using Shouldly;
using Xunit;
using ZB.MOM.WW.OtOpcUa.ControlPlane.Fleet;

namespace ZB.MOM.WW.OtOpcUa.ControlPlane.Tests;

/// <summary>
///     Per-cluster mesh Phase 1 Task 4: <c>ClusterNode.AkkaPort</c> and the node's own
///     <c>Cluster:Port</c> are the same fact in two places, and nothing makes them agree. These pin
///     the shapes that drift takes.
/// </summary>
public sealed class ClusterNodeAddressReconcilerTests
{
    private static ClusterNodeAddress Row(string host, int akkaPort, string? nodeId = null) =>
        new(nodeId ?? $"{host}:{akkaPort}", host, akkaPort);

    /// <summary>A fleet whose rows match membership reports nothing.</summary>
    [Fact]
    public void Matching_rows_and_membership_produce_no_findings()
    {
        var findings = ClusterNodeAddressReconciler.Reconcile(
            [("site-a-1", 4053), ("site-a-2", 4053)],
            [Row("site-a-1", 4053), Row("site-a-2", 4053)],
            ["site-a-1:4053", "site-a-2:4053"]);

        findings.ShouldBeEmpty();
    }

    /// <summary>
    ///     The drift the plan names: a node binds 4054 while its row says 4053. Membership shows it
    ///     at an address no row claims, and the row it should have matched looks absent — both halves
    ///     are reported, because either alone reads as a different problem.
    /// </summary>
    [Fact]
    public void Node_bound_to_the_wrong_port_is_reported_from_both_sides()
    {
        var findings = ClusterNodeAddressReconciler.Reconcile(
            [("site-a-1", 4054)],
            [Row("site-a-1", 4053)],
            ["site-a-1:4053"]);

        findings.Count.ShouldBe(2);
        findings.ShouldContain(f =>
            f.Kind == AddressMismatchKind.RunningNodeHasNoRow && f.NodeId == "site-a-1:4054");
        findings.ShouldContain(f =>
            f.Kind == AddressMismatchKind.EnabledRowNotInCluster && f.NodeId == "site-a-1:4053");
    }

    /// <summary>
    ///     The Phase 2 shape: the row's NodeId still matches membership, but its <c>Host</c> /
    ///     <c>AkkaPort</c> columns — the values central will actually dial — have been edited away
    ///     from it. Gossip still works today, so nothing else would notice.
    /// </summary>
    [Fact]
    public void Row_whose_dial_target_disagrees_with_its_own_NodeId_is_reported()
    {
        var findings = ClusterNodeAddressReconciler.Reconcile(
            [("site-a-1", 4053)],
            [Row("site-a-1", 4054, nodeId: "site-a-1:4053")],
            ["site-a-1:4053"]);

        var only = findings.ShouldHaveSingleItem();
        only.Kind.ShouldBe(AddressMismatchKind.RowDialTargetDisagrees);
        only.NodeId.ShouldBe("site-a-1:4053");
        only.Detail.ShouldContain("site-a-1:4054");
    }

    /// <summary>A running driver node nobody registered — the coordinator discards its acks.</summary>
    [Fact]
    public void Running_node_with_no_row_is_reported()
    {
        var findings = ClusterNodeAddressReconciler.Reconcile(
            [("ghost-9", 4053)], [], []);

        findings.ShouldHaveSingleItem().Kind.ShouldBe(AddressMismatchKind.RunningNodeHasNoRow);
    }

    /// <summary>
    ///     A disabled row for an absent node is silence, not a finding — being absent is the entire
    ///     point of disabling it. Without this the maintenance hatch would trade a failed deploy for
    ///     a permanent warning.
    /// </summary>
    [Fact]
    public void Disabled_row_for_an_absent_node_is_not_reported()
    {
        var findings = ClusterNodeAddressReconciler.Reconcile(
            [("site-a-1", 4053)],
            [Row("site-a-1", 4053), Row("site-a-2", 4053)],
            ["site-a-1:4053"]);

        findings.ShouldBeEmpty();
    }

    /// <summary>
    ///     An admin-only member has no <c>ClusterNode</c> row by design, so the caller filters
    ///     membership to driver-role members. Passing an unfiltered list would report correct
    ///     configuration as broken — pinned here because the filter lives at the call site.
    /// </summary>
    [Fact]
    public void Admin_only_members_are_the_callers_responsibility_to_exclude()
    {
        // What the actor passes: driver members only.
        ClusterNodeAddressReconciler.Reconcile(
            [("central-1", 4053)], [Row("central-1", 4053)], ["central-1:4053"])
            .ShouldBeEmpty();

        // What an unfiltered call would produce — the false positive this guards against.
        ClusterNodeAddressReconciler.Reconcile(
            [("central-1", 4053), ("admin-only-1", 4053)],
            [Row("central-1", 4053)],
            ["central-1:4053"])
            .ShouldHaveSingleItem().Kind.ShouldBe(AddressMismatchKind.RunningNodeHasNoRow);
    }

    /// <summary>
    ///     Host matching is case-insensitive, matching the coordinator's <c>NodeIdComparer</c> — DNS
    ///     and SQL collation are both case-insensitive, so the same node surfaces with either casing.
    /// </summary>
    [Fact]
    public void Host_matching_is_case_insensitive()
    {
        ClusterNodeAddressReconciler.Reconcile(
            [("SITE-A-1", 4053)], [Row("site-a-1", 4053)], ["site-a-1:4053"])
            .ShouldBeEmpty();
    }
}