using System.Data.Common;
using System.Net;
using System.Text.Json;
using JobTrackerApi.Data;
using JobTrackerApi.Models;
using JobTrackerApi.Services;
using JobTrackerApi.Services.JobImport;
using JobTrackerApi.Services.JobImport.Translation;
using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Diagnostics;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;
using Moq;

namespace IndependentAuditValidation;

public static class Entry
{
    public static async Task Main(string[] args)
    {
        if (args.Any(arg => arg.StartsWith("--print-to-pdf=")))
        {
            // Inert browser substitute. It opens no network connection and renders no HTML.
            var root = Environment.GetEnvironmentVariable("VALIDATION_FAKE_BROWSER_ROOT")!;
            await File.WriteAllTextAsync(Path.Combine(root, Environment.ProcessId + ".started"), "started");
            for (var i = 0; i < 100 && !File.Exists(Path.Combine(root, "release")); i++) await Task.Delay(50);
            await File.WriteAllTextAsync(args.Single(arg => arg.StartsWith("--print-to-pdf="))[15..], "%PDF-synthetic-launch-probe");
            return;
        }
        var output = new List<object>();
        foreach (var target in new[] { "http://10.1.2.3/", "http://[::ffff:10.1.2.3]/", "http://169.254.169.254/", "http://[::ffff:169.254.169.254]/", "http://192.168.1.1/", "http://[::ffff:192.168.1.1]/", "http://[::1]/", "http://[::ffff:127.0.0.1]/" })
        {
            var handler = new RecordingHandler();
            var clientFactory = new Mock<IHttpClientFactory>();
            clientFactory.Setup(x => x.CreateClient(It.IsAny<string>())).Returns(new HttpClient(handler));
            var resolver = new Mock<IHostAddressResolver>();
            resolver.Setup(x => x.ResolveAsync(It.IsAny<string>(), It.IsAny<CancellationToken>())).ReturnsAsync([IPAddress.Parse("93.184.216.34")]);
            var service = new JobImportService(clientFactory.Object, new UniversalJobParser(), Array.Empty<IJobSitePlugin>(), new NoOpTranslationService(), resolver.Object);
            var result = await service.PreviewAsync(target, default);
            output.Add(new { probe = "URL guard with non-network HTTP fake", target, handler.Calls, result.Parser, result.Error });
        }
        var folder = Path.Combine(Path.GetTempPath(), "jobjakt-boundary-" + Guid.NewGuid().ToString("N"));
        Directory.CreateDirectory(folder);
        var fakeRoot = Path.Combine(folder, "fake-browser");
        Directory.CreateDirectory(fakeRoot);
        var executable = Path.ChangeExtension(typeof(Entry).Assembly.Location, OperatingSystem.IsWindows() ? ".exe" : null);
        Environment.SetEnvironmentVariable("CV_PDF_BROWSER_PATH", executable);
        Environment.SetEnvironmentVariable("VALIDATION_FAKE_BROWSER_ROOT", fakeRoot);
        var pdfConfig = new ConfigurationBuilder().AddInMemoryCollection(new Dictionary<string, string?> { ["Data:Root"] = folder }).Build();
        var environment = new Mock<IHostEnvironment>();
        environment.SetupGet(x => x.ContentRootPath).Returns(folder);
        var pdf = new PlaywrightCvPdfExporter(new AppPaths(pdfConfig, environment.Object), Microsoft.Extensions.Logging.Abstractions.NullLogger<PlaywrightCvPdfExporter>.Instance, pdfConfig);
        var renders = Enumerable.Range(0, 3).Select(i => pdf.ExportAsync("synthetic-owner", new TailoredCvRenderResult("synthetic", "synthetic.pdf", "<p>Inert</p>"), default)).ToArray();
        for (var i = 0; i < 100 && Directory.GetFiles(fakeRoot, "*.started").Length < 3; i++) await Task.Delay(50);
        var concurrentLaunches = Directory.GetFiles(fakeRoot, "*.started").Length;
        await File.WriteAllTextAsync(Path.Combine(fakeRoot, "release"), "release");
        await Task.WhenAll(renders);
        output.Add(new { probe = "actual PDF exporter with three inert child processes", concurrentLaunches });
        var connectionString = "Data Source=" + Path.Combine(folder, "independent.db");
        var options = new DbContextOptionsBuilder<JobTrackerContext>().UseSqlite(connectionString).Options;
        using (var db = new JobTrackerContext(options, new FixedOwner()))
        {
            await db.Database.EnsureCreatedAsync();
            db.Users.Add(new ApplicationUser { Id = "synthetic-owner", UserName = "owner@example.test", NormalizedUserName = "OWNER@EXAMPLE.TEST" });
            await db.SaveChangesAsync();
        }
        var career = new Mock<ICareerProfileService>().Object;
        var renderer = new Mock<IThemedCvRenderer>().Object;
        int id;
        using (var db = new JobTrackerContext(options, new FixedOwner()))
            id = (await new CvVariantService(db, career, renderer).CreateAsync("synthetic-owner", "Initial", null, new CvVariantSettings(), default)).Id;
        using (var dbA = new JobTrackerContext(options, new FixedOwner()))
        using (var dbB = new JobTrackerContext(options, new FixedOwner()))
        {
            var a = new CvVariantService(dbA, career, renderer);
            var b = new CvVariantService(dbB, career, renderer);
            await a.GetAsync("synthetic-owner", id, default);
            await b.GetAsync("synthetic-owner", id, default);
            await a.SaveAsync("synthetic-owner", id, "Writer A", new CvVariantSettings(), "a", default);
            await b.SaveAsync("synthetic-owner", id, "Writer B", new CvVariantSettings(), "b", default);
        }
        using (var db = new JobTrackerContext(options, new FixedOwner()))
        {
            var current = await db.CvVariants.SingleAsync();
            var versions = await db.CvVariantVersions.OrderBy(v => v.Id).Select(v => v.Version).ToListAsync();
            output.Add(new { probe = "two preloaded real SQLite contexts", current.Name, current.Version, historyVersions = versions });
        }
        foreach (var concurrency in new[] { 1, 2 })
        {
            var fault = new OneShotDbFailure();
            var config = new ConfigurationBuilder().AddInMemoryCollection(new Dictionary<string, string?>
            {
                ["Workers:AiOperationsEnabled"] = "true", ["AiQueue:WorkerConcurrency"] = concurrency.ToString(),
                ["AiQueue:IdleDelayMs"] = "100"
            }).Build();
            using var host = new HostBuilder().ConfigureLogging(l => l.ClearProviders()).ConfigureServices(services =>
            {
                services.AddSingleton<IConfiguration>(config);
                services.AddSingleton<TimeProvider>(TimeProvider.System);
                services.AddScoped<ICurrentUserService, NeutralOwner>();
                services.AddDbContext<JobTrackerContext>(o => o.UseSqlite(connectionString).AddInterceptors(fault));
                services.AddScoped<UserOperationStore>();
                services.AddSingleton<AiPrivacyPolicy>();
                services.AddSingleton<AiOperationExecutionScope>();
                services.AddSingleton<IAiOperationHandler, UnusedHandler>();
                services.AddSingleton<AiOperationWorker>();
                services.AddSingleton<AiOperationHostedService>();
                services.AddHostedService(p => p.GetRequiredService<AiOperationHostedService>());
            }).Build();
            await host.StartAsync();
            await Task.Delay(150);
            fault.Armed = true;
            await Task.Delay(700);
            var lifetime = host.Services.GetRequiredService<IHostApplicationLifetime>();
            var service = host.Services.GetRequiredService<AiOperationHostedService>();
            output.Add(new { probe = "one transient database command failure", concurrency, fault.Failures, hostStopping = lifetime.ApplicationStopping.IsCancellationRequested, hostedTaskFaulted = service.ExecuteTask?.IsFaulted, error = service.ExecuteTask?.Exception?.GetBaseException().GetType().Name });
            using var shutdown = new CancellationTokenSource(TimeSpan.FromSeconds(3));
            await host.StopAsync(shutdown.Token);
        }
        Console.WriteLine(JsonSerializer.Serialize(output, new JsonSerializerOptions { WriteIndented = true }));
    }
}

