using System.Threading.Tasks;

namespace TestPooling {
  using System;
  using System.Collections.Generic;
  using System.Diagnostics;
  using System.Linq;
  using System.Text;
  using System.Threading;
  using DirtyList;
  using HeuristicLab.Problems.ProgramSynthesis.Push.Configuration;
  using HeuristicLab.Problems.ProgramSynthesis.Push.Data.Pool;
  using HeuristicLab.Problems.ProgramSynthesis.Push.Expressions;
  using HeuristicLab.Problems.ProgramSynthesis.Push.Extensions;
  using HeuristicLab.Problems.ProgramSynthesis.Push.Generators.CodeGenerator;
  using HeuristicLab.Problems.ProgramSynthesis.Push.Interpreter;
  using HeuristicLab.Problems.ProgramSynthesis.Push.Parser;
  using HeuristicLab.Problems.ProgramSynthesis.Push.Simplifier;
  using HeuristicLab.Problems.ProgramSynthesis.Push.Stack;
  using HeuristicLab.Random;

  class Program {
    private const int PartitionSize = 512;
    private const int ExampleCount = 200;
    private const int InstanceCount = 1024;
    private const int PopulationCount = 1000;

    private static int TotalInstanceCount => PopulationCount * InstanceCount * ExampleCount;

    static void Main(string[] args) {
      // object pooling
      //Test1();
      //Test1_2();
      //Test3();

      //TestCollectionPooling();

      //DirtyListTest();

      //TestAddRangeNConcat();

      //TestStacks();

      //SimpleTest();
      //Stepwise().Wait();
      //PerformanceTestInterpreter();
      //PerformanceParallelTestInterpreter();
      //PerformanceTestLinearCodeGenerator();
      //TestRobustness();
      //TestPool();
      //TestPoolPerformance();
      //TestSimplifier();
      //FlagsTest();
      //TestExpressionDependencies();
      //TestSplitLogic();
      //TestStringBuilder();
      //TestRandomReset();

      //TestRandomBiased(0, 4, 0.01);
      //TestRandomBiased(0, 4, 0.25);
      //TestRandomBiased(0, 4, 0.5);
      //TestRandomBiased(0, 4, 1);
      //TestRandomBiased(0, 4, 2);
      //TestRandomBiased(0, 4, 3);
      //TestRandomBiased(0, 4, 4);
      TestOverflowException();


      Console.WriteLine("\nPress any key to continue...");
      Console.ReadKey(false);
    }

    private static void TestOverflowException() {
      // overflow
      //var x = long.MinValue / -1;
      var y = unchecked(long.MaxValue + long.MaxValue);
      var z = unchecked((long)double.MaxValue);
      var a = double.MaxValue + (double.MaxValue - 1);
    }

    private static void TestRandomBiased(int min, int max, double bias) {
      var random = new MersenneTwister();
      var total = 100000;

      var distribution = Enumerable
        .Range(0, total)
        .Select(_ => random.NextBiased(min, max, bias))
        .GroupBy(x => x)
        .OrderBy(g => g.Key)
        .ToDictionary(g => g.Key, g => g.Count() / (double)total * 100);

      Console.WriteLine($@"{min}|{max}|{bias}");

      foreach (var entry in distribution) {
        Console.WriteLine($@"{entry.Key}: {entry.Value}");
      }

      Console.WriteLine();
    }

    private static void TestStringBuilder() {
      var sb = new StringBuilder();
      sb.Append("test");

      var s1 = sb.ToString();
      var s2 = sb.ToString();

