using Microsoft.Extensions.Logging.Abstractions;
using Omika.Core.Observability.Deployment;
using Omika.Core.Observability.Forwarding;
using Omika.Core.Observability.Outbox;

namespace Omika.Tests.Observability.Forwarding;

/// <summary>Tests de l'orchestrateur du forwarder (ACK → checkpoint/suppression, erreurs, reprise).</summary>
public class DiagnosticsForwarderTests : IDisposable
{
    private const string File001 = "omika-mobile-diagnostic-20261002-001.jsonl";
    private const string File002 = "omika-mobile-diagnostic-20261002-002.jsonl";
    private const string File003 = "omika-mobile-diagnostic-20261002-003.jsonl";

    private readonly string _dir = ForwardingTestHarness.CreateTempDirectory();

    public void Dispose() => ForwardingTestHarness.DeleteDirectory(_dir);

    private static DiagnosticsForwardingOptions Options(int batchSize = 100) =>
        new() { Enabled = true, Endpoint = "https://diagnostics.example/api/v1/diagnostics/batches", ApiKey = "omkdiag_x", BatchSize = batchSize, MaxBatchBytes = 1024 * 1024 };

    private DiagnosticsForwarderSpool NewSpool() =>
        new(_dir, "forwarder-checkpoint.json", new DiagnosticsForwardingSpoolOptions());

    [Fact]
    public async Task ForwardOnce_Success_CommitsCheckpoint()
    {
        ForwardingTestHarness.WriteSpoolFile(_dir, File001, [ForwardingTestHarness.NewRecord()]);
        var forwarder = new DiagnosticsForwarder(
            NewSpool(),
            new FakeClient(DiagnosticsForwardOutcome.Success, accepted: 1),
            Options(),
            new FakeDeployment("BATIK.01"),
            NullLogger<DiagnosticsForwarder>.Instance);

        bool progressed = await forwarder.FlushAsync();

        Assert.True(progressed);
        Assert.NotNull(NewSpool().LoadCheckpoint());
        Assert.True(File.Exists(Path.Combine(_dir, File001))); // fichier actif non supprimé.
    }

    [Fact]
    public async Task ForwardOnce_Success_DrainsAndPrunesOlderFiles()
    {
        ForwardingTestHarness.WriteSpoolFile(_dir, File001, [ForwardingTestHarness.NewRecord()]);
        ForwardingTestHarness.WriteSpoolFile(_dir, File002, [ForwardingTestHarness.NewRecord()]);
        var forwarder = new DiagnosticsForwarder(
            NewSpool(),
            new FakeClient(DiagnosticsForwardOutcome.Success, accepted: 1),
            Options(batchSize: 1),
            new FakeDeployment("BATIK.01"),
            NullLogger<DiagnosticsForwarder>.Instance);

        Assert.True(await forwarder.FlushAsync()); // 001 forwardé
        Assert.True(File.Exists(Path.Combine(_dir, File001)));

        Assert.True(await forwarder.FlushAsync()); // 002 forwardé → 001 purgé
        Assert.False(File.Exists(Path.Combine(_dir, File001)));
        Assert.True(File.Exists(Path.Combine(_dir, File002)));
    }

    [Fact]
    public async Task ForwardOnce_Unauthorized_DoesNotCommit_KeepsSpool()
    {
        ForwardingTestHarness.WriteSpoolFile(_dir, File001, [ForwardingTestHarness.NewRecord()]);
        var forwarder = new DiagnosticsForwarder(
            NewSpool(),
            new FakeClient(DiagnosticsForwardOutcome.Unauthorized),
            Options(),
            new FakeDeployment("BATIK.01"),
            NullLogger<DiagnosticsForwarder>.Instance);

        bool progressed = await forwarder.FlushAsync();

        Assert.False(progressed);
        Assert.Null(NewSpool().LoadCheckpoint()); // aucun avancement.
        Assert.True(File.Exists(Path.Combine(_dir, File001))); // spool conservé.
    }

    [Fact]
    public async Task ForwardOnce_Rejected_AdvancesCheckpoint_DropsBatch()
    {
        ForwardingTestHarness.WriteSpoolFile(_dir, File001, [ForwardingTestHarness.NewRecord()]);
        var forwarder = new DiagnosticsForwarder(
            NewSpool(),
            new FakeClient(DiagnosticsForwardOutcome.Rejected),
            Options(),
            new FakeDeployment("BATIK.01"),
            NullLogger<DiagnosticsForwarder>.Instance);

        bool progressed = await forwarder.FlushAsync();

        Assert.False(progressed);
        Assert.NotNull(NewSpool().LoadCheckpoint()); // avancé pour ne pas rejouer indéfiniment.
    }

