using Microsoft.Extensions.Logging.Abstractions;
using Microsoft.Extensions.Options;
using Omika.Diagnostics.Configuration;
using Omika.Diagnostics.Models;
using Omika.Diagnostics.Repositories;
using Omika.Diagnostics.Tests.Fakes;
using Omika.Diagnostics.Worker;

namespace Omika.Diagnostics.Tests;

/// <summary>Rétention télémétrie (telemetry_metric_hourly) : 6 mois, lots bornés, fail-open.</summary>
public class DiagnosticTelemetryRetentionTests
{
    private static TelemetryMetricHourly At(DateTimeOffset bucket) =>
        new()
        {
            BucketUtc = bucket,
            MetricName = "test.metric",
            Component = string.Empty,
            Value = 1,
            Count = 1,
            MinValue = 1,
            MaxValue = 1,
            TagsJson = "{}"
        };

    // ---------------------------------------------------------------- repo ----

    [Fact]
    public async Task DeleteOlderThan_RemovesOnlyOlderThanCutoff()
    {
        var repo = new FakeTelemetryMetricRepository();
        DateTimeOffset cutoff = DateTimeOffset.UtcNow.AddDays(-180); // 6 mois

        await repo.UpsertHourlyAsync([
            At(cutoff.AddDays(-10)),
            At(cutoff.AddDays(-1)),
            At(DateTimeOffset.UtcNow)
        ]);

        int deleted = await repo.DeleteOlderThanAsync(cutoff, batchSize: 100);

        Assert.Equal(2, deleted);
        Assert.Single(repo.All);
    }

    [Fact]
    public async Task DeleteOlderThan_RespectsBatchSize()
    {
        var repo = new FakeTelemetryMetricRepository();
        DateTimeOffset cutoff = DateTimeOffset.UtcNow.AddDays(-180);

        var old = new List<TelemetryMetricHourly>();
        for (int i = 0; i < 5; i++)
        {
            old.Add(At(cutoff.AddDays(-i - 1)));
        }

        await repo.UpsertHourlyAsync(old);

        int first = await repo.DeleteOlderThanAsync(cutoff, batchSize: 2);
        int second = await repo.DeleteOlderThanAsync(cutoff, batchSize: 2);
        int third = await repo.DeleteOlderThanAsync(cutoff, batchSize: 2);

        Assert.Equal(2, first);
        Assert.Equal(2, second);
        Assert.Equal(1, third);
    }

    [Fact]
    public async Task DeleteOlderThan_NonPositiveBatchSize_ReturnsZero()
    {
        var repo = new FakeTelemetryMetricRepository();
        await repo.UpsertHourlyAsync([At(DateTimeOffset.UtcNow.AddDays(-200))]);

        int deleted = await repo.DeleteOlderThanAsync(DateTimeOffset.UtcNow.AddDays(-180), batchSize: 0);

        Assert.Equal(0, deleted);
        Assert.Single(repo.All);
    }

    // -------------------------------------------------------------- worker ----

    private static DiagnosticTelemetryRetentionWorker CreateWorker(
        ITelemetryMetricRepository repo,
        DiagnosticStoreOptions options) =>
        new(repo, Options.Create(options), NullLogger<DiagnosticTelemetryRetentionWorker>.Instance);

    [Fact]
    public async Task TelemetryRetentionWorker_PurgesOlderAggregates()
    {
        var repo = new FakeTelemetryMetricRepository();
        DateTimeOffset cutoff = DateTimeOffset.UtcNow.AddDays(-180);

        await repo.UpsertHourlyAsync([
            At(cutoff.AddDays(-5)),
            At(cutoff.AddDays(-1)),
            At(DateTimeOffset.UtcNow)
        ]);

        var worker = CreateWorker(repo, new DiagnosticStoreOptions
        {
            TelemetryRetentionDays = 180,
            RetentionBatchSize = 100,
            RetentionIntervalHours = 1
        });

        using var cts = new CancellationTokenSource();
        await worker.StartAsync(cts.Token);

        int remaining = 3;
        for (int i = 0; i < 50; i++)
        {
            remaining = repo.All.Count;
            if (remaining == 1)
            {
                break;
            }

            await Task.Delay(100);
        }

        cts.Cancel();
        await worker.StopAsync(cts.Token);

        Assert.Equal(1, remaining); // seul l'agrégat récent subsiste
    }

    [Fact]
    public async Task TelemetryRetentionWorker_Disabled_DoesNotPurge()
    {
        var repo = new FakeTelemetryMetricRepository();
        await repo.UpsertHourlyAsync([At(DateTimeOffset.UtcNow.AddDays(-200))]);

        var worker = CreateWorker(repo, new DiagnosticStoreOptions
        {
            TelemetryRetentionDays = 0, // désactivé
            RetentionBatchSize = 100,
            RetentionIntervalHours = 1
        });

        using var cts = new CancellationTokenSource();
        await worker.StartAsync(cts.Token);
        await Task.Delay(300);
        cts.Cancel();
        await worker.StopAsync(cts.Token);

        Assert.Single(repo.All); // rien de purgé
    }

    [Fact]
    public async Task TelemetryRetentionWorker_DbDown_DoesNotCrash()
    {
        var worker = CreateWorker(new ThrowingTelemetryMetricRepository(), new DiagnosticStoreOptions
        {
            TelemetryRetentionDays = 180,
            RetentionBatchSize = 100,
            RetentionIntervalHours = 1
        });

        using var cts = new CancellationTokenSource();
        await worker.StartAsync(cts.Token); // ne doit pas lever
        await Task.Delay(300);
        cts.Cancel();
        await worker.StopAsync(cts.Token); // arrêt propre
    }
}