SVSimServer/SVSim.UnitTests/BattleNode/Sessions/BattleSessionDispatchTests.cs

using Microsoft.Extensions.Logging.Abstractions;
using NUnit.Framework;
using SVSim.BattleNode.Bridge;
using SVSim.BattleNode.Lifecycle;
using SVSim.BattleNode.Protocol;
using SVSim.BattleNode.Protocol.Bodies;
using SVSim.BattleNode.Sessions;
using SVSim.BattleNode.Sessions.Participants;

namespace SVSim.UnitTests.BattleNode.Sessions;

[TestFixture]
public class BattleSessionDispatchTests
{
    [Test]
    public void InitNetwork_acks_to_sender_transitions_to_AwaitingInitBattle()
    {
        var (s, a, b) = NewSession();
        var routes = s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.InitNetwork));

        Assert.That(routes.Count, Is.EqualTo(1));
        Assert.That(routes[0].Target, Is.SameAs(a));
        Assert.That(routes[0].Frame.Uri, Is.EqualTo(NetworkBattleUri.InitNetwork));
        Assert.That(routes[0].NoStock, Is.True);
        Assert.That(a.Phase, Is.EqualTo(BattleSessionPhase.AwaitingInitBattle));
    }

    [Test]
    public void InitBattle_pushes_Matched_to_sender_only()
    {
        var (s, a, b) = NewSession();
        s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.InitNetwork));
        var routes = s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.InitBattle));

        Assert.That(routes.Count, Is.EqualTo(1));
        Assert.That(routes[0].Target, Is.SameAs(a));
        Assert.That(routes[0].Frame.Uri, Is.EqualTo(NetworkBattleUri.Matched));
        Assert.That(a.Phase, Is.EqualTo(BattleSessionPhase.AwaitingLoaded));
    }

    [Test]
    public void Loaded_pushes_BattleStart_then_Deal_to_sender()
    {
        var (s, a, b) = NewSession();
        s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.InitNetwork));
        s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.InitBattle));
        var routes = s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.Loaded));

        Assert.That(routes.Select(r => r.Frame.Uri),
            Is.EqualTo(new[] { NetworkBattleUri.BattleStart, NetworkBattleUri.Deal }));
        Assert.That(routes.All(r => ReferenceEquals(r.Target, a)), Is.True);
        Assert.That(a.Phase, Is.EqualTo(BattleSessionPhase.AwaitingSwap));
    }

    [Test]
    public void Swap_pushes_SwapResponse_then_Ready_to_sender()
    {
        var (s, a, b) = NewSession();
        s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.InitNetwork));
        s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.InitBattle));
        s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.Loaded));
        var routes = s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.Swap));

        Assert.That(routes.Select(r => r.Frame.Uri),
            Is.EqualTo(new[] { NetworkBattleUri.Swap, NetworkBattleUri.Ready }));
        Assert.That(a.Phase, Is.EqualTo(BattleSessionPhase.AfterReady));
    }

    [Test]
    public void TurnEnd_from_real_forwards_to_other_participant()
    {
        var (s, a, b) = NewSession();
        s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.InitNetwork));
        s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.InitBattle));
        s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.Loaded));
        s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.Swap));
        var routes = s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.TurnEnd));

        Assert.That(routes.Count, Is.EqualTo(1));
        Assert.That(routes[0].Target, Is.SameAs(b));
        Assert.That(routes[0].Frame.Uri, Is.EqualTo(NetworkBattleUri.TurnEnd));
        Assert.That(a.Phase, Is.EqualTo(BattleSessionPhase.AfterReady));
    }

    [Test]
    public void Handshake_dispatch_reads_per_participant_Phase_not_session_Phase()
    {
        var a = new FakeRealParticipant(viewerId: 1, FixtureCtx());
        var b = new FakeRealParticipant(viewerId: 2, FixtureCtx());
        var s = new BattleSession("bid-1", BattleType.Pvp, a, b, NullLogger<BattleSession>.Instance);

