using System.Collections.Concurrent;
using System.Diagnostics;
using SPTarkov.Server.Core.Utils;

namespace UnitTests.Tests.Utils;

[TestClass]
public class HashUtilTests
{
    private HashUtil _hashUtil;

    [TestInitialize]
    public void Initialize()
    {
        _hashUtil = DI.GetService<HashUtil>();
    }

    [TestMethod]
    public void GenerateTest()
    {
        // Generate 100 MongoId's
        for (var i = 0; i < 100; i++)
        {
            // Invalid mongoId character
            var result = _hashUtil.Generate();

            // Invalid mongoId length
            var test = _hashUtil.IsValidMongoId(result);

            Assert.AreEqual(true, test, $"IsValidMongoId() `{result}` is not a valid MongoId.");
        }
    }

    [TestMethod]
    [DataRow(
        "677ddb67406e9918a0264bbz",
        false,
        "677ddb67406e9918a0264bbz contains invalid char `z`, but result was true"
    )]
    [DataRow(
        "677ddb67406e9918a0264bbcc",
        false,
        "677ddb67406e9918a0264bbcc is 25 characters, but result was true"
    )]
    [DataRow(
        "677ddb67406e9918a0264bbc",
        true,
        "IsValidMongoId() `677ddb67406e9918a0264bbc` is a valid mongoId, but result was false"
    )]
    public void IsValidMongoIdTest(string mongoId, bool passes, string failMessage)
    {
        var result = _hashUtil.IsValidMongoId(mongoId);
        Assert.AreEqual(passes, result, failMessage);
    }

    [TestMethod]
    [DataRow(
        "123456789",
        "25F9E794323B453885F5181F1B624D0B",
        "Not valid output, expected '25F9E794323B453885F5181F1B624D0B'"
    )]
    public void GenerateValidMd5Test(string input, string expectedOutput, string failMessage)
    {
        var result = _hashUtil.GenerateHashForData(HashingAlgorithm.MD5, input);
        Assert.AreEqual(expectedOutput, result, failMessage);
    }

    [TestMethod]
    public void MultiThreadedMongoIDGenerationTest()
    {
        var concurrentBag = new ConcurrentBag<string>();
        var random = new Random();
        var stopwatch = new Stopwatch();
        stopwatch.Start();

        Parallel.For(
            0,
            1000,
            i =>
            {
                Thread.Sleep(random.Next(0, 10));
                var mongoId = _hashUtil.Generate();
                concurrentBag.Add(mongoId);
            }
        );

        stopwatch.Stop();
        Console.WriteLine($"Elapsed time: {stopwatch.ElapsedMilliseconds} ms");
        var uniqueCount = concurrentBag.Distinct().Count();
        var totalCount = concurrentBag.Count;
        Assert.AreEqual(
            totalCount,
            uniqueCount,
            $"Expected all generated MongoId's to be unique, but found {totalCount - uniqueCount} duplicates."
        );
    }
}