using HSchool.Ai;
using HSchool.Content;
using HSchool.People;
using HSchool.Protocol;
using HSchool.Schedule;
using HSchool.Simulation;

namespace HSchool.Architecture.Tests;

public class LayerBoundaryTests
{
    private static readonly string[] LibraryFolders =
    [
        "HSchool.Protocol",
        "HSchool.Content",
        "HSchool.People",
        "HSchool.Schedule",
        "HSchool.Ai",
        "HSchool.Simulation"
    ];

    private static readonly string[] OldTestProjects =
    [
        "HSchool.People.Tests",
        "HSchool.Ai.Tests",
        "HSchool.Schedule.Tests",
        "HSchool.Simulation.Tests"
    ];

    [Fact]
    public void Protocol_DoesNotReferenceArchAspNetSocketsContentOrSimulation()
    {
        var names = References(typeof(ProtocolCodec));
        AssertNoArchAspNetOrSockets(names);
        Assert.DoesNotContain("HSchool.Content", names, StringComparer.Ordinal);
        Assert.DoesNotContain("HSchool.People", names, StringComparer.Ordinal);
        Assert.DoesNotContain("HSchool.Schedule", names, StringComparer.Ordinal);
        Assert.DoesNotContain("HSchool.Ai", names, StringComparer.Ordinal);
        Assert.DoesNotContain("HSchool.Simulation", names, StringComparer.Ordinal);
    }

    [Fact]
    public void Content_DoesNotReferenceArchAspNetSocketsProtocolPeopleScheduleAiOrSimulation()
    {
        var names = References(typeof(MapLayout));
        AssertNoArchAspNetOrSockets(names);
        Assert.DoesNotContain("HSchool.Protocol", names, StringComparer.Ordinal);
        Assert.DoesNotContain("HSchool.People", names, StringComparer.Ordinal);
        Assert.DoesNotContain("HSchool.Schedule", names, StringComparer.Ordinal);
        Assert.DoesNotContain("HSchool.Ai", names, StringComparer.Ordinal);
        Assert.DoesNotContain("HSchool.Simulation", names, StringComparer.Ordinal);
    }

    [Theory]
    [InlineData(typeof(RosterGenerator))]
    [InlineData(typeof(TimetablePlanner))]
    [InlineData(typeof(WalkGraph))]
    public void PeopleScheduleAi_DoNotReferenceArchAspNetOrSockets(Type marker)
    {
        var names = References(marker);
        AssertNoArchAspNetOrSockets(names);
        Assert.DoesNotContain("HSchool.Protocol", names, StringComparer.Ordinal);
        Assert.DoesNotContain("HSchool.Simulation", names, StringComparer.Ordinal);
    }

    [Fact]
    public void People_DoesNotReferenceScheduleOrAi()
    {
        var names = References(typeof(RosterGenerator));
        Assert.DoesNotContain("HSchool.Schedule", names, StringComparer.Ordinal);
        Assert.DoesNotContain("HSchool.Ai", names, StringComparer.Ordinal);
    }

    [Fact]
    public void Schedule_DoesNotReferencePeopleOrAi()
    {
        var names = References(typeof(TimetablePlanner));
        Assert.DoesNotContain("HSchool.People", names, StringComparer.Ordinal);
        Assert.DoesNotContain("HSchool.Ai", names, StringComparer.Ordinal);
    }

    [Fact]
    public void Simulation_DoesNotReferenceAspNetSocketsOrProtocol()
    {
        var names = References(typeof(School));
        Assert.DoesNotContain(names, name => name.Contains("AspNet", StringComparison.OrdinalIgnoreCase));
        Assert.DoesNotContain(names, name => name.Contains("Sockets", StringComparison.OrdinalIgnoreCase));
        Assert.DoesNotContain("HSchool.Protocol", names, StringComparer.Ordinal);
    }

    [Fact]
    public void SixLibrarySources_DoNotUseWallClock()
    {
        foreach (var folder in LibraryFolders)
        {
            var root = Path.Combine(RepoRoot(), "src", folder);
            Assert.True(Directory.Exists(root), root);
            foreach (var path in SourceFiles(root))
            {
                var text = File.ReadAllText(path);
                Assert.DoesNotContain("DateTime.Now", text, StringComparison.Ordinal);
                Assert.DoesNotContain("DateTime.UtcNow", text, StringComparison.Ordinal);
                // Unused `using System.Net.Http` never becomes a referenced assembly.
                Assert.DoesNotContain("System.Net.Http", text, StringComparison.Ordinal);
            }
        }
    }

    [Fact]
    public void ArchitectureTests_DoNotReferenceHostOrNetArchTest()
    {
        var csproj = File.ReadAllText(
            Path.Combine(RepoRoot(), "tests", "HSchool.Architecture.Tests", "HSchool.Architecture.Tests.csproj"));
        Assert.DoesNotContain("HSchool.Server", csproj, StringComparison.Ordinal);
        Assert.DoesNotContain("HSchool.AppHost", csproj, StringComparison.Ordinal);
        Assert.DoesNotContain("NetArchTest", csproj, StringComparison.OrdinalIgnoreCase);
    }

    [Fact]
    public void PeopleAiScheduleSimulationTests_NoLongerCarryLayerBans()
    {
        foreach (var project in OldTestProjects)
        {
            var root = Path.Combine(RepoRoot(), "tests", project);
            Assert.True(Directory.Exists(root), root);
            foreach (var path in SourceFiles(root))
            {
                var text = File.ReadAllText(path);
                Assert.DoesNotContain("Assembly_DoesNotReference", text, StringComparison.Ordinal);
                Assert.DoesNotContain("Sources_DoNotUseWallClock", text, StringComparison.Ordinal);
            }
        }
    }

    private static IEnumerable<string> SourceFiles(string root) =>
        Directory.EnumerateFiles(root, "*.cs", SearchOption.AllDirectories)
            .Where(path => path.Split(Path.DirectorySeparatorChar).All(part => part is not ("bin" or "obj")));

    private static string[] References(Type marker) =>
        [.. marker.Assembly.GetReferencedAssemblies().Select(assembly => assembly.Name!)];

    private static void AssertNoArchAspNetOrSockets(IEnumerable<string> names)
    {
        Assert.DoesNotContain(names, name => name.StartsWith("Arch", StringComparison.OrdinalIgnoreCase));
        Assert.DoesNotContain(names, name => name.Contains("AspNet", StringComparison.OrdinalIgnoreCase));
        Assert.DoesNotContain(names, name => name.Contains("Sockets", StringComparison.OrdinalIgnoreCase));
    }

    private static string RepoRoot()
    {
        var dir = new DirectoryInfo(AppContext.BaseDirectory);
        while (dir is not null && !File.Exists(Path.Combine(dir.FullName, "h-school.sln")))
        {
            dir = dir.Parent;
        }

        if (dir is null)
        {
            throw new InvalidOperationException("Could not find h-school.sln from the test output directory.");
        }

        return dir.FullName;
    }
}