using System.Text.Json;
using System.Text.Json.Serialization;
using Shouldly;
using Xunit;
using ZB.MOM.WW.OtOpcUa.AdminUI.Components.Shared.Drivers.Forms;
using ZB.MOM.WW.OtOpcUa.Driver.AbLegacy;
using ZB.MOM.WW.OtOpcUa.Driver.AbLegacy.PlcFamilies;

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

public sealed class AbLegacyDriverPageFormSerializationTests
{
    private static readonly JsonSerializerOptions _opts = new()
    {
        PropertyNamingPolicy = JsonNamingPolicy.CamelCase,
        WriteIndented = false,
    };

    private static readonly JsonSerializerOptions TestJsonOpts = new()
    {
        PropertyNamingPolicy = JsonNamingPolicy.CamelCase,
        UnmappedMemberHandling = JsonUnmappedMemberHandling.Skip,
    };

    [Fact]
    public void RoundTrip_PreservesKnownFields()
    {
        var original = new AbLegacyDriverOptions
        {
            Timeout = TimeSpan.FromSeconds(4),
            Probe = new AbLegacyProbeOptions
            {
                Enabled = true,
                Interval = TimeSpan.FromSeconds(8),
                Timeout = TimeSpan.FromSeconds(3),
                ProbeAddress = "N7:0",
            },
            ProbeTimeoutSeconds = 10,
            Devices =
            [
                new AbLegacyDeviceOptions("10.0.0.10", AbLegacyPlcFamily.Slc500, "PLC-A"),
                new AbLegacyDeviceOptions("10.0.0.11", AbLegacyPlcFamily.MicroLogix),
            ],
        };

        var json = JsonSerializer.Serialize(original, _opts);
        var back = JsonSerializer.Deserialize<AbLegacyDriverOptions>(json, _opts);

        back.ShouldNotBeNull();
        back.Timeout.ShouldBe(TimeSpan.FromSeconds(4));
        back.Probe.Enabled.ShouldBeTrue();
        back.Probe.Interval.ShouldBe(TimeSpan.FromSeconds(8));
        back.Probe.Timeout.ShouldBe(TimeSpan.FromSeconds(3));
        back.Probe.ProbeAddress.ShouldBe("N7:0");
        back.ProbeTimeoutSeconds.ShouldBe(10);
        back.Devices.Count.ShouldBe(2);
        back.Devices[0].HostAddress.ShouldBe("10.0.0.10");
        back.Devices[0].PlcFamily.ShouldBe(AbLegacyPlcFamily.Slc500);
        back.Devices[0].DeviceName.ShouldBe("PLC-A");
        back.Devices[1].PlcFamily.ShouldBe(AbLegacyPlcFamily.MicroLogix);
    }

    [Fact]
    public void Deserialize_DropsUnknownFields()
    {
        var jsonWithExtra = """{"unknownField":"old-value","probeTimeoutSeconds":10}""";

        var optsWithSkip = new JsonSerializerOptions(_opts)
        {
            UnmappedMemberHandling = JsonUnmappedMemberHandling.Skip,
        };

        var back = JsonSerializer.Deserialize<AbLegacyDriverOptions>(jsonWithExtra, optsWithSkip);
        back.ShouldNotBeNull();
        back.ProbeTimeoutSeconds.ShouldBe(10);
    }

    // v3 Batch-2 (WP3): the embedded-Devices CollectionEditor + AbLegacyDeviceRow retired — devices are now
    // separate Device entities authored via the raw-tree DeviceModal (AbLegacyDeviceModel, HostAddress/PlcFamily
    // into DeviceConfig). The former DeviceRow_* / ValidateDeviceRow_* tests were removed. The channel-config
    // FormModel now lives in AbLegacyDriverForm; the multi-device Devices array it preserves is covered below.

    [Fact]
    public void Device_list_survives_form_serialize_round_trip()
    {
        var devices = new List<AbLegacyDeviceOptions>
        {
            new("10.0.0.10", AbLegacyPlcFamily.Slc500, "PLC-1"),
            new("10.0.0.11", AbLegacyPlcFamily.MicroLogix, "PLC-2"),
        };
        var opts = new AbLegacyDriverForm.FormModel().ToOptions(devices);
        var json = JsonSerializer.Serialize(opts, TestJsonOpts);
        var back = JsonSerializer.Deserialize<AbLegacyDriverOptions>(json, TestJsonOpts)!;
        back.Devices.Count.ShouldBe(2);
        back.Devices[0].HostAddress.ShouldBe("10.0.0.10");
        back.Devices[0].PlcFamily.ShouldBe(AbLegacyPlcFamily.Slc500);
        back.Devices[1].PlcFamily.ShouldBe(AbLegacyPlcFamily.MicroLogix);
    }

    // ---- Task 19: Transport (native AB transport switch) ----
    // These drive the form's OWN load/save path (TryDeserialize -> FromOptions -> ToOptions -> Serialize),
    // which uses the production JsonSerializerOptions, so a numeric enum or a dropped field shows up here.

