using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Tasks;

namespace Tango.StubsUtils.PerformanceTest.CLI
{
    class Program
    {
        private const int ROUNDS_SMALL = 100;
        private const int ROUNDS_BIG = 1000;
        private const int DELAY = 0;

        static void Main(string[] args)
        {
            PerformanceTestStandard();
            Console.WriteLine();
            PerformanceTestSession();
            Console.WriteLine();
            PerformanceTestProcedure();

            Console.WriteLine();
            Console.WriteLine();
            Console.WriteLine("Completed.");
            Console.ReadLine();
        }

        private static void PerformanceTestStandard()
        {
            List<double> durations = new List<double>();

            Stopwatch watch = new Stopwatch();

            for (int i = 0; i < ROUNDS_SMALL; i++)
            {
                watch.Restart();

                Process process = new Process();
                process.StartInfo.FileName = "tangostub.exe";
                process.StartInfo.CreateNoWindow = true;
                process.StartInfo.WindowStyle = ProcessWindowStyle.Hidden;
                process.StartInfo.Arguments = "calculate 10 15";
                process.StartInfo.RedirectStandardOutput = true;
                process.StartInfo.UseShellExecute = false;
                process.Start();
                process.WaitForExit();

                String response = process.StandardOutput.ReadToEnd();

                if (!response.StartsWith("Status: OK"))
                {
                    OnError(response);
                    return;
                }

                if (DELAY > 0)
                {
                    Thread.Sleep(DELAY);
                }

                durations.Add(watch.ElapsedMilliseconds);

                Console.SetCursorPosition(0, 0);
                Console.Write($"Performance Test (Standard): {i + 1}/{ROUNDS_SMALL}, Avg: {Math.Round(durations.Average(), 2)} ms            ");
            }
        }

        private static void PerformanceTestSession()
        {
            List<double> durations = new List<double>();

            Process process = new Process();
            process.StartInfo.FileName = "tangostub_s.exe";
            process.StartInfo.CreateNoWindow = true;
            process.StartInfo.WindowStyle = ProcessWindowStyle.Hidden;
            process.StartInfo.RedirectStandardOutput = true;
            process.StartInfo.RedirectStandardInput = true;
            process.StartInfo.UseShellExecute = false;
            process.Start();
            process.PriorityClass = ProcessPriorityClass.RealTime;

            process.StandardOutput.ReadLine(); //Read the first welcome line...

            Stopwatch watch = new Stopwatch();

            for (int i = 0; i < ROUNDS_BIG; i++)
            {
                watch.Restart();

                process.StandardInput.WriteLine("calculate 10 15");
                StringBuilder builder = new StringBuilder();

                char[] buffer = new char[1];

                while (process.StandardOutput.Read(buffer, 0, 1) > 0)
                {
                    char c = buffer[0];

                    if (c == '\r')
                    {
                        process.StandardOutput.Read();
                        break;
                    }
                    else if (c == '>')
                    {
                        process.StandardOutput.Read();
                    }
                    else
                    {
                        builder.Append(buffer[0]);
                    }
                }

                String response = builder.ToString();

                if (!response.StartsWith("Status: OK"))
                {
                    OnError(response);
                    return;
                }

                if (DELAY > 0)
                {
                    Thread.Sleep(DELAY);
                }

                durations.Add(watch.ElapsedMilliseconds);

                Console.SetCursorPosition(0, 1);
                Console.Write($"Performance Test (Session) : {i + 1}/{ROUNDS_BIG}, Avg: {Math.Round(durations.Average(), 2)} ms            ");
            }
        }

        private static void PerformanceTestProcedure()
        {
            List<double> durations = new List<double>();

            Process process = new Process();
            process.StartInfo.FileName = "tangostub_p.exe";
            process.StartInfo.Arguments = $"procedure_test.pproj {ROUNDS_BIG} 10 15";
            process.StartInfo.CreateNoWindow = true;
            process.StartInfo.WindowStyle = ProcessWindowStyle.Hidden;
            process.StartInfo.RedirectStandardOutput = true;
            process.StartInfo.RedirectStandardInput = true;
            process.StartInfo.UseShellExecute = false;
            process.Start();
            process.PriorityClass = ProcessPriorityClass.RealTime;

            Stopwatch watch = new Stopwatch();
            Stopwatch realWatch = new Stopwatch();
            realWatch.Stop();

            int count = 0;

            do
            {
                watch.Restart();

                String line = process.StandardOutput.ReadLine();

                if (count == 0)
                {
                    realWatch.Start();
                }

                if (line == null)
                {
                    break;
                }

                if (line.StartsWith("Status: Error"))
                {
                    OnError(process.StandardOutput.ReadToEnd());
                    return;
                }
                else if (line.StartsWith("Status: Completed"))
                {
                    break;
                }

                if (count > 0)
                {
                    durations.Add(watch.ElapsedMilliseconds);
                    Console.SetCursorPosition(0, 2);
                    Console.Write($"Performance Test (Procedure) : {count + 1}/{ROUNDS_BIG}, Avg: {Math.Round(durations.Average(), 2)} ms            ");
                }

                count++;
            } while (!process.HasExited);

            Console.SetCursorPosition(0, 2);
            Console.Write($"Performance Test (Procedure) : {ROUNDS_BIG}/{ROUNDS_BIG}, Avg: {Math.Round(realWatch.ElapsedMilliseconds / (double)ROUNDS_BIG, 2)} ms            ");
        }

        private static void OnError(String error)
        {
            Console.ForegroundColor = ConsoleColor.Red;
            Console.WriteLine(error);
            Console.ForegroundColor = ConsoleColor.Gray;
            Console.ReadLine();
        }
    }
}