using System;
using System.Collections;
using System.Collections.Generic;
using System.Drawing;
using UnityEngine;
using UnityEngine.UI;
using TMPro;

/// <summary>
/// This class connects a grid view for buy state of the shop to a controller to manipulate the BuyModel via a ShopController
/// interface, it contains specific methods to setup and update a grid view, with the data from a BuyModel. If you want to display
/// informationoutside of the BuyModel, for example, the money amount from the player's inventory, then you need to either keep a
/// reference to all the related models, or make this class an observer/event subscriber of the related models.
/// </summary>
public abstract class ShopView : MonoBehaviour, IShopModelObserver<Item>
{ 
    public ShopModel ShopModel => model; //A getter to access shopModel.

    [SerializeField]
    protected GameObject itemPrefab; //A prefab to display an item in the view

    [SerializeField]
    protected Button buyButton; 

    [SerializeField]
    protected TextMeshProUGUI instructionText;

    [SerializeField] protected LayoutGroup layoutGroup;   // The layout group that represents this view visually

    protected ShopModel model; // Model in MVC pattern
    protected ShopModel other; // Other model in MVC pattern (our own inventory)
    private ShopController shopController; //Controller in MVC pattern

    // Set up the view's necessary stuff before the view is enabled
    protected virtual void Awake()
    {
        model = new BuyModel(2f, 16, 500); //Right now use magic values to set up the shop
        shopController = gameObject.AddComponent<MouseController>().Initialize(model);//Set the default controller to be the mouse controller
        SetupItemIconView(); //Setup the grid view's properties
        InitializeButtons(); //Connect the buttons to the controller
        //model.Subscribe(this);
    }

    private void OnEnable()
    {
        PopulateItemIconView(); //Display items
    }

    private void OnDisable()
    {
        ClearIconView();
    }

    //------------------------------------------------------------------------------------------------------------------------
    //                                                  SetupItemIconView()
    //------------------------------------------------------------------------------------------------------------------------        
    //Setup the grid view according to the ViewConfig object's requirements, right now it just sets the constraint mode and column count,
    //you can make cosmetic adjustments to the GridLayoutGroup by adding more configurations to ViewConfig and use them adjusting properties
    //like cellSize, spacing, padding, etc.
    protected abstract void SetupItemIconView();

    //------------------------------------------------------------------------------------------------------------------------
    //                                                  RepopulateItems()
    //------------------------------------------------------------------------------------------------------------------------        
    //Clears the grid view and repopulates it with new icons (updates the visible icons)
    private void RepopulateItemIconView() {
        ClearIconView();
        PopulateItemIconView();
    }

    //------------------------------------------------------------------------------------------------------------------------
    //                                                  PopulateItems()
    //------------------------------------------------------------------------------------------------------------------------        
    //Adds one icon for each item in the shop
    private void PopulateItemIconView() {
        foreach (Item item in model.inventory.GetItems()) {
            AddItemToView(item);
        }
    }

    //------------------------------------------------------------------------------------------------------------------------
    //                                                  ClearIconView()
    //------------------------------------------------------------------------------------------------------------------------        
    //Removes all existing icons in the gridview
    protected abstract void ClearIconView();

    //------------------------------------------------------------------------------------------------------------------------
    //                                                  AddItemToView()
    //------------------------------------------------------------------------------------------------------------------------        
    //Adds a new item container to the view, each view can have its way of displaying items
    protected abstract void AddItemToView(Item item);

    protected abstract void RemoveItemFromView(Item item);

    //------------------------------------------------------------------------------------------------------------------------
    //                                                  InitializeButtons()
    //------------------------------------------------------------------------------------------------------------------------        
    //This method adds a listener to the 'Buy' button. They are forwarded to the controller. Since this is the confirm button of
    //the buy view, it will just call the controller interface's ConfirmSelectedItem function, the controller will handle the rest.
    private void InitializeButtons() {
        buyButton.onClick.AddListener(
            delegate {
                shopController.ConfirmSelectedItem();
            }
        );
    }

    private void Update()
    {
        //RepopulateItemIconView();//Repopulate the view each frame, this is very inefficient and won't work in many scenarios and SHOULD NOT be in
                                 //the final implementation, the view should be modified by the models via an observer or event queue pattern

        //Switch between mouse and keyboard controllers
        if (Input.GetKeyUp(KeyCode.K))
        {
            if (shopController is MouseController)
            {
                SwitchToKeyboardControl();
            }
        }

        else if (Input.GetMouseButtonUp(0))
        {
            if (shopController is GridViewKeyboardController)
            {
                SwitchToMouseControl();
            }
        }

        //Let the current controller handle input
        shopController.HandleInput();
    }


    //------------------------------------------------------------------------------------------------------------------------
    //                                                  SwitchToKeyboardControl()
    //------------------------------------------------------------------------------------------------------------------------    
    private 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
    }

    //------------------------------------------------------------------------------------------------------------------------
    //                                                  SwitchToMouseControl()
    //------------------------------------------------------------------------------------------------------------------------ 
    private 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
    }

    public void OnSelected(Item item)
    {
        Debug.Log("View selects item: " + item.name,this);
        RepopulateItemIconView();
    }

    public void OnRemoved(Item item)
    {
        RemoveItemFromView(item);
    }

    public void OnAdded(Item item)
    {
        throw new NotImplementedException();
    }
}