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

namespace Wing.Utils
{
    public enum EMouseButton
    {
        None = -1,
        Left = 0,
        Right = 1,
        Middle = 2,
    }

    public class TouchInteraction : MonoBehaviour
    {
        public delegate void InteractionEventHandler(ElementTag tag);
        public event InteractionEventHandler SelectedEvent;
        public event InteractionEventHandler HoverTargetChangedEvent;

        public delegate void InteractionEventHandlerEx(GameObject go);
        public event InteractionEventHandlerEx SelectedGoEvent;
        public event InteractionEventHandlerEx HoverGoTargetChangedEvent;

        private Camera m_camera = null;
        private int m_layerMask = 0;

        private ElementTag m_currentTag = null;
        private ElementTag m_lastTag = null;

        private GameObject m_currentGameObject = null;

        private bool mMouseDown = false;
        private Vector3 mMousePos;

        public KeyCode CurrentCode
        {
            get;
            private set;
        }
        public EMouseButton CurrentMouseCode
        {
            get;
            private set;
        }
        public bool IsShift
        {
            get;
            private set;
        }

        public void Set(Camera camera, int layerMask)
        {
            m_camera = camera;
            m_layerMask = layerMask;
        }

        void Awake()
        {
            m_camera = Camera.main;
            m_layerMask = int.MaxValue;
        }

        void OnGUI()
        {
            if (Event.current != null && Input.anyKey)
            {
                IsShift = Event.current.shift;
                if (Event.current.isKey)
                {
                    CurrentCode = Event.current.keyCode;
                }
                
                if(Event.current.isMouse)
                {
                    CurrentMouseCode = (EMouseButton)Event.current.button;
                }

                
            }
            else
            {
                IsShift = false;
            }
        }

        private void checkClick()
        {
            if (Input.GetMouseButtonDown(0))
            {
                mMouseDown = true;
                mMousePos = Input.mousePosition;
            }
            else if (Input.GetMouseButtonUp(0))
            {
                var df = Input.mousePosition - mMousePos;
                var dx = Mathf.Abs(df.x);
                var dy = Mathf.Abs(df.y);
                if (mMouseDown && (dx < 2f && dy < 2f))
                {
                    OnClick();
                }
                mMouseDown = false;
            }
        }

        void Update()
        {     
            if (EventSystem.current != null && EventSystem.current.IsPointerOverGameObject())
            {
                return;
            }

            checkClick();

            GameObject go = null;
            if (Input.touches.Length > 0)
            {
                go = DetectiveGameObject(Input.touches[0].position);
            }
            else
            {
                go = DetectiveGameObject(Input.mousePosition);
            }
            if (go != m_currentGameObject)
            {
                if(HoverGoTargetChangedEvent != null)
                {
                    HoverGoTargetChangedEvent(go);
                }

                ElementTag newTag = m_currentTag;
                if (go != null)
                {
                    newTag = go.GetComponent<ElementTag>();
                }
                else
                {
                    newTag = null;
                }

                if(newTag != m_currentTag)
                {
                    m_lastTag = m_currentTag;
                    m_currentTag = newTag;


#if UNITY_EDITOR || UNITY_STANDALONE_WIN || UNITY_STANDALONE_OSX

                    if (m_lastTag != m_currentTag)
                    {
                        if (HoverTargetChangedEvent != null)
                        {
                            HoverTargetChangedEvent(m_currentTag);
                        }
                    }
#endif
                }
            }
            m_currentGameObject = go;
        }

        public ElementTag CurrentSelectedTag
        {
            get
            {
                return m_currentTag;
            }
        }

        public ElementTag LastSelectedTag
        {
            get
            {
                return m_lastTag;
            }
        }

        public void Destroy()
        {
            GameObject.Destroy(this);
        }

        private void OnClick()
        {
            if(SelectedGoEvent != null)
            {
                SelectedGoEvent(m_currentGameObject);
            }

            if (m_currentTag != null && SelectedEvent != null)
            {
                SelectedEvent(m_currentTag);
            }
        }

        public GameObject DetectiveGameObject(Vector2 screenPoint)
        {
            Ray ray = m_camera.ScreenPointToRay(new Vector3(screenPoint.x, screenPoint.y, 0));
            RaycastHit hitInfo;

            if (Physics.Raycast(ray, out hitInfo, 1000 , m_layerMask))
            {
                GameObject go = hitInfo.collider.gameObject;

                return go;
            }

            return null;
        }

        public ElementTag DetectiveTag(Vector2 screenPoint)
        {
            Ray ray = m_camera.ScreenPointToRay(new Vector3(screenPoint.x, screenPoint.y, 0));
            RaycastHit hitInfo;

            if (Physics.Raycast(ray, out hitInfo, 1000, m_layerMask))
            {
                GameObject go = hitInfo.collider.gameObject;
                ElementTag tag = go.GetComponent<ElementTag>();

                //MaterialSetter setter = new MaterialSetter(tag.Element.ObjInstance);
                //setter.Set("Custom/Outline");

                return tag;
            }

            return null;
        }
    }
}