using System.Collections.Immutable;
using System.Text.Json.Serialization;

namespace StellaOps.Policy.Engine.EffectiveDecisionMap;

/// <summary>
/// Represents an effective policy decision for an asset/snapshot.
/// Stored in Redis for Graph overlay lookups.
/// </summary>
public sealed record EffectiveDecisionEntry
{
    /// <summary>
    /// Tenant identifier.
    /// </summary>
    [JsonPropertyName("tenant_id")]
    public required string TenantId { get; init; }

    /// <summary>
    /// Asset identifier (PURL or SBOM ID).
    /// </summary>
    [JsonPropertyName("asset_id")]
    public required string AssetId { get; init; }

    /// <summary>
    /// Snapshot identifier (SBOM version or evaluation run).
    /// </summary>
    [JsonPropertyName("snapshot_id")]
    public required string SnapshotId { get; init; }

    /// <summary>
    /// Policy pack ID that produced this decision.
    /// </summary>
    [JsonPropertyName("pack_id")]
    public required string PackId { get; init; }

    /// <summary>
    /// Policy pack version.
    /// </summary>
    [JsonPropertyName("pack_version")]
    public required int PackVersion { get; init; }

    /// <summary>
    /// Final decision status (allow, warn, deny, blocked).
    /// </summary>
    [JsonPropertyName("status")]
    public required string Status { get; init; }

    /// <summary>
    /// Severity level if applicable.
    /// </summary>
    [JsonPropertyName("severity")]
    public string? Severity { get; init; }

    /// <summary>
    /// Rule name that determined the decision.
    /// </summary>
    [JsonPropertyName("rule_name")]
    public string? RuleName { get; init; }

    /// <summary>
    /// Priority of the applied rule.
    /// </summary>
    [JsonPropertyName("priority")]
    public int? Priority { get; init; }

    /// <summary>
    /// Exception ID if an exception was applied.
    /// </summary>
    [JsonPropertyName("exception_id")]
    public string? ExceptionId { get; init; }

    /// <summary>
    /// Count of advisories affecting this asset.
    /// </summary>
    [JsonPropertyName("advisory_count")]
    public int AdvisoryCount { get; init; }

    /// <summary>
    /// Count of critical/high severity findings.
    /// </summary>
    [JsonPropertyName("high_severity_count")]
    public int HighSeverityCount { get; init; }

    /// <summary>
    /// Aggregated annotations from the decision.
    /// </summary>
    [JsonPropertyName("annotations")]
    public ImmutableDictionary<string, string> Annotations { get; init; } = ImmutableDictionary<string, string>.Empty;

    /// <summary>
    /// Version counter for cache coherency.
    /// </summary>
    [JsonPropertyName("version")]
    public required long Version { get; init; }

    /// <summary>
    /// When this entry was evaluated.
    /// </summary>
    [JsonPropertyName("evaluated_at")]
    public required DateTimeOffset EvaluatedAt { get; init; }

    /// <summary>
    /// When this entry expires.
    /// </summary>
    [JsonPropertyName("expires_at")]
    public required DateTimeOffset ExpiresAt { get; init; }

    /// <summary>
    /// Correlation ID for tracing.
    /// </summary>
    [JsonPropertyName("correlation_id")]
    public string? CorrelationId { get; init; }
}

/// <summary>
/// Result of an effective decision map query.
/// </summary>
public sealed record EffectiveDecisionQueryResult
{
    /// <summary>
    /// Found entries mapped by asset ID.
    /// </summary>
    public required IReadOnlyDictionary<string, EffectiveDecisionEntry> Entries { get; init; }

    /// <summary>
    /// Asset IDs that were not found.
    /// </summary>
    public required IReadOnlyList<string> NotFound { get; init; }

    /// <summary>
    /// Current version of the decision map.
    /// </summary>
    public long MapVersion { get; init; }

    /// <summary>
    /// Whether the result came from cache.
    /// </summary>
    public bool FromCache { get; init; }
}

/// <summary>
/// Summary statistics for a snapshot's effective decisions.
/// </summary>
public sealed record EffectiveDecisionSummary
{
    /// <summary>
    /// Snapshot ID.
    /// </summary>
    public required string SnapshotId { get; init; }

    /// <summary>
    /// Total assets evaluated.
    /// </summary>
    public int TotalAssets { get; init; }

    /// <summary>
    /// Count by status.
    /// </summary>
    public required IReadOnlyDictionary<string, int> StatusCounts { get; init; }

    /// <summary>
    /// Count by severity.
    /// </summary>
    public required IReadOnlyDictionary<string, int> SeverityCounts { get; init; }

    /// <summary>
    /// Assets with exceptions applied.
    /// </summary>
    public int ExceptionCount { get; init; }

    /// <summary>
    /// Map version at time of summary.
    /// </summary>
    public long MapVersion { get; init; }

    /// <summary>
    /// When this summary was computed.
    /// </summary>
    public DateTimeOffset ComputedAt { get; init; }
}

/// <summary>
/// Filter options for querying effective decisions.
/// </summary>
public sealed record EffectiveDecisionFilter
{
    /// <summary>
    /// Filter by status values.
    /// </summary>
    public IReadOnlyList<string>? Statuses { get; init; }

    /// <summary>
    /// Filter by severity values.
    /// </summary>
    public IReadOnlyList<string>? Severities { get; init; }

    /// <summary>
    /// Include only assets with exceptions.
    /// </summary>
    public bool? HasException { get; init; }

    /// <summary>
    /// Filter by minimum advisory count.
    /// </summary>
    public int? MinAdvisoryCount { get; init; }

    /// <summary>
    /// Filter by minimum high severity count.
    /// </summary>
    public int? MinHighSeverityCount { get; init; }

    /// <summary>
    /// Maximum results to return.
    /// </summary>
    public int Limit { get; init; } = 1000;

    /// <summary>
    /// Offset for pagination.
    /// </summary>
    public int Offset { get; init; } = 0;
}