package JobServ;

import io.grpc.Server;
import io.grpc.ServerBuilder;
import io.grpc.stub.StreamObserver;

import java.io.IOException;
import java.util.logging.Logger;

public class JobServServer {
    private static final Logger logger = Logger.getLogger(JobServServer.class.getName());

    private Server server;

    // starts the GRPC API Server
    private void start() throws IOException {
        // TODO: this should be passed in from a configuration manager
        int port = 8448;
        server = ServerBuilder.forPort(port)
            .addService(new ShellServerImpl())
            .build()
            .start();
        logger.info("Server initialized without tls");
        Runtime.getRuntime().addShutdownHook(new Thread() {
                @Override
                public void run() {
                    // JVM shutdown might break logger functionality
                    // so investigate this....
                    logger.info("Shutting down server");
                    JobServServer.this.stop();
                }
            });
    }

    private void stop() {
        if (server != null) {
            server.shutdown();
        }
    }
    
    // spinlock for main()
    private void blockUntilShutdown() throws InterruptedException {
        if (server != null) {
            server.awaitTermination();
        }
    }

    // Main function. starts GRPC server and spins until server is shutdown
    public static void main(String[] args) throws IOException, InterruptedException {
        final JobServServer server = new JobServServer();
        server.start();
        server.blockUntilShutdown();
    }

    // wrap around stub code generated by GRPC
    static class ShellServerImpl extends ShellServerGrpc.ShellServerImplBase {
	
        @Override
        public void getStatusDetail(RequestMessage request,
                                    StreamObserver<JobStatusMessage> responder) {
            // TODO: Implement job controller, check request type, do the thing
            JobStatusMessage reply = JobStatusMessage.newBuilder()
                .setPID(-1)
                .setProcessStatus(-1)
                .build();
            responder.onNext(reply);
            responder.onCompleted();
        }
        
        @Override
        public void getJobOutput(RequestMessage request,
                                 StreamObserver<OutputMessage> responder) {
            // TODO: Implement job controller, get output, do the thing
            OutputMessage reply = OutputMessage.newBuilder()
                .build();
            responder.onNext(reply);
            responder.onCompleted();
        }
        
        @Override
        public void makeNewJob(NewJobMessage request,
                               StreamObserver<JobStatusMessage> responder) {
            // TODO: Implement job controller, Start Job, do the thing
            JobStatusMessage reply = JobStatusMessage.newBuilder()
                .setPID(-1)
                .setProcessStatus(-1)
                .build();
            responder.onNext(reply);
            responder.onCompleted();
        }
    }
}