using System.Collections;
using System.Collections.Generic;
using System.Linq;
using Unity.VectorGraphics;
using UnityEngine;
using UntitledLogicGame.Workspace;

namespace UntitledLogicGame
{
    public class PointerManager : MonoBehaviour
    {
        #region Static Properties

        public static PointerManager Instance => GameManager.Instance.PointerManager;

        #endregion

        #region Unity Properties

        [Header("Click")]
        public float DoubleClickThreshold;
        public float DoubleClickDelay;

        [Header("Cursor")]
        public Texture2D DefaultCursor;
        public Texture2D PointerCursor;
        public Texture2D MoveCursor;

        #endregion

        #region Public Properties

        public static Vector3 MousePos { get; set; }
        public bool Interacting => _currentCable != null || _currentGate != null;
        public bool MovingObject => _currentGate != null;
        public bool Clicking => Input.GetButton("Fire1");
        public bool DeleteOnRelease { get; set; }

        #endregion

        #region Private Properties

        private Cable _currentCable;
        private Gate _currentGate;
        private Vector3? _currentGateInitialPos;
        private Vector3 _currentGateDelta;
        private Texture2D _currentCursor;
        private float _clicked = 0f;
        private float _clicktime = 0f;

        #endregion

        #region Unity Methods

        private void FixedUpdate()
        {
            UpdateMousePos();

            if (Clicking)
            {
                UpdateDrag();
            }
            else
            {
                UpdateDrop();
            }

            UpdateCursor();
        }

        #endregion

        #region Public Methods

        public void DragGate(Gate gate, bool created)
        {
            _currentGate = gate;
            _currentGateDelta = MousePos - _currentGate.transform.position;
            _currentGateInitialPos = created ? (Vector3?)null : _currentGate.transform.position;
            foreach (var renderer in _currentGate.GetComponentsInChildren<SpriteRenderer>())
            {
                renderer.sortingLayerName = "moving";
            }
        }

        public void RequestDelete()
        {
            if (_currentGate != null)
            {
                Destroy(_currentGate.gameObject);
                _currentGate = null;
            }
        }

        public bool DoubleClick()
        {
            
            if (Clicking)
            {
                _clicked += Time.deltaTime;
            }
            else
            {
                if(_clicked >= DoubleClickThreshold)
                {
                    if(Time.time - _clicktime < DoubleClickDelay)
                    {
                        _clicked = 0f;
                        _clicktime = 0f;
                        return true;
                    }
                    else
                    {
                        _clicktime = Time.time;
                    }
                }
                _clicked = 0f;
            }
            return false;
        }

        #endregion

        #region Private Methods

        private static void UpdateMousePos()
        {
            var mousePos = Camera.main.ScreenToWorldPoint(Input.mousePosition);
            mousePos.z = 0f;
            MousePos = mousePos;
        }

        private void UpdateCursor()
        {
            var cursor = DefaultCursor;
            var position = Vector2.zero;

            if (!Interacting && GameManager.Instance.CurrentAnchor != null || Interacting && _currentCable != null)
            {
                cursor = PointerCursor;
                position = new Vector2(cursor.width / 2f, 0f);
            }
            else if (!Interacting && GameManager.Instance.CurrentGate != null || Interacting && _currentGate != null)
            {
                cursor = MoveCursor;
                position = new Vector2(cursor.width / 2f, cursor.height / 2f);
            }

            if(_currentCursor != cursor)
            {
                //TODO Invalid texture used for cursor - check importer settings or texture creation. Texture must be RGBA32, readable, have alphaIsTransparency enabled and have no mip chain.
                Cursor.SetCursor(cursor, position, CursorMode.Auto);
                _currentCursor = cursor;
            }
        }

        private void UpdateDrag()
        {
            if (_currentCable != null) // Dragging cable
            {
                _currentCable.FallbackEndPos = MousePos;
            }
            else if (_currentGate != null) // Dragging gate
            {
                _currentGate.transform.position = MousePos - _currentGateDelta;
            }
            else if (GameManager.Instance.CurrentAnchor != null) // Dragging new cable
            {
                _currentCable = Instantiate(GameManager.Instance.CablePrefab, GameManager.Instance.CablesGroup, true);
                _currentCable.StartAnchor = GameManager.Instance.CurrentAnchor;
                _currentCable.FallbackEndPos = MousePos;
            }
            else if (GameManager.Instance.CurrentGate != null) // Dragging new gate
            {
                DragGate(GameManager.Instance.CurrentGate, false);
            }
        }

        private void UpdateDrop()
        {
            if (_currentCable != null) // Dropping cable
            {
                if (GameManager.Instance.CurrentAnchor == null || _currentCable.StartAnchor.IsInput == GameManager.Instance.CurrentAnchor.IsInput)
                {
                    Destroy(_currentCable.gameObject);
                }
                else
                {
                    _currentCable.EndAnchor = GameManager.Instance.CurrentAnchor;
                }
                _currentCable = null;
            }
            else if (_currentGate != null) // Dropping gate
            {
                if (DeleteOnRelease)
                {
                    Destroy(_currentGate.gameObject);
                }
                else
                {
                    foreach (var renderer in _currentGate.GetComponentsInChildren<SpriteRenderer>())
                    {
                        renderer.sortingLayerName = "default";
                    }
                    _currentGate.transform.position = _currentGate.transform.position.Round();
                    var currentBox = _currentGate.Box;
                    if (FindObjectsOfType<Gate>()
                        .Where(g => !g.Equals(_currentGate))
                        .Select(g => g.Box)
                        .Any(b => currentBox.IsTouching(b)))
                    {
                        // Collision with another gate
                        if (_currentGateInitialPos == null)
                        {
                            Destroy(_currentGate.gameObject);
                        }
                        else
                        {
                            _currentGate.transform.position = _currentGateInitialPos.Value; // Reset pos
                        }
                    }
                }
                _currentGate = null;
                DeleteOnRelease = false;
            }
        }

        

        #endregion
    }
}