using System;
using System.Collections.Generic;
using UnityEngine;

namespace ET
{
    public class PetAwakeSystem : AwakeSystem<Pet>
    {
        public override void Awake(Pet self)
        {
            self.timerId = TimerComponent.Instance.NewRepeatedTimer(500, self.Update);
        }
    }

    public class PetDestroySystem : DestroySystem<Pet>
    {
        public override void Destroy(Pet self)
        {
            TimerComponent.Instance.Remove(ref self.timerId);
        }
    }

    public static class PetSystem
    {
        const float XDis = 0.5f;
        const float yDis = 0.5f;

        public static void Update(this Pet self)
        {
            if (self.petUnitId == 0)
                return;
            Unit unit = self.ZoneScene().GetComponent<UnitComponent>().Get(self.petUnitId);
            if (!unit) return;
            Unit player = self.GetParent<Unit>();
            Vector3 targetPos = GetTargetPos(unit.Position, player.Position);
            using var listComponent = ListComponent<Vector3>.Create();
            listComponent.List.Add(unit.Position);
            listComponent.List.Add(targetPos);
            unit.GetComponent<MoveComponent>().MoveToAsync(listComponent.List, 3.5f).Coroutine();
        }

        private static Vector3 GetTargetPos(Vector2 position0, Vector2 position1)
        {
            Vector2 vector = position1 - position0;
            float gradient;
            if (Mathf.Abs(vector.x) < XDis)
            {
                if (Mathf.Abs(vector.y) < XDis)
                    return new Vector3(position0.x, position0.y, PosHelper.PlayerPos_Z);
                gradient = Mathf.Abs((vector.y > 0 ? (vector.y - XDis) : (vector.y + XDis)) / vector.y);
            }
            else
            {
                gradient = Mathf.Abs((vector.x > 0 ? (vector.x - XDis) : (vector.x + XDis)) / vector.x);
            }

            float dx = vector.x * gradient;
            float x = position0.x + dx;
            float dy = vector.y * gradient;
            float y = position0.y + dy;
            return new Vector3(x, y, PosHelper.PlayerPos_Z);
        }
    }
}