      // false
      var equal = ReferenceEquals(s1, s2);
    }

    private static void TestRandomReset() {
      var random = new MersenneTwister(1000);

      var x = random.Next();
      random.Reset();
      var y = random.Next();

      if (x != y) {
        throw new InvalidOperationException();
      }
    }

    private static void TestSplitLogic() {
      var sw = new Stopwatch();
      var iMax = 100000000u;
      var repeats = 10;
      var or = new BooleanOrExpression();
      var and = new BooleanAndExpression();
      var ors = new Expression[iMax];
      var ands = new Expression[iMax];
      var booleans = new bool[iMax];

      for (var i = 0u; i < iMax; i++) {
        ors[i] = or;
        ands[i] = and;
        booleans[i] = i % 2 == 0;
      }

      var orsProgram = new PushProgram(ors);
      var andsProgram = new PushProgram(ands);

      using (var interpreter = new PushInterpreter()) {
        for (var i = 0u; i < repeats; i++) {
          interpreter.BooleanStack.Push(booleans);

          sw.Start();
          interpreter.Run(orsProgram);
          sw.Stop();
          interpreter.Reset();
        }

        Console.WriteLine("ors:\t" + sw.ElapsedTicks / repeats + " - " + sw.ElapsedMilliseconds);

        sw.Reset();
        interpreter.Reset();

        for (var i = 0u; i < repeats; i++) {
          interpreter.BooleanStack.Push(booleans);

          sw.Start();
          interpreter.Run(andsProgram);
          sw.Stop();
          interpreter.Reset();
        }

        Console.WriteLine("ands:\t" + sw.ElapsedTicks / repeats + " - " + sw.ElapsedMilliseconds);

        sw.Reset();
        interpreter.Reset();

        for (var i = 0u; i < repeats; i++) {
          interpreter.BooleanStack.Push(booleans);

          sw.Start();
          interpreter.Run(orsProgram);
          sw.Stop();
          interpreter.Reset();
        }

        Console.WriteLine("ors:\t" + sw.ElapsedTicks / repeats + " - " + sw.ElapsedMilliseconds);

        sw.Reset();
        interpreter.Reset();

        for (var i = 0u; i < repeats; i++) {
          interpreter.BooleanStack.Push(booleans);

          sw.Start();
          interpreter.Run(andsProgram);
          sw.Stop();
          interpreter.Reset();
        }

        Console.WriteLine("ands:\t" + sw.ElapsedTicks / repeats + " - " + sw.ElapsedMilliseconds);
      }
    }

    private static void TestExpressionDependencies() {
      var enabledExpressions = ExpressionTable.GetExpressionsByStackTypes(StackTypes.Boolean | StackTypes.Integer);
    }

    private static void FlagsTest() {
      var types = StackTypes.Boolean | StackTypes.Char | StackTypes.Integer;

      StackTypes test1 = (StackTypes)(StackTypes.Boolean - types);
      StackTypes test2 = (StackTypes)((StackTypes.Boolean | StackTypes.Float) - types);
      StackTypes test3 = ((StackTypes.Boolean | StackTypes.Float) & types);
      StackTypes test4 = ((StackTypes.Boolean | StackTypes.Float) ^ types);
      StackTypes test5 = ((StackTypes.Boolean | StackTypes.Float) | types);
      StackTypes test6 = (StackTypes.Boolean | StackTypes.Float) & ~types;
      StackTypes test7 = StackTypes.Boolean & ~types;
    }

    private static void TestStacks() {
      var sw = new Stopwatch();
      var stack = new DirtyList.PushStack<int>();
      var stack2 = new PushStack2<int>();
      var stack3 = new PushStack3<int>();
      var listC = new List<int>(1000);
      var count = 200000;
      var repeats = 10;

      for (var i = 0; i < 100; i++) {
        listC.Add(i);
      }

      sw.Start();
      for (var j = 0; j < repeats; j++) {
        stack.Clear();

        for (int i = 0; i < count; i++) {
          stack.Push(listC);
        }
      }
      sw.Stop();

      Console.WriteLine("{0}", sw.ElapsedMilliseconds / repeats);

      sw.Restart();
      for (var j = 0; j < repeats; j++) {
        stack2.Clear();

        for (int i = 0; i < count; i++) {
          stack2.PushRange(listC);
        }
      }
      sw.Stop();

      Console.WriteLine("{0}", sw.ElapsedMilliseconds / repeats);

      sw.Restart();
      for (var j = 0; j < repeats; j++) {
        stack3.Clear();

        for (int i = 0; i < count; i++) {
          stack3.PushRange(listC);
        }
      }
      sw.Stop();

