using System;
using System.Collections;
using System.Collections.Generic;
using System.Security.Permissions;
using UnityEngine;
using UnityEngine.Assertions;
using UnityEngine.UI;

public class ShopViewGrid : ShopView
{
    private GridLayoutGroup _gridLayoutGroup;    // This is essentially just a reference to ShopView's layout group but with the correct type
    
    protected ViewConfig viewConfig; //To set up the grid view, we need to know how many columns the grid view has, in the current setup,
    //this information can be found in a ViewConfig scriptable object, which serves as a configuration file for
    //views.
    
    // Start is called before the first frame update
    protected override void Awake()
    {
        viewConfig = Resources.Load<ViewConfig>("ViewConfig");//Load the ViewConfig scriptable object from the Resources folder
        Debug.Assert(viewConfig != null);
        Debug.Assert(_gridLayoutGroup != null);
        base.Awake();
        print("ShopView Grid Initialised");
    }

    protected override void SetupItemIconView()
    {
        _gridLayoutGroup.constraint = GridLayoutGroup.Constraint.FixedColumnCount;//Set the constraint mode of the GridLayoutGroup
        _gridLayoutGroup.constraintCount = viewConfig.gridViewColumnCount; //Set the column count according to the ViewConfig object
    }

    protected override void ClearIconView()
    {
        Transform[] allIcons = layoutGroup.transform.GetComponentsInChildren<Transform>();
        foreach (Transform child in allIcons) {
            if (child != layoutGroup.transform) {
                Destroy(child.gameObject);
            }
        }
    }

    protected override void AddItemToView(Item item)
    {
        GameObject newItemIcon = GameObject.Instantiate(itemPrefab);
        newItemIcon.transform.SetParent(layoutGroup.transform);
        newItemIcon.transform.localScale = Vector3.one;//The scale would automatically change in Unity so we set it back to Vector3.one.

        ViewItemContainer itemContainer = newItemIcon.GetComponent<ViewItemContainer>();
        Debug.Assert(itemContainer != null);
        //bool isSelected = (item == model.GetSelectedItem());
        var unsub = model.RegisterObserver(itemContainer);
        itemContainer.Initialize(item,model,unsub);
        //print("Attempt to add item " + item.name + " to view");
    }

    protected override void RemoveItemFromView(Item item)
    {
        var items = layoutGroup.transform.GetComponentsInChildren<ViewItemContainer>();
        foreach (var itemView in items)
        {
            if (itemView.Item == item)
            {
                model.RemoveObserver(itemView);
                Destroy(itemView.gameObject);
                return;
            }
        }
    }

    protected override void SwitchToKeyboardControl()
    {
        Destroy(shopController);//Remove the current controller component
        shopController = gameObject.AddComponent<GridViewKeyboardController>().Initialize(model);//Create and add a keyboard controller
        instructionText.text = "The current control mode is: Keyboard Control, WASD to select item, press K to buy. Press left mouse button to switch to Mouse Control.";
        buyButton.gameObject.SetActive(false);//Hide the buy button because we only use keyboard
    }

    protected override void SwitchToMouseControl()
    {
        Destroy(shopController);//Remove the current controller component
        shopController = gameObject.AddComponent<MouseController>().Initialize(model);//Create and add a mouse controller
        instructionText.text = "The current control mode is: Mouse Control, press 'K' to switch to Keyboard Control.";
        buyButton.gameObject.SetActive(true);//Show the buy button for the mouse controler
    }

    private void OnValidate()
    {
        _gridLayoutGroup = (GridLayoutGroup) layoutGroup;
        bool correctLayout = _gridLayoutGroup != null;
        if(!correctLayout) Debug.LogError("Layout group is not of type Grid!",this);
        //else Debug.Log("Grid shop view validated",this);
    }
}