using NUnit.Framework;
using ProjectM.Server;
using ProjectM.Simulation;
using Unity.Entities;

namespace ProjectM.Tests
{
    /// <summary>
    /// Guards the ComponentSystemSorter "circular dependency" hazard that is INVISIBLE to the rest of the suite:
    /// every other fixture registers a single system then sorts, so a cross-system [UpdateBefore/After] cycle can
    /// never surface — it only throws at world creation in Play. This registers the REAL ordered server-sim set
    /// (every system that participates in an UpdateBefore/After relation, or its constraint is silently ignored)
    /// into one SimulationSystemGroup and sorts, reproducing the Play-time sort headlessly. Only SortSystems runs
    /// (never Update), so a bare world with no entities/singletons suffices.
    /// </summary>
    public class SystemOrderingCycleTests
    {
        [Test]
        public void RunCycleCombatChain_Sorts_Without_A_Dependency_Cycle()
        {
            using var world = new World("OrderCycleGuard");
            var group = world.GetOrCreateSystemManaged<SimulationSystemGroup>();

            void Add<T>() where T : unmanaged, ISystem
                => group.AddSystemToUpdateList(world.GetOrCreateSystem<T>());

            // RPC-receive systems + the surviving server spine. The 2026-08-07 audit purge removed
            // ReadyToggle / RouteSelect / PortalInteract / MetaSpend / BoonApply / PrepPurchase / RunDirector /
            // RoomField / RoomEnemyDirector / BoonOffer / BossAI / EnemyProjectile* along with the shell.
            Add<ClassSelectReceiveSystem>();
            Add<WaveSystem>();
            Add<EnemyAISystem>();
            Add<ReelSystem>();
            Add<ZonePulseSystem>();
            Add<LightRelevancySystem>();
            Add<RegionRelevancySystem>();

            Assert.DoesNotThrow(() => group.SortSystems(),
                "A [UpdateBefore/After] cycle in the run/cycle/combat chain throws here instead of only at Play world-creation.");
        }
    

        [Test]
        public void PredictedCombatChain_Sorts_Without_A_Dependency_Cycle()
        {
            // A cycle in the predicted combat chain's [UpdateBefore/After] edges is INVISIBLE to per-system
            // fixtures — it only throws at Play world creation. Co-register the chain and sort to reproduce that
            // headlessly (SortSystems only, never Update). DashTrailDamageSystem and KillRewardSystem were
            // removed from this roster with the 2026-08-07 boon purge.
            using var world = new World("OrderCyclePredicted");
            var group = world.GetOrCreateSystemManaged<SimulationSystemGroup>();
            void Add<T>() where T : unmanaged, ISystem
                => group.AddSystemToUpdateList(world.GetOrCreateSystem<T>());

            Add<StatRecomputeSystem>(); Add<MeleeComboSystem>(); Add<DashSystem>();
            Add<AbilityFireSystem>();   Add<ProjectileMoveSystem>(); Add<ProjectileDamageSystem>();
            Add<HealthApplyDamageSystem>();
            // 07-15 facing rework: PlayerAimSystem gained [UpdateAfter(MeleeComboSystem)] (plus the existing
            // StatRecompute/PlayerDeathState UpdateBefore edges) - co-register the full facing neighborhood so a
            // cycle in these edges throws here instead of only at Play world-creation.
            Add<PlayerAimSystem>(); Add<PlayerControlSystem>(); Add<BlinkSystem>(); Add<PlayerDeathStateSystem>();

            Assert.DoesNotThrow(() => group.SortSystems(),
                "A cycle in the Phase 1.7 predicted combat chain throws here instead of only at Play world-creation.");
        }
}
}