      Console.WriteLine("{0}", sw.ElapsedMilliseconds / repeats);

      sw.Restart();
      for (int i = 0; i < count * listC.Count; i++) {
        stack.Pop();
      }

      Console.WriteLine("{0}", sw.ElapsedMilliseconds);

      sw.Restart();
      for (int i = 0; i < count * listC.Count; i++) {
        stack2.Pop();
      }

      Console.WriteLine("{0}", sw.ElapsedMilliseconds);


    }

    private static void TestAddRangeNConcat() {
      var sw = new Stopwatch();
      var count = 10000;
      var listA = new List<int>();
      var listB = new List<int>();
      var listC = new List<int>(1000);

      for (var i = 0; i < 1000; i++) {
        listC.Add(i);
      }

      sw.Start();
      for (int i = 0; i < count; i++) {
        listA.AddRange(listC);
      }
      sw.Stop();

      Console.WriteLine("{0}", sw.ElapsedMilliseconds);

      sw.Restart();
      for (int i = 0; i < count; i++) {
        listB = listB.Concat(listC).ToList();
      }
      sw.Stop();

      Console.WriteLine("{0}", sw.ElapsedMilliseconds);

    }

    private static void DirtyListTest() {
      var sw = new Stopwatch();
      var provider = new ManagedPoolProvider<Person>(100, () => new Person());
      var provider2 = new ManagedPoolProvider<Person>(100, () => new Person());
      var dl = new DirtyList<Person>();
      var l = new List<Person>();

      sw.Start();
      for (var i = 0; i < 30000000; i++) {
        using (var pool = provider.CreatePool()) {
          for (var j = 0; j < 2; j++) {
            var person = pool.Get();
            person.Age = i + j;
            person.Name = (i + j).ToString();

            dl.Add(person);
          }
        }

        dl.Clear();
      }
      sw.Stop();

      Console.WriteLine("DirtyList: {0}", sw.Elapsed.TotalSeconds);

      sw.Restart();
      for (var i = 0; i < 30000000; i++) {
        using (var pool = provider2.CreatePool()) {
          for (var j = 0; j < 2; j++) {
            var person = pool.Get();
            person.Age = i + j;
            person.Name = (i + j).ToString();

            l.Add(person);
          }
        }

        l.Clear();
      }
      sw.Stop();

      Console.WriteLine("List: {0}", sw.Elapsed.TotalSeconds);
    }

    private static void TestCollectionPooling() {
      var sw = new Stopwatch();
      sw.Start();

      var provider = new ManagedPoolProvider<PooledList<Person>>(PartitionSize, () => new PooledList<Person>());

      Parallel.For(0, PopulationCount, pc => {
        for (var e = 0; e < ExampleCount; e++) {
          using (var pool = provider.CreatePool()) {
            var list = pool.Get();

            for (var i = 0; i < InstanceCount; i++)
              list.Add(new Person {
                Age = pc + e + i,
                Name = string.Format("{0} - {1} - {2}", pc, e, i)
              });
          }
        }
      });
      sw.Stop();

      Console.WriteLine("Collection Pooling - Duration: {0} - {1} for {2}/{3} instances", sw.ElapsedTicks, sw.Elapsed.TotalSeconds, provider.InstanceCount, TotalInstanceCount);
    }

    private static void Test1_2() {
      var sw = new Stopwatch();
      sw.Start();

      var provider = new ManagedPoolProvider<Person>(PartitionSize, () => new Person());

      Parallel.For(0, PopulationCount, pc => {
        for (var e = 0; e < ExampleCount; e++) {
          using (var pool = provider.CreatePool()) {
            for (var i = 0; i < InstanceCount; i++) {
              var person = pool.Get();
              person.Age = pc + e + i;
              person.Name = string.Format("{0} - {1} - {2}", pc, e, i);
            }
          }
        }
      });
      sw.Stop();