    [Fact]
    public async Task ForwardOnce_BacklogOverQuota_StillEnforcesBounds()
    {
        // T22 : le quota doit borner le spool même pendant une panne centrale
        // (client Transient = jamais d'ACK → le spool n'est jamais « vide »).
        int chunk = 400 * 1024; // 3 × 400 Ko = 1.2 Mo > 1 Mo de quota.
        string padding = new string('a', chunk);
        ForwardingTestHarness.WriteRawSpoolFile(_dir, File001, padding);
        ForwardingTestHarness.WriteRawSpoolFile(_dir, File002, padding);
        ForwardingTestHarness.WriteRawSpoolFile(_dir, File003, padding);

        var spool = new DiagnosticsForwarderSpool(
            _dir,
            "forwarder-checkpoint.json",
            new DiagnosticsForwardingSpoolOptions { MaxTotalSizeMb = 1 });
        var forwarder = new DiagnosticsForwarder(
            spool,
            new FakeClient(DiagnosticsForwardOutcome.Transient),
            Options(),
            new FakeDeployment("BATIK.01"),
            NullLogger<DiagnosticsForwarder>.Instance);

        bool progressed = await forwarder.FlushAsync();

        Assert.False(progressed);
        Assert.False(File.Exists(Path.Combine(_dir, File001))); // plus ancien évincé par quota (sans ACK).
        Assert.True(File.Exists(Path.Combine(_dir, File002)));
        Assert.True(File.Exists(Path.Combine(_dir, File003)));  // actif préservé.
    }

    [Fact]
    public async Task ForwardOnce_NoClientCode_DoesNotSend()
    {
        ForwardingTestHarness.WriteSpoolFile(_dir, File001, [ForwardingTestHarness.NewRecord()]);
        var client = new FakeClient(DiagnosticsForwardOutcome.Success, accepted: 1);
        var forwarder = new DiagnosticsForwarder(
            NewSpool(),
            client,
            Options(),
            new FakeDeployment(null),
            NullLogger<DiagnosticsForwarder>.Instance);

        bool progressed = await forwarder.FlushAsync();

        Assert.False(progressed);
        Assert.Equal(0, client.SendCount);
        Assert.True(File.Exists(Path.Combine(_dir, File001)));
    }

    // ------------------------- T20 §38 : Production + HTTP central refusé ----
    [Fact]
    public async Task ForwardOnce_HttpEndpointInProduction_RefusesSend_KeepsSpool()
    {
        ForwardingTestHarness.WriteSpoolFile(_dir, File001, [ForwardingTestHarness.NewRecord()]);
        var client = new FakeClient(DiagnosticsForwardOutcome.Success, accepted: 1);
        var options = new DiagnosticsForwardingOptions
        {
            Enabled = true,
            Endpoint = "http://diagnostics.example/api/v1/diagnostics/batches",
            ApiKey = "omkdiag_x",
            BatchSize = 100,
            MaxBatchBytes = 1024 * 1024
        };
        var forwarder = new DiagnosticsForwarder(
            NewSpool(),
            client,
            options,
            new FakeDeployment("BATIK.01"),
            NullLogger<DiagnosticsForwarder>.Instance,
            isProduction: true);

        bool progressed = await forwarder.FlushAsync();

        Assert.False(progressed);
        Assert.Equal(0, client.SendCount);          // aucun envoi réseau.
        Assert.Null(NewSpool().LoadCheckpoint());   // spool conservé, checkpoint inchangé.
        Assert.True(File.Exists(Path.Combine(_dir, File001)));
    }

    [Fact]
    public async Task ForwardOnce_HttpsEndpointInProduction_Sends()
    {
        ForwardingTestHarness.WriteSpoolFile(_dir, File001, [ForwardingTestHarness.NewRecord()]);
        var client = new FakeClient(DiagnosticsForwardOutcome.Success, accepted: 1);
        var forwarder = new DiagnosticsForwarder(
            NewSpool(),
            client,
            Options(), // https://
            new FakeDeployment("BATIK.01"),
            NullLogger<DiagnosticsForwarder>.Instance,
            isProduction: true);

        bool progressed = await forwarder.FlushAsync();

        Assert.True(progressed);
        Assert.Equal(1, client.SendCount);
    }

    // ------------------------- Options : règle Production/HTTPS (pure) ----
    [Theory]
    [InlineData("http://diagnostics.example/x", true, false)]
    [InlineData("https://diagnostics.example/x", true, true)]
    [InlineData("http://diagnostics.example/x", false, true)]
    [InlineData("https://diagnostics.example/x", false, true)]
    [InlineData("", true, false)]
    public void Options_IsAllowedForEnvironment(string endpoint, bool isProduction, bool expected)
    {
        var options = new DiagnosticsForwardingOptions { Endpoint = endpoint };
        Assert.Equal(expected, options.IsAllowedForEnvironment(isProduction));
    }

    private sealed class FakeClient(DiagnosticsForwardOutcome outcome, int accepted = 0) : IDiagnosticsForwarderClient
    {
        public int SendCount { get; private set; }

        public Task<DiagnosticsForwardResult> SendAsync(
            CentralDiagnosticBatchDto batch,
            string clientCode,
            string apiKey,
            CancellationToken cancellationToken = default)
        {
            SendCount++;
            return Task.FromResult(new DiagnosticsForwardResult(outcome, accepted));
        }
    }

    private sealed class FakeDeployment(string? clientCode) : IDiagnosticDeploymentContextProvider
    {
        public Task<DiagnosticDeploymentContext> GetAsync(CancellationToken cancellationToken = default) =>
            Task.FromResult(new DiagnosticDeploymentContext { ClientCode = clientCode });
    }
}