/**
 * Base class for requests.
 *
 * @since 4.0.0
 */
@Experimental
abstract class BaseRequest<S extends ProtoSession> implements Request<S> {

    private final S session;
    private final RequestTrace trace;

    protected BaseRequest(@Nonnull S session) {
        this(session, null);
    }

    protected BaseRequest(@Nonnull S session, RequestTrace trace) {

        @Nonnull
        public ArtifactInstallerRequest build() {
            return new DefaultArtifactInstallerRequest(session, trace, artifacts);
        }

        static class DefaultArtifactInstallerRequest extends BaseRequest<Session> implements ArtifactInstallerRequest {

            private final Collection<ProducedArtifact> artifacts;

            DefaultArtifactInstallerRequest(
                    @Nonnull Session session,

            return new DefaultVersionResolverRequest(session, trace, artifactCoordinates, repositories);
        }

        private static class DefaultVersionResolverRequest extends BaseRequest<Session>
                implements VersionRangeResolverRequest {
            private final ArtifactCoordinates artifactCoordinates;
            private final List<RemoteRepository> repositories;

            return new DefaultVersionResolverRequest(session, trace, artifactCoordinates, repositories);
        }

        private static class DefaultVersionResolverRequest extends BaseRequest<Session>
                implements VersionResolverRequest {
            private final ArtifactCoordinates artifactCoordinates;
            private final List<RemoteRepository> repositories;

            return new DefaultArtifactDeployerRequest(
                    session, trace, repository, artifacts, retryFailedDeploymentCount);
        }

        private static class DefaultArtifactDeployerRequest extends BaseRequest<Session>
                implements ArtifactDeployerRequest {

            private final RemoteRepository repository;
            private final Collection<ProducedArtifact> artifacts;

            return new DefaultArtifactResolverRequest(session, trace, coordinates, repositories);
        }

        private static class DefaultArtifactResolverRequest extends BaseRequest<Session>
                implements ArtifactResolverRequest {
            @Nonnull
            private final Collection<? extends ArtifactCoordinates> coordinates;

            @Nullable

                    session, trace, installationToolchainsSource, userToolchainsSource);
        }

        private static class DefaultToolchainsBuilderRequest extends BaseRequest<ProtoSession>
                implements ToolchainsBuilderRequest {
            private final Source installationToolchainsSource;
            private final Source userToolchainsSource;

                    session, trace, groupId, artifactId, version, classifier, extension, type);
        }

        private static class DefaultArtifactFactoryRequest extends BaseRequest<Session>
                implements ArtifactFactoryRequest {
            private final String groupId;
            private final String artifactId;
            private final String version;

                    session, trace, groupId, artifactId, version, classifier, extension, type, coordinateString);
        }

        private static class DefaultArtifactFactoryRequestArtifact extends BaseRequest<Session>
                implements ArtifactCoordinatesFactoryRequest {
            private final String groupId;
            private final String artifactId;
            private final String version;

                    projectSettingsSource,
                    userSettingsSource,
                    interpolationSource);
        }

        private static class DefaultSettingsBuilderRequest extends BaseRequest<ProtoSession>
                implements SettingsBuilderRequest {
            private final Source installationSettingsSource;
            private final Source projectSettingsSource;