I am relatively new to programming, and I wish to use this simple minesweeper game in a portfolio. A few questions:

1. Currently, game setup gets progressively slower with each reset button call, and the window height slightly increases downward. This is very apparent on medium and hard difficulties. What changes can speed up this code? I want to reuse the same window with each reset if possible.
2. The code uses a Model-View-Controller approach. Does this make sense for a project using tkinter? Is there a better approach?
3. Some parts such as the additions variable are repeated, but I cannot find a way to make them instance variables.

I know it's long, but any suggestions/constructive feedback is appreciated. Thanks!

"""
Minesweeper

Implements a basic minesweeper game using tkinter. 
Uses Model-View-Controller architecture.
"""

import tkinter as tk
import random


class Model(object):
    """Crates a board and adds mines to it"""
    def __init__(self, width, height, num_mines):
        self.width = width
        self.height = height
        self.num_mines = num_mines
        self.create_grid()       
        self.add_mines()
   
    def create_grid(self):
        """Create a self.width by self.height grid of elements with value 0"""
        self.grid = [[0]*self.width for i in range(self.height)]
    
    def add_mines(self):
        """Randomly adds the amount of self.num_mines to grid"""
        def get_coords():
            row = random.randint(0, self.height - 1)
            col = random.randint(0, self.width - 1)
            return row, col
        for i in range(self.num_mines):
            row, col = get_coords()
            while self.grid[row][col] == "b":
                row, col = get_coords()
            self.grid[row][col] = "b"
        for i in self.grid:
            print (i)


class View(tk.Frame):
    """Creates a main window and grid of button cells"""
    def __init__(self, master, width, height, num_mines):
        tk.Frame.__init__(self, master)
        self.master = master    
        self.width = width
        self.height = height
        self.num_mines = num_mines
        self.master.title("Minesweeper")
        self.grid()
        self.top_panel = TopPanel(self.master, self.height, 
                                  self.width, self.num_mines)
        self.create_widgets()
        
    def create_widgets(self):
        """Create cell button widgets"""
        self.buttons = {} 
        for i in range(self.height): 
            for j in range(self.width):
                self.buttons[str(i) + "," + str(j)] = tk.Button(
                        self.master, width=5, bg="grey")                                                          
                self.buttons[str(i) + "," + str(j)].grid(row=i+1, column=j+1)                          
        
    def disp_loss(self):
        """Display the loss label when loss condition is reached""" 
        self.top_panel.loss_label.grid(row=0, columnspan=5)
     
    def disp_win(self):
        """Display the win label when win condition is reached""" 
        self.top_panel.win_label.grid(row=0, columnspan=5)
    
    def hide_labels(self, condition=None):
        """Hides labels based on condition argument"""
        if condition:
            self.top_panel.mines_left.grid_remove()
        else: 
            self.top_panel.loss_label.grid_remove()
            self.top_panel.win_label.grid_remove()
            
            
class TopPanel(tk.Frame):
    """Create top panel which houses reset button and win/loss and 
    mines left labels."""
    def __init__(self, master, width, height, num_mines):
        tk.Frame.__init__(self, master)
        self.master = master
        self.height = height
        self.width = width
        self.num_mines = num_mines
        self.grid()
        self.create_widgets()
   
    def create_widgets(self):
        self.reset_button = tk.Button(self.master, width = 7, text="Reset")
        self.reset_button.grid(row=0, columnspan=int((self.width*7)/2))
#        Create win and loss labels
        self.loss_label = tk.Label(text="You Lose!", bg="red")
        self.win_label = tk.Label(text="You Win!", bg="green")
#        Create number of mines remaining label
        self.mine_count = tk.StringVar()
        self.mine_count.set("Mines remaining: " + str(self.num_mines))
        self.mines_left = tk.Label(textvariable=self.mine_count)
        self.mines_left.grid(row=0, columnspan=5)
    
   
class Controller(object):
    """Sets up button bindings and minsweeper game logic.
    
    The act of revealing cells is delegated to the methods: give_val(), 
    reveal_cell(), reveal_adj(), and reveal_cont(). End conditions are handled
    by the loss() and win() methods.
    """
    def __init__(self, width, height, num_mines):        
        self.width = width
        self.height = height
        self.num_mines = num_mines
        self.model = Model(self.width, self.height, self.num_mines)
        self.root = tk.Tk()
        self.view = View(self.root, self.width, self.height, self.num_mines)        
#        self.color_dict is used to assign colors to cells
        self.color_dict = {
            0: "white", 1:"blue", 2:"green", 
            3:"red", 4:"orange", 5:"purple", 
            6: "grey", 7:"grey", 8: "grey"
            }         
#        Self.count keeps track of cells with value of 0 so that they
#        get revealed with self.reveal_cont call only once
        self.count = []
        self.cells_revealed = []
        self.cells_flagged = []
        self.game_state = None
        self.bindings()
        self.root.mainloop()  
   
    def bindings(self):
        """Set up reveal cell and flag cell key bindings"""
        for i in range(self.height):
            for j in range(self.width):
#                Right click bind to reveal decision method
                self.view.buttons[str(i) + "," + str(j)].bind(
                        "<Button-1>", 
                        lambda event, index=[i, j]:self.reveal(event, index))
#                Left click bind to flag method
                self.view.buttons[str(i) + "," + str(j)].bind(
                        "<Button-3>", 
                        lambda event, index=[i, j]:self.flag(event, index))
#        Set up reset button
        self.view.top_panel.reset_button.bind("<Button>", self.reset)
    
    def reset(self, event): 
        """Resets game. Currently, game setup gets slower with each reset call,
        and window height slightly increases"""
        self.view.hide_labels()
        self.count = []
        self.cells_revealed = []    
        self.cells_flagged = [] 
        self.game_state = None
        self.model = Model(self.width, self.height, self.num_mines)
        self.view = View(self.root, self.width, 
                         self.height, self.num_mines)
        self.bindings()
    
