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));
    }

    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);
    }
}