decode method

@override UncheckedExtrinsic decode(Input input)

Implementation

@override
UncheckedExtrinsic decode(final Input input) {
  // Read version byte and extract the actual version and type
  final int versionByte = input.read();
  final (int version, ExtrinsicType type) = _parseVersionByte(versionByte);

  // Validate version - accept both v4 and v5
  // Note: Metadata may report v4 even when v5 extrinsics are used (known issue)
  if (version != _extrinsicV4 && version != _extrinsicV5) {
    throw MetadataException(
      'Unsupported extrinsic version: $version (supported: $_extrinsicV4, $_extrinsicV5)',
    );
  }

  ExtrinsicSignature? signature;
  Map<String, dynamic>? extensions;

  switch (type) {
    case ExtrinsicType.signed:
      // Signed extrinsic: signature (address + sig + extra) followed by call
      signature = _signatureCodec.decode(input);
      break;

    case ExtrinsicType.general:
      // General extrinsic (v5): extension version byte + extensions followed by call
      final extensionVersion = input.read();
      extensions = {'extensionVersion': extensionVersion, ..._extensionsCodec.decode(input)};
      break;

    case ExtrinsicType.bare:
      // Bare extrinsic: just the call, no signature or extensions
      break;
  }

  final call = _callCodec.decode(input);

  return UncheckedExtrinsic(
    version: version,
    type: type,
    signature: signature,
    extensions: extensions,
    call: call,
  );
}