// -----------------------------------------------------------------------------
// IHumanApprovalAttestationService.cs
// Sprint: SPRINT_3801_0001_0004_human_approval_attestation (APPROVE-001)
// Description: Interface for creating human approval attestations.
// -----------------------------------------------------------------------------

using System.Threading;
using System.Threading.Tasks;
using StellaOps.Scanner.WebService.Contracts;
using StellaOps.Scanner.WebService.Domain;

namespace StellaOps.Scanner.WebService.Services;

/// <summary>
/// Creates DSSE attestations for human approval decisions.
/// </summary>
/// <remarks>
/// <para>
/// Human approvals record decisions made by authorized personnel to
/// accept, defer, reject, suppress, or escalate security findings.
/// </para>
/// <para>
/// These attestations have a 30-day default TTL to force periodic
/// re-review of risk acceptance decisions.
/// </para>
/// </remarks>
public interface IHumanApprovalAttestationService
{
    /// <summary>
    /// Creates a human approval attestation.
    /// </summary>
    /// <param name="input">The approval input parameters.</param>
    /// <param name="cancellationToken">Cancellation token.</param>
    /// <returns>
    /// A <see cref="HumanApprovalAttestationResult"/> containing the
    /// attestation statement and content-addressed attestation ID.
    /// </returns>
    Task<HumanApprovalAttestationResult> CreateAttestationAsync(
        HumanApprovalAttestationInput input,
        CancellationToken cancellationToken = default);

    /// <summary>
    /// Gets an existing approval attestation.
    /// </summary>
    /// <param name="scanId">The scan ID.</param>
    /// <param name="findingId">The finding ID.</param>
    /// <param name="cancellationToken">Cancellation token.</param>
    /// <returns>The attestation result if found, null otherwise.</returns>
    Task<HumanApprovalAttestationResult?> GetAttestationAsync(
        ScanId scanId,
        string findingId,
        CancellationToken cancellationToken = default);

    /// <summary>
    /// Gets all active approval attestations for a scan.
    /// </summary>
    /// <param name="scanId">The scan ID.</param>
    /// <param name="cancellationToken">Cancellation token.</param>
    /// <returns>List of active approval attestations.</returns>
    Task<IReadOnlyList<HumanApprovalAttestationResult>> GetApprovalsByScanAsync(
        ScanId scanId,
        CancellationToken cancellationToken = default);

    /// <summary>
    /// Revokes an existing approval attestation.
    /// </summary>
    /// <param name="scanId">The scan ID.</param>
    /// <param name="findingId">The finding ID.</param>
    /// <param name="revokedBy">Who revoked the approval.</param>
    /// <param name="reason">Reason for revocation.</param>
    /// <param name="cancellationToken">Cancellation token.</param>
    /// <returns>True if revoked, false if not found.</returns>
    Task<bool> RevokeApprovalAsync(
        ScanId scanId,
        string findingId,
        string revokedBy,
        string reason,
        CancellationToken cancellationToken = default);
}

/// <summary>
/// Input for creating a human approval attestation.
/// </summary>
public sealed record HumanApprovalAttestationInput
{
    /// <summary>
    /// The scan ID.
    /// </summary>
    public required ScanId ScanId { get; init; }

    /// <summary>
    /// The finding ID (e.g., CVE identifier).
    /// </summary>
    public required string FindingId { get; init; }

    /// <summary>
    /// The approval decision.
    /// </summary>
    public required ApprovalDecision Decision { get; init; }

    /// <summary>
    /// The approver's user ID.
    /// </summary>
    public required string ApproverUserId { get; init; }

    /// <summary>
    /// The approver's display name.
    /// </summary>
    public string? ApproverDisplayName { get; init; }

    /// <summary>
    /// The approver's role.
    /// </summary>
    public string? ApproverRole { get; init; }

    /// <summary>
    /// Justification for the decision.
    /// </summary>
    public required string Justification { get; init; }

    /// <summary>
    /// Optional custom TTL for the approval.
    /// </summary>
    public TimeSpan? ApprovalTtl { get; init; }

    /// <summary>
    /// Reference to the policy decision attestation.
    /// </summary>
    public string? PolicyDecisionRef { get; init; }

    /// <summary>
    /// Optional restrictions on the approval scope.
    /// </summary>
    public ApprovalRestrictions? Restrictions { get; init; }

    /// <summary>
    /// Optional prior approval being superseded.
    /// </summary>
    public string? Supersedes { get; init; }

    /// <summary>
    /// Optional metadata.
    /// </summary>
    public IDictionary<string, string>? Metadata { get; init; }
}

/// <summary>
/// Result of creating a human approval attestation.
/// </summary>
public sealed record HumanApprovalAttestationResult
{
    /// <summary>
    /// Whether the attestation was created successfully.
    /// </summary>
    public required bool Success { get; init; }

    /// <summary>
    /// The human approval statement.
    /// </summary>
    public HumanApprovalStatement? Statement { get; init; }

    /// <summary>
    /// The content-addressed attestation ID.
    /// </summary>
    public string? AttestationId { get; init; }

    /// <summary>
    /// The DSSE envelope (if signing is enabled).
    /// </summary>
    public string? DsseEnvelope { get; init; }

    /// <summary>
    /// Error message if creation failed.
    /// </summary>
    public string? Error { get; init; }

    /// <summary>
    /// Whether the approval has been revoked.
    /// </summary>
    public bool IsRevoked { get; init; }

    /// <summary>
    /// Creates a successful result.
    /// </summary>
    public static HumanApprovalAttestationResult Succeeded(
        HumanApprovalStatement statement,
        string attestationId,
        string? dsseEnvelope = null)
        => new()
        {
            Success = true,
            Statement = statement,
            AttestationId = attestationId,
            DsseEnvelope = dsseEnvelope
        };

    /// <summary>
    /// Creates a failed result.
    /// </summary>
    public static HumanApprovalAttestationResult Failed(string error)
        => new()
        {
            Success = false,
            Error = error
        };
}