        // A is AwaitingInitNetwork; B is AwaitingInitBattle (manually set).
        b.Phase = BattleSessionPhase.AwaitingInitBattle;

        // A's InitNetwork should ack (matches A's phase).
        var routesA = s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.InitNetwork));
        Assert.That(routesA.Count, Is.EqualTo(1));
        Assert.That(routesA[0].Frame.Uri, Is.EqualTo(NetworkBattleUri.InitNetwork));
        Assert.That(a.Phase, Is.EqualTo(BattleSessionPhase.AwaitingInitBattle));

        // B's InitBattle should produce Matched (matches B's phase, set above).
        var routesB = s.ComputeFrames(b, NewEnvelope(NetworkBattleUri.InitBattle));
        Assert.That(routesB.Count, Is.EqualTo(1));
        Assert.That(routesB[0].Frame.Uri, Is.EqualTo(NetworkBattleUri.Matched));
        Assert.That(b.Phase, Is.EqualTo(BattleSessionPhase.AwaitingLoaded));
    }

    [Test]
    public void ScriptedBot_emitted_OpponentTurnStart_forwards_to_real()
    {
        var (s, a, b) = NewSession();
        // Bot emits a TurnStart frame (carrying ViewerId == FakeOpponentViewerId per the
        // ScriptedBotParticipant impl). Session should route it to the real participant.
        var botFrame = ScriptedLifecycle.BuildOpponentTurnStart();
        var routes = s.ComputeFrames(b, botFrame);

        Assert.That(routes.Count, Is.EqualTo(1));
        Assert.That(routes[0].Target, Is.SameAs(a));
        Assert.That(routes[0].Frame.Uri, Is.EqualTo(NetworkBattleUri.TurnStart));
    }

    [Test]
    public void ScriptedBot_emitted_Judge_forwards_to_real()
    {
        var (s, a, b) = NewSession();
        var botFrame = ScriptedLifecycle.BuildOpponentJudge();
        var routes = s.ComputeFrames(b, botFrame);

        Assert.That(routes.Count, Is.EqualTo(1));
        Assert.That(routes[0].Target, Is.SameAs(a));
        Assert.That(routes[0].Frame.Uri, Is.EqualTo(NetworkBattleUri.Judge));
    }

    [Test]
    public void ScriptedBot_emitted_TurnEnd_forwards_to_real()
    {
        // TurnEnd from the bot is also one of the burst frames. The case is handled
        // by the TurnEnd-from-scripted arm (bot ViewerId matches FakeOpponentViewerId).
        var (s, a, b) = NewSession();
        s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.InitNetwork));
        s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.InitBattle));
        s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.Loaded));
        s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.Swap));
        // Drive player TurnEnd first (transitions Phase if needed) — but TurnEnd from bot
        // arrives in Phase AfterReady too. The bot's TurnEnd is routed via the dispatch
        // arm that forwards any frame from the FakeOpponentViewerId participant.

        var botFrame = ScriptedLifecycle.BuildOpponentTurnEnd();
        var routes = s.ComputeFrames(b, botFrame);

        Assert.That(routes.Count, Is.EqualTo(1));
        Assert.That(routes[0].Target, Is.SameAs(a));
        Assert.That(routes[0].Frame.Uri, Is.EqualTo(NetworkBattleUri.TurnEnd));
    }

    [Test]
    public void Retire_pushes_BattleFinish_no_contest_terminates()
    {
        var (s, a, _) = NewSession();
        var routes = s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.Retire));

        Assert.That(routes.Count, Is.EqualTo(1));
        Assert.That(routes[0].Target, Is.SameAs(a));
        Assert.That(routes[0].Frame.Uri, Is.EqualTo(NetworkBattleUri.BattleFinish));
        Assert.That(routes[0].NoStock, Is.True);
        Assert.That(s.Phase, Is.EqualTo(BattleSessionPhase.Terminal));
    }

