using System;
using System.Collections.Generic;
using Entitas;

namespace CoreGame.Render
{
    public class SuppressorSys : IExecuteSystem
    {
        private readonly IGroup<CombatEntity> m_SuppressorGroup;
        private readonly IGroup<CombatEntity> m_BulletGroup;

        private readonly List<CombatEntity> m_CacheSuppressorEntities = new List<CombatEntity>();
        private readonly List<CombatEntity> m_CacheBulletEntities = new List<CombatEntity>();

        public SuppressorSys(CombatContext contexts)
        {
            m_SuppressorGroup = contexts.GetGroup(CombatMatcher.Suppressor);
            m_BulletGroup = contexts.GetGroup(CombatMatcher.Bullet);
        }

        public void Execute(float deltaTime)
        {
            m_SuppressorGroup.GetEntities(m_CacheSuppressorEntities);
            if (m_CacheSuppressorEntities.Count == 0)
                return;
            
            m_BulletGroup.GetEntities(m_CacheBulletEntities);
            for (int i = 0; i < m_CacheSuppressorEntities.Count; i++)
            {
                var suppressorEnt = m_CacheSuppressorEntities[i];
                var suppressor = suppressorEnt.suppressor;
                suppressor.duration -= deltaTime;
                if (suppressor.duration <= 0)
                {
                    suppressorEnt.isDestroyEnt = true;
                    continue;
                }

                var casterEnt = Contexts.Combat.GetEntity(suppressor.casterEid);
                if (casterEnt.IsValid() == false || casterEnt.isDead)
                {
                    suppressorEnt.isDestroyEnt = true;
                    continue;
                }

                var suppressorTrans = suppressorEnt.transformProxy;
                var distanceSqr = suppressor.radius * suppressor.radius;

                for (int j = 0; j < m_CacheBulletEntities.Count; j++)
                {
                    var bulletEnt = m_CacheBulletEntities[j];
                    if (bulletEnt.IsValid() == false || bulletEnt.bullet.hasInvalidated)
                        continue;
                    var bulletTrans = bulletEnt.transformProxy;

                    var curDistanceSqr = (suppressorTrans.position - bulletTrans.position).sqrMagnitude - distanceSqr;
                    var lastDistanceSqr = (suppressorTrans.lastPosition - bulletTrans.lastPosition).sqrMagnitude - distanceSqr;
                    if (Math.Sign(curDistanceSqr) != Math.Sign(lastDistanceSqr))
                    {
                        bulletEnt.isDestroyEnt = true;
                    }
                }
                suppressorTrans.SetPosition(casterEnt.transformProxy.position);
                suppressorTrans.SetDirection(casterEnt.transformProxy.direction);
            }
        }
    }
}