// <copyright file="ActionAuditLedger.cs" company="StellaOps">
// Copyright (c) StellaOps. Licensed under the AGPL-3.0-or-later.
// </copyright>

using System.Collections.Concurrent;
using System.Collections.Immutable;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Options;

namespace StellaOps.AdvisoryAI.Actions;

/// <summary>
/// In-memory action audit ledger for development and testing.
/// In production, this would use PostgreSQL with proper indexing.
/// Sprint: SPRINT_20260109_011_004_BE Task PACT-006
/// </summary>
internal sealed class ActionAuditLedger : IActionAuditLedger
{
    private readonly ConcurrentDictionary<string, ActionAuditEntry> _entries = new();
    private readonly ILogger<ActionAuditLedger> _logger;
    private readonly AuditLedgerOptions _options;

    public ActionAuditLedger(
        IOptions<AuditLedgerOptions> options,
        ILogger<ActionAuditLedger> logger)
    {
        _options = options?.Value ?? new AuditLedgerOptions();
        _logger = logger ?? throw new ArgumentNullException(nameof(logger));
    }

    /// <inheritdoc />
    public Task RecordAsync(ActionAuditEntry entry, CancellationToken cancellationToken)
    {
        ArgumentNullException.ThrowIfNull(entry);

        _entries[entry.EntryId] = entry;

        _logger.LogDebug(
            "Recorded audit entry {EntryId}: {ActionType} by {Actor} -> {Outcome}",
            entry.EntryId, entry.ActionType, entry.Actor, entry.Outcome);

        return Task.CompletedTask;
    }

    /// <inheritdoc />
    public Task<ImmutableArray<ActionAuditEntry>> QueryAsync(
        ActionAuditQuery query,
        CancellationToken cancellationToken)
    {
        ArgumentNullException.ThrowIfNull(query);

        var entries = _entries.Values.AsEnumerable();

        // Apply filters
        if (!string.IsNullOrEmpty(query.TenantId))
        {
            entries = entries.Where(e => e.TenantId.Equals(query.TenantId, StringComparison.OrdinalIgnoreCase));
        }

        if (!string.IsNullOrEmpty(query.ActionType))
        {
            entries = entries.Where(e => e.ActionType.Equals(query.ActionType, StringComparison.OrdinalIgnoreCase));
        }

        if (!string.IsNullOrEmpty(query.Actor))
        {
            entries = entries.Where(e => e.Actor.Equals(query.Actor, StringComparison.OrdinalIgnoreCase));
        }

        if (query.Outcome.HasValue)
        {
            entries = entries.Where(e => e.Outcome == query.Outcome.Value);
        }

        if (!string.IsNullOrEmpty(query.RunId))
        {
            entries = entries.Where(e => e.RunId != null && e.RunId.Equals(query.RunId, StringComparison.OrdinalIgnoreCase));
        }

        if (!string.IsNullOrEmpty(query.CveId))
        {
            entries = entries.Where(e => e.CveId != null && e.CveId.Equals(query.CveId, StringComparison.OrdinalIgnoreCase));
        }

        if (!string.IsNullOrEmpty(query.ImageDigest))
        {
            entries = entries.Where(e => e.ImageDigest != null && e.ImageDigest.Equals(query.ImageDigest, StringComparison.OrdinalIgnoreCase));
        }

        if (query.FromTimestamp.HasValue)
        {
            entries = entries.Where(e => e.Timestamp >= query.FromTimestamp.Value);
        }

        if (query.ToTimestamp.HasValue)
        {
            entries = entries.Where(e => e.Timestamp < query.ToTimestamp.Value);
        }

        // Order by timestamp descending, apply pagination
        var result = entries
            .OrderByDescending(e => e.Timestamp)
            .Skip(query.Offset)
            .Take(query.Limit)
            .ToImmutableArray();

        return Task.FromResult(result);
    }

    /// <inheritdoc />
    public Task<ActionAuditEntry?> GetAsync(
        string entryId,
        CancellationToken cancellationToken)
    {
        ArgumentException.ThrowIfNullOrEmpty(entryId);

        _entries.TryGetValue(entryId, out var entry);
        return Task.FromResult(entry);
    }

    /// <inheritdoc />
    public Task<ImmutableArray<ActionAuditEntry>> GetByRunAsync(
        string runId,
        CancellationToken cancellationToken)
    {
        ArgumentException.ThrowIfNullOrEmpty(runId);

        var entries = _entries.Values
            .Where(e => e.RunId != null && e.RunId.Equals(runId, StringComparison.OrdinalIgnoreCase))
            .OrderBy(e => e.Timestamp)
            .ToImmutableArray();

        return Task.FromResult(entries);
    }
}

/// <summary>
/// Configuration options for the audit ledger.
/// </summary>
public sealed class AuditLedgerOptions
{
    /// <summary>
    /// Days to retain audit entries.
    /// </summary>
    public int RetentionDays { get; set; } = 365;

    /// <summary>
    /// Whether audit logging is enabled.
    /// </summary>
    public bool Enabled { get; set; } = true;
}