    [Test]
    public void Kill_pushes_BattleFinish_no_contest_terminates()
    {
        var (s, a, _) = NewSession();
        var routes = s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.Kill));

        Assert.That(routes.Count, Is.EqualTo(1));
        Assert.That(routes[0].Target, Is.SameAs(a));
        Assert.That(routes[0].Frame.Uri, Is.EqualTo(NetworkBattleUri.BattleFinish));
        Assert.That(routes[0].NoStock, Is.True);
        Assert.That(s.Phase, Is.EqualTo(BattleSessionPhase.Terminal));
    }

    [Test]
    public void OutOfOrder_dispatch_returns_empty_and_does_not_advance_phase()
    {
        var (s, a, _) = NewSession();
        var routes = s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.Swap));

        Assert.That(routes, Is.Empty);
        Assert.That(a.Phase, Is.EqualTo(BattleSessionPhase.AwaitingInitNetwork));
    }

    [Test]
    public void Pvp_InitBattle_from_A_pushes_Matched_with_B_oppoInfo_to_A_only()
    {
        var (s, a, b) = NewPvpSession();
        s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.InitNetwork));
        var routes = s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.InitBattle));

        Assert.That(routes.Count, Is.EqualTo(1));
        Assert.That(routes[0].Target, Is.SameAs(a));
        Assert.That(routes[0].Frame.Uri, Is.EqualTo(NetworkBattleUri.Matched));

        var body = (MatchedBody)routes[0].Frame.Body;
        Assert.That(body.SelfInfo.UserName, Is.EqualTo("PlayerA"),
            "Matched.selfInfo must reflect the sender (A).");
        Assert.That(body.SelfInfo.OppoId, Is.EqualTo(b.ViewerId));
        Assert.That(body.OppoInfo.UserName, Is.EqualTo("PlayerB"),
            "Matched.oppoInfo must reflect the OTHER participant (B).");
        Assert.That(body.OppoInfo.OppoId, Is.EqualTo(a.ViewerId));
        Assert.That(body.SelfInfo.Seed, Is.EqualTo(body.OppoInfo.Seed),
            "Both sides must see the same seed.");
    }

    [Test]
    public void Pvp_InitBattle_from_B_pushes_Matched_with_A_oppoInfo_to_B_only()
    {
        var (s, a, b) = NewPvpSession();
        s.ComputeFrames(b, NewEnvelope(NetworkBattleUri.InitNetwork));
        var routes = s.ComputeFrames(b, NewEnvelope(NetworkBattleUri.InitBattle));

        Assert.That(routes.Count, Is.EqualTo(1));
        Assert.That(routes[0].Target, Is.SameAs(b));
        var body = (MatchedBody)routes[0].Frame.Body;
        Assert.That(body.SelfInfo.UserName, Is.EqualTo("PlayerB"));
        Assert.That(body.OppoInfo.UserName, Is.EqualTo("PlayerA"));
    }

    [Test]
    public void Pvp_Loaded_from_A_pushes_BattleStart_with_B_oppoInfo_plus_Deal_to_A()
    {
        var (s, a, b) = NewPvpSession();
        s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.InitNetwork));
        s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.InitBattle));
        var routes = s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.Loaded));

        Assert.That(routes.Count, Is.EqualTo(2));
        Assert.That(routes[0].Frame.Uri, Is.EqualTo(NetworkBattleUri.BattleStart));
        Assert.That(routes[1].Frame.Uri, Is.EqualTo(NetworkBattleUri.Deal));
        Assert.That(routes.All(r => ReferenceEquals(r.Target, a)), Is.True);

        var bs = (BattleStartBody)routes[0].Frame.Body;
        Assert.That(bs.SelfInfo.ClassId, Is.EqualTo("3"), "A is class 3 per fixture.");
        Assert.That(bs.OppoInfo.ClassId, Is.EqualTo("5"), "B is class 5 per fixture.");
    }

