a buffer.
	// It takes a buffer and a maximum number of encrypted data keys as input.
	// It returns a MessageHeader, MessageHeaderAuth, and an error if any.
	DeserializeHeader(buf *bytes.Buffer, maxEncryptedDataKeys int) (MessageHeader, MessageHeaderAuth, error)

	// DeserializeBody deserializes a message body from a buffer.
	// It takes a buffer, an algorithm suite, and a frame length as input.
	// It returns a MessageBody and an error if any.
	DeserializeBody(buf *bytes.Buffer, alg *suite.AlgorithmSuite, frameLen int) (MessageBody, error)

	// DeserializeFooter deserializes a message footer from a buffer.
	// It takes a buffer and an algorithm suite as input.
	// It returns a MessageFooter and an error if any.
	DeserializeFooter(buf *bytes.Buffer, alg *suite.AlgorithmSuite) (MessageFooter, error)
}

type HeaderParams struct {
	AlgorithmSuite     *suite.AlgorithmSuite
	MessageID          []byte
	EncryptionContext  suite.EncryptionContext
	EncryptedDataKeys  []MessageEDK
	ContentType        suite.ContentType
	FrameLength        int
	AlgorithmSuiteData []byte
}

type MessageAAD interface {
	Serializable

	// EncryptionContext returns the encryption context.
	EncryptionContext() suite.EncryptionContext
}

type MessageBody interface {
	Serializable

	// Frames returns the body frames.
	Frames() []BodyFrame

	// AddFrame adds new BodyFrame to the body.
	AddFrame(final bool, seqNum int, IV []byte, contentLength int, ciphertext, authTag []byte) error
}

type MessageEDK interface {
	Serializable

	// ProviderID returns the provider ID.
	ProviderID() string

	// ProviderInfo returns the provider info.
	ProviderInfo() string

	// EncryptedDataKey returns the encrypted data key.
	EncryptedDataKey() []byte
}

type MessageFooter interface {
	Serializable

	// SignLen returns the length of the signature.
	SignLen() int

	// Signature returns the signature.
	Signature() []byte
}

type MessageHeader interface {
	Serializable
	MessageHeaderBase

	// Type returns the message type. Present only in V1.
	Type() MessageType

	// Reserved returns the reserved bytes. Present only in V1.
	Reserved() []byte

	// IVLength returns the length of the IV. Present only in V1.
	IVLength() int

	// AlgorithmSuiteData returns the algorithm suite data. Present only in V2.
	AlgorithmSuiteData() []byte
}

type MessageHeaderAuth interface {
	Serializable

	// AuthData returns the authentication data.
	AuthData() []byte

	// IV returns the IV. Present only in V1.
	IV() []byte
}

type MessageHeaderBase interface {
	// Version returns the message format version.
	Version() suite.MessageFormatVersion

	// AlgorithmSuite returns the algorithm suite used with the message.
	AlgorithmSuite() *suite.AlgorithmSuite

	// MessageID returns the message ID.
	MessageID() []byte

	// AADLength returns the length of the additional authenticated data.
	AADLength() int

	// AADData returns the additional authenticated data.
	AADData() MessageAAD

	// EncryptedDataKeyCount returns the number of encrypted data keys.
	EncryptedDataKeyCount() int

	// EncryptedDataKeys returns the encrypted data keys.
	EncryptedDataKeys() []MessageEDK

	// ContentType returns the content type.
	ContentType() suite.ContentType

	// FrameLength returns the frame length.
	FrameLength() int
}

type MessageType int

type Serializable interface {
	// Len returns the length of the serialized object.
	Len() int
	// Bytes returns the serialized object.
	Bytes() []byte
}

type Serializer interface {
	// SerializeHeader serializes a message header.
	// It takes header parameters as input and returns a MessageHeader and an error if any.
	SerializeHeader(p HeaderParams) (MessageHeader, error)

	// SerializeHeaderAuth serializes a message header authentication data.
	// It takes a message format version, an initialization vector, and authentication data as input.
	// It returns a MessageHeaderAuth and an error if any.
	SerializeHeaderAuth(v suite.MessageFormatVersion, iv, authData []byte) (MessageHeaderAuth, error)

	// SerializeBody serializes a message body.
	// It takes an algorithm suite and a frame length as input.
	// It returns a MessageBody and an error if any.
	SerializeBody(alg *suite.AlgorithmSuite, frameLength int) (MessageBody, error)

	// SerializeFooter serializes a message footer.
	// It takes an algorithm suite and a signature as input.
	// It returns a MessageFooter and an error if any.
	SerializeFooter(alg *suite.AlgorithmSuite, signature []byte) (MessageFooter, error)
}