namespace StellaOps.Metrics.Kpi;

/// <summary>
/// Quality KPIs for explainable triage.
/// </summary>
public sealed record TriageQualityKpis
{
    /// <summary>
    /// Reporting period start.
    /// </summary>
    public required DateTimeOffset PeriodStart { get; init; }

    /// <summary>
    /// Reporting period end.
    /// </summary>
    public required DateTimeOffset PeriodEnd { get; init; }

    /// <summary>
    /// Tenant ID (null for global).
    /// </summary>
    public string? TenantId { get; init; }

    /// <summary>
    /// Reachability KPIs.
    /// </summary>
    public required ReachabilityKpis Reachability { get; init; }

    /// <summary>
    /// Runtime KPIs.
    /// </summary>
    public required RuntimeKpis Runtime { get; init; }

    /// <summary>
    /// Explainability KPIs.
    /// </summary>
    public required ExplainabilityKpis Explainability { get; init; }

    /// <summary>
    /// Replay/Determinism KPIs.
    /// </summary>
    public required ReplayKpis Replay { get; init; }

    /// <summary>
    /// Unknown budget KPIs.
    /// </summary>
    public required UnknownBudgetKpis Unknowns { get; init; }

    /// <summary>
    /// Operational KPIs.
    /// </summary>
    public required OperationalKpis Operational { get; init; }
}

public sealed record ReachabilityKpis
{
    /// <summary>
    /// Total findings analyzed.
    /// </summary>
    public required int TotalFindings { get; init; }

    /// <summary>
    /// Findings with non-UNKNOWN reachability.
    /// </summary>
    public required int WithKnownReachability { get; init; }

    /// <summary>
    /// Percentage with known reachability.
    /// </summary>
    public decimal PercentKnown => TotalFindings > 0
        ? (decimal)WithKnownReachability / TotalFindings * 100
        : 0;

    /// <summary>
    /// Breakdown by reachability state.
    /// </summary>
    public required IReadOnlyDictionary<string, int> ByState { get; init; }

    /// <summary>
    /// Findings confirmed unreachable.
    /// </summary>
    public int ConfirmedUnreachable =>
        ByState.GetValueOrDefault("ConfirmedUnreachable", 0);

    /// <summary>
    /// Noise reduction (unreachable / total).
    /// </summary>
    public decimal NoiseReductionPercent => TotalFindings > 0
        ? (decimal)ConfirmedUnreachable / TotalFindings * 100
        : 0;
}

public sealed record RuntimeKpis
{
    /// <summary>
    /// Total findings in environments with sensors.
    /// </summary>
    public required int TotalWithSensorDeployed { get; init; }

    /// <summary>
    /// Findings with runtime observations.
    /// </summary>
    public required int WithRuntimeCorroboration { get; init; }

    /// <summary>
    /// Coverage percentage.
    /// </summary>
    public decimal CoveragePercent => TotalWithSensorDeployed > 0
        ? (decimal)WithRuntimeCorroboration / TotalWithSensorDeployed * 100
        : 0;

    /// <summary>
    /// Breakdown by posture.
    /// </summary>
    public required IReadOnlyDictionary<string, int> ByPosture { get; init; }
}

public sealed record ExplainabilityKpis
{
    /// <summary>
    /// Total verdicts generated.
    /// </summary>
    public required int TotalVerdicts { get; init; }

    /// <summary>
    /// Verdicts with reason steps.
    /// </summary>
    public required int WithReasonSteps { get; init; }

    /// <summary>
    /// Verdicts with at least one proof pointer.
    /// </summary>
    public required int WithProofPointer { get; init; }

    /// <summary>
    /// Verdicts that are "complete" (both reason steps AND proof pointer).
    /// </summary>
    public required int FullyExplainable { get; init; }

    /// <summary>
    /// Explainability completeness percentage.
    /// </summary>
    public decimal CompletenessPercent => TotalVerdicts > 0
        ? (decimal)FullyExplainable / TotalVerdicts * 100
        : 0;
}

public sealed record ReplayKpis
{
    /// <summary>
    /// Total replay attempts.
    /// </summary>
    public required int TotalAttempts { get; init; }

    /// <summary>
    /// Successful replays (identical verdict).
    /// </summary>
    public required int Successful { get; init; }

    /// <summary>
    /// Replay success rate.
    /// </summary>
    public decimal SuccessRate => TotalAttempts > 0
        ? (decimal)Successful / TotalAttempts * 100
        : 0;

    /// <summary>
    /// Common failure reasons.
    /// </summary>
    public required IReadOnlyDictionary<string, int> FailureReasons { get; init; }
}

public sealed record UnknownBudgetKpis
{
    /// <summary>
    /// Total environments tracked.
    /// </summary>
    public required int TotalEnvironments { get; init; }

    /// <summary>
    /// Budget breaches by environment.
    /// </summary>
    public required IReadOnlyDictionary<string, int> BreachesByEnvironment { get; init; }

    /// <summary>
    /// Total overrides/exceptions granted.
    /// </summary>
    public required int OverridesGranted { get; init; }

    /// <summary>
    /// Average override age (days).
    /// </summary>
    public decimal AvgOverrideAgeDays { get; init; }
}

public sealed record OperationalKpis
{
    /// <summary>
    /// Median time to first verdict (seconds).
    /// </summary>
    public required double MedianTimeToVerdictSeconds { get; init; }

    /// <summary>
    /// Cache hit rate for graphs/proofs.
    /// </summary>
    public required decimal CacheHitRate { get; init; }

    /// <summary>
    /// Average evidence size per scan (bytes).
    /// </summary>
    public required long AvgEvidenceSizeBytes { get; init; }

    /// <summary>
    /// 95th percentile verdict time (seconds).
    /// </summary>
    public required double P95VerdictTimeSeconds { get; init; }
}