// -----------------------------------------------------------------------------
// ServiceCollectionExtensions.cs
// Sprint: SPRINT_20260118_017_Evidence_artifact_store_unification
// Tasks: AS-002, AS-003 - Service registration
// Description: DI registration for artifact store services
// -----------------------------------------------------------------------------


using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Options;
using StellaOps.Artifact.Core;
using StellaOps.Infrastructure.Postgres.Options;

namespace StellaOps.Artifact.Infrastructure;

/// <summary>
/// Extension methods for registering artifact store services.
/// </summary>
public static class ServiceCollectionExtensions
{
    /// <summary>
    /// Adds unified artifact store services with S3 backend.
    /// </summary>
    /// <param name="services">Service collection.</param>
    /// <param name="configuration">Configuration root.</param>
    /// <param name="sectionName">Configuration section for options.</param>
    /// <returns>Service collection for chaining.</returns>
    public static IServiceCollection AddUnifiedArtifactStore(
        this IServiceCollection services,
        IConfiguration configuration,
        string sectionName = "ArtifactStore")
    {
        // Configure S3 store options
        services.Configure<S3UnifiedArtifactStoreOptions>(configuration.GetSection($"{sectionName}:S3"));

        // Configure PostgreSQL options for index
        services.Configure<PostgresOptions>("Artifact", configuration.GetSection($"{sectionName}:Postgres"));

        // Register data source
        services.AddSingleton<ArtifactDataSource>(sp =>
        {
            var options = sp.GetRequiredService<IOptionsSnapshot<PostgresOptions>>().Get("Artifact");
            var logger = sp.GetRequiredService<Microsoft.Extensions.Logging.ILogger<ArtifactDataSource>>();
            return new ArtifactDataSource(Options.Create(options), logger);
        });

        // Register core services
        services.AddSingleton<ICycloneDxExtractor, CycloneDxExtractor>();

        // Register index repository
        services.AddScoped<IArtifactIndexRepository>(sp =>
        {
            var dataSource = sp.GetRequiredService<ArtifactDataSource>();
            var logger = sp.GetRequiredService<Microsoft.Extensions.Logging.ILogger<PostgresArtifactIndexRepository>>();
            // TODO: Get tenant ID from context
            return new PostgresArtifactIndexRepository(dataSource, logger, "default");
        });

        // Register S3 artifact store
        services.AddScoped<IArtifactStore, S3UnifiedArtifactStore>();

        return services;
    }

    /// <summary>
    /// Adds unified artifact store with in-memory backend (for testing).
    /// </summary>
    /// <param name="services">Service collection.</param>
    /// <returns>Service collection for chaining.</returns>
    public static IServiceCollection AddInMemoryArtifactStore(this IServiceCollection services)
    {
        services.AddSingleton<ICycloneDxExtractor, CycloneDxExtractor>();
        services.AddSingleton<IArtifactIndexRepository, InMemoryArtifactIndexRepository>();
        services.AddSingleton<IArtifactStore, InMemoryArtifactStore>();

        return services;
    }

    /// <summary>
    /// Adds artifact migration services.
    /// </summary>
    /// <param name="services">Service collection.</param>
    /// <param name="configure">Options configuration.</param>
    /// <returns>Service collection for chaining.</returns>
    public static IServiceCollection AddArtifactMigration(
        this IServiceCollection services,
        Action<ArtifactMigrationOptions>? configure = null)
    {
        var options = new ArtifactMigrationOptions();
        configure?.Invoke(options);
        services.AddSingleton(options);

        services.AddScoped<ArtifactMigrationService>();

        return services;
    }
}

/// <summary>
/// In-memory artifact store for testing.
/// </summary>
public sealed class InMemoryArtifactStore : IArtifactStore
{
    private readonly Dictionary<string, (byte[] Content, ArtifactMetadata Metadata)> _artifacts = new();
    private readonly object _lock = new();

    public Task<ArtifactStoreResult> StoreAsync(ArtifactStoreRequest request, CancellationToken ct = default)
    {
        var key = $"{request.BomRef}/{request.SerialNumber}/{request.ArtifactId}";
        using var ms = new MemoryStream();
        request.Content.CopyTo(ms);
        var content = ms.ToArray();

        using var sha = System.Security.Cryptography.SHA256.Create();
        var hash = sha.ComputeHash(content);
        var sha256 = Convert.ToHexStringLower(hash);

        var metadata = new ArtifactMetadata
        {
            StorageKey = key,
            BomRef = request.BomRef,
            SerialNumber = request.SerialNumber,
            ArtifactId = request.ArtifactId,
            ContentType = request.ContentType,
            SizeBytes = content.Length,
            Sha256 = sha256,
            CreatedAt = DateTimeOffset.UtcNow,
            Type = request.Type,
            TenantId = request.TenantId
        };

        lock (_lock)
        {
            var wasCreated = !_artifacts.ContainsKey(key);
            _artifacts[key] = (content, metadata);
            return Task.FromResult(ArtifactStoreResult.Succeeded(key, sha256, content.Length, wasCreated));
        }
    }

    public Task<ArtifactReadResult> ReadAsync(string bomRef, string? serialNumber, string? artifactId, CancellationToken ct = default)
    {
        lock (_lock)
        {
            var matching = _artifacts
                .Where(kvp => kvp.Value.Metadata.BomRef == bomRef)
                .Where(kvp => serialNumber == null || kvp.Value.Metadata.SerialNumber == serialNumber)
                .Where(kvp => artifactId == null || kvp.Value.Metadata.ArtifactId == artifactId)
                .FirstOrDefault();

            if (matching.Value.Content == null)
            {
                return Task.FromResult(ArtifactReadResult.NotFound());
            }

            return Task.FromResult(ArtifactReadResult.Succeeded(
                new MemoryStream(matching.Value.Content),
                matching.Value.Metadata));
        }
    }

    public Task<IReadOnlyList<ArtifactMetadata>> ListAsync(string bomRef, string? serialNumber = null, CancellationToken ct = default)
    {
        lock (_lock)
        {
            var result = _artifacts.Values
                .Where(x => x.Metadata.BomRef == bomRef)
                .Where(x => serialNumber == null || x.Metadata.SerialNumber == serialNumber)
                .Select(x => x.Metadata)
                .ToList();

            return Task.FromResult<IReadOnlyList<ArtifactMetadata>>(result);
        }
    }

    public Task<bool> ExistsAsync(string bomRef, string serialNumber, string artifactId, CancellationToken ct = default)
    {
        var key = $"{bomRef}/{serialNumber}/{artifactId}";
        lock (_lock)
        {
            return Task.FromResult(_artifacts.ContainsKey(key));
        }
    }

    public Task<ArtifactMetadata?> GetMetadataAsync(string bomRef, string serialNumber, string artifactId, CancellationToken ct = default)
    {
        var key = $"{bomRef}/{serialNumber}/{artifactId}";
        lock (_lock)
        {
            return Task.FromResult(_artifacts.TryGetValue(key, out var entry) ? entry.Metadata : null);
        }
    }

    public Task<bool> DeleteAsync(string bomRef, string serialNumber, string artifactId, CancellationToken ct = default)
    {
        var key = $"{bomRef}/{serialNumber}/{artifactId}";
        lock (_lock)
        {
            return Task.FromResult(_artifacts.Remove(key));
        }
    }
}