using Microsoft.EntityFrameworkCore;
using TeamUp.Bootstrap;
using TeamUp.Infrastructure.Persistence;
using TeamUp.SharedKernel.Modularity;
using Xunit;

namespace TeamUp.ArchitectureTests;

/// <summary>
/// Guards persistence encapsulation and module shape. A module's DbContext/entities are its
/// private business — never public — and each module exposes exactly one registration seam.
/// </summary>
public sealed class PersistenceEncapsulationTests
{
    private static readonly System.Reflection.Assembly[] AllProductionAssemblies =
    [
        typeof(IModule).Assembly,
        typeof(MigrationRunner).Assembly,
        typeof(ModuleCatalog).Assembly,
        .. ArchitectureFixture.ModuleAssemblies,
    ];

    [Fact]
    public void No_DbContext_is_publicly_visible()
    {
        var publicContexts = AllProductionAssemblies
            .SelectMany(assembly => assembly.GetTypes())
            .Where(type => typeof(DbContext).IsAssignableFrom(type) && type.IsPublic)
            .Select(type => type.FullName)
            .ToList();

        Assert.True(
            publicContexts.Count == 0,
            $"A DbContext must be internal to its module. Public contexts found: {string.Join(", ", publicContexts)}");
    }

    [Fact]
    public void Each_module_assembly_exposes_exactly_one_IModule()
    {
        foreach (var assembly in ArchitectureFixture.ModuleAssemblies)
        {
            var implementations = assembly.GetTypes()
                .Where(type => typeof(IModule).IsAssignableFrom(type)
                    && type is { IsInterface: false, IsAbstract: false })
                .ToList();

            Assert.True(
                implementations.Count == 1,
                $"{assembly.GetName().Name} must expose exactly one IModule; found {implementations.Count}.");
        }
    }

    [Fact]
    public void ModuleCatalog_lists_every_module_with_a_unique_name()
    {
        var modules = ModuleCatalog.All;

        Assert.Equal(ArchitectureFixture.ModuleAssemblies.Length, modules.Count);

        var names = modules.Select(module => module.Name).ToList();
        Assert.All(names, name => Assert.False(string.IsNullOrWhiteSpace(name)));
        Assert.Equal(names.Count, names.Distinct(StringComparer.Ordinal).Count());
    }
}