using System.Collections.Generic;
using System.Linq;
using System.Collections.Immutable;
using Microsoft.AspNetCore.Authentication;
using Microsoft.Extensions.Options;
using StellaOps.Excititor.Attestation.Extensions;
using StellaOps.Excititor.Attestation;
using StellaOps.Excititor.Attestation.Transparency;
using StellaOps.Excititor.ArtifactStores.S3.Extensions;
using StellaOps.Excititor.Connectors.RedHat.CSAF.DependencyInjection;
using StellaOps.Excititor.Core;
using StellaOps.Excititor.Export;
using StellaOps.Excititor.Formats.CSAF;
using StellaOps.Excititor.Formats.CycloneDX;
using StellaOps.Excititor.Formats.OpenVEX;
using StellaOps.Excititor.Policy;
using StellaOps.Excititor.Storage.Mongo;
using StellaOps.Excititor.WebService.Endpoints;
using StellaOps.Excititor.WebService.Services;
using StellaOps.Excititor.Core;

var builder = WebApplication.CreateBuilder(args);
var configuration = builder.Configuration;
var services = builder.Services;

services.AddOptions<VexMongoStorageOptions>()
    .Bind(configuration.GetSection("Excititor:Storage:Mongo"))
    .ValidateOnStart();

services.AddExcititorMongoStorage();
services.AddCsafNormalizer();
services.AddCycloneDxNormalizer();
services.AddOpenVexNormalizer();
services.AddSingleton<IVexSignatureVerifier, NoopVexSignatureVerifier>();
services.AddScoped<IVexIngestOrchestrator, VexIngestOrchestrator>();
services.AddVexExportEngine();
services.AddVexExportCacheServices();
services.AddVexAttestation();
services.Configure<VexAttestationClientOptions>(configuration.GetSection("Excititor:Attestation:Client"));
services.AddVexPolicy();
services.AddRedHatCsafConnector();
services.Configure<MirrorDistributionOptions>(configuration.GetSection(MirrorDistributionOptions.SectionName));
services.AddSingleton<MirrorRateLimiter>();

var rekorSection = configuration.GetSection("Excititor:Attestation:Rekor");
if (rekorSection.Exists())
{
    services.AddVexRekorClient(opts => rekorSection.Bind(opts));
}

var fileSystemSection = configuration.GetSection("Excititor:Artifacts:FileSystem");
if (fileSystemSection.Exists())
{
    services.AddVexFileSystemArtifactStore(opts => fileSystemSection.Bind(opts));
}
else
{
    services.AddVexFileSystemArtifactStore(_ => { });
}

var s3Section = configuration.GetSection("Excititor:Artifacts:S3");
if (s3Section.Exists())
{
    services.AddVexS3ArtifactClient(opts => s3Section.GetSection("Client").Bind(opts));
    services.AddSingleton<IVexArtifactStore, S3ArtifactStore>(provider =>
    {
        var options = new S3ArtifactStoreOptions();
        s3Section.GetSection("Store").Bind(options);
        return new S3ArtifactStore(
            provider.GetRequiredService<IS3ArtifactClient>(),
            Microsoft.Extensions.Options.Options.Create(options),
            provider.GetRequiredService<Microsoft.Extensions.Logging.ILogger<S3ArtifactStore>>());
    });
}

var offlineSection = configuration.GetSection("Excititor:Artifacts:OfflineBundle");
if (offlineSection.Exists())
{
    services.AddVexOfflineBundleArtifactStore(opts => offlineSection.Bind(opts));
}

services.AddEndpointsApiExplorer();
services.AddHealthChecks();
services.AddSingleton(TimeProvider.System);
services.AddMemoryCache();
services.AddAuthentication();
services.AddAuthorization();

var app = builder.Build();

app.UseAuthentication();
app.UseAuthorization();

app.MapGet("/excititor/status", async (HttpContext context,
    IEnumerable<IVexArtifactStore> artifactStores,
    IOptions<VexMongoStorageOptions> mongoOptions,
    TimeProvider timeProvider) =>
{
    var payload = new StatusResponse(
        timeProvider.GetUtcNow(),
        mongoOptions.Value.RawBucketName,
        mongoOptions.Value.GridFsInlineThresholdBytes,
        artifactStores.Select(store => store.GetType().Name).ToArray());

    context.Response.ContentType = "application/json";
    await System.Text.Json.JsonSerializer.SerializeAsync(context.Response.Body, payload);
});

app.MapHealthChecks("/excititor/health");

app.MapPost("/excititor/statements", async (
    VexStatementIngestRequest request,
    IVexClaimStore claimStore,
    TimeProvider timeProvider,
    CancellationToken cancellationToken) =>
{
    if (request?.Statements is null || request.Statements.Count == 0)
    {
        return Results.BadRequest("At least one statement must be provided.");
    }

