using System.Net;
using System.Text;
using ClawdDotNet.Core.Deploymentcenter;
using Microsoft.Extensions.Logging.Abstractions;
using Shouldly;

namespace ClawdDotNet.Manager.Tests;

/// <summary>Captures the last request and answers with a fixed response, without network access.</summary>
internal sealed class CapturingHandler(
    HttpStatusCode status = HttpStatusCode.OK,
    string responseBody = """{"status":"success","item_id":1,"is_new":true,"occurrence_count":1}""")
    : HttpMessageHandler
{
    public string? LastBody { get; private set; }

    public int Calls { get; private set; }

    protected override async Task<HttpResponseMessage> SendAsync(
        HttpRequestMessage request, CancellationToken cancellationToken)
    {
        Calls++;

        if (request.Content is not null)
            LastBody = await request.Content.ReadAsStringAsync(cancellationToken);

        return new HttpResponseMessage(status)
        {
            Content = new StringContent(responseBody, Encoding.UTF8, "application/json")
        };
    }
}

/// <summary>
/// The report on the instance's behalf (#528, concept section 4).
///
/// <para>On 2026-09-08 an instance hung and was ended by Windows:
/// no log line, no error message, no bug tracker entry. Inherent in the design —
/// reporting path and watchdog lived in the process they were supposed to report on. The
/// manager therefore reports in their place, and <b>only</b> what is relevant from its point of view.</para>
/// </summary>
public sealed class SupervisionReporterTests
{
    private readonly CapturingHandler _handler = new();

    private SupervisionReporter Melder(Func<string, IReadOnlyList<string>>? auszug = null)
    {
        var api = new DeploymentcenterApi("https://dc.example", "t", new HttpClient(_handler));
        var bugtracker = new BugtrackerClient(api, "clawddotnet", "production", "0.1.2");

        return new SupervisionReporter(bugtracker, NullLogger.Instance, auszug ?? (_ => []));
    }

    private static SupervisionEvent Ereignis(
        InstanceEventKind kind, int? exitCode = null, string dir = @"C:\Instanzen\Instance-Alpha")
        => new(kind, dir, "Alpha", 4711, exitCode, "Instanz Alpha ist unerwartet beendet worden.",
            DateTimeOffset.Parse("2026-09-08T17:27:45Z"));

    [Fact]
    public async Task Ein_Absturz_geht_raus()
    {
        (await Melder().ReportAsync(Ereignis(InstanceEventKind.Crashed, exitCode: 137)))
            .ShouldBeTrue();

        _handler.Calls.ShouldBe(1);

        var rumpf = _handler.LastBody.ShouldNotBeNull();
        rumpf.ShouldContain("unerwartet beendet");
        rumpf.ShouldContain("4711");
        rumpf.ShouldContain("137");
        rumpf.ShouldContain("instanzmanager");
        rumpf.ShouldContain("clawddotnet");   // project binding
        rumpf.ShouldContain("0.1.2");         // build_version
    }

    /// <summary>
    /// What concerns the instance stays in the instance — it reports it itself, with its
    /// own sub-token. The manager only reports what nobody ordered.
    /// </summary>
    [Theory]
    [InlineData(InstanceEventKind.Started)]
    [InlineData(InstanceEventKind.StoppedOrderly)]
    [InlineData(InstanceEventKind.Recovered)]
    public async Task Alltag_wird_nicht_gemeldet(InstanceEventKind kind)
    {
        (await Melder().ReportAsync(Ereignis(kind))).ShouldBeFalse();
        _handler.Calls.ShouldBe(0);
    }

    /// <summary>
    /// If the same instance crashes repeatedly, the server should count up instead of filling the
    /// bug tracker with twins — repeated crashes are one finding and
    /// not a dozen identical ones.
    /// </summary>
    [Fact]
    public async Task Dieselbe_Instanz_und_dieselbe_Art_ergeben_denselben_Schluessel()
    {
        var melder = Melder();

        await melder.ReportAsync(Ereignis(InstanceEventKind.Crashed));
        var erster = SchluesselAus(_handler.LastBody!);

        await melder.ReportAsync(Ereignis(InstanceEventKind.Crashed));
        SchluesselAus(_handler.LastBody!).ShouldBe(erster);

        // A different kind is a different finding.
        await melder.ReportAsync(Ereignis(InstanceEventKind.Unresponsive));
        SchluesselAus(_handler.LastBody!).ShouldNotBe(erster);

        // And a different instance all the more.
        await melder.ReportAsync(
            Ereignis(InstanceEventKind.Crashed, dir: @"C:\Instanzen\Instance-Beta"));
        SchluesselAus(_handler.LastBody!).ShouldNotBe(erster);
    }

    [Fact]
    public async Task Der_Protokollauszug_kommt_mit()
    {
        await Melder(_ => ["Startup.log: [17:26:50] [INF] Application is shutting down"])
            .ReportAsync(Ereignis(InstanceEventKind.Crashed));

        _handler.LastBody.ShouldNotBeNull().ShouldContain("Application is shutting down");
    }

    /// <summary>
    /// An empty excerpt is the most meaningful line of the whole report: a process
    /// that was killed before its write buffer was flushed leaves nothing.
    /// Exactly that was the state from #529.
    /// </summary>
    [Fact]
    public async Task Ein_leerer_Protokollauszug_wird_ausdruecklich_gesagt()
    {
        await Melder(_ => []).ReportAsync(Ereignis(InstanceEventKind.Crashed));

        _handler.LastBody.ShouldNotBeNull().ShouldContain("KEINE");
    }

    /// <summary>
    /// A reporting path that throws itself would be the worst of all worlds: the
    /// original finding would get lost, and the supervision would die of its
    /// own report.
    /// </summary>
    [Fact]
    public async Task Ein_Serverfehler_reisst_die_Aufsicht_nicht_mit()
    {
        var handler = new CapturingHandler(HttpStatusCode.InternalServerError,
            """{"status":"error","error":{"code":"boom","message":"kaputt"}}""");

        var api = new DeploymentcenterApi("https://dc.example", "t", new HttpClient(handler));
        var melder = new SupervisionReporter(
            new BugtrackerClient(api, "clawddotnet", "production", "0.1.2"),
            NullLogger.Instance, _ => []);

        (await melder.ReportAsync(Ereignis(InstanceEventKind.Crashed))).ShouldBeFalse();
    }

    private static string SchluesselAus(string body)
    {
        using var doc = System.Text.Json.JsonDocument.Parse(body);
        return doc.RootElement.GetProperty("client_ref").GetString()!;
    }
}