using System.Xml.Linq;

namespace ItWorx.KnowledgeHub.Architecture.Tests;

public sealed class ProjectReferenceTests
{
    [Fact]
    public void Domain_and_contracts_have_no_project_dependencies()
    {
        Assert.Empty(ReadProjectReferences("src/backend/ItWorx.KnowledgeHub.Domain/ItWorx.KnowledgeHub.Domain.csproj"));
        Assert.Empty(ReadProjectReferences("src/backend/ItWorx.KnowledgeHub.Contracts/ItWorx.KnowledgeHub.Contracts.csproj"));
    }

    [Fact]
    public void Application_depends_only_on_domain_and_contracts()
    {
        var references = ReadProjectReferences(
            "src/backend/ItWorx.KnowledgeHub.Application/ItWorx.KnowledgeHub.Application.csproj");

        Assert.Equal(
            new[]
            {
                "ItWorx.KnowledgeHub.Contracts",
                "ItWorx.KnowledgeHub.Domain"
            },
            references.Order(StringComparer.Ordinal));
    }

    [Fact]
    public void Infrastructure_does_not_depend_on_api()
    {
        var references = ReadProjectReferences(
            "src/backend/ItWorx.KnowledgeHub.Infrastructure/ItWorx.KnowledgeHub.Infrastructure.csproj");

        Assert.DoesNotContain("ItWorx.KnowledgeHub.Api", references);
    }

    private static IReadOnlyCollection<string> ReadProjectReferences(string relativeProjectPath)
    {
        var repositoryRoot = FindRepositoryRoot();
        var projectPath = Path.Combine(
            repositoryRoot.FullName,
            relativeProjectPath.Replace('/', Path.DirectorySeparatorChar));

        var document = XDocument.Load(projectPath);
        return document
            .Descendants("ProjectReference")
            .Select(element => element.Attribute("Include")?.Value)
            .Where(value => !string.IsNullOrWhiteSpace(value))
            .Select(value => Path.GetFileNameWithoutExtension(value!))
            .ToArray();
    }

    private static DirectoryInfo FindRepositoryRoot()
    {
        DirectoryInfo? current = new DirectoryInfo(AppContext.BaseDirectory);

        while (current is not null)
        {
            if (File.Exists(Path.Combine(current.FullName, "global.json"))
                && (File.Exists(Path.Combine(current.FullName, "CLAUDE.md"))
                    || File.Exists(Path.Combine(current.FullName, "PUBLIC_SOURCE_EXPORT.md"))))
            {
                return current;
            }

            current = current.Parent;
        }

        throw new DirectoryNotFoundException("Could not locate the repository root.");
    }
}