    [Test]
    public void Pvp_Swap_from_A_pushes_SwapResponse_plus_Ready_to_A_only()
    {
        var (s, a, b) = NewPvpSession();
        s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.InitNetwork));
        s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.InitBattle));
        s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.Loaded));
        var routes = s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.Swap));

        Assert.That(routes.Select(r => r.Frame.Uri),
            Is.EqualTo(new[] { NetworkBattleUri.Swap, NetworkBattleUri.Ready }));
        Assert.That(routes.All(r => ReferenceEquals(r.Target, a)), Is.True);
        Assert.That(a.Phase, Is.EqualTo(BattleSessionPhase.AfterReady));
        Assert.That(b.Phase, Is.EqualTo(BattleSessionPhase.AwaitingInitNetwork),
            "Swap from A doesn't advance B's phase.");
    }

    [Test]
    public void Pvp_TurnStart_from_A_in_BothAfterReady_forwards_to_B()
    {
        var (s, a, b) = NewPvpSession();
        DriveToAfterReady(s, a);
        DriveToAfterReady(s, b);

        var routes = s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.TurnStart));

        Assert.That(routes.Count, Is.EqualTo(1));
        Assert.That(routes[0].Target, Is.SameAs(b));
        Assert.That(routes[0].Frame.Uri, Is.EqualTo(NetworkBattleUri.TurnStart));
    }

    [Test]
    public void Pvp_PlayActions_from_A_in_BothAfterReady_forwards_to_B()
    {
        var (s, a, b) = NewPvpSession();
        DriveToAfterReady(s, a);
        DriveToAfterReady(s, b);

        var routes = s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.PlayActions));

        Assert.That(routes.Count, Is.EqualTo(1));
        Assert.That(routes[0].Target, Is.SameAs(b));
        Assert.That(routes[0].Frame.Uri, Is.EqualTo(NetworkBattleUri.PlayActions));
    }

    [Test]
    public void Pvp_Echo_from_A_in_BothAfterReady_forwards_to_B()
    {
        var (s, a, b) = NewPvpSession();
        DriveToAfterReady(s, a);
        DriveToAfterReady(s, b);

        var routes = s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.Echo));

        Assert.That(routes.Count, Is.EqualTo(1));
        Assert.That(routes[0].Target, Is.SameAs(b));
    }

    [Test]
    public void Pvp_TurnEndActions_from_A_in_BothAfterReady_forwards_to_B()
    {
        var (s, a, b) = NewPvpSession();
        DriveToAfterReady(s, a);
        DriveToAfterReady(s, b);

        var routes = s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.TurnEndActions));

        Assert.That(routes.Count, Is.EqualTo(1));
        Assert.That(routes[0].Target, Is.SameAs(b));
    }

    [Test]
    public void Pvp_JudgeResult_from_A_in_BothAfterReady_forwards_to_B()
    {
        var (s, a, b) = NewPvpSession();
        DriveToAfterReady(s, a);
        DriveToAfterReady(s, b);

        var routes = s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.JudgeResult));

        Assert.That(routes.Count, Is.EqualTo(1));
        Assert.That(routes[0].Target, Is.SameAs(b));
    }

    [Test]
    public void Pvp_PlayActions_when_B_still_AwaitingSwap_drops()
    {
        var (s, a, b) = NewPvpSession();
        DriveToAfterReady(s, a);
        // B is still AwaitingInitNetwork — BothAfterReady is false.

        var routes = s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.PlayActions));

        Assert.That(routes, Is.Empty,
            "PvP gameplay forwarding must wait until BOTH sides reach AfterReady.");
    }

    [Test]
    public void Pvp_TurnEnd_from_A_in_BothAfterReady_broadcasts_TurnEnd_plus_Judge_to_both()
    {
        var (s, a, b) = NewPvpSession();
        DriveToAfterReady(s, a);
        DriveToAfterReady(s, b);

        var routes = s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.TurnEnd));