      Console.WriteLine("1_2 - Duration: {0} - {1} for {2}/{3} instances", sw.ElapsedTicks, sw.Elapsed.TotalSeconds, provider.InstanceCount, TotalInstanceCount);
    }

    private static void Test3() {
      var count = 0;
      var sw = new Stopwatch();

      sw.Start();
      Parallel.For(0, PopulationCount, pc => {
        for (var e = 0; e < ExampleCount; e++) {
          var list = new Person[InstanceCount];
          for (var i = 0; i < InstanceCount; i++) {
            list[i] = new Person {
              Age = pc + e + i,
              Name = string.Format("{0} - {1} - {2}", pc, e, i)
            };
          }

          Interlocked.Add(ref count, list.Length);
        }
      });
      sw.Stop();

      Console.WriteLine("3 - Duration: {0} - {1}", sw.ElapsedTicks, sw.Elapsed.TotalSeconds);
      Console.WriteLine("PartitionSize: {0}", count);
    }

    private static void Test2() {
      var pool = new ObjectPool<Person>(() => new Person(), 2048);

      Parallel.For(0, 10000, i => {
        for (var j = 0; j < 3000; j++) {
          var person = pool.Allocate();
          person.Age = i + j;
          person.Name = string.Format("{0} - {1}", i, j);
        }

        //pool.Free()
      });
    }

    static void SimpleTest() {
      var interpreter = new PushInterpreter();

      interpreter.Run("5 INTEGER.DUP INTEGER.+");

      interpreter.PrintStacks();
    }

    static async Task Stepwise() {
      var interpreter = new PushInterpreter();

      interpreter.Run("( 0 2 CODE.QUOTE ( 1 INTEGER.+ 0 3 CODE.QUOTE ( 1 INTEGER.+ INTEGER.* ) CODE.DO*RANGE INTEGER.+ ) CODE.DO*RANGE )");

      while (!interpreter.IsCompleted) {
        Console.Clear();
        interpreter.PrintStacks();
        interpreter.Step();

        var input = Console.ReadKey();
        if (input.Key == ConsoleKey.Escape) {
          break;
        } else if (input.Key == ConsoleKey.Spacebar) {
          await interpreter.ResumeAsync();
        }
      }

      Console.Clear();
      interpreter.PrintStacks();
    }

    static void PerformanceTestInterpreter() {
      var program = PushParser.Parse("( 5 INTEGER.DUP INTEGER.+ )");

      var interpreter = new PushInterpreter();
      var sw = new Stopwatch();

      sw.Start();
      for (var i = 0; i < 60000000; i++) {
        interpreter.Run(program);
        interpreter.ClearStacks();
      }
      sw.Stop();

      Console.WriteLine(sw.Elapsed);
    }

    static void PerformanceParallelTestInterpreter() {
      var program = PushParser.Parse("( 5 INTEGER.DUP INTEGER.+ )");

      var sw = new Stopwatch();
      var iterations = 100;
      var amount = 600000;
      var pool = new PushInterpreterPool(iterations, 1024);

      sw.Start();
      Parallel.For(0, iterations, i => {
        using (var interpreter = pool.Create()) {
          for (var j = 0; j < amount; j++) {
            interpreter.Run(program);
            interpreter.ClearStacks();
          }
        }
      });
      sw.Stop();

      Console.WriteLine(sw.Elapsed);
    }

    static void PerformanceTestRecursiveCodeGenerator() {
      var sw = new Stopwatch();
      var random = new FastRandom(1337);

      sw.Start();
      var expressions = RecursiveCodeGenerator.RandomCode(60000000, random).ToList();
      sw.Stop();

      Console.WriteLine("Generated {0} in {1}", expressions.Count, sw.Elapsed);
    }

    static void PerformanceTestLinearCodeGenerator() {
      var sw = new Stopwatch();
      var random = new FastRandom(1337);
      var config = new PushConfiguration();

      sw.Start();
      var expressions = LinearCodeGenerator.RandomCode(60000000, null, random, config).ToList();
      sw.Stop();

