using System;

using Rhino.Etl.Core;

using Xunit;

using Rhino.Etl.Core.Infrastructure;



namespace Rhino.Etl.Tests.Branches

{

    public abstract class BranchesFixture : BaseFibonacciTest

    {

        [Fact]

        public void CanBranchThePipeline()

        {

            using (var process = CreateBranchingProcess(30, 2))

                process.Execute();



            AssertFibonacci(30, 2);

        }



        [Fact] 

        public void CanBranchThePipelineEfficiently()

        {

            const int iterations = 30000;

            const int childOperations = 10;



            var initialMemory = GC.GetTotalMemory(true);



            using (var process = CreateBranchingProcess(iterations, childOperations))

                process.Execute();



            var finalMemory = GC.GetTotalMemory(true);

            var consumedMemory = finalMemory - initialMemory;

            var tooMuchMemory = Math.Pow(2, 20);

            

            Assert.True(consumedMemory < tooMuchMemory, "Consuming too much memory - (" + consumedMemory.ToString() + " >= " + tooMuchMemory + ")");

            AssertFibonacci(iterations, childOperations);

        }



        protected abstract EtlProcess CreateBranchingProcess(int iterations, int childOperations);



        protected static void AssertFibonacci(int iterations, int repetitionsPerIteration)

        {

            AssertTotalItems(iterations * repetitionsPerIteration);



            AssertRepetitions(repetitionsPerIteration);

        }



        private static void AssertRepetitions(int repetitionsPerIteration)

        {

            int wrongRepetitions = Use.Transaction("test", cmd =>

            {

                cmd.CommandText =

string.Format(@"    SELECT count(*) 

    FROM (

        SELECT id, count(*) as count

        FROM Fibonacci

        GROUP BY id

        HAVING count(*) <> {0}

    ) as ignored", repetitionsPerIteration);

                return (int)cmd.ExecuteScalar();

            });



            Assert.Equal(1 /* 1 is repetated twice the others */, wrongRepetitions);

        }



        private static void AssertTotalItems(int expectedCount)

        {

            int totalCount = Use.Transaction("test", cmd =>

                                                     {

                                                         cmd.CommandText = "SELECT count(*) FROM Fibonacci";

                                                         return (int) cmd.ExecuteScalar();

                                                     });

            

            Assert.Equal(expectedCount, totalCount);

        }

    }

}