        Assert.That(routes.Count, Is.EqualTo(4));
        Assert.That(routes.Select(r => (r.Target, r.Frame.Uri)), Is.EquivalentTo(new[]
        {
            ((IBattleParticipant)a, NetworkBattleUri.TurnEnd),
            ((IBattleParticipant)b, NetworkBattleUri.TurnEnd),
            ((IBattleParticipant)a, NetworkBattleUri.Judge),
            ((IBattleParticipant)b, NetworkBattleUri.Judge),
        }));
    }

    [Test]
    public void Pvp_TurnEndFinal_from_A_in_BothAfterReady_broadcasts_TurnEnd_plus_Judge_to_both()
    {
        var (s, a, b) = NewPvpSession();
        DriveToAfterReady(s, a);
        DriveToAfterReady(s, b);

        var routes = s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.TurnEndFinal));

        Assert.That(routes.Count, Is.EqualTo(4));
        Assert.That(routes.Select(r => r.Frame.Uri).Distinct(),
            Is.EquivalentTo(new[] { NetworkBattleUri.TurnEnd, NetworkBattleUri.Judge }));
    }

    [Test]
    public void Pvp_TurnEnd_when_B_still_AwaitingSwap_drops()
    {
        var (s, a, b) = NewPvpSession();
        DriveToAfterReady(s, a);
        // B not at AfterReady.

        var routes = s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.TurnEnd));

        Assert.That(routes, Is.Empty);
    }

    [Test]
    public void Pvp_Retire_from_A_pushes_BattleFinish_Lose_to_A_and_Win_to_B()
    {
        var (s, a, b) = NewPvpSession();
        DriveToAfterReady(s, a);
        DriveToAfterReady(s, b);

        var routes = s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.Retire));

        Assert.That(routes.Count, Is.EqualTo(2));
        var aRoute = routes.Single(r => ReferenceEquals(r.Target, a));
        var bRoute = routes.Single(r => ReferenceEquals(r.Target, b));
        Assert.That(aRoute.Frame.Uri, Is.EqualTo(NetworkBattleUri.BattleFinish));
        Assert.That(((BattleFinishBody)aRoute.Frame.Body).Result, Is.EqualTo(BattleResult.Lose));
        Assert.That(bRoute.Frame.Uri, Is.EqualTo(NetworkBattleUri.BattleFinish));
        Assert.That(((BattleFinishBody)bRoute.Frame.Body).Result, Is.EqualTo(BattleResult.Win));
        Assert.That(aRoute.NoStock, Is.True);
        Assert.That(bRoute.NoStock, Is.True);
        Assert.That(s.Phase, Is.EqualTo(BattleSessionPhase.Terminal));
    }

    [Test]
    public void Pvp_Kill_from_A_same_as_Retire()
    {
        var (s, a, b) = NewPvpSession();
        DriveToAfterReady(s, a);
        DriveToAfterReady(s, b);

        var routes = s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.Kill));

        Assert.That(routes.Count, Is.EqualTo(2));
        Assert.That(s.Phase, Is.EqualTo(BattleSessionPhase.Terminal));
    }

    [Test]
    public void Scripted_Retire_still_pushes_BattleFinish_Win_to_sender_only()
    {
        // Regression guard — Phase 1 behavior preserved for Scripted.
        var (s, a, _) = NewSession();
        var routes = s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.Retire));

