// -----------------------------------------------------------------------------
// S3UnifiedArtifactStore.Read.cs
// Sprint: SPRINT_20260118_017_Evidence_artifact_store_unification
// Task: AS-002 - Implement S3-backed ArtifactStore
// Description: Read operations for the unified artifact store
// -----------------------------------------------------------------------------
using Microsoft.Extensions.Logging;
using StellaOps.Artifact.Core;

namespace StellaOps.Artifact.Infrastructure;

public sealed partial class S3UnifiedArtifactStore
{
    /// <inheritdoc />
    public async Task<ArtifactReadResult> ReadAsync(
        string bomRef,
        string? serialNumber,
        string? artifactId,
        CancellationToken ct = default)
    {
        try
        {
            var entry = await ResolveEntryAsync(bomRef, serialNumber, artifactId, ct).ConfigureAwait(false);
            if (entry == null)
            {
                return ArtifactReadResult.NotFound($"No artifact found for bom-ref: {bomRef}");
            }

            var stream = await _client.GetObjectAsync(_options.BucketName, entry.StorageKey, ct)
                .ConfigureAwait(false);
            if (stream == null)
            {
                return ArtifactReadResult.NotFound($"Object not found in S3: {entry.StorageKey}");
            }

            return ArtifactReadResult.Succeeded(stream, CreateMetadata(entry));
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Failed to read artifact for bom-ref {BomRef}", bomRef);
            return ArtifactReadResult.NotFound(ex.Message);
        }
    }

    private async Task<ArtifactIndexEntry?> ResolveEntryAsync(
        string bomRef,
        string? serialNumber,
        string? artifactId,
        CancellationToken ct)
    {
        if (serialNumber != null && artifactId != null)
        {
            return await _indexRepository.GetAsync(bomRef, serialNumber, artifactId, ct).ConfigureAwait(false);
        }

        if (serialNumber != null)
        {
            var entries = await _indexRepository.FindByBomRefAndSerialAsync(bomRef, serialNumber, ct)
                .ConfigureAwait(false);
            return entries.FirstOrDefault();
        }

        var candidates = await _indexRepository.FindByBomRefAsync(bomRef, ct).ConfigureAwait(false);
        return candidates.FirstOrDefault();
    }
}