using Unity.Mathematics;

namespace DanieleMarotta.RiversongCodeShowcase
{
    [GameSystemGroup(typeof(EarlyAgentsSystemGroup))]
    [UpdateAfter(typeof(AgentSpawnSystemsGroup))]
    public class HunterBehaviorSystem : GameSystem, IUpdatable
    {
        private const int HunterFireRange = 8;

        [InjectService]
        private IEntityCollection _entityCollection;

        [InjectService]
        private IEntityCache _entityCache;

        [InjectService]
        private ITileSpace _tileSpace;

        [InjectService]
        private IIntentLogicExecutor _intentLogicExecutor;

        [InjectService]
        private IProjectileManager _projectileManager;

        public HunterBehaviorSystem(IServiceLocator serviceLocator) : base(serviceLocator)
        {
        }

        public void Update()
        {
            foreach (var hunter in _entityCache.GetHunterAgents())
            {
                if (hunter.LifecycleState != AgentLifecycleState.Live) continue;

                ref var jobState = ref hunter.GetJobStateRW();
                if (jobState.StateMachineStep != AgentStateMachineStep.Hunter_SeekingPrey) continue;

                if (UpdateSeekingPrey(hunter)) jobState.StateMachineStep = AgentStateMachineStep.ReturningHome;
            }
        }

        private bool UpdateSeekingPrey(Agent hunter)
        {
            const float hunterRangeSq = HunterFireRange * HunterFireRange;

            if (!_entityCollection.TryGet<Building>(hunter.HomeId, out var hunterBuilding)) return false;

            var hunterTile = _tileSpace.WorldToTile(hunter.Position);

            var critterDefinitionId = hunterBuilding.Definition.TargetCritter.RuntimeId;

            foreach (var critter in _entityCache.GetCritterAgents())
            {
                ref var critterState = ref critter.GetCritterStateRW();

                if (critterState.CritterDefinitionId != critterDefinitionId || critter.LifecycleState != AgentLifecycleState.Live || critterState.LockId != Entity.InvalidId)
                    continue;

                var critterTile = _tileSpace.WorldToTile(critter.Position);
                if (math.distancesq(hunterTile, critterTile) > hunterRangeSq) continue;

                critterState.LockId = hunter.Id;

                ref var hunterIntentQueue = ref _intentLogicExecutor.CancelRemainingIntents(hunter);
                var projectileTravelTime = _projectileManager.ComputeProjectileTravelTime(hunter, critter);
                IntentQueue.FireAtPreyAndReturnHome(ref hunterIntentQueue, hunterBuilding.Rect, hunterBuilding.Id, critterTile, critter.Id, projectileTravelTime);

                ref var critterIntentQueue = ref _intentLogicExecutor.CancelRemainingIntents(critter);
                critterIntentQueue.EnqueueIntent(AgentIntent.WaitForever());

                return true;
            }

            return false;
        }
    }
}