using System.Diagnostics;
using FluentAssertions;
using IBKRTrader.Core.Logging;
using IBKRTrader.Core.Persistence.Ef;
using IBKRTrader.Core.Workers;
using Microsoft.EntityFrameworkCore;

namespace IBKRTrader.Tests.Workers;

[Trait("cat", "unit")]
public class WorkerBaseTests
{
    /// <summary>
    /// Testbarer Worker: überschreibt den DB-Log-Seam (kein MySQL-Zugriff) und
    /// zählt seine Läufe. Zustände werden per Polling geprüft, weil WorkerBase
    /// Info.Status intern (und nach dem Log-Abschluss) setzt.
    /// </summary>
    private sealed class TestWorker : WorkerBase
    {
        private readonly TimeSpan? _interval;
        private readonly Func<CancellationToken, Task> _body;

        public int Runs;

        public override string     Name   => "TestWorker";
        public override string     Module => "TEST";
        protected override TimeSpan? Interval => _interval;

        private sealed class InMemoryFactory(DbContextOptions<CoreDbContext> o) : IDbContextFactory<CoreDbContext>
        {
            public CoreDbContext CreateDbContext() => new(o);
        }

        private static IDbContextFactory<CoreDbContext> Dbf() =>
            new InMemoryFactory(new DbContextOptionsBuilder<CoreDbContext>()
                .UseInMemoryDatabase(Guid.NewGuid().ToString()).Options);

        public TestWorker(TimeSpan? interval, Func<CancellationToken, Task> body)
            : base(new LoggingService(), Dbf())
        {
            _interval = interval;
            _body     = body;
        }

        protected override async Task ExecuteAsync(CancellationToken ct)
        {
            Interlocked.Increment(ref Runs);
            await _body(ct);
        }

        // Seam überschreiben → kein DB-Zugriff. Positive Id, damit die End-Log-Aufrufe
        // (in WorkerBase mit `logId > 0` geschützt) auch im Fehlerpfad laufen.
        protected override Task<long> BeginRunLogAsync() => Task.FromResult(1L);
        protected override Task EndRunLogAsync(long logId, bool success, string? message = null)
            => Task.CompletedTask;
    }

    private static readonly TimeSpan Timeout = TimeSpan.FromSeconds(5);

    private static async Task WaitUntilAsync(Func<bool> condition, string because)
    {
        var sw = Stopwatch.StartNew();
        while (!condition())
        {
            if (sw.Elapsed > Timeout)
                throw new TimeoutException($"Bedingung nicht innerhalb {Timeout.TotalSeconds}s erfüllt: {because}");
            await Task.Delay(15);
        }
    }

    [Fact]
    public async Task RunsOnce_WhenIntervalIsNull_AndReportsIdle()
    {
        var worker = new TestWorker(interval: null, _ => Task.CompletedTask);

        await worker.StartAsync(CancellationToken.None);
        // Hinweis: WorkerBase startet bereits im Zustand Idle – deshalb auf den
        // abgeschlossenen Lauf warten (Runs == 1 UND wieder Idle).
        await WaitUntilAsync(
            () => worker.Runs == 1 && worker.Info.Status == WorkerStatus.Idle,
            "ein Lauf ist abgeschlossen und Status zurück auf Idle");

        worker.Runs.Should().Be(1);

        await worker.StopAsync(CancellationToken.None);
    }

    [Fact]
    public async Task Trigger_ForcesImmediateRun_BeforeIntervalElapses()
    {
        // Langes Intervall → ein zweiter Lauf kann nur durch Trigger entstehen.
        var worker = new TestWorker(TimeSpan.FromMinutes(10), _ => Task.CompletedTask);

        await worker.StartAsync(CancellationToken.None);
        await WaitUntilAsync(() => worker.Runs == 1, "erster Lauf erfolgt");

        await worker.TriggerAsync();
        await WaitUntilAsync(() => worker.Runs == 2, "Trigger löst zweiten Lauf aus");

        await worker.StopAsync(CancellationToken.None);
    }

    [Fact]
    public async Task Exception_SetsStatusError_AndCapturesMessage()
    {
        var worker = new TestWorker(interval: null,
            _ => throw new InvalidOperationException("boom"));

        await worker.StartAsync(CancellationToken.None);
        await WaitUntilAsync(() => worker.Info.Status == WorkerStatus.Error, "Status wird Error");

        worker.Runs.Should().Be(1);
        worker.Info.Info.Should().Contain("boom");

        await worker.StopAsync(CancellationToken.None);
    }

    [Fact]
    public async Task Stop_SetsStatusStopped()
    {
        var worker = new TestWorker(TimeSpan.FromMinutes(10), _ => Task.CompletedTask);

        await worker.StartAsync(CancellationToken.None);
        await WaitUntilAsync(() => worker.Runs == 1, "erster Lauf erfolgt");
        await worker.StopAsync(CancellationToken.None);

        worker.Info.Status.Should().Be(WorkerStatus.Stopped);
    }
}