    def reveal(self, event, index):
        """Main decision method determining how to reveal cell"""
        i = index[0]
        j = index[1] 
        val = self.give_val(index)
        if val in [x for x in range(1, 9)]:
            self.reveal_cell(val, index)
            self.count.append(index)
        if (val == "b" and self.game_state != "win" and
                self.view.buttons[str(i) + "," + str(j)]["text"] != "FLAG"):
            self.game_state = "Loss"
            self.loss()
#        Begin the revealing recursive method when cell value is 0
        if val == 0:            
            self.reveal_cont(index)
    
    def give_val(self, index):
        """Returns the number of adjacent mine. Returns "b" if cell is mine"""
        i = index[0]
        j = index[1]               
        num_mines = 0
        try:
            if self.model.grid[i][j] == "b":
                return "b"
        except IndexError:
            pass                
        def increment():
            try:
                if self.model.grid[pos[0]][pos[1]] == "b":
                    return 1
            except IndexError:
                pass
            return 0       
        additions = [
            [i,j+1], [i+1,j], [i+1,j+1], [i,j-1],
            [i+1,j-1], [i-1,j], [i-1,j+1], [i-1,j-1]
            ]                   
        #Adds 1 to num_mines if cell is adjacent to a mine
        for pos in additions:
            if 0 <= pos[0] <= self.height -1 and 0 <= pos[1] <= self.width - 1:
                num_mines += increment()           
        return num_mines
    
    def reveal_cell(self, value, index):
        """Reveals cell value and assigns an associated color for that value"""
        i = index[0]
        j = index[1]
        cells_unrev = self.height * self.width - len(self.cells_revealed) - 1
        button_key = str(i) + "," + str(j)
        if self.view.buttons[button_key]["text"] == "FLAG":
            pass
        elif value == "b":
            self.view.buttons[button_key].configure(bg="black")
        else:
#           Checks if cell is in the board limits
            if (0 <= i <= self.height - 1 and 
                    0 <= j <= self.width - 1 and 
                    [button_key] not in self.cells_revealed):
                self.view.buttons[button_key].configure(
                        text=value, bg=self.color_dict[value])                     
                self.count.append(button_key)
                self.cells_revealed.append([button_key])               
#            Removes cell from flagged list when the cell gets revealed
            if button_key in self.cells_flagged:
                self.cells_flagged.remove(button_key)
                self.update_mines()
#            Check for win condition
            if (cells_unrev == self.num_mines and not self.game_state):
                self.win()       
    
    def reveal_adj(self, index):        
        """Reveals the 8 adjacent cells to the input cell index"""
        org_val = self.give_val(index)
        self.reveal_cell(org_val, index)
        i = index[0]
        j = index[1]
        additions = [
            [i,j+1], [i+1,j], [i+1,j+1], [i,j-1],
            [i+1,j-1], [i-1,j], [i-1,j+1], [i-1,j-1]
            ]        
        for pos in additions:
            if (0 <= pos[0] <= self.height - 1 and 
                    0 <= pos[1] <= self.width - 1):
                new_val = self.give_val(pos)
                self.reveal_cell(new_val, pos) 
    
    def reveal_cont(self, index):
        """Recursive formula that reveals all adjacent cells only if the 
        selected cell has no adjacent mines. 
        (meaning self.give_val(index) == 0)"""     
        i = index[0]
        j = index[1]
        additions = [
            [i,j+1], [i+1,j], [i+1,j+1], [i,j-1],
            [i+1,j-1], [i-1,j], [i-1,j+1], [i-1,j-1]
            ]
        val = self.give_val(index)
        self.reveal_adj(index)
        if val != 0:
            return None
        else:            
            for pos in additions:
                if (0 <= pos[0] <= self.height - 1 and 
                        0 <= pos[1] <= self.width -1 and 
                        self.give_val(pos) == 0 and pos not in self.count):
                    self.count.append(pos)
                    self.reveal_cont(pos)
        
    def win(self):
        """Display win"""
        self.view.hide_labels("mine")
        self.view.disp_win()
        self.game_state = "win"
        
    def loss(self):
        """Display loss. Reveal all cells when a mine is clicked"""
        self.view.hide_labels("mine")
        for i in range(self.height):
            for j in range(self.width):
                val = self.give_val([i, j])
                self.reveal_cell(val, [i, j]) 
        self.view.disp_loss()
    
    def flag(self, event, index):
        """Allows player to flag cells for possible mines. 
        Does not reveal cell."""
        i = index[0]
        j = index[1]
        button_key = str(i) + "," + str(j)
        button_val = self.view.buttons[button_key]       
        if button_val["bg"] == "grey":
            button_val.configure(bg="yellow", text="FLAG")
            self.cells_flagged.append(button_key)
        elif button_val["text"] == "FLAG":
            button_val.configure(bg="grey", text="")
            self.cells_flagged.remove(button_key)
        self.update_mines()
    
    def update_mines(self):
        """Update mine counter"""
        mines_left = self.num_mines - len(self.cells_flagged)
        if mines_left >= 0:
            self.view.top_panel.mine_count.set(
                    "Mines remaining: " + str(mines_left))
                                            
def main():
    n = input("Pick a difficulty: Easy, Medium, or Hard. ")
    if n[0] == "E" or n[0] == "e":
        return Controller(9, 9, 10)
    elif n[0] == "M" or n[0] == "m":
        return Controller(16, 16, 40)
    elif n[0] == "H" or n[0] == "h":
        return Controller(30, 16, 99)

    
if __name__ == "__main__":
    main()