using FluentAssertions;
using System.Text.RegularExpressions;
using Xunit;

namespace BluejayInfraLint.Tests;

[Trait("Category", "Unit")]
public sealed class MonitoringCoverageLintTests
{
    private static readonly ManifestInventory Inventory = ManifestInventory.Load();

    private static readonly string[] Sprint57ProbeTargets =
    {
        "https://dns.iamworkin.lan/",
        "https://flowercore.iamworkin.lan/healthz",
        "https://replay.iamworkin.lan/healthz",
        "https://signalcontrol.iamworkin.lan/health",
        "https://updatecenter-internal.iamworkin.lan/api/v1/manifests/_schema",
        "https://updates.iamworkin.lan/api/v1/manifests/_schema",
        "https://worldbuilder.iamworkin.lan/healthz",
    };

    [Fact]
    public void PrometheusScrape_MustNotTargetDeadPiManagerPort()
    {
        var monitoring = ReadMonitoringMirror();

        monitoring.Should().NotContain("10.0.58.113:5100");
        monitoring.Should().Contain("10.0.58.113:5200");
    }

    [Fact]
    public void ProbeJobs_MustKeepEnvironmentSpecificBlackboxRelabels()
    {
        var monitoring = ReadMonitoringMirror();
        var probeJobs = FindProbeJobs(monitoring);

        probeJobs.Should().NotBeEmpty();
        probeJobs.Should().OnlyContain(
            job => job.Contains("replacement: blackbox-exporter.monitoring.svc:9115", StringComparison.Ordinal),
            "the bluejay-infra mirror runs Prometheus in-cluster and should use the blackbox service DNS");

        var livePodmanPrometheus = TryReadNotesMonitoringFile("prometheus.yml");
        if (livePodmanPrometheus is not null)
        {
            FindProbeJobs(livePodmanPrometheus).Should().OnlyContain(
                job => job.Contains("replacement: localhost:9115", StringComparison.Ordinal),
                "live Podman monitoring uses host networking, so blackbox probes must relabel to localhost:9115");
        }
    }

    [Fact]
    public void TraefikServiceProbes_MustCoverSprint57LiveFlowerCoreHosts()
    {
        var monitoring = ReadMonitoringMirror();

        foreach (var target in Sprint57ProbeTargets)
        {
            monitoring.Should().Contain(target);
        }
    }

    [Fact]
    public void EpsonPrinterDown_MustUseRangeWindowForStaleScrapeCoverage()
    {
        var alerts = ReadMonitoringMirror();

        alerts.Should().Contain("- alert: EpsonPrinterDown");
        alerts.Should().Contain("max_over_time(up{job=\"snmp-printer\"}[35m]) == bool 0");
        alerts.Should().NotContain("expr: up{job=\"snmp-printer\"} == 0");
    }

    [Fact]
    public void MonitoringMirror_MustCarryRunnerExclusionsAndEpsonGrafanaDelivery()
    {
        var mirror = ReadMonitoringMirror();

        GetAlertBlock(mirror, "KubeContainerRestartingFrequently")
            .Should()
            .Contain("kube_pod_container_status_restarts_total{namespace!=\"github-runner\"}[1h]");
        GetAlertBlock(mirror, "KubeContainerCrashLooping")
            .Should()
            .Contain("kube_pod_container_status_restarts_total{namespace!=\"github-runner\"}[15m]");
        GetAlertBlock(mirror, "KubeDeploymentReplicasMismatch")
            .Should()
            .Contain("kube_deployment_spec_replicas{namespace!=\"github-runner\"} != kube_deployment_status_replicas_available{namespace!=\"github-runner\"}");
        mirror.Should().Contain("uid: epson-printer-down-stale-window");
        mirror.Should().Contain("title: EpsonPrinterDown");
        mirror.Should().Contain("alert_channel: irc");
    }

    private static string ReadMonitoringMirror() =>
        File.ReadAllText(Path.Combine(Inventory.BluejayRoot, "apps", "monitoring", "noc-monitoring.yaml"));

    private static string? TryReadNotesMonitoringFile(string fileName)
    {
        var overrideRoot = Environment.GetEnvironmentVariable("FLOWERCORE_NOTES_ROOT");
        if (string.IsNullOrWhiteSpace(overrideRoot))
        {
            return null;
        }

        var path = Path.Combine(overrideRoot, "scripts", "monitoring", fileName);
        return File.ReadAllText(path);
    }

    private static IReadOnlyList<string> FindProbeJobs(string yaml) =>
        Regex.Matches(
                yaml,
                "(?ms)^\\s+- job_name: \"probe-[^\"]+\".*?(?=^\\s+- job_name:|\\z)")
            .Cast<Match>()
            .Select(match => match.Value)
            .ToList();

    private static string GetAlertBlock(string yaml, string alertName)
    {
        var match = Regex.Match(
            yaml,
            $"(?ms)^\\s+- alert: {Regex.Escape(alertName)}\\s*$.*?(?=^\\s+- alert:|\\z)");

        match.Success.Should().BeTrue($"alert {alertName} should be present in noc-monitoring.yaml");
        return match.Value;
    }
}