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

namespace AibisDream
{
    public class GearController : MonoBehaviour
    {
        [SerializeField]
        private GameObject gearPrefab;

        private ShaftGraph shaftGraph;

        private Shaft[] shafts;

        private Vector3 offset; // 鼠标点击位置与物体pos偏移量

        private Gear draggingGear;

        private void Awake()
        {
            shafts = GetComponentsInChildren<Shaft>();
            
        }

        private void OnEnable()
        {
            shaftGraph = new ShaftGraph(shafts);
        }

        private void OnDisable()
        {
            shaftGraph = null;
        }

        private void Update()
        {
            // 鼠标按下
            if (Input.GetMouseButtonDown(0))
            {
                OnMouseClickDown();
            }

            // 鼠标拖动
            if (Input.GetMouseButton(0) && draggingGear != null)
            {
                draggingGear.Move(GetMouseAsWorldPoint() + offset);
            }

            // 鼠标释放
            if (Input.GetMouseButtonUp(0)) // 检查鼠标左键释放
            {
                draggingGear?.StopMove();
                

                if (draggingGear.targetShaft != null)
                {
                    shaftGraph.ChangeVertex(draggingGear.targetShaft.GetInstanceID());
                }
                draggingGear = null;
            }
        }

        private void OnMouseClickDown()
        {
            // 按下时发出检查射线
            Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
            RaycastHit2D hit = Physics2D.Raycast(ray.origin, ray.direction);

            // 检测命中的物体
            if (hit.collider != null && hit.collider.CompareTag("Moveable"))
            {
                offset = hit.collider.transform.position - GetMouseAsWorldPoint();
                draggingGear = hit.collider.gameObject.GetComponent<Gear>();
                draggingGear.StartMove();
            }
        }

        /// <summary>
        /// 判断吸附位置
        /// </summary>
        /// <param name="pos">齿轮当前位置</param>
        /// <param name="gearRadius">齿轮半径</param>
        /// <returns>能够被吸附的轴</returns>
        public Shaft CheckClosestShaft(Vector3 pos, float gearRadius)
        {
            return shaftGraph.QuerySnapShaft(pos, gearRadius);
        }

        private Vector3 GetMouseAsWorldPoint()
        {
            Vector3 mousePoint = Input.mousePosition;
            mousePoint.z = Camera.main.nearClipPlane;
            return Camera.main.ScreenToWorldPoint(mousePoint);
        }

        /// <summary>
        /// 生成齿轮
        /// </summary>
        /// <param name="pos">位置</param>
        /// <param name="gearModel">齿轮数据</param>
        /// <param name="speed">速度</param>
        /// <returns>齿轮Obj</returns>
        public GameObject InitGear(Vector3 pos, GearModel gearModel, float speed)
        {
            GameObject gear = Instantiate(gearPrefab, pos, Quaternion.identity);
            gear.transform.parent = transform.GetChild(0).transform;
            gear.GetComponent<Gear>().Data = gearModel;
            return gear;
        }
    }

    public class ShaftPair
    {
        public int shaft1;

        public int shaft2;

        public float distence;
    }
}