using System.Text.Json;
using StellaOps.TaskRunner.Core.Execution;

namespace StellaOps.TaskRunner.Infrastructure.Execution;

public sealed class FilesystemPackRunArtifactReader : IPackRunArtifactReader
{
    private static readonly JsonSerializerOptions SerializerOptions = new(JsonSerializerDefaults.Web);

    private readonly string rootPath;

    public FilesystemPackRunArtifactReader(string rootPath)
    {
        ArgumentException.ThrowIfNullOrWhiteSpace(rootPath);
        this.rootPath = Path.GetFullPath(rootPath);
    }

    public async Task<IReadOnlyList<PackRunArtifactRecord>> ListAsync(string runId, CancellationToken cancellationToken)
    {
        ArgumentException.ThrowIfNullOrWhiteSpace(runId);

        var manifestPath = Path.Combine(rootPath, Sanitize(runId), "artifact-manifest.json");
        if (!File.Exists(manifestPath))
        {
            return Array.Empty<PackRunArtifactRecord>();
        }

        await using var stream = File.OpenRead(manifestPath);
        var manifest = await JsonSerializer.DeserializeAsync<ArtifactManifest>(stream, SerializerOptions, cancellationToken)
            .ConfigureAwait(false);

        if (manifest is null || manifest.Outputs is null)
        {
            return Array.Empty<PackRunArtifactRecord>();
        }

        return manifest.Outputs
            .OrderBy(output => output.Name, StringComparer.Ordinal)
            .Select(output => new PackRunArtifactRecord(
                output.Name,
                output.Type,
                output.SourcePath,
                output.StoredPath,
                output.Status,
                output.Notes,
                manifest.UploadedAt,
                output.ExpressionJson))
            .ToList();
    }

    private static string Sanitize(string value)
    {
        var safe = value.Trim();
        foreach (var invalid in Path.GetInvalidFileNameChars())
        {
            safe = safe.Replace(invalid, '_');
        }

        return string.IsNullOrWhiteSpace(safe) ? "run" : safe;
    }

    private sealed record ArtifactManifest(
        string RunId,
        DateTimeOffset UploadedAt,
        List<ArtifactRecord> Outputs);

    private sealed record ArtifactRecord(
        string Name,
        string Type,
        string? SourcePath,
        string? StoredPath,
        string Status,
        string? Notes,
        string? ExpressionJson);
}