    [Theory]
    [InlineData(AbLegacyTransport.Libplctag)]
    [InlineData(AbLegacyTransport.Native)]
    [InlineData(null)]
    public void Transport_survives_FromOptions_ToOptions(AbLegacyTransport? transport)
    {
        var original = new AbLegacyDriverOptions { Transport = transport };
        var back = AbLegacyDriverForm.FormModel.FromOptions(original).ToOptions([]);
        back.Transport.ShouldBe(transport);
    }

    [Fact]
    public void Native_transport_serializes_as_a_string()
    {
        var form = new AbLegacyDriverForm.FormModel { Transport = AbLegacyTransport.Native };
        var json = AbLegacyDriverForm.Serialize(form.ToOptions([]));
        json.ShouldContain("\"transport\":\"Native\"");
    }

    [Theory]
    [InlineData("Native", AbLegacyTransport.Native)]
    [InlineData("Libplctag", AbLegacyTransport.Libplctag)]
    public void Editing_an_unrelated_field_preserves_an_explicit_transport(string savedValue, AbLegacyTransport expected)
    {
        // The regression the review found: FromOptions/ToOptions dropped Transport, so an operator who set
        // a transport was silently reverted the next time they saved ANY other edit.
        var saved = $$"""{"transport":"{{savedValue}}","timeout":"00:00:02","devices":[]}""";
        var loaded = AbLegacyDriverForm.TryDeserialize(saved);
        loaded.ShouldNotBeNull();
        loaded.Transport.ShouldBe(expected);

        var form = AbLegacyDriverForm.FormModel.FromOptions(loaded);
        form.TimeoutSeconds = 7;
        var json = AbLegacyDriverForm.Serialize(form.ToOptions(loaded.Devices));

        json.ShouldContain($"\"transport\":\"{savedValue}\"");
        json.ShouldContain("\"timeoutMs\":7000");
    }

    [Fact]
    public void A_config_without_transport_loads_as_Default_and_an_unrelated_edit_keeps_the_key_absent()
    {
        // Task 22 reverses Task 19's "re-emit an explicit Libplctag": that would pin every edited driver to
        // a concrete transport and bypass the driver-side default (Libplctag since final review I3). Absent loads as Default (null) and a save that edits something else still omits it.
        var loaded = AbLegacyDriverForm.TryDeserialize("""{"probeTimeoutSeconds":5}""");
        loaded.ShouldNotBeNull();
        var form = AbLegacyDriverForm.FormModel.FromOptions(loaded);
        form.Transport.ShouldBeNull();

        form.TimeoutSeconds = 7;
        var json = AbLegacyDriverForm.Serialize(form.ToOptions(loaded.Devices));
        json.ShouldNotContain("transport", Case.Insensitive);
        json.ShouldContain("\"timeoutMs\":7000");
    }

    [Fact]
    public void Choosing_Default_over_an_explicit_transport_drops_the_key()
    {
        var loaded = AbLegacyDriverForm.TryDeserialize("""{"transport":"Libplctag"}""");
        loaded.ShouldNotBeNull();
        var form = AbLegacyDriverForm.FormModel.FromOptions(loaded);
        form.Transport.ShouldBe(AbLegacyTransport.Libplctag);

        form.Transport = null; // the "Default (...)" dropdown option
        AbLegacyDriverForm.Serialize(form.ToOptions(loaded.Devices)).ShouldNotContain("transport", Case.Insensitive);
    }

    /// <summary>
    ///     Final review I3: the dropdown labels must say what an absent key does (libplctag) and that Native is
    ///     opt-in. Source scan (no bUnit in this repo); the labels are static option text.
    /// </summary>
    [Fact]
    public void The_transport_dropdown_labels_name_libplctag_as_the_default_and_native_as_opt_in()
    {
        var dir = new DirectoryInfo(AppContext.BaseDirectory);
        while (dir is not null && !File.Exists(Path.Combine(dir.FullName, "ZB.MOM.WW.OtOpcUa.slnx")))
            dir = dir.Parent;
        dir.ShouldNotBeNull("could not locate the repository root");
        var razor = File.ReadAllText(Path.Combine(dir!.FullName, "src", "Server", "ZB.MOM.WW.OtOpcUa.AdminUI",
            "Components", "Shared", "Drivers", "Forms", "AbLegacyDriverForm.razor"));

        razor.ShouldContain("<option value=\"\">Default (libplctag)</option>");
        razor.ShouldContain("<option value=\"@AbLegacyTransport.Native\">Native (managed, opt-in)</option>");
        razor.ShouldContain("<option value=\"@AbLegacyTransport.Libplctag\">libplctag</option>");
        razor.ShouldNotContain("Default (Native");
    }

    // ---- #576: preserve-unknown ----

    private const string FullConfig = """
        {"transport":"Native","timeout":"00:00:05","probeTimeoutSeconds":12,
         "probe":{"enabled":true,"interval":"00:00:10","timeout":"00:00:03","probeAddress":"S:1","futureProbeKnob":7},
         "devices":[{"hostAddress":"ab://10.0.0.1/1,0","plcFamily":"Slc500","futureDeviceKey":"keep"}],
         "rawTags":[{"rawPath":"a/b"}],
         "futureOption":{"nested":[1,2,3]}}
        """;