    var claims = request.Statements.Select(statement => statement.ToDomainClaim());
    await claimStore.AppendAsync(claims, timeProvider.GetUtcNow(), cancellationToken).ConfigureAwait(false);
    return Results.Accepted();
});

app.MapGet("/excititor/statements/{vulnerabilityId}/{productKey}", async (
    string vulnerabilityId,
    string productKey,
    DateTimeOffset? since,
    IVexClaimStore claimStore,
    CancellationToken cancellationToken) =>
{
    if (string.IsNullOrWhiteSpace(vulnerabilityId) || string.IsNullOrWhiteSpace(productKey))
    {
        return Results.BadRequest("vulnerabilityId and productKey are required.");
    }

    var claims = await claimStore.FindAsync(vulnerabilityId.Trim(), productKey.Trim(), since, cancellationToken).ConfigureAwait(false);
    return Results.Ok(claims);
});

app.MapPost("/excititor/admin/backfill-statements", async (
    VexStatementBackfillRequest? request,
    VexStatementBackfillService backfillService,
    CancellationToken cancellationToken) =>
{
    request ??= new VexStatementBackfillRequest();
    var result = await backfillService.RunAsync(request, cancellationToken).ConfigureAwait(false);
    var message = FormattableString.Invariant(
        $"Backfill completed: evaluated {result.DocumentsEvaluated}, backfilled {result.DocumentsBackfilled}, claims written {result.ClaimsWritten}, skipped {result.SkippedExisting}, failures {result.NormalizationFailures}.");

    return Results.Ok(new
    {
        message,
        summary = result
    });
});

IngestEndpoints.MapIngestEndpoints(app);
ResolveEndpoint.MapResolveEndpoint(app);
MirrorEndpoints.MapMirrorEndpoints(app);

app.Run();

public partial class Program;

internal sealed record StatusResponse(DateTimeOffset UtcNow, string MongoBucket, int InlineThreshold, string[] ArtifactStores);

internal sealed record VexStatementIngestRequest(IReadOnlyList<VexStatementEntry> Statements);

internal sealed record VexStatementEntry(
    string VulnerabilityId,
    string ProviderId,
    string ProductKey,
    string? ProductName,
    string? ProductVersion,
    string? ProductPurl,
    string? ProductCpe,
    IReadOnlyList<string>? ComponentIdentifiers,
    VexClaimStatus Status,
    VexJustification? Justification,
    string? Detail,
    DateTimeOffset FirstSeen,
    DateTimeOffset LastSeen,
    VexDocumentFormat DocumentFormat,
    string DocumentDigest,
    string DocumentUri,
    string? DocumentRevision,
    VexSignatureMetadataRequest? Signature,
    VexConfidenceRequest? Confidence,
    VexSignalRequest? Signals,
    IReadOnlyDictionary<string, string>? Metadata)
{
    public VexClaim ToDomainClaim()
    {
        var product = new VexProduct(
            ProductKey,
            ProductName,
            ProductVersion,
            ProductPurl,
            ProductCpe,
            ComponentIdentifiers ?? Array.Empty<string>());

        if (!Uri.TryCreate(DocumentUri, UriKind.Absolute, out var uri))
        {
            throw new InvalidOperationException($"DocumentUri '{DocumentUri}' is not a valid absolute URI.");
        }

        var document = new VexClaimDocument(
            DocumentFormat,
            DocumentDigest,
            uri,
            DocumentRevision,
            Signature?.ToDomain());

        var additionalMetadata = Metadata is null
            ? ImmutableDictionary<string, string>.Empty
            : Metadata.ToImmutableDictionary(StringComparer.Ordinal);

        return new VexClaim(
            VulnerabilityId,
            ProviderId,
            product,
            Status,
            document,
            FirstSeen,
            LastSeen,
            Justification,
            Detail,
            Confidence?.ToDomain(),
            Signals?.ToDomain(),
            additionalMetadata);
    }
}

internal sealed record VexSignatureMetadataRequest(
    string Type,
    string? Subject,
    string? Issuer,
    string? KeyId,
    DateTimeOffset? VerifiedAt,
    string? TransparencyLogReference)
{
    public VexSignatureMetadata ToDomain()
        => new(Type, Subject, Issuer, KeyId, VerifiedAt, TransparencyLogReference);
}

internal sealed record VexConfidenceRequest(string Level, double? Score, string? Method)
{
    public VexConfidence ToDomain() => new(Level, Score, Method);
}

internal sealed record VexSignalRequest(VexSeveritySignalRequest? Severity, bool? Kev, double? Epss)
{
    public VexSignalSnapshot ToDomain()
        => new(Severity?.ToDomain(), Kev, Epss);
}

internal sealed record VexSeveritySignalRequest(string Scheme, double? Score, string? Label, string? Vector)
{
    public VexSeveritySignal ToDomain() => new(Scheme, Score, Label, Vector);
}