using System.Text.Json;
using System.Text.Json.Serialization;
using Shouldly;
using Xunit;
using ZB.MOM.WW.OtOpcUa.AdminUI.Components.Pages.Clusters.Drivers;
using ZB.MOM.WW.OtOpcUa.Driver.S7;

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

public sealed class S7DriverPageFormSerializationTests
{
    private static readonly JsonSerializerOptions _opts = new()
    {
        PropertyNamingPolicy = JsonNamingPolicy.CamelCase,
        WriteIndented = false,
    };

    [Fact]
    public void RoundTrip_PreservesKnownFields()
    {
        var original = new S7DriverOptions
        {
            Host = "10.0.0.5",
            Port = 102,
            CpuType = S7CpuType.S71200,
            Rack = 0,
            Slot = 1,
            Timeout = TimeSpan.FromSeconds(10),
            Probe = new S7ProbeOptions
            {
                Enabled = false,
                Interval = TimeSpan.FromSeconds(15),
                Timeout = TimeSpan.FromSeconds(3),
            },
            ProbeTimeoutSeconds = 30,
            Tags = [],
        };

        var json = JsonSerializer.Serialize(original, _opts);
        var back = JsonSerializer.Deserialize<S7DriverOptions>(json, _opts);

        back.ShouldNotBeNull();
        back.Host.ShouldBe("10.0.0.5");
        back.Port.ShouldBe(102);
        back.CpuType.ShouldBe(S7CpuType.S71200);
        back.Rack.ShouldBe((short)0);
        back.Slot.ShouldBe((short)1);
        back.Timeout.ShouldBe(TimeSpan.FromSeconds(10));
        back.Probe.ShouldNotBeNull();
        back.Probe.Enabled.ShouldBeFalse();
        back.Probe.Interval.ShouldBe(TimeSpan.FromSeconds(15));
        back.Probe.Timeout.ShouldBe(TimeSpan.FromSeconds(3));
        back.ProbeTimeoutSeconds.ShouldBe(30);
        back.Tags.ShouldBeEmpty();
    }

    [Fact]
    public void Deserialize_DropsUnknownFields()
    {
        var jsonWithExtra = """{"unknownField":"old-value","probeTimeoutSeconds":12}""";
        var optsSkip = new JsonSerializerOptions(_opts)
        {
            UnmappedMemberHandling = JsonUnmappedMemberHandling.Skip,
        };
        var back = JsonSerializer.Deserialize<S7DriverOptions>(jsonWithExtra, optsSkip);
        back.ShouldNotBeNull();
        back.ProbeTimeoutSeconds.ShouldBe(12);
    }

    [Fact]
    public void FormModel_RoundTrip_PreservesEditableFields()
    {
        var tags = new[]
        {
            new S7TagDefinition("Speed",  "DB1.DBD0",  S7DataType.Float32, Writable: true),
            new S7TagDefinition("Status", "DB1.DBW4",  S7DataType.Int16,   Writable: false),
        };

        var opts = new S7DriverOptions
        {
            Host = "192.168.1.50",
            Port = 102,
            CpuType = S7CpuType.S7300,
            Rack = 0,
            Slot = 2,
            Timeout = TimeSpan.FromSeconds(7),
            Probe = new S7ProbeOptions
            {
                Enabled = true,
                Interval = TimeSpan.FromSeconds(8),
                Timeout = TimeSpan.FromSeconds(4),
            },
            ProbeTimeoutSeconds = 20,
            Tags = tags,
        };

        var form = ZB.MOM.WW.OtOpcUa.AdminUI.Components.Pages.Clusters.Drivers
            .S7DriverPage.FormModel.FromOptions(opts);
        var tagRows = opts.Tags
            .Select(ZB.MOM.WW.OtOpcUa.AdminUI.Components.Pages.Clusters.Drivers.S7DriverPage.S7TagRow.FromDefinition)
            .ToList();
        var roundTripped = form.ToOptions(tagRows.Select(r => r.ToDefinition()).ToList());

        roundTripped.Host.ShouldBe("192.168.1.50");
        roundTripped.Port.ShouldBe(102);
        roundTripped.CpuType.ShouldBe(S7CpuType.S7300);
        roundTripped.Rack.ShouldBe((short)0);
        roundTripped.Slot.ShouldBe((short)2);
        roundTripped.Timeout.ShouldBe(TimeSpan.FromSeconds(7));
        roundTripped.Probe.Enabled.ShouldBeTrue();
        roundTripped.Probe.Interval.ShouldBe(TimeSpan.FromSeconds(8));
        roundTripped.Probe.Timeout.ShouldBe(TimeSpan.FromSeconds(4));
        roundTripped.ProbeTimeoutSeconds.ShouldBe(20);

