using Shouldly;
using Xunit;

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

public sealed class Phase7PlannerTests
{
    /// <summary>Verifies that empty inputs produce an empty plan.</summary>
    [Fact]
    public void Empty_inputs_produce_empty_plan()
    {
        var prev = new Phase7CompositionResult(Array.Empty<EquipmentNode>(), Array.Empty<DriverInstancePlan>(), Array.Empty<ScriptedAlarmPlan>());
        var next = prev;

        var plan = Phase7Planner.Compute(prev, next);

        plan.IsEmpty.ShouldBeTrue();
    }

    /// <summary>Verifies that identical compositions produce an empty plan.</summary>
    [Fact]
    public void Identical_compositions_produce_empty_plan()
    {
        var eq = new EquipmentNode("eq-1", "Eq 1", "line-1");
        var prev = new Phase7CompositionResult(new[] { eq }, Array.Empty<DriverInstancePlan>(), Array.Empty<ScriptedAlarmPlan>());
        var next = new Phase7CompositionResult(new[] { eq }, Array.Empty<DriverInstancePlan>(), Array.Empty<ScriptedAlarmPlan>());

        var plan = Phase7Planner.Compute(prev, next);

        plan.IsEmpty.ShouldBeTrue();
    }

    /// <summary>Verifies an equipment-tag-only delta (no equipment/driver/alarm/galaxy change)
    /// yields a NON-empty plan, so OpcUaPublishActor.HandleRebuild does not short-circuit at the
    /// IsEmpty gate before materialising the new equipment variables.</summary>
    [Fact]
    public void Equipment_tag_only_change_yields_non_empty_plan_with_added_tag()
    {
        var prev = new Phase7CompositionResult(
            Array.Empty<EquipmentNode>(), Array.Empty<DriverInstancePlan>(), Array.Empty<ScriptedAlarmPlan>());
        var next = new Phase7CompositionResult(
            Array.Empty<EquipmentNode>(), Array.Empty<DriverInstancePlan>(), Array.Empty<ScriptedAlarmPlan>())
        {
            EquipmentTags = new[]
            {
                new EquipmentTagPlan("tag-1", "eq-1", "drv", FolderPath: "", Name: "Speed", DataType: "Float", FullName: "40001"),
            },
        };

        var plan = Phase7Planner.Compute(prev, next);

        plan.IsEmpty.ShouldBeFalse();
        plan.AddedEquipmentTags.Single().TagId.ShouldBe("tag-1");
        plan.RemovedEquipmentTags.ShouldBeEmpty();
        plan.ChangedEquipmentTags.ShouldBeEmpty();
    }

    /// <summary>Verifies that new equipment goes to the AddedEquipment list.</summary>
    [Fact]
    public void New_equipment_goes_to_AddedEquipment()
    {
        var prev = new Phase7CompositionResult(Array.Empty<EquipmentNode>(), Array.Empty<DriverInstancePlan>(), Array.Empty<ScriptedAlarmPlan>());
        var next = new Phase7CompositionResult(
            new[] { new EquipmentNode("eq-1", "A", "line-1") },
            Array.Empty<DriverInstancePlan>(),
            Array.Empty<ScriptedAlarmPlan>());

        var plan = Phase7Planner.Compute(prev, next);

        plan.AddedEquipment.Single().EquipmentId.ShouldBe("eq-1");
        plan.RemovedEquipment.ShouldBeEmpty();
        plan.ChangedEquipment.ShouldBeEmpty();
    }

    /// <summary>Verifies that disappeared equipment goes to the RemovedEquipment list.</summary>
    [Fact]
    public void Disappeared_equipment_goes_to_RemovedEquipment()
    {
        var prev = new Phase7CompositionResult(
            new[] { new EquipmentNode("eq-1", "A", "line-1") },
            Array.Empty<DriverInstancePlan>(),
            Array.Empty<ScriptedAlarmPlan>());
        var next = new Phase7CompositionResult(Array.Empty<EquipmentNode>(), Array.Empty<DriverInstancePlan>(), Array.Empty<ScriptedAlarmPlan>());

        var plan = Phase7Planner.Compute(prev, next);

        plan.RemovedEquipment.Single().EquipmentId.ShouldBe("eq-1");
        plan.AddedEquipment.ShouldBeEmpty();
    }