    [Fact]
    public void Editing_one_field_preserves_every_other_option_and_unknown_keys()
    {
        var loaded = AbLegacyDriverForm.TryDeserialize(FullConfig)!;
        var form = AbLegacyDriverForm.FormModel.FromOptions(loaded);
        form.TimeoutSeconds = 9;

        var root = System.Text.Json.Nodes.JsonNode.Parse(
            AbLegacyDriverForm.Serialize(form.ToOptions(loaded.Devices), FullConfig))!.AsObject();

        root["timeoutMs"]!.GetValue<int>().ShouldBe(9000);
        root.ContainsKey("timeout").ShouldBeFalse();
        root["transport"]!.GetValue<string>().ShouldBe("Native");
        root["probeTimeoutSeconds"]!.GetValue<int>().ShouldBe(12);
        root["probe"]!["enabled"]!.GetValue<bool>().ShouldBeTrue();
        root["probe"]!["intervalMs"]!.GetValue<int>().ShouldBe(10000);
        root["probe"]!["timeoutMs"]!.GetValue<int>().ShouldBe(3000);
        root["probe"]!["probeAddress"]!.GetValue<string>().ShouldBe("S:1");
        root["probe"]!["futureProbeKnob"]!.GetValue<int>().ShouldBe(7);
        root["devices"]![0]!["futureDeviceKey"]!.GetValue<string>().ShouldBe("keep");
        root["rawTags"]![0]!["rawPath"]!.GetValue<string>().ShouldBe("a/b");
        root["futureOption"]!["nested"]!.AsArray().Count.ShouldBe(3);
    }

    [Fact]
    public void Choosing_Default_transport_removes_the_key_but_keeps_unknown_ones()
    {
        var loaded = AbLegacyDriverForm.TryDeserialize(FullConfig)!;
        var form = AbLegacyDriverForm.FormModel.FromOptions(loaded);
        form.Transport = null;

        var root = System.Text.Json.Nodes.JsonNode.Parse(
            AbLegacyDriverForm.Serialize(form.ToOptions(loaded.Devices), FullConfig))!.AsObject();

        root.ContainsKey("transport").ShouldBeFalse();
        root["futureOption"].ShouldNotBeNull();
    }

    // ---- #576: the saved JSON must be what the driver FACTORY binds (integer-ms keys) ----

    [Fact]
    public void An_edited_timeout_reaches_the_factory_bound_options()
    {
        var original = """{"timeoutMs":5000,"probe":{"enabled":true,"intervalMs":7000,"timeoutMs":1500,"probeAddress":"S:1"},"devices":[{"hostAddress":"ab://10.0.0.1/1,0","plcFamily":"Slc500"}]}""";
        var loaded = AbLegacyDriverForm.TryDeserialize(original)!;
        var form = AbLegacyDriverForm.FormModel.FromJson(original, loaded);
        form.TimeoutSeconds.ShouldBe(5);
        form.TimeoutSeconds = 11;

        var saved = AbLegacyDriverForm.Serialize(form.ToOptions(loaded.Devices), original);
        var bound = ZB.MOM.WW.OtOpcUa.Driver.AbLegacy.AbLegacyDriverFactoryExtensions.ParseOptions("t", saved);

        bound.Timeout.ShouldBe(TimeSpan.FromSeconds(11));
        bound.Probe.Interval.ShouldBe(TimeSpan.FromSeconds(7));
        bound.Probe.Timeout.ShouldBe(TimeSpan.FromMilliseconds(1500));
        bound.Probe.ProbeAddress.ShouldBe("S:1");
    }

    [Fact]
    public void A_legacy_TimeSpan_string_key_is_loaded_then_migrated_to_ms_and_removed()
    {
        var original = """{"timeout":"00:00:05","probe":{"interval":"00:00:10","timeout":"00:00:03"}}""";
        var loaded = AbLegacyDriverForm.TryDeserialize(original)!;
        var form = AbLegacyDriverForm.FormModel.FromJson(original, loaded);
        form.TimeoutSeconds.ShouldBe(5);
        form.TimeoutSeconds = 6;

        var saved = AbLegacyDriverForm.Serialize(form.ToOptions(loaded.Devices), original);
        var root = System.Text.Json.Nodes.JsonNode.Parse(saved)!.AsObject();
        root.ContainsKey("timeout").ShouldBeFalse();
        root["probe"]!.AsObject().ContainsKey("interval").ShouldBeFalse();
        root["probe"]!.AsObject().ContainsKey("timeout").ShouldBeFalse();

        var bound = ZB.MOM.WW.OtOpcUa.Driver.AbLegacy.AbLegacyDriverFactoryExtensions.ParseOptions("t", saved);
        bound.Timeout.ShouldBe(TimeSpan.FromSeconds(6));
        bound.Probe.Interval.ShouldBe(TimeSpan.FromSeconds(10));
        bound.Probe.Timeout.ShouldBe(TimeSpan.FromSeconds(3));
    }
}