        // Tags must survive the FormModel round-trip unchanged (regression guard for the
        // Tags = [] data-loss bug fixed in this PR).
        roundTripped.Tags.Count.ShouldBe(2);
        roundTripped.Tags[0].Name.ShouldBe("Speed");
        roundTripped.Tags[0].Address.ShouldBe("DB1.DBD0");
        roundTripped.Tags[0].DataType.ShouldBe(S7DataType.Float32);
        roundTripped.Tags[1].Name.ShouldBe("Status");
        roundTripped.Tags[1].Writable.ShouldBeFalse();
    }

    [Fact]
    public void S7TagRow_RoundTrip_PreservesEditableFields()
    {
        var def = new S7TagDefinition("Speed", "DB1.DBD0", S7DataType.Float32, Writable: true, StringLength: 80);

        var row = S7DriverPage.S7TagRow.FromDefinition(def);
        var back = row.ToDefinition();

        back.Name.ShouldBe("Speed");
        back.Address.ShouldBe("DB1.DBD0");
        back.DataType.ShouldBe(S7DataType.Float32);
        back.Writable.ShouldBeTrue();
        back.StringLength.ShouldBe(80);
    }

    [Fact]
    public void S7TagRow_CarriesThroughUneditedFields()
    {
        // WriteIdempotent is not exposed by the editor; it must survive FromDefinition→edit→ToDefinition.
        var def = new S7TagDefinition("Setpoint", "DB10.DBD0", S7DataType.Float32, Writable: true, WriteIdempotent: true);

        var row = S7DriverPage.S7TagRow.FromDefinition(def);
        row.Name = "SetpointRenamed";
        row.Writable = false;
        var back = row.ToDefinition();

        back.Name.ShouldBe("SetpointRenamed");
        back.Writable.ShouldBeFalse();
        // Un-edited field carried through via _source.
        back.WriteIdempotent.ShouldBeTrue();
    }

    [Fact]
    public void S7TagRow_ValidateRow_RejectsDuplicateNames()
    {
        var all = new List<S7DriverPage.S7TagRow>
        {
            S7DriverPage.S7TagRow.FromDefinition(new S7TagDefinition("Speed", "DB1.DBD0", S7DataType.Float32)),
            S7DriverPage.S7TagRow.FromDefinition(new S7TagDefinition("Status", "DB1.DBW4", S7DataType.Int16)),
        };

        // Editing index 1 to a name that case-insensitively collides with index 0.
        var edited = all[1].Clone();
        edited.Name = "speed";
        S7DriverPage.S7TagRow.ValidateRow(edited, all, editIndex: 1)
            .ShouldBe("Duplicate tag name 'speed'.");

        // Required-name guard.
        var blank = new S7DriverPage.S7TagRow();
        S7DriverPage.S7TagRow.ValidateRow(blank, all, editIndex: null)
            .ShouldBe("Name is required.");

        // Unique name passes.
        var ok = all[1].Clone();
        ok.Name = "Torque";
        S7DriverPage.S7TagRow.ValidateRow(ok, all, editIndex: 1).ShouldBeNull();
    }

    [Fact]
    public void TagList_SerializeRoundTrip_PreservesTags()
    {
        var opts = new S7DriverOptions
        {
            Host = "10.1.1.1",
            Tags =
            [
                new S7TagDefinition("Speed",  "DB1.DBD0", S7DataType.Float32, Writable: true),
                new S7TagDefinition("Name",   "DB2.DBB0", S7DataType.String,  Writable: false, StringLength: 32),
            ],
        };

        var optsSkip = new JsonSerializerOptions(_opts)
        {
            UnmappedMemberHandling = JsonUnmappedMemberHandling.Skip,
        };
        var json = JsonSerializer.Serialize(opts, optsSkip);
        var back = JsonSerializer.Deserialize<S7DriverOptions>(json, optsSkip);

        back.ShouldNotBeNull();
        back.Tags.Count.ShouldBe(2);
        back.Tags[0].Name.ShouldBe("Speed");
        back.Tags[0].Address.ShouldBe("DB1.DBD0");
        back.Tags[0].DataType.ShouldBe(S7DataType.Float32);
        back.Tags[0].Writable.ShouldBeTrue();
        back.Tags[1].Name.ShouldBe("Name");
        back.Tags[1].DataType.ShouldBe(S7DataType.String);
        back.Tags[1].StringLength.ShouldBe(32);
        back.Tags[1].Writable.ShouldBeFalse();
    }
}