using Shouldly;
using Xunit;
using ZB.MOM.WW.OtOpcUa.Driver.FOCAS;

namespace ZB.MOM.WW.OtOpcUa.Driver.FOCAS.Tests;

/// <summary>
///     Regression coverage for the FOCAS driver factory and fixed-tree capability
///     bootstrap — Driver.FOCAS-001 (config sections dropped) and Driver.FOCAS-002
///     (false-positive ProgramInfo capability).
/// </summary>
[Trait("Category", "Unit")]
public sealed class FocasFactoryConfigTests
{
    // ---- Driver.FOCAS-001: FixedTree / AlarmProjection / HandleRecycle config sections ----

    [Fact]
    public void CreateInstance_maps_FixedTree_section_onto_options()
    {
        const string json = """
        {
          "Backend": "unimplemented",
          "FixedTree": {
            "Enabled": true,
            "PollInterval": "00:00:00.250",
            "ProgramPollInterval": "00:00:01",
            "TimerPollInterval": "00:00:30"
          }
        }
        """;

        var drv = FocasDriverFactoryExtensions.CreateInstance("drv-1", json);

        drv.Options.FixedTree.Enabled.ShouldBeTrue();
        drv.Options.FixedTree.PollInterval.ShouldBe(TimeSpan.FromMilliseconds(250));
        drv.Options.FixedTree.ProgramPollInterval.ShouldBe(TimeSpan.FromSeconds(1));
        drv.Options.FixedTree.TimerPollInterval.ShouldBe(TimeSpan.FromSeconds(30));
    }

    [Fact]
    public void CreateInstance_maps_AlarmProjection_section_onto_options()
    {
        const string json = """
        {
          "Backend": "unimplemented",
          "AlarmProjection": { "Enabled": true, "PollInterval": "00:00:02" }
        }
        """;

        var drv = FocasDriverFactoryExtensions.CreateInstance("drv-1", json);

        drv.Options.AlarmProjection.Enabled.ShouldBeTrue();
        drv.Options.AlarmProjection.PollInterval.ShouldBe(TimeSpan.FromSeconds(2));
    }

    [Fact]
    public void CreateInstance_maps_HandleRecycle_section_onto_options()
    {
        const string json = """
        {
          "Backend": "unimplemented",
          "HandleRecycle": { "Enabled": true, "Interval": "01:00:00" }
        }
        """;

        var drv = FocasDriverFactoryExtensions.CreateInstance("drv-1", json);

        drv.Options.HandleRecycle.Enabled.ShouldBeTrue();
        drv.Options.HandleRecycle.Interval.ShouldBe(TimeSpan.FromHours(1));
    }

    [Fact]
    public void CreateInstance_round_trips_all_three_opt_in_sections_together()
    {
        const string json = """
        {
          "Backend": "unimplemented",
          "FixedTree": { "Enabled": true },
          "AlarmProjection": { "Enabled": true },
          "HandleRecycle": { "Enabled": true }
        }
        """;

        var drv = FocasDriverFactoryExtensions.CreateInstance("drv-1", json);

        drv.Options.FixedTree.Enabled.ShouldBeTrue();
        drv.Options.AlarmProjection.Enabled.ShouldBeTrue();
        drv.Options.HandleRecycle.Enabled.ShouldBeTrue();
    }

    [Fact]
    public void CreateInstance_keeps_disabled_defaults_when_sections_absent()
    {
        var drv = FocasDriverFactoryExtensions.CreateInstance("drv-1", """{ "Backend": "unimplemented" }""");

        drv.Options.FixedTree.Enabled.ShouldBeFalse();
        drv.Options.AlarmProjection.Enabled.ShouldBeFalse();
        drv.Options.HandleRecycle.Enabled.ShouldBeFalse();
    }

