// <copyright file="ReplayIntegrationTestBase.cs" company="StellaOps">
// Copyright (c) StellaOps. Licensed under AGPL-3.0-or-later.
// </copyright>
// Sprint: SPRINT_20260105_002_002_TEST_trace_replay_evidence
// Task: TREP-007, TREP-008

using System.Collections.Immutable;
using FluentAssertions;
using Microsoft.Extensions.DependencyInjection;
using StellaOps.Replay.Anonymization;
using StellaOps.Testing.Temporal;
using Xunit;

namespace StellaOps.Testing.Replay;

/// <summary>
/// Base class for integration tests that replay production traces.
/// </summary>
public abstract class ReplayIntegrationTestBase : IAsyncLifetime
{
    /// <summary>
    /// Gets the trace corpus manager.
    /// </summary>
    protected ITraceCorpusManager CorpusManager { get; private set; } = null!;

    /// <summary>
    /// Gets the replay orchestrator.
    /// </summary>
    protected IReplayOrchestrator ReplayOrchestrator { get; private set; } = null!;

    /// <summary>
    /// Gets the simulated time provider.
    /// </summary>
    protected SimulatedTimeProvider TimeProvider { get; private set; } = null!;

    /// <summary>
    /// Gets the service provider.
    /// </summary>
    protected IServiceProvider Services { get; private set; } = null!;

    /// <inheritdoc/>
    public virtual async ValueTask InitializeAsync()
    {
        var services = new ServiceCollection();
        ConfigureServices(services);

        Services = services.BuildServiceProvider();
        CorpusManager = Services.GetRequiredService<ITraceCorpusManager>();
        ReplayOrchestrator = Services.GetRequiredService<IReplayOrchestrator>();
        TimeProvider = Services.GetRequiredService<SimulatedTimeProvider>();

        await OnInitializedAsync();
    }

    /// <summary>
    /// Configure services for the test.
    /// </summary>
    /// <param name="services">The service collection.</param>
    protected virtual void ConfigureServices(IServiceCollection services)
    {
        services.AddReplayTesting();
    }

    /// <summary>
    /// Called after initialization is complete.
    /// </summary>
    protected virtual Task OnInitializedAsync() => Task.CompletedTask;

    /// <summary>
    /// Replay a trace and verify behavior matches expected outcome.
    /// </summary>
    /// <param name="trace">The trace to replay.</param>
    /// <param name="expectation">Expected outcome.</param>
    /// <returns>The replay result.</returns>
    protected async Task<ReplayResult> ReplayAndVerifyAsync(
        TraceCorpusEntry trace,
        ReplayExpectation expectation)
    {
        var result = await ReplayOrchestrator.ReplayAsync(
            trace.Trace,
            TimeProvider);

        VerifyExpectation(result, expectation);
        return result;
    }

    /// <summary>
    /// Replay all traces matching query and collect results.
    /// </summary>
    /// <param name="query">Query for traces to replay.</param>
    /// <param name="expectationFactory">Factory to create expectations per trace.</param>
    /// <returns>Batch replay results.</returns>
    protected async Task<ReplayBatchResult> ReplayBatchAsync(
        TraceQuery query,
        Func<TraceCorpusEntry, ReplayExpectation> expectationFactory)
    {
        var results = new List<(TraceCorpusEntry Trace, ReplayResult Result, bool Passed)>();

        await foreach (var trace in CorpusManager.QueryAsync(query))
        {
            var expectation = expectationFactory(trace);
            var result = await ReplayOrchestrator.ReplayAsync(trace.Trace, TimeProvider);

            var passed = VerifyExpectationSafe(result, expectation);
            results.Add((trace, result, passed));
        }

        return new ReplayBatchResult([.. results]);
    }

    private static void VerifyExpectation(ReplayResult result, ReplayExpectation expectation)
    {
        if (expectation.ShouldSucceed)
        {
            result.Success.Should().BeTrue(
                $"Replay should succeed: {result.FailureReason}");
        }
        else
        {
            result.Success.Should().BeFalse(
                $"Replay should fail with: {expectation.ExpectedFailure}");
        }

        if (expectation.ExpectedOutputHash is not null)
        {
            result.OutputHash.Should().Be(expectation.ExpectedOutputHash,
                "Output hash should match expected");
        }
    }

    private static bool VerifyExpectationSafe(ReplayResult result, ReplayExpectation expectation)
    {
        try
        {
            VerifyExpectation(result, expectation);
            return true;
        }
        catch
        {
            return false;
        }
    }

    /// <inheritdoc/>
    public virtual ValueTask DisposeAsync() => ValueTask.CompletedTask;
}

/// <summary>
/// Expected outcome of a trace replay.
/// </summary>
/// <param name="ShouldSucceed">Whether replay should succeed.</param>
/// <param name="ExpectedFailure">Expected failure reason, if should fail.</param>
/// <param name="ExpectedOutputHash">Expected output hash for determinism check.</param>
/// <param name="ExpectedWarnings">Expected warnings.</param>
public sealed record ReplayExpectation(
    bool ShouldSucceed,
    string? ExpectedFailure = null,
    string? ExpectedOutputHash = null,
    ImmutableArray<string> ExpectedWarnings = default);

/// <summary>
/// Result of a batch replay operation.
/// </summary>
/// <param name="Results">Individual trace results.</param>
public sealed record ReplayBatchResult(
    ImmutableArray<(TraceCorpusEntry Trace, ReplayResult Result, bool Passed)> Results)
{
    /// <summary>
    /// Gets the total number of traces replayed.
    /// </summary>
    public int TotalCount => Results.Length;

    /// <summary>
    /// Gets the number of traces that passed.
    /// </summary>
    public int PassedCount => Results.Count(r => r.Passed);

    /// <summary>
    /// Gets the number of traces that failed.
    /// </summary>
    public int FailedCount => Results.Count(r => !r.Passed);

    /// <summary>
    /// Gets the pass rate as a decimal (0-1).
    /// </summary>
    public decimal PassRate => TotalCount > 0 ? (decimal)PassedCount / TotalCount : 0;
}