using System.Collections.Concurrent;
using Akka.Actor;
using Shouldly;
using Xunit;
using ZB.MOM.WW.OtOpcUa.Commons.OpcUa;
using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
using ZB.MOM.WW.OtOpcUa.Driver.Calculation;
using ZB.MOM.WW.OtOpcUa.Runtime.Drivers;
using ZB.MOM.WW.OtOpcUa.Runtime.Tests.Harness;
using ZB.MOM.WW.OtOpcUa.Runtime.VirtualTags;

namespace ZB.MOM.WW.OtOpcUa.Runtime.Tests.Drivers;

/// <summary>
///     WP7 register-AND-consume proof: dependency values actually FLOW end-to-end through the REAL
///     <see cref="DependencyMuxActor"/> → <see cref="DependencyConsumerMuxAdapter"/> →
///     <see cref="CalculationDriver"/> path (not merely that <see cref="IDependencyConsumer"/> exists).
///     A source value published to the mux is fed into the calc driver, which computes and publishes a
///     value; and a calc tag reading ANOTHER calc tag's output (calc-of-calc) recomputes when the first
///     tag's output re-enters the mux — the exact re-entry the host's <c>ForwardToMux</c> performs, mirrored
///     here by looping the driver's <see cref="ISubscribable.OnDataChange"/> back into the mux.
/// </summary>
public sealed class CalculationDependencyFlowTests : RuntimeActorTestBase
{
    private static readonly DateTime Ts = new(2026, 7, 16, 10, 0, 0, DateTimeKind.Utc);

    private static RawTagEntry CalcTag(string rawPath, string source)
    {
        var json = $"{{\"scriptId\":\"s-{rawPath}\",\"changeTriggered\":true," +
                   $"\"scriptSource\":{System.Text.Json.JsonSerializer.Serialize(source)}}}";
        return new RawTagEntry(rawPath, json, WriteIdempotent: false);
    }

    /// <summary>Build the merged DriverConfig JSON the ApplyDelta path re-binds from (mirrors the deploy
    /// artifact folding the driver's RawTags into DriverInstanceSpec.DriverConfig).</summary>
    private static string ConfigJson(params RawTagEntry[] tags) =>
        System.Text.Json.JsonSerializer.Serialize(new { rawTags = tags });

    [Fact]
    public async Task Source_value_flows_through_mux_and_adapter_into_the_calc_driver_and_propagates_calc_of_calc()
    {
        // A: out = src/a * 2.   B: b = A.out + 1  (calc-of-calc; B depends on A's RawPath).
        var driver = new CalculationDriver(
            new CalculationDriverOptions
            {
                RawTags =
                [
                    CalcTag("calc/engine/out", "return (double)ctx.GetTag(\"src/a\").Value * 2.0;"),
                    CalcTag("calc/engine/b", "return (double)ctx.GetTag(\"calc/engine/out\").Value + 1.0;"),
                ],
            },
            "calc-drv");
        await driver.InitializeAsync("{}", CancellationToken.None);

        // The driver declares interest in both the external source AND the first calc tag's output.
        driver.DependencyRefs.OrderBy(r => r).ShouldBe(new[] { "calc/engine/out", "src/a" });

        var published = new ConcurrentQueue<DataChangeEventArgs>();
        var mux = Sys.ActorOf(DependencyMuxActor.Props(), "dep-mux");

        // Loop the driver's outputs back into the mux exactly as DriverHostActor.ForwardToMux does — this
        // is what makes calc-of-calc chains work.
        driver.OnDataChange += (_, e) =>
        {
            published.Enqueue(e);
            var quality = e.Snapshot.StatusCode == 0u ? OpcUaQuality.Good : OpcUaQuality.Bad;
            mux.Tell(new DriverInstanceActor.AttributeValuePublished(
                "calc-drv", e.FullReference, e.Snapshot.Value, quality, Ts));
        };

        // The REAL adapter registers the driver's dependency refs on the mux + forwards changes into it.
        Sys.ActorOf(DependencyConsumerMuxAdapter.Props(driver, mux), "dep-adapter");

        // Publish the external source into the mux. AwaitAssert re-Tells (idempotent after the first
        // compute dedups) until the computed value has flowed all the way through.
        AwaitAssert(() =>
        {
            mux.Tell(new DriverInstanceActor.AttributeValuePublished(
                "src-drv", "src/a", 21.0, OpcUaQuality.Good, Ts));

            // Leg 1 — dep flow: src/a=21 → A computes 42 and publishes on calc/engine/out.
            published.ShouldContain(e => e.FullReference == "calc/engine/out" && Equals(e.Snapshot.Value, 42.0));
            // Leg 2 — calc-of-calc: A's 42 re-entered the mux → B computes 43 on calc/engine/b.
            published.ShouldContain(e => e.FullReference == "calc/engine/b" && Equals(e.Snapshot.Value, 43.0));
        }, TimeSpan.FromSeconds(5), TimeSpan.FromMilliseconds(100));
    }