        Assert.That(routes.Count, Is.EqualTo(1));
        Assert.That(routes[0].Target, Is.SameAs(a));
        Assert.That(((BattleFinishBody)routes[0].Frame.Body).Result, Is.EqualTo(BattleResult.Win));
    }

    private static (BattleSession, FakeRealParticipant, FakeParticipant) NewBotSession()
    {
        var a = new FakeRealParticipant(viewerId: 1001, PlayerACtx());
        var b = new FakeParticipant(viewerId: ScriptedLifecycle.FakeOpponentViewerId, NoOpBotContext());
        var s = new BattleSession("bid-bot-1", BattleType.Bot, a, b, NullLogger<BattleSession>.Instance);
        return (s, a, b);
    }

    private static MatchContext NoOpBotContext() => new(
        SelfDeckCardIds: Array.Empty<long>(),
        ClassId: "0", CharaId: "0", CardMasterName: "card_master_node_10015",
        CountryCode: "", UserName: "Bot", SleeveId: "0",
        EmblemId: "0", DegreeId: "0", FieldId: 0, IsOfficial: 0, BattleType: 0);

    [Test]
    public void Bot_InitNetwork_acks_to_sender()
    {
        var (s, a, _) = NewBotSession();
        var routes = s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.InitNetwork));

        Assert.That(routes.Count, Is.EqualTo(1));
        Assert.That(routes[0].Target, Is.SameAs(a));
        Assert.That(routes[0].Frame.Uri, Is.EqualTo(NetworkBattleUri.InitNetwork));
        Assert.That(a.Phase, Is.EqualTo(BattleSessionPhase.AwaitingInitBattle));
    }

    [Test]
    public void Bot_InitBattle_acks_to_sender_with_no_Matched_push()
    {
        var (s, a, _) = NewBotSession();
        s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.InitNetwork));
        var routes = s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.InitBattle));

        // Bot InitBattle is ack-only — NO Matched push. Matched would be ignored
        // by the client anyway (gated on status == Connect, which is already
        // past by the time the wire round-trip completes), but the spec is to
        // not send it for clarity.
        Assert.That(routes.Count, Is.EqualTo(1));
        Assert.That(routes[0].Target, Is.SameAs(a));
        Assert.That(routes[0].Frame.Uri, Is.EqualTo(NetworkBattleUri.InitBattle),
            "Expected an ack envelope for InitBattle, NOT a Matched envelope.");
        Assert.That(a.Phase, Is.EqualTo(BattleSessionPhase.AwaitingLoaded));
    }

    [Test]
    public void Bot_Loaded_produces_no_routes_but_advances_phase()
    {
        var (s, a, _) = NewBotSession();
        s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.InitNetwork));
        s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.InitBattle));
        var routes = s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.Loaded));

        // Bot Loaded is silent — no BattleStart, no Deal. Pushing BattleStart
        // would actively CORRUPT OppoBattleStartInfo on the client (the wire
        // handler at Matching.cs:417 → SetNetworkInfo overwrites it with our
        // placeholder NoOpBotParticipant.Context zeros).
        Assert.That(routes, Is.Empty, "Bot Loaded is silent.");
        Assert.That(a.Phase, Is.EqualTo(BattleSessionPhase.AwaitingSwap),
            "Phase still advances even though there are no outbound routes.");
    }

    [Test]
    public void Bot_Swap_per_sender_SwapResponse_plus_Ready()
    {
        var (s, a, _) = NewBotSession();
        s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.InitNetwork));
        s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.InitBattle));
        s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.Loaded));
        var routes = s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.Swap));

        Assert.That(routes.Select(r => r.Frame.Uri),
            Is.EqualTo(new[] { NetworkBattleUri.Swap, NetworkBattleUri.Ready }));
        Assert.That(routes.All(r => ReferenceEquals(r.Target, a)), Is.True);
        Assert.That(a.Phase, Is.EqualTo(BattleSessionPhase.AfterReady));
    }

    [Test]
    public void Bot_TurnEnd_pushes_Judge_to_sender_only()
    {
        var (s, a, b) = NewBotSession();
        s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.InitNetwork));
        s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.InitBattle));
        s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.Loaded));
        s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.Swap));

        var routes = s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.TurnEnd));

