using Microsoft.Extensions.Diagnostics.HealthChecks;
using ZB.MOM.WW.ScadaBridge.AuditLog.Central.HeadExport;
using ZB.MOM.WW.ScadaBridge.Host.Health;

namespace ZB.MOM.WW.ScadaBridge.Host.Tests;

/// <summary>ScadaBridge#115: the chain-head export readiness entry.</summary>
public sealed class AuditChainHeadExportHealthCheckTests
{
    private sealed class Clock(DateTime now) : TimeProvider
    {
        public DateTime Now { get; set; } = now;
        public override DateTimeOffset GetUtcNow() => new(DateTime.SpecifyKind(Now, DateTimeKind.Utc));
    }

    private static readonly DateTime T0 = new(2026, 11, 10, 12, 0, 0, DateTimeKind.Utc);

    private static async Task<HealthStatus> Check(AuditChainHeadExportStatus s, Clock c)
        => (await new AuditChainHeadExportHealthCheck(s, c).CheckHealthAsync(new HealthCheckContext())).Status;

    /// <summary>Disabled export is healthy; failing or stale export is Degraded; recovery clears it.</summary>
    [Fact]
    public async Task Status_follows_export_outcome()
    {
        var clock = new Clock(T0);
        var status = new AuditChainHeadExportStatus();
        Assert.Equal(HealthStatus.Healthy, await Check(status, clock)); // disabled

        status.MarkStarted(60, T0);
        Assert.Equal(HealthStatus.Healthy, await Check(status, clock));

        status.RecordFailure(T0, "share offline");
        var result = await new AuditChainHeadExportHealthCheck(status, clock).CheckHealthAsync(new HealthCheckContext());
        Assert.Equal(HealthStatus.Degraded, result.Status);
        Assert.Contains("share offline", result.Description);

        status.RecordSuccess(T0);
        Assert.Equal(HealthStatus.Healthy, await Check(status, clock));

        clock.Now = T0.AddMinutes(121); // no success for > 2 intervals
        Assert.Equal(HealthStatus.Degraded, await Check(status, clock));
        status.RecordSuccess(clock.Now);
        Assert.Equal(HealthStatus.Healthy, await Check(status, clock));
    }
}