using RTG;
using System;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.EventSystems;
using XRLib;
using XED;

public class ObjectHandler : MonoBehaviour, ISingle
{
    Vector3 groundPoint;
    bool onClickGround;
    bool onClickTwinObject;

    public TwinObject heldObject;
    public TwinObject clickObject;

    Dictionary<(bool, bool, bool), HandState> handleStateTable = new();
    public event Action<TwinObject> onDrop;
    public event Action<TwinObject> onSelect;
    public event Action<TwinObject> onDeselect;

    List<TwinObject> selectedObjects = new();

    public override void AfterAwake()
    {
        GenerateStateTable();
    }

    void GenerateStateTable()
    {
        //heldObject==null && onClickGround && onClickTwinObject
        handleStateTable.Add((true, true, true), HandState.Select);
        handleStateTable.Add((true, true, false), HandState.Ground);
        handleStateTable.Add((true, false, true), HandState.Nothing);
        handleStateTable.Add((true, false, false), HandState.Nothing);
        handleStateTable.Add((false, true, true), HandState.Drop);
        handleStateTable.Add((false, true, false), HandState.Nothing);
        handleStateTable.Add((false, false, true), HandState.Nothing);
        handleStateTable.Add((false, false, false), HandState.Nothing);
    }

    public void Grab(TwinObject to)
    {
        heldObject = to;
    }

    public void Select(TwinObject to)
    {
        if (!to.physics.activeSelf)
            return;

        if (multiSelect)
        {
            if (selectedObjects.Remove(clickObject))
            {
                onDeselect?.Invoke(clickObject);
                return;
            }
        }
        else
        {
            foreach (var twinobj in selectedObjects)
            {
                onDeselect?.Invoke(twinobj);
            }
            selectedObjects.Clear();
        }
        clickObject = to;
        selectedObjects.Add(clickObject);
        onSelect?.Invoke(clickObject);
    }

    public void OnClickGround(RaycastHit hit, Component comp)
    {
        if (EventSystem.current.IsPointerOverGameObject())
        {
            return;
        }
        onClickGround = true;
        groundPoint = hit.point;
    }

    public void OnClickTwinObject(RaycastHit hit, Component comp)
    {
        //if (FindSingle<GizmoController>().GetGizmoHover())
        //    return;
        onClickTwinObject = true;
        clickObject = comp as TwinObject;
    }

    public void OnStayGround(RaycastHit hit, Component comp)
    {
        //if (FindSingle<GizmoController>().GetGizmoHover())
        //    return;

        var pos = hit.point;

        if (heldObject != null)
        {
            var height = heldObject.physics.areabox.bounds.size.y * 0.5f;
            pos = new Vector3(pos.x, height, pos.z);
        }
        groundPoint = pos;
    }

    public enum HandState
    {
        Select,
        Drop,
        Ground,
        Nothing,
    }

    public HandState eventState
    {
        get
        {
            var key = (heldObject == null, onClickGround, onClickTwinObject);
            return handleStateTable[key];
        }
    }

    public bool multiSelect;
    void Update()
    {
        multiSelect = Input.GetKey(KeyCode.LeftShift);
        HandlingAction();
    }

    void HandlingAction()
    {
        switch (eventState)
        {
            case HandState.Select:
                Select(clickObject);
                break;
            case HandState.Drop:
                onDrop?.Invoke(heldObject);
                heldObject = null;
                break;

            case HandState.Ground:
                if (multiSelect)
                    break;

                //if (FindSingle<GizmoController>().GetGizmoHover())
                //    break;

                foreach (var twinobj in selectedObjects)
                {
                    onDeselect?.Invoke(twinobj);
                }
                selectedObjects.Clear();
                break;

            case HandState.Nothing:
                if (heldObject == null)
                {
                    break;
                }

                heldObject.transform.position = groundPoint;
                break;
        }
        clickObject = null;
        onClickGround = false;
        onClickTwinObject = false;
    }

    void DeselectObject(TwinObject to)
    {
        onDeselect?.Invoke(to);
    }

    public void Remove(TwinObject to)
    {
        if (selectedObjects.Contains(to))
        {
            //onDeselectEvent?.Invoke(to);
            selectedObjects.Remove(to);
        }
    }
}