    /// <summary>
    ///     REDEPLOY proof (review HIGH): a pure DriverConfig change (calc tags added / removed, a script
    ///     edited) routes to an in-place <see cref="CalculationDriver.ReinitializeAsync"/> — NOT a respawn. The
    ///     driver must rebuild its tag table + dependency-ref set so the new authored set actually takes effect,
    ///     and the mux adapter must re-register the NEW refs AFTER reinit. This asserts all four failure modes
    ///     the pre-fix code exhibited: an added tag reading a NEW dep computes; a removed tag stops publishing;
    ///     an edited script serves the NEW result; and the changed dependency-ref set re-registers on the mux.
    /// </summary>
    [Fact]
    public async Task Redeploy_rebuilds_calc_tag_state_and_reregisters_new_dependency_refs()
    {
        // Initial authored set: "keep" = src/a*10 (script gets EDITED), "remove" = src/a+5 (gets REMOVED).
        var driver = new CalculationDriver(
            new CalculationDriverOptions
            {
                RawTags =
                [
                    CalcTag("calc/keep", "return (double)ctx.GetTag(\"src/a\").Value * 10.0;"),
                    CalcTag("calc/remove", "return (double)ctx.GetTag(\"src/a\").Value + 5.0;"),
                ],
            },
            "calc-drv");
        await driver.InitializeAsync("{}", CancellationToken.None);

        // Initially the driver only cares about src/a.
        driver.DependencyRefs.OrderBy(r => r).ShouldBe(new[] { "src/a" });

        var published = new ConcurrentQueue<DataChangeEventArgs>();
        var mux = Sys.ActorOf(DependencyMuxActor.Props(), "dep-mux2");
        driver.OnDataChange += (_, e) =>
        {
            published.Enqueue(e);
            var quality = e.Snapshot.StatusCode == 0u ? OpcUaQuality.Good : OpcUaQuality.Bad;
            mux.Tell(new DriverInstanceActor.AttributeValuePublished("calc-drv", e.FullReference, e.Snapshot.Value, quality, Ts));
        };
        var adapter = Sys.ActorOf(DependencyConsumerMuxAdapter.Props(driver, mux), "dep-adapter2");

        // Leg 1 — before redeploy: src/a=2 → keep=20, remove=7.
        AwaitAssert(() =>
        {
            mux.Tell(new DriverInstanceActor.AttributeValuePublished("src-drv", "src/a", 2.0, OpcUaQuality.Good, Ts));
            published.ShouldContain(e => e.FullReference == "calc/keep" && Equals(e.Snapshot.Value, 20.0));
            published.ShouldContain(e => e.FullReference == "calc/remove" && Equals(e.Snapshot.Value, 7.0));
        }, TimeSpan.FromSeconds(5), TimeSpan.FromMilliseconds(100));

        // ---- REDEPLOY (in-place ApplyDelta) ----
        // New authored set: "keep" script EDITED to src/a*1000; "add" is a NEW tag reading a NEW dep src/b;
        // "remove" is dropped entirely.
        var newConfig = ConfigJson(
            CalcTag("calc/keep", "return (double)ctx.GetTag(\"src/a\").Value * 1000.0;"),
            CalcTag("calc/add", "return (double)ctx.GetTag(\"src/b\").Value + 100.0;"));
        await driver.ReinitializeAsync(newConfig, CancellationToken.None);

        // The rebuilt dependency-ref set reflects the NEW authored tags (src/a from keep, src/b from add).
        driver.DependencyRefs.OrderBy(r => r).ShouldBe(new[] { "src/a", "src/b" });

        // Part 2 sequencing: the host re-registers the adapter AFTER reinit (DeltaApplied → HandleDeltaApplied).
        // Mirror that here — re-register so the adapter adopts the NEW ref set (incl. the brand-new src/b).
        adapter.Tell(new DependencyConsumerMuxAdapter.ReRegister());

        // Leg 2 — after redeploy: the NEW dep src/b flows + the NEW tag computes; the EDITED script serves the
        // new result; the REMOVED tag never publishes a value derived from the post-redeploy input.
        AwaitAssert(() =>
        {
            mux.Tell(new DriverInstanceActor.AttributeValuePublished("src-drv", "src/b", 50.0, OpcUaQuality.Good, Ts));
            mux.Tell(new DriverInstanceActor.AttributeValuePublished("src-drv", "src/a", 3.0, OpcUaQuality.Good, Ts));

            // (a) new dep B flows through the RE-REGISTERED interest → new tag computes: 50 + 100 = 150.
            published.ShouldContain(e => e.FullReference == "calc/add" && Equals(e.Snapshot.Value, 150.0));
            // (c) edited script produces the NEW result: 3 * 1000 = 3000 (NOT the pre-edit 3 * 10 = 30).
            published.ShouldContain(e => e.FullReference == "calc/keep" && Equals(e.Snapshot.Value, 3000.0));
        }, TimeSpan.FromSeconds(5), TimeSpan.FromMilliseconds(100));

        // (b) the removed tag never recomputes on the post-redeploy src/a=3 (it would be 3 + 5 = 8) and the
        // edited "keep" never serves the stale *10 result (3 * 10 = 30). Give any errant compute a moment to land.
        await Task.Delay(200);
        published.ShouldNotContain(e => e.FullReference == "calc/remove" && Equals(e.Snapshot.Value, 8.0));
        published.ShouldNotContain(e => e.FullReference == "calc/keep" && Equals(e.Snapshot.Value, 30.0));
    }
}