    /// <summary>Verifies that equipment with same id but different display name routes to ChangedEquipment.</summary>
    [Fact]
    public void Same_id_with_different_display_name_routes_to_ChangedEquipment()
    {
        var prev = new Phase7CompositionResult(
            new[] { new EquipmentNode("eq-1", "Old", "line-1") },
            Array.Empty<DriverInstancePlan>(),
            Array.Empty<ScriptedAlarmPlan>());
        var next = new Phase7CompositionResult(
            new[] { new EquipmentNode("eq-1", "New", "line-1") },
            Array.Empty<DriverInstancePlan>(),
            Array.Empty<ScriptedAlarmPlan>());

        var plan = Phase7Planner.Compute(prev, next);

        plan.ChangedEquipment.Single().Previous.DisplayName.ShouldBe("Old");
        plan.ChangedEquipment.Single().Current.DisplayName.ShouldBe("New");
        plan.AddedEquipment.ShouldBeEmpty();
        plan.RemovedEquipment.ShouldBeEmpty();
    }

    /// <summary>Verifies that driver config changes route to ChangedDrivers.</summary>
    [Fact]
    public void Driver_config_change_routes_to_ChangedDrivers()
    {
        var prev = new Phase7CompositionResult(
            Array.Empty<EquipmentNode>(),
            new[] { new DriverInstancePlan("drv-1", "Modbus", "{\"host\":\"old\"}") },
            Array.Empty<ScriptedAlarmPlan>());
        var next = new Phase7CompositionResult(
            Array.Empty<EquipmentNode>(),
            new[] { new DriverInstancePlan("drv-1", "Modbus", "{\"host\":\"new\"}") },
            Array.Empty<ScriptedAlarmPlan>());

        var plan = Phase7Planner.Compute(prev, next);

        plan.ChangedDrivers.Single().Current.ConfigJson.ShouldContain("new");
    }

    /// <summary>Verifies that alarm message template changes route to ChangedAlarms.</summary>
    [Fact]
    public void Alarm_message_template_change_routes_to_ChangedAlarms()
    {
        var prev = new Phase7CompositionResult(
            Array.Empty<EquipmentNode>(),
            Array.Empty<DriverInstancePlan>(),
            new[] { new ScriptedAlarmPlan("a-1", "eq-1", "script-1", "old") });
        var next = new Phase7CompositionResult(
            Array.Empty<EquipmentNode>(),
            Array.Empty<DriverInstancePlan>(),
            new[] { new ScriptedAlarmPlan("a-1", "eq-1", "script-1", "new") });

        var plan = Phase7Planner.Compute(prev, next);

        plan.ChangedAlarms.Single().Current.MessageTemplate.ShouldBe("new");
    }

    /// <summary>Verifies that added and removed lists are sorted by id for deterministic ordering.</summary>
    [Fact]
    public void Added_and_removed_lists_are_sorted_by_id_for_deterministic_ordering()
    {
        var prev = new Phase7CompositionResult(
            new[] { new EquipmentNode("z", "Z", "line-1"), new EquipmentNode("a", "A", "line-1") },
            Array.Empty<DriverInstancePlan>(),
            Array.Empty<ScriptedAlarmPlan>());
        var next = new Phase7CompositionResult(Array.Empty<EquipmentNode>(), Array.Empty<DriverInstancePlan>(), Array.Empty<ScriptedAlarmPlan>());

        var plan = Phase7Planner.Compute(prev, next);

        plan.RemovedEquipment.Select(e => e.EquipmentId).ShouldBe(new[] { "a", "z" });
    }

    /// <summary>Verifies that mixed changes across all three classes are captured in one pass.</summary>
    [Fact]
    public void Mixed_changes_across_all_three_classes_are_captured_in_one_pass()
    {
        var prev = new Phase7CompositionResult(
            new[] { new EquipmentNode("eq-keep", "Keep", "line-1"), new EquipmentNode("eq-drop", "Drop", "line-1") },
            new[] { new DriverInstancePlan("drv-keep", "Modbus", "{}"), new DriverInstancePlan("drv-change", "Modbus", "{\"v\":1}") },
            new[] { new ScriptedAlarmPlan("a-keep", "eq-keep", "s1", "t1") });
        var next = new Phase7CompositionResult(
            new[] { new EquipmentNode("eq-keep", "Keep", "line-1"), new EquipmentNode("eq-new", "New", "line-1") },
            new[] { new DriverInstancePlan("drv-keep", "Modbus", "{}"), new DriverInstancePlan("drv-change", "Modbus", "{\"v\":2}") },
            new[] { new ScriptedAlarmPlan("a-keep", "eq-keep", "s1", "t1"), new ScriptedAlarmPlan("a-new", "eq-new", "s2", "t2") });

        var plan = Phase7Planner.Compute(prev, next);

        plan.AddedEquipment.Single().EquipmentId.ShouldBe("eq-new");
        plan.RemovedEquipment.Single().EquipmentId.ShouldBe("eq-drop");
        plan.ChangedEquipment.ShouldBeEmpty();
        plan.ChangedDrivers.Single().Current.DriverInstanceId.ShouldBe("drv-change");
        plan.AddedAlarms.Single().ScriptedAlarmId.ShouldBe("a-new");
    }
}