using Microsoft.AspNetCore.Authentication;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Mvc.Testing;
using Microsoft.AspNetCore.TestHost;
using Microsoft.Data.Sqlite;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using SVSim.Database;
using SVSim.Database.Enums;
using SVSim.Database.Models;
using SVSim.Database.Repositories.Deck;
using SVSim.Database.Repositories.Viewer;
using SVSim.EmulatedEntrypoint;
using SVSim.EmulatedEntrypoint.Security.SteamSessionAuthentication;

namespace SVSim.UnitTests.Infrastructure;

/// <summary>
/// Test host for the EmulatedEntrypoint app. Each instance opens a private SQLite in-memory
/// database, swaps the production DbContext + Steam auth handler for SQLite-friendly +
/// header-driven test versions, and exposes a <see cref="SeedViewerAsync"/> helper for tests
/// to create realistic viewer rows.
/// </summary>
internal sealed class SVSimTestFactory : WebApplicationFactory<Program>
{
    private readonly SqliteConnection _connection;
    private long _nextSeededShortUdid = 400_000_001;

    public SVSimTestFactory()
    {
        // SQLite :memory: lives only as long as a connection is open — keep ours open for the
        // factory's lifetime so the DbContext can reattach to the same DB across scopes.
        _connection = new SqliteConnection("DataSource=:memory:");
        _connection.Open();
    }

    protected override void ConfigureWebHost(IWebHostBuilder builder)
    {
        // Tell Program.cs we're in tests so it skips UpdateDatabase() — the Postgres-targeted
        // migrations would fail against SQLite. We call EnsureCreated below instead.
        builder.UseEnvironment("Testing");

        builder.ConfigureTestServices(services =>
        {
            ReplaceDbContext(services);
            ReplaceAuthHandler(services);
        });
    }

    protected override IHost CreateHost(IHostBuilder builder)
    {
        var host = base.CreateHost(builder);

        using var scope = host.Services.CreateScope();
        var db = scope.ServiceProvider.GetRequiredService<SVSimDbContext>();
        db.Database.EnsureCreated();

        return host;
    }

    private void ReplaceDbContext(IServiceCollection services)
    {
        // Production registered DbContextOptions<SVSimDbContext> with the Npgsql provider; tear
        // out every related descriptor so AddDbContext below installs a clean SQLite-backed one.
        foreach (var descriptor in services
                     .Where(d => d.ServiceType == typeof(DbContextOptions<SVSimDbContext>)
                              || d.ServiceType == typeof(DbContextOptions)
                              || d.ServiceType == typeof(SVSimDbContext))
                     .ToList())
        {
            services.Remove(descriptor);
        }

        services.AddDbContext<SVSimDbContext>(opt =>
        {
            opt.UseSqlite(_connection);
            opt.ReplaceService<Microsoft.EntityFrameworkCore.Infrastructure.IModelCustomizer, SqliteFriendlyModelCustomizer>();
        });
    }

    private static void ReplaceAuthHandler(IServiceCollection services)
    {
        // Production Program.cs registered SteamSessionAuthenticationHandler under the
        // "SteamAuthentication" scheme. Drop that scheme from BOTH the SchemeMap and the
        // parallel Schemes list (AddScheme writes to both — and the provider iterates the
        // list, not the map, so leaving the old builder behind throws "Scheme already exists"
        // when it re-adds during provider construction).
        services.AddTransient<TestAuthHandler>();
        services.PostConfigure<AuthenticationOptions>(opt =>
        {
            opt.SchemeMap.Remove(SteamAuthenticationConstants.SchemeName, out _);
            var schemesList = (IList<AuthenticationSchemeBuilder>)opt.Schemes;
            foreach (var stale in schemesList
                         .Where(s => s.Name == SteamAuthenticationConstants.SchemeName)
                         .ToList())
            {
                schemesList.Remove(stale);
            }

            opt.AddScheme(SteamAuthenticationConstants.SchemeName, b =>
            {
                b.HandlerType = typeof(TestAuthHandler);
            });
        });
    }

    /// <summary>
    /// Creates a fully-formed viewer via the real <see cref="IViewerRepository.RegisterViewer"/>
    /// path (so the test exercises the same nav-graph wiring real users hit). The viewer's
    /// <c>ShortUdid</c> is overwritten to a unique non-zero value because the Postgres sequence
    /// is disabled on SQLite — without this every test viewer collides on 0.
    /// </summary>
    public async Task<long> SeedViewerAsync(
        ulong steamId = 76_561_198_000_000_001UL,
        string displayName = "Test Viewer")
    {
        long viewerId;
        long shortUdid;

        using (var scope = Services.CreateScope())
        {
            var repo = scope.ServiceProvider.GetRequiredService<IViewerRepository>();
            var v = await repo.RegisterViewer(displayName, SocialAccountType.Steam, steamId);
            viewerId = v.Id;
            shortUdid = Interlocked.Increment(ref _nextSeededShortUdid);
        }

        // Second scope: assign a real ShortUdid so claim-based lookups in tests have something
        // to find (and so per-viewer ShortUdids don't collide across SeedViewerAsync calls).
        using (var scope = Services.CreateScope())
        {
            var db = scope.ServiceProvider.GetRequiredService<SVSimDbContext>();
            var v = await db.Viewers.FirstAsync(x => x.Id == viewerId);
            v.ShortUdid = shortUdid;
            await db.SaveChangesAsync();
        }

        return viewerId;
    }

    /// <summary>Convenience: bake the X-Test-Viewer-Id header into a fresh client.</summary>
    public HttpClient CreateAuthenticatedClient(long viewerId)
    {
        var client = CreateClient();
        client.DefaultRequestHeaders.Add(TestAuthHandler.ViewerIdHeader, viewerId.ToString());
        return client;
    }

    /// <summary>
    /// Inserts a deck for the viewer via the real <see cref="IDeckRepository.UpsertDeck"/>
    /// path. Picks the first seeded class/sleeve/leader-skin from the master tables; tests
    /// that need specific ids should hit the DB directly.
    /// </summary>
    public async Task SeedDeckAsync(long viewerId, Format format, int number, string name = "Test Deck")
    {
        using var scope = Services.CreateScope();
        var db = scope.ServiceProvider.GetRequiredService<SVSimDbContext>();
        var repo = scope.ServiceProvider.GetRequiredService<IDeckRepository>();

        var cls = await db.Classes.FirstAsync();
        var sleeve = await db.Sleeves.FirstAsync();
        var skin = await db.LeaderSkins.FirstAsync();

        await repo.UpsertDeck(viewerId, format, number, d =>
        {
            d.Name = name;
            d.Class = cls;
            d.Sleeve = sleeve;
            d.LeaderSkin = skin;
        });
    }

    protected override void Dispose(bool disposing)
    {
        base.Dispose(disposing);
        if (disposing)
        {
            _connection.Dispose();
        }
    }
}