//go:build signal_legacy

package libsignal

/*
#include <signal_protocol.h>
#include <session_builder.h>
#include <session_cipher.h>
*/
import "C"

import "errors"

// errModernOMEMOUnavailable is returned whenever the caller asks this
// legacy build to do something only libomemo-c can do.
var errModernOMEMOUnavailable = errors.New("libsignal: modern OMEMO (protocol v4) requires linking libomemo-c; this build links vanilla libsignal-protocol-c (build tag \"signal_legacy\")")

// Vanilla libsignal-protocol-c has no session_builder_set_version /
// session_cipher_set_version - it only ever produces/consumes
// CIPHERTEXT_CURRENT_VERSION (protocol v3, legacy/siacs OMEMO) messages.
// Requesting ProtocolVersionLegacy is a no-op (that's the library's only
// behavior); requesting anything else is rejected rather than silently
// ignored.

func setBuilderVersion(b *C.session_builder, version int) error {
	if version != ProtocolVersionLegacy {
		return errModernOMEMOUnavailable
	}
	return nil
}

func setCipherVersion(c *C.session_cipher, version int) error {
	if version != ProtocolVersionLegacy {
		return errModernOMEMOUnavailable
	}
	return nil
}