        Assert.That(routes.Count, Is.EqualTo(1), "Bot TurnEnd → exactly one Judge frame back.");
        Assert.That(routes[0].Target, Is.SameAs(a), "Judge target is the sender, not broadcast.");
        Assert.That(routes[0].Frame.Uri, Is.EqualTo(NetworkBattleUri.Judge));
    }

    [Test]
    public void Bot_TurnEndFinal_pushes_Judge_to_sender_only()
    {
        var (s, a, _) = NewBotSession();
        s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.InitNetwork));
        s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.InitBattle));
        s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.Loaded));
        s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.Swap));

        var routes = s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.TurnEndFinal));

        Assert.That(routes.Count, Is.EqualTo(1));
        Assert.That(routes[0].Frame.Uri, Is.EqualTo(NetworkBattleUri.Judge));
        Assert.That(routes[0].Target, Is.SameAs(a));
    }

    [Test]
    public void Bot_PlayActions_drops_no_recipient()
    {
        var (s, a, _) = NewBotSession();
        s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.InitNetwork));
        s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.InitBattle));
        s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.Loaded));
        s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.Swap));

        // Bot's PlayActions falls through the default arm — the Pvp forwarder is gated
        // on Type == Pvp, so Bot's gameplay frames have no routing rule and drop.
        // (The PvP semantics would have been "forward to NoOp which swallows" — same
        // observable result, but cleaner to leave them as default-drops.)
        var routes = s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.PlayActions));

        Assert.That(routes, Is.Empty);
    }

    [Test]
    public void Bot_Retire_pushes_BattleFinish_Win_to_sender()
    {
        var (s, a, _) = NewBotSession();
        s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.InitNetwork));
        s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.InitBattle));
        s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.Loaded));
        s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.Swap));

        var routes = s.ComputeFrames(a, NewEnvelope(NetworkBattleUri.Retire));

        Assert.That(routes.Count, Is.EqualTo(1));
        Assert.That(routes[0].Target, Is.SameAs(a));
        Assert.That(routes[0].Frame.Uri, Is.EqualTo(NetworkBattleUri.BattleFinish));
    }

    private static (BattleSession, FakeRealParticipant, FakeRealParticipant) NewPvpSession()
    {
        var a = new FakeRealParticipant(viewerId: 1001, PlayerACtx());
        var b = new FakeRealParticipant(viewerId: 2002, PlayerBCtx());
        var s = new BattleSession("bid-pvp-1", BattleType.Pvp, a, b, NullLogger<BattleSession>.Instance);
        return (s, a, b);
    }

    private static void DriveToAfterReady(BattleSession s, FakeRealParticipant p)
    {
        s.ComputeFrames(p, NewEnvelope(NetworkBattleUri.InitNetwork));
        s.ComputeFrames(p, NewEnvelope(NetworkBattleUri.InitBattle));
        s.ComputeFrames(p, NewEnvelope(NetworkBattleUri.Loaded));
        s.ComputeFrames(p, NewEnvelope(NetworkBattleUri.Swap));
        // p.Phase should now be AfterReady.
    }

    private static MatchContext PlayerACtx() => new(
        SelfDeckCardIds: Enumerable.Range(1, 30).Select(_ => 100_011_010L).ToList(),
        ClassId: "3", CharaId: "3", CardMasterName: "card_master_node_10015",
        CountryCode: "KOR", UserName: "PlayerA", SleeveId: "3000011",
        EmblemId: "701441011", DegreeId: "300003", FieldId: 43, IsOfficial: 0,
        BattleType: 11);

    private static MatchContext PlayerBCtx() => new(
        SelfDeckCardIds: Enumerable.Range(1, 30).Select(_ => 200_011_010L).ToList(),
        ClassId: "5", CharaId: "5", CardMasterName: "card_master_node_10015",
        CountryCode: "JPN", UserName: "PlayerB", SleeveId: "3000022",
        EmblemId: "701441022", DegreeId: "300004", FieldId: 44, IsOfficial: 0,
        BattleType: 11);

