using Grpc.Core;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Examples
{
    class Program
    {
        /// <summary>
        /// Sample client code that makes gRPC calls to the server.
        /// </summary>
        public class RouteGuideClient
        {
            readonly RouteGuide.IRouteGuideClient client;

            public RouteGuideClient(RouteGuide.IRouteGuideClient client)
            {
                this.client = client;
            }

            /// <summary>
            /// Blocking unary call example.  Calls GetFeature and prints the response.
            /// </summary>
            public void GetFeature(int lat, int lon)
            {
                try
                {
                    Log("*** GetFeature: lat={0} lon={1}", lat, lon);

                    Point request = Point.CreateBuilder().SetLatitude(lat).SetLongitude(lon).Build();
                    
                    Feature feature = client.GetFeature(request);
                    if (RouteGuideUtil.Exists(feature))
                    {
                        Log("Found feature called \"{0}\" at {1}, {2}",
                            feature.Name,
                            RouteGuideUtil.GetLatitude(feature.Location),
                            RouteGuideUtil.GetLongitude(feature.Location));
                    }
                    else
                    {
                        Log("Found no feature at {0}, {1}",
                            RouteGuideUtil.GetLatitude(feature.Location),
                            RouteGuideUtil.GetLongitude(feature.Location));
                    }
                }
                catch (RpcException e)
                {
                    Log("RPC failed " + e);
                    throw e;
                }
            }

  
            /// <summary>
            /// Server-streaming example. Calls listFeatures with a rectangle of interest. Prints each response feature as it arrives.
            /// </summary>
            public async Task ListFeatures(int lowLat, int lowLon, int hiLat, int hiLon)
            {
                try
                {
                    Log("*** ListFeatures: lowLat={0} lowLon={1} hiLat={2} hiLon={3}", lowLat, lowLon, hiLat,
                        hiLon);

                    Rectangle request =
                        Rectangle.CreateBuilder()
                            .SetLo(Point.CreateBuilder().SetLatitude(lowLat).SetLongitude(lowLon).Build())
                            .SetHi(Point.CreateBuilder().SetLatitude(hiLat).SetLongitude(hiLon).Build()).Build();
                    
                    using (var call = client.ListFeatures(request))
                    {
                        StringBuilder responseLog = new StringBuilder("Result: ");

                        while (await call.ResponseStream.MoveNext())
                        {
                            Feature feature = call.ResponseStream.Current;
                            responseLog.Append(feature.ToString());
                        }
                        Log(responseLog.ToString());
                    }
                }
                catch (RpcException e)
                {
                    Log("RPC failed " + e); 
                    throw e;
                }
            }

            /// <summary>
            /// Client-streaming example. Sends numPoints randomly chosen points from features 
            /// with a variable delay in between. Prints the statistics when they are sent from the server.
            /// </summary>
            public async Task RecordRoute(List<Feature> features, int numPoints)
            {
                try
                {
                    Log("*** RecordRoute");
                    using (var call = client.RecordRoute())
                    {
                        // Send numPoints points randomly selected from the features list.
                        StringBuilder numMsg = new StringBuilder();
                        Random rand = new Random();
                        for (int i = 0; i < numPoints; ++i)
                        {
                            int index = rand.Next(features.Count);
                            Point point = features[index].Location;
                            Log("Visiting point {0}, {1}", RouteGuideUtil.GetLatitude(point),
                                RouteGuideUtil.GetLongitude(point));

                            await call.RequestStream.WriteAsync(point);

                            // A bit of delay before sending the next one.
                            await Task.Delay(rand.Next(1000) + 500);    
                        }
                        await call.RequestStream.CompleteAsync();

                        RouteSummary summary = await call.Result;
                        Log("Finished trip with {0} points. Passed {1} features. "
                            + "Travelled {2} meters. It took {3} seconds.", summary.PointCount,
                            summary.FeatureCount, summary.Distance, summary.ElapsedTime);

                        Log("Finished RecordRoute");
                    }
                }
                catch (RpcException e)
                {
                    Log("RPC failed", e);
                    throw e;
                }
            }

            /// <summary>
            /// Bi-directional streaming example. Send some chat messages, and print any
            /// chat messages that are sent from the server.
            /// </summary>
            public async Task RouteChat()
            {
                try
                {
                    Log("*** RouteChat");
                    var requests =
                        new List<RouteNote> { NewNote("First message", 0, 0), NewNote("Second message", 0, 1), NewNote("Third message", 1, 0), NewNote("Fourth message", 1, 1) };

                    using (var call = client.RouteChat())
                    {
                        var responseReaderTask = Task.Run(async () =>
                        {
                            while (await call.ResponseStream.MoveNext())
                            {
                                var note = call.ResponseStream.Current;
                                Log("Got message \"{0}\" at {1}, {2}", note.Message, 
                                    note.Location.Latitude, note.Location.Longitude);
                            }
                        });

                        foreach (RouteNote request in requests)
                        {
                            Log("Sending message \"{0}\" at {1}, {2}", request.Message,
                                request.Location.Latitude, request.Location.Longitude);

                            await call.RequestStream.WriteAsync(request);
                        }
                        await call.RequestStream.CompleteAsync();
                        await responseReaderTask;

                        Log("Finished RouteChat");
                    }
                }
                catch (RpcException e)
                {
                    Log("RPC failed", e);
                    throw e;
                }
            }

            private void Log(string s, params object[] args)
            {
                Console.WriteLine(string.Format(s, args));
            }

            private void Log(string s)
            {
                Console.WriteLine(s);
            }

            private RouteNote NewNote(string message, int lat, int lon)
            {
                return RouteNote.CreateBuilder().SetMessage(message).SetLocation(
                    Point.CreateBuilder().SetLatitude(lat).SetLongitude(lat).Build()).Build();
            }
        }

        static void Main(string[] args)
        {
            GrpcEnvironment.Initialize();

            using (Channel channel = new Channel("127.0.0.1:50052"))
            {
                var client = new RouteGuideClient(RouteGuide.NewStub(channel));

                // Looking for a valid feature
                client.GetFeature(409146138, -746188906);

                // Feature missing.
                client.GetFeature(0, 0);

                // Looking for features between 40, -75 and 42, -73.
                client.ListFeatures(400000000, -750000000, 420000000, -730000000).Wait();

                // Record a few randomly selected points from the features file.
                client.RecordRoute(RouteGuideUtil.ParseFeatures(RouteGuideUtil.DefaultFeaturesFile), 10).Wait();

                // Send and receive some notes.
                client.RouteChat().Wait();
            }

            GrpcEnvironment.Shutdown();
        }
    }
}