      Console.WriteLine("Generated {0} in {1}", expressions.Count, sw.Elapsed);
    }

    static void TestRobustness() {
      var sw = new Stopwatch();
      var parallelism = Environment.ProcessorCount;
      var maxProgramSizeLimit = 1024;
      var partitionSize = 100000;
      var execCounters = new long[parallelism];

      var config = new PushConfiguration {
        EvalPushLimit = 1024,
        MaxProgramLength = 1024
      };

      config.DisableStack(StackTypes.Exec);
      config.DisableStack(StackTypes.Code);
      config.DisableStack(StackTypes.Float);

      var errors = config.EnabledExpressions.Where(
        name => {
          var type = ExpressionTable.NameToTypeTable[name];
          var attribute = ExpressionTable.TypeToAttributeTable[type];

          return attribute.StackType == StackTypes.Exec
              || attribute.AdditionalStackDependencies.HasFlag(StackTypes.Exec)
              || attribute.StackType == StackTypes.Code
              || attribute.AdditionalStackDependencies.HasFlag(StackTypes.Code)
              || attribute.StackType == StackTypes.Float
              || attribute.AdditionalStackDependencies.HasFlag(StackTypes.Float);
        });

      var pool = new PushInterpreterPool(config);

      sw.Start();
      Parallel.For(0, parallelism, i => {
        var random = new FastRandom(1337);

        using (var interpreter = pool.Create(random)) {
          for (var j = 0; j < partitionSize; j++) {
            var program = LinearCodeGenerator.RandomProgram(maxProgramSizeLimit, random, config);
            interpreter.Run(program);

            execCounters[i] += interpreter.ExecCounter;
            interpreter.Reset();
          }
        }
      });
      sw.Stop();

      Console.WriteLine("ExecCount: {0}", execCounters.Sum());
      Console.WriteLine("Duration: {0}", sw.Elapsed);
    }

    static void TestPool() {
      var pool = new PushInterpreterPool();
      var normal = new PushInterpreter();
      int id;

      using (var interpreter = pool.Create()) {
        interpreter.Run("( 1 2 INTEGER.+ )");

        id = interpreter.GetHashCode();
        if (id == normal.GetHashCode()) Console.WriteLine("equal 1");
      }

      using (var interpreter = pool.Create())
      using (var interpreter2 = pool.Create()) {
        interpreter.Run("( 1 2 INTEGER.+ )");
        if (id == interpreter.GetHashCode()) Console.WriteLine("equal 2");
        if (id == interpreter2.GetHashCode()) Console.WriteLine("equal 3");
      }
    }

    static void TestPoolPerformance() {
      var sw = new Stopwatch();
      var iterations = 100000000;

      sw.Start();
      for (var i = 0; i < iterations; i++) {
        var interpreter = new PushInterpreter();
        interpreter.ClearStacks();
      }
      sw.Stop();

      Console.WriteLine(sw.Elapsed);

      var pool = new PushInterpreterPool();
      sw.Restart();
      for (var i = 0; i < iterations; i++) {
        using (var interpreter = pool.Create()) {
          interpreter.ClearStacks();
        }
      }
      sw.Stop();

      Console.WriteLine(sw.Elapsed);
    }

    static void TestSimplifier() {
      var program = PushParser.ParseProgram("( 5 ( INTEGER.DUP FLOAT.+ FLOAT.- ) ( EXEC.DO ( EXEC.IF ) EXEC.Y ) INTEGER.+ )");
      var pool = new PushInterpreterPool();
      var random = new FastRandom(1337);

      var randomProg = LinearCodeGenerator.RandomProgram(4096 * 4, random);    // 53

      Func<PushProgram, double> evaluator = prog => {
        using (var interpreter = pool.Create(random)) {
          interpreter.Run(prog);
          return interpreter.IntegerStack.IsEmpty
            ? double.MaxValue
            : Math.Abs(interpreter.IntegerStack.Top - 10);
        }
      };

      var simplerProgram = Simplifier.Simplify(program, pool.PushConfiguration, evaluator);

      Console.WriteLine(simplerProgram);
    }
  }

  [Serializable]
  class Person : IPooledObject {
    public string Name { get; set; }
    public int Age { get; set; }

    public void Init() { }

    public void Reset() {
      Age = default(int);
      Name = null;
    }
  }
}