using System;
using System.Collections.Generic;
using System.IO;
using System.IO.Compression;
using System.Linq;
using System.Reflection;
using System.Text.RegularExpressions;

namespace HeuristicLab.Tests.Benchmark.Problem
{
    public class Problem<Tin, Tout>
    {
        public const char ExampleSeparator = ',';
        public const string ArchiveFileName = "BenchmarkExamples.zip";

        private static string instanceArchiveName = GetResourceName(ArchiveFileName);

        protected List<Example<Tin, Tout>> Examples { get; set; }

        protected List<Example<Tin, Tout>> GetExamples(string problemName, Converter<string, Tin> inputConverter, Converter<string, Tout> outputConverter)
        {
            using (var file = GetType().Assembly.GetManifestResourceStream(instanceArchiveName))
            using (var archive = new ZipArchive(file, ZipArchiveMode.Read))
            {
                var entry = archive.Entries.SingleOrDefault(x => x.Name == problemName);

                using (var reader = new StreamReader(entry.Open()))
                {
                    var examples = new List<Example<Tin, Tout>>();

                    // skip training headline
                    if (reader.Peek() >= 0)
                    {
                        reader.ReadLine();
                    }

                    while (reader.Peek() >= 0)
                    {
                        var line = reader.ReadLine();

                        // return
                        if (line.StartsWith("test"))
                        {
                            break;
                        }

                        var values = line.Split(ExampleSeparator);

                        examples.Add(new Example<Tin, Tout>
                        {
                            Input = inputConverter(values[0]),
                            Output = outputConverter(values[1])
                        });
                    }

                    return examples;
                }
            }
        }

        private static string GetResourceName(string fileName)
        {
            return Assembly
                .GetExecutingAssembly()
                .GetManifestResourceNames()
                .Where(x => Regex.Match(x, @".*\.Data\." + fileName).Success)
                .SingleOrDefault();
        }
    }
}