sealed class FixedOwner : ICurrentUserService { public string? UserId => "synthetic-owner"; }
sealed class NeutralOwner : ICurrentUserService { public string? UserId => null; }
sealed class RecordingHandler : HttpMessageHandler
{
    public int Calls;
    protected override Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
    {
        Calls++;
        return Task.FromResult(new HttpResponseMessage(HttpStatusCode.OK) { Content = new StringContent("<html><body>Synthetic inert HTML; no sockets are opened.</body></html>") });
    }
}
sealed class OneShotDbFailure : DbCommandInterceptor
{
    public volatile bool Armed;
    private int fired;
    public int Failures => fired;
    public override ValueTask<InterceptionResult<DbDataReader>> ReaderExecutingAsync(DbCommand command, CommandEventData eventData, InterceptionResult<DbDataReader> result, CancellationToken cancellationToken = default)
    {
        if (Armed && Interlocked.CompareExchange(ref fired, 1, 0) == 0) throw new TimeoutException("Synthetic one-shot database timeout");
        return base.ReaderExecutingAsync(command, eventData, result, cancellationToken);
    }
}
sealed class UnusedHandler : IAiOperationHandler
{
    public string TaskType => "synthetic.validation";
    public Task<AiOperationExecutionResult> ExecuteAsync(AiOperationExecutionContext context, IServiceProvider services, CancellationToken cancellationToken) => throw new InvalidOperationException("No operations were queued in this probe.");
}