// <copyright file="SignedEvidencePack.cs" company="StellaOps">
// Copyright (c) StellaOps. Licensed under the BUSL-1.1.
// </copyright>

using System.Collections.Immutable;

namespace StellaOps.Evidence.Pack.Models;

/// <summary>
/// A signed evidence pack with DSSE envelope.
/// Sprint: SPRINT_20260109_011_005 Task: EVPK-001
/// </summary>
public sealed record SignedEvidencePack
{
    /// <summary>Gets the evidence pack.</summary>
    public required EvidencePack Pack { get; init; }

    /// <summary>Gets the DSSE envelope containing the signature.</summary>
    public required DsseEnvelope Envelope { get; init; }

    /// <summary>Gets when the pack was signed.</summary>
    public required DateTimeOffset SignedAt { get; init; }
}

/// <summary>
/// DSSE (Dead Simple Signing Envelope) for evidence pack signatures.
/// See: https://github.com/secure-systems-lab/dsse
/// </summary>
public sealed record DsseEnvelope
{
    /// <summary>Gets the payload type URI.</summary>
    public required string PayloadType { get; init; }

    /// <summary>Gets the base64-encoded payload.</summary>
    public required string Payload { get; init; }

    /// <summary>Gets the computed payload digest.</summary>
    public required string PayloadDigest { get; init; }

    /// <summary>Gets the signatures.</summary>
    public required ImmutableArray<DsseSignature> Signatures { get; init; }
}

/// <summary>
/// A signature within a DSSE envelope.
/// </summary>
public sealed record DsseSignature
{
    /// <summary>Gets the key identifier.</summary>
    public required string KeyId { get; init; }

    /// <summary>Gets the base64-encoded signature.</summary>
    public required string Sig { get; init; }
}

/// <summary>
/// Result of verifying an evidence pack.
/// </summary>
public sealed record EvidencePackVerificationResult
{
    /// <summary>Gets whether the pack is valid.</summary>
    public required bool Valid { get; init; }

    /// <summary>Gets the pack content digest.</summary>
    public required string PackDigest { get; init; }

    /// <summary>Gets the signing key identifier.</summary>
    public required string SignatureKeyId { get; init; }

    /// <summary>Gets any verification issues.</summary>
    public ImmutableArray<string> Issues { get; init; } = ImmutableArray<string>.Empty;

    /// <summary>Gets individual evidence resolution results.</summary>
    public ImmutableArray<EvidenceResolutionResult> EvidenceResolutions { get; init; } = ImmutableArray<EvidenceResolutionResult>.Empty;
}

/// <summary>
/// Result of resolving a single evidence item.
/// </summary>
public sealed record EvidenceResolutionResult
{
    /// <summary>Gets the evidence identifier.</summary>
    public required string EvidenceId { get; init; }

    /// <summary>Gets the evidence URI.</summary>
    public required string Uri { get; init; }

    /// <summary>Gets whether the evidence was resolved.</summary>
    public required bool Resolved { get; init; }

    /// <summary>Gets whether the digest matches.</summary>
    public required bool DigestMatches { get; init; }

    /// <summary>Gets any resolution error.</summary>
    public string? Error { get; init; }
}

/// <summary>
/// Export format options for evidence packs.
/// </summary>
public enum EvidencePackExportFormat
{
    /// <summary>Raw JSON format.</summary>
    Json,

    /// <summary>Signed JSON with DSSE envelope.</summary>
    SignedJson,

    /// <summary>Human-readable Markdown.</summary>
    Markdown,

    /// <summary>PDF report.</summary>
    Pdf,

    /// <summary>Styled HTML report.</summary>
    Html,

    // Sprint: SPRINT_20260112_005_BE_evidence_card_api (EVPCARD-BE-001)

    /// <summary>Single-file evidence card with SBOM excerpt, DSSE envelope, and Rekor receipt.</summary>
    EvidenceCard,

    /// <summary>Compact evidence card without full SBOM.</summary>
    EvidenceCardCompact
}

/// <summary>
/// Result of exporting an evidence pack.
/// </summary>
public sealed record EvidencePackExport
{
    /// <summary>Gets the pack identifier.</summary>
    public required string PackId { get; init; }

    /// <summary>Gets the export format.</summary>
    public required EvidencePackExportFormat Format { get; init; }

    /// <summary>Gets the content bytes.</summary>
    public required byte[] Content { get; init; }

    /// <summary>Gets the content type.</summary>
    public required string ContentType { get; init; }

    /// <summary>Gets the suggested filename.</summary>
    public required string FileName { get; init; }
}