    [Fact]
    public void CreateInstance_keeps_per_field_defaults_when_only_Enabled_supplied()
    {
        var defaults = new FocasFixedTreeOptions();
        var drv = FocasDriverFactoryExtensions.CreateInstance(
            "drv-1", """{ "Backend": "unimplemented", "FixedTree": { "Enabled": true } }""");

        drv.Options.FixedTree.PollInterval.ShouldBe(defaults.PollInterval);
        drv.Options.FixedTree.ProgramPollInterval.ShouldBe(defaults.ProgramPollInterval);
        drv.Options.FixedTree.TimerPollInterval.ShouldBe(defaults.TimerPollInterval);
    }

    // ---- Driver.FOCAS-002: fixed-tree bootstrap must not declare a false ProgramInfo capability ----

    [Fact]
    public async Task FixedTree_bootstrap_marks_ProgramInfo_unsupported_when_probe_throws()
    {
        // A CNC series without cnc_exeprgname2 / cnc_rdopmode now surfaces as a thrown
        // exception from GetProgramInfoAsync — SafeTryProbe must classify it as unsupported.
        var factory = new FakeFocasClientFactory
        {
            Customise = () => new ProgramInfoFailingFocasClient(),
        };
        var drv = new FocasDriver(new FocasDriverOptions
        {
            Devices = [new FocasDeviceOptions("focas://10.0.0.5:8193")],
            Probe = new FocasProbeOptions { Enabled = false },
            FixedTree = new FocasFixedTreeOptions { Enabled = true },
        }, "drv-1", factory);

        await drv.InitializeAsync("{}", CancellationToken.None);
        await WaitForAsync(
            () => drv.GetDeviceState("focas://10.0.0.5:8193")?.FixedTreeCache is not null,
            TimeSpan.FromSeconds(2));

        var caps = drv.GetDeviceState("focas://10.0.0.5:8193")!.FixedTreeCache!.Capabilities;
        caps.ProgramInfo.ShouldBeFalse();
        await drv.ShutdownAsync(CancellationToken.None);
    }

    [Fact]
    public async Task FixedTree_bootstrap_marks_ProgramInfo_supported_when_probe_succeeds()
    {
        var factory = new FakeFocasClientFactory();
        var drv = new FocasDriver(new FocasDriverOptions
        {
            Devices = [new FocasDeviceOptions("focas://10.0.0.5:8193")],
            Probe = new FocasProbeOptions { Enabled = false },
            FixedTree = new FocasFixedTreeOptions { Enabled = true },
        }, "drv-1", factory);

        await drv.InitializeAsync("{}", CancellationToken.None);
        await WaitForAsync(
            () => drv.GetDeviceState("focas://10.0.0.5:8193")?.FixedTreeCache is not null,
            TimeSpan.FromSeconds(2));

        var caps = drv.GetDeviceState("focas://10.0.0.5:8193")!.FixedTreeCache!.Capabilities;
        caps.ProgramInfo.ShouldBeTrue();
        await drv.ShutdownAsync(CancellationToken.None);
    }

    // ---- helpers ----

    private static async Task WaitForAsync(Func<bool> condition, TimeSpan timeout)
    {
        var deadline = DateTime.UtcNow + timeout;
        while (!condition() && DateTime.UtcNow < deadline)
            await Task.Delay(20);
    }

    /// <summary>
    ///     Fake whose <see cref="GetProgramInfoAsync"/> throws — mirrors the fixed
    ///     <see cref="Wire.WireFocasClient.GetProgramInfoAsync"/> behaviour on a series
    ///     that answers EW_FUNC / EW_NOOPT for cnc_exeprgname2 / cnc_rdopmode.
    /// </summary>
    private sealed class ProgramInfoFailingFocasClient : FakeFocasClient
    {
        public override Task<FocasProgramInfo> GetProgramInfoAsync(CancellationToken ct) =>
            throw new InvalidOperationException(
                "cnc_exeprgname2 failed EW_6 and cnc_rdopmode failed EW_6.");
    }
}