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

public class PowerSelectionManager : MonoBehaviour
{
    /*
    public static PowerSelectionManager Instance;
    public static List<GameObject> Sets = new List<GameObject>();
    public bool canMakeSelections = true;
    //public bool selectByLayer = true;
    //public int selectedLayer;
    public KeyCode keyMultiselect = KeyCode.LeftControl;
    public KeyCode keyDeselect = KeyCode.LeftAlt;
    public KeyCode DracRectKey = KeyCode.LeftShift;

    private static List<SelectableObject> selectedGameObjects = new List<SelectableObject>();
    private bool isSelecting = false;
    private Vector3 mousePosition;

    private void Awake()
    {
        Instance = this;
    }

    private struct SelectableObject
    {
        public GameObject gameObject;
        public SelectableUnit selectable;
        public bool isActive;
    }

    private void Start()
    {
        if (!Camera.main)
            Debug.Log("The SelectionManager requires a camera with the tag 'MainCamera'");
        ClearSelection();
    }

    void Update()
    {
        if (!Camera.main)
            return;
        if (Sets.Count > 0)
        {
            selectedGameObjects = selectedGameObjects.Where(i => i.gameObject != null).ToList();
            if (canMakeSelections)
            {
                if (Input.GetMouseButtonDown(0))
                {
                    isSelecting = true;
                    mousePosition = Input.mousePosition;
                }
            }
            if (Input.GetMouseButtonUp(0))
            {
                if (!EventSystem.current.IsPointerOverGameObject())
                {
                    if (isSelecting)
                    {
                        if (!(Input.GetKey(keyMultiselect)) && !(Input.GetKey(keyDeselect)))
                        {
                            ClearSelection();
                        }
                        List<GameObject> newSelectedObjects = new List<GameObject>();
                        bool isFiltered = false;
                        //if (selectByLayer)
                        //{
                        //    isFiltered = true;
                        //    newSelectedObjects.AddRange(Utils.FindGameObjectsWithLayer(selectedLayer, Sets));
                        //}
                        if (!isFiltered && newSelectedObjects.Count == 0)
                        {
                            newSelectedObjects.AddRange(Utils.FindGameObjectsInList(Sets));
                        }
                        if (Input.GetKey(DracRectKey))
                        {
                            foreach (GameObject selectedObject in newSelectedObjects)
                            {
                                if (IsWithinSelectionBounds(selectedObject))
                                {
                                    parseGameObjectForSelection(selectedObject);
                                }
                            }
                        }
                    }
                    isSelecting = false;
                    RaycastHit selectionHit;
                    if (Physics.Raycast(Camera.main.ScreenPointToRay(Input.mousePosition), out selectionHit))
                    {
                        parseGameObjectForSelection(selectionHit.transform.gameObject);
                    }
                }
            }
        }
    }

    #region Private Methods
    void detachSelection(SelectableObject selectedObject)
    {
        if (selectedObject.gameObject != null)
        {

            selectedObject.gameObject.GetComponent<HighlightEffect>().highlighted = false;
            PowerManager.Instance.PowerModel = null;
            if (selectedObject.selectable)
            {
                selectedObject.selectable.OnEndSelection();
            }
        }

    }
    void parseGameObjectForSelection(GameObject sender)
    {
        bool validObject = true;

        //if (selectByLayer && sender.layer != selectedLayer)
        //{
        //    validObject = false;
        //}
        if (Sets.Contains(sender) == false)
            validObject = false;

        if (validObject)
        {
            bool containsObject = false;
            List<SelectableObject> objectsToRemove = new List<SelectableObject>();
            for (int x = 0; x < selectedGameObjects.Count; x++)
            {
                SelectableObject selectedObject = selectedGameObjects[x];

                if (selectedObject.gameObject == sender)
                {
                    containsObject = true;
                    selectedObject.isActive = true;
                }

                selectedGameObjects[x] = selectedObject;

                if (Input.GetKey(keyDeselect) && selectedObject.gameObject == sender)
                {
                    detachSelection(selectedObject);
                    objectsToRemove.Add(selectedObject);
                }
            }
            selectedGameObjects = selectedGameObjects.Except(objectsToRemove).ToList();

            if (!containsObject && !Input.GetKey(keyDeselect))
            {
                var selectable = sender.GetComponent<SelectableUnit>();
                if (selectable && selectable != selectable.playerOwned)
                {
                    return;
                }


                if (sender.GetComponent<PowerController>().PowerMode == CreationMode.Single)
                {
                    SelectableObject selectedGameObject = new SelectableObject();
                    selectedGameObject.gameObject = sender;
                    selectedGameObject.isActive = true;
                    if (selectable)
                    {
                        selectedGameObject.selectable = selectable;
                        selectedGameObject.selectable.OnBeginSelection();
                    }
                    selectedGameObjects.Add(selectedGameObject);
                    PowerManager.Instance.PowerModel = selectedGameObject.gameObject;
                }
                else
                {
                    foreach (Transform go in sender.transform.parent)
                    {
                        SelectableObject selectedGameObject = new SelectableObject();
                        selectedGameObject.gameObject = go.gameObject;
                        selectedGameObject.isActive = true;
                        if (selectable)
                        {
                            selectedGameObject.selectable = selectable;
                            selectedGameObject.selectable.OnBeginSelection();
                        }
                        selectedGameObjects.Add(selectedGameObject);
                        PowerManager.Instance.PowerModel = selectedGameObject.gameObject;
                    }
                }



                for (int i = 0; i < selectedGameObjects.Count; i++)
                {
                    selectedGameObjects[i].gameObject.GetComponent<HighlightEffect>().highlighted = true;
                }
            }
        }
    }
    #endregion
    void OnGUI()
    {
        if (isSelecting && Input.GetKey(DracRectKey))
        {
            // Create a rect from both mouse positions
            var rect = Utils.GetScreenRect(mousePosition, Input.mousePosition);
            Utils.DrawScreenRect(rect, new Color(0.2f, 0.8f, 0.2f, 0.25f));
            Utils.DrawScreenRectBorder(rect, 1, new Color(0.2f, 0.8f, 0.2f));
        }
    }
    bool IsWithinSelectionBounds(GameObject gameObject)
    {
        if (!isSelecting)
            return false;

        var camera = Camera.main;
        var viewportBounds = Utils.GetViewportBounds(camera, mousePosition, Input.mousePosition);
        return viewportBounds.Contains(camera.WorldToViewportPoint(gameObject.transform.position));
    }

    #region Public Methods
    //returns a list of currently selected objects
    public static GameObject[] GetSelectedObjects()
    {
        return selectedGameObjects.Select(i => i.gameObject).ToArray();
    }
    public void AddGameObjectToSelection(GameObject newObject)
    {
        parseGameObjectForSelection(newObject);

    }
    public void RemoveGameObjectFromSelection(GameObject removedObject)
    {
        foreach (SelectableObject selectedObject in selectedGameObjects)
        {
            if (selectedObject.gameObject == removedObject)
            {
                detachSelection(selectedObject);
                selectedGameObjects.Remove(selectedObject);
            }
        }
    }
    public void ClearSelection()
    {
        foreach (SelectableObject selectedObject in selectedGameObjects)
        {
            detachSelection(selectedObject);
        }
        selectedGameObjects.Clear();
    }
    #endregion
    */
}