using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Linq;
using FizzWare.NBuilder;
using Microsoft.VisualStudio.TestTools.UnitTesting;

namespace UnitTestProject1
{
    [TestClass]
    public class FileReadingTest
    {
        [ClassInitialize]
        public static void ClassInitialize(TestContext context)
        {
            Directory.CreateDirectory("Content");

            var generator = new RandomGenerator();

            var numberOfFiles = generator.Next(100, 1000);

            foreach (var file in Enumerable.Range(0, numberOfFiles).Select(x => $"Content/file_{x}.txt"))
            {
                File.WriteAllLines(file, Enumerable.Range(0, generator.Next(100, 1000)).Select(i => generator.Phrase(generator.Next(0, 100))));
            }

        }

        [ClassCleanup]
        public static void ClassCleanup()
        {
            Directory.Delete("Content", true);
        }

        public static Tuple<string[], string[][]> Linq()
        {
            var fileCount = Directory.GetFiles("Content/", "*.txt").Count();

            var fileContents = Enumerable.Range(0, fileCount).Select(i =>
            {
                using (var fileStream = new FileStream($"Content/file_{i}.txt", FileMode.Open))
                using (var streamReader = new StreamReader(fileStream))
                {
                    return streamReader.ReadToEnd();
                }
            }).ToArray();

            var fileContentsLines = Enumerable.Range(0, fileCount).Select(i => File.ReadAllLines($"Content/file_{i}.txt")).ToArray();

            return new Tuple<string[], string[][]>(fileContents, fileContentsLines);
        }

        public static Tuple<string[], string[][]> ForUnsafe()
        {
            var fileCount = Directory.GetFiles("Content/", "*.txt").Count();

            var fileContents = new string[fileCount];

            for (var i = 0; i < fileContents.Length; i++)
            {
                var fileStream = new FileStream($"Content/file_{i}.txt", FileMode.Open);
                var streamReader = new StreamReader(fileStream);
                fileContents[i] = streamReader.ReadToEnd();
                streamReader.Dispose();
                fileStream.Dispose();
            }

            var fileContentsLines = new string[fileCount][];

            for (var i = 0; i < fileContentsLines.Length; i++)
            {
                fileContentsLines[i] = File.ReadAllLines($"Content/file_{i}.txt");
            }

            return new Tuple<string[], string[][]>(fileContents, fileContentsLines);
        }

        public static Tuple<string[], string[][]> ForUsing()
        {
            var fileCount = Directory.GetFiles("Content/", "*.txt").Count();

            var fileContents = new string[fileCount];

            for (var i = 0; i < fileContents.Length; i++)
            {
                using (var fileStream = new FileStream($"Content/file_{i}.txt", FileMode.Open))
                using (var streamReader = new StreamReader(fileStream))
                {
                    fileContents[i] = streamReader.ReadToEnd();
                }
            }

            var fileContentsLines = new string[fileCount][];

            for (var i = 0; i < fileContentsLines.Length; i++)
            {
                fileContentsLines[i] = File.ReadAllLines($"Content/file_{i}.txt");
            }

            return new Tuple<string[], string[][]>(fileContents, fileContentsLines);
        }

        public static Tuple<string[], string[][]> ForSafe()
        {
            var fileCount = Directory.GetFiles("Content/", "*.txt").Count();

            var fileContents = new string[fileCount];

            for (var i = 0; i < fileContents.Length; i++)
            {
                FileStream fileStream = null;
                StreamReader streamReader = null;

                try
                {
                    fileStream = new FileStream($"Content/file_{i}.txt", FileMode.Open);
                    streamReader = new StreamReader(fileStream);
                    fileContents[i] = streamReader.ReadToEnd();
                }
                finally
                {
                    streamReader?.Dispose();
                    fileStream?.Dispose();
                }
            }

            var fileContentsLines = new string[fileCount][];

            for (var i = 0; i < fileContentsLines.Length; i++)
            {
                fileContentsLines[i] = File.ReadAllLines($"Content/file_{i}.txt");
            }

            return new Tuple<string[], string[][]>(fileContents, fileContentsLines);
        }

        [TestMethod]
        public void TestMethod1()
        {
            Stopwatch stopWatch;

            stopWatch = Stopwatch.StartNew();
            var forUnsafeResult = ForUnsafe();
            stopWatch.Stop();

            Console.WriteLine($"For Unsafe Time: {stopWatch.ElapsedMilliseconds} ms.");

            stopWatch = Stopwatch.StartNew();
            var forSafeResult = ForSafe();
            stopWatch.Stop();

            Console.WriteLine($"For Safe Time: {stopWatch.ElapsedMilliseconds} ms.");

            stopWatch = Stopwatch.StartNew();
            var linqResult = Linq();
            stopWatch.Stop();

            Console.WriteLine($"Linq Time: {stopWatch.ElapsedMilliseconds} ms.");

            stopWatch = Stopwatch.StartNew();
            var forUsingResult =ForUsing();
            stopWatch.Stop();

            Console.WriteLine($"For Using Time: {stopWatch.ElapsedMilliseconds} ms.");

            CollectionAssert.AreEqual(forUnsafeResult.Item1, forSafeResult.Item1);
            CollectionAssert.AreEqual(forUnsafeResult.Item1, linqResult.Item1);
            CollectionAssert.AreEqual(forUnsafeResult.Item1, forUsingResult.Item1);

            CollectionAssert.AreEqual(forUnsafeResult.Item2.SelectMany(line => line).ToArray(), forSafeResult.Item2.SelectMany(line => line).ToArray());
            CollectionAssert.AreEqual(forUnsafeResult.Item2.SelectMany(line => line).ToArray(), linqResult.Item2.SelectMany(line => line).ToArray());
            CollectionAssert.AreEqual(forUnsafeResult.Item2.SelectMany(line => line).ToArray(), forUsingResult.Item2.SelectMany(line => line).ToArray());
        }
    }
}