    private static (BattleSession, FakeRealParticipant, FakeParticipant) NewSession()
    {
        var a = new FakeRealParticipant(viewerId: 1, FixtureCtx());
        var b = new FakeParticipant(viewerId: ScriptedLifecycle.FakeOpponentViewerId, ScriptedBotContext());
        var s = new BattleSession("bid-1", BattleType.Scripted, a, b, NullLogger<BattleSession>.Instance);
        return (s, a, b);
    }

    private static MatchContext FixtureCtx() => new(
        SelfDeckCardIds: Enumerable.Range(1, 30).Select(_ => 100_011_010L).ToList(),
        ClassId: "1", CharaId: "1", CardMasterName: "card_master_node_10015",
        CountryCode: "KOR", UserName: "Player", SleeveId: "3000011",
        EmblemId: "701441011", DegreeId: "300003", FieldId: 43, IsOfficial: 0,
        BattleType: 11);

    private static MatchContext ScriptedBotContext() => new(
        SelfDeckCardIds: Array.Empty<long>(),
        ClassId: "0", CharaId: "0", CardMasterName: "card_master_node_10015",
        CountryCode: "JPN", UserName: "Opponent", SleeveId: "704141010",
        EmblemId: "400001100", DegreeId: "120027", FieldId: 5, IsOfficial: 0,
        BattleType: 0);

    private static MsgEnvelope NewEnvelope(NetworkBattleUri uri) =>
        new(uri, ViewerId: 1, Uuid: "u", Bid: null, Try: 0,
            Cat: EmitCategory.Battle, PubSeq: null, PlaySeq: null,
            Body: new RawBody(new Dictionary<string, object?>()));

    /// <summary>Data-only IBattleParticipant stub for dispatch tests. PushAsync/RunAsync
    /// are no-ops; FrameEmitted exists but is never invoked by the test.</summary>
    private sealed class FakeParticipant : IBattleParticipant
    {
        public long ViewerId { get; }
        public MatchContext Context { get; }
        public event Func<MsgEnvelope, CancellationToken, Task>? FrameEmitted;
        public FakeParticipant(long viewerId, MatchContext context) { ViewerId = viewerId; Context = context; }
        public Task PushAsync(MsgEnvelope env, bool noStock, CancellationToken ct) => Task.CompletedTask;
        public Task RunAsync(CancellationToken ct) => Task.CompletedTask;
        public Task TerminateAsync(BattleFinishReason reason) => Task.CompletedTask;
        public ValueTask DisposeAsync() => ValueTask.CompletedTask;
        private void Touch() => FrameEmitted?.Invoke(null!, default);
    }

    /// <summary>Like <see cref="FakeParticipant"/> but additionally implements
    /// <see cref="IHasHandshakePhase"/> so the dispatch tests can drive a participant's
    /// Phase without instantiating a full <c>RealParticipant</c> (which needs a real
    /// WebSocket).</summary>
    private sealed class FakeRealParticipant : IBattleParticipant, IHasHandshakePhase
    {
        public long ViewerId { get; }
        public MatchContext Context { get; }
        public BattleSessionPhase Phase { get; set; } = BattleSessionPhase.AwaitingInitNetwork;
        public event Func<MsgEnvelope, CancellationToken, Task>? FrameEmitted;
        public FakeRealParticipant(long viewerId, MatchContext context) { ViewerId = viewerId; Context = context; }
        public Task PushAsync(MsgEnvelope env, bool noStock, CancellationToken ct) => Task.CompletedTask;
        public Task RunAsync(CancellationToken ct) => Task.CompletedTask;
        public Task TerminateAsync(BattleFinishReason reason) => Task.CompletedTask;
        public ValueTask DisposeAsync() => ValueTask.CompletedTask;
        private void Touch() => FrameEmitted?.Invoke(null!, default);
    }
}