# Author: Peter Andreae
#   Date: 02 Dec 2011



# A little Peg Puzzle, Sometimes called
#      "Traffic Jam" or "Toads and Frogs"
#      See   http://mathforum.org/alejandre/java/jam/Jam.html for an example.
#
#    Program to allow user to try to solve the linear peg solitaire problem:
#    setup: 7 holes, 3 red pegs in left 3 holes, 3 green pegs in right 3 holes.
#    Goal: exchange the positions of the red and green pegs
#    Movement rules:
#      Red pegs can only move to the right,
#      Left pegs can only move to the right.
#      A peg can move into the hole if it is next to the hole
#      A peg can jump over a peg of the opposite color if the hole is on the other side
#
#    Design:
#
#      Classes:
#        PegBoard represents a board
#
#      TopLevel
#        create interface
#            canvas
#            three buttons for reset, move green, move red
#        create board
#        draw board
#
#       PegBoard class:
#           Fields: board = an array of 7 strings ("Red", "Green", or "Black")
#           Functions:
#                reset()
#                draw(canvas)
#                moveRed()
#                moveGreen()
#                checkComplete()
#
#         initialise:
#             create an array of 7 strings
#      
#         reset
#           set the first three cells to be red
#           set the middle cell to be empty
#           set the last three cells to be green
#
#
#        drawBoard
#           erase screen
#           for each cell
#              compute x position of cell
#              if cell contains red, draw red peg in hole
#              if cell contains green, draw green peg in hole
#              if cell contains hole, draw just a hole
#
#        moveRed
#          For each cell except the rightmost
#            if cell contains red and cell+1 contains hole
#              swap contents of cell and cell+1
#              exit
#          For each cell except the rightmost two cells
#            if cell contains red and cell+1 contains green, and cell+2 contains hole
#              swap contents of this cell and cell+2
#              exit
#           Report "Can't move a red peg"
#
#        moveGreen
#          For each cell except the leftmost
#            if cell contains green and cell-1 contains hole
#              swap contents of cell and cell-1
#              exit
#          For each cell except the leftmost two cells
#            if cell contains green and cell-1 contains red, and cell-2 contains hole
#              swap contents of this cell and cell-2
#              exit
#          Report "Can't move a green peg"
#     
#               
#        checkComplete
#          set answer to true
#          For first three cells
#            if cell does not contain green
#               set answer to false
#          For last three cells
#            if cell does not contain red
#               set answer to false
#          return answer
#    


from tkinter import *
from tkinter.messagebox import showerror, showwarning

def main() :
    global window
    global canvas
    global board
    window = Tk()
    board = PegBoard(3)
    # root.title('Peg Puzzle')
    canvas = Canvas(window, width=450, height=300, bg = 'white')
    canvas.pack()
    Button(window, text="Move Green", command=performGreenAction).pack()
    Button(window, text="Move Red", command=performRedAction).pack()
    Button(window, text="Restart", command=restart).pack()
    board.draw()
    window.mainloop()

def performGreenAction() :
    board.moveGreen()
    board.draw()
    board.reportIfComplete()
    
def performRedAction() :
    board.moveRed()   
    board.draw() 
    board.reportIfComplete()
    
def restart() :
    board.reset()
    board.draw()

#----------------------------------------------------------------

class PegBoard() :          
    def __init__(self, pegs) :
        self.pegs = pegs         # The number of green pegs (same as number of red pegs)
        self.size = pegs*2 + 1  
        self.cells = []
        for i in range(self.size) :  
            self.cells.append("")
        self.reset()

    def moveRed(self) :
        for i in range(self.size-1) :   # Can't move red peg in rightmost cell 
            if self.cells[i] == "Red" :
                if self.cells[i+1] == "Black" :
                    self.cells[i] = "Black"
                    self.cells[i+1] = "Red"
                    return 
                if i < self.size-2 and self.cells[i+1] == "Green" and self.cells[i+2] == "Black" :
                    self.cells[i] = "Black"
                    self.cells[i+2] = "Red"
                    return 
        showerror("", "Can't move a red peg in this configuration!")
      


    def moveGreen(self) :   
        print("moving green")
        for i in range(1,self.size) :  # Can't move green peg in leftmost cell
            if self.cells[i] == "Green" :
                if self.cells[i-1] == "Black" :
                    self.cells[i] = "Black"
                    self.cells[i-1] = "Green"
                    return 
                if i>1 and self.cells[i-1] == "Red" and self.cells[i-2] == "Black" :
                    self.cells[i] = "Black"
                    self.cells[i-2] = "Green"
                    return        
        showerror("", "Can't move a green peg in this configuration!")
    
                
    def reset(self) :
        for i in range(self.pegs) :  
            self.cells[i] = "Red"
        self.cells[self.pegs] = "Black"      
        for i in range(self.pegs+1, self.size) :  
            self.cells[i] = "Green"
    
    def reportIfComplete(self) :
        for i in range(self.pegs) :
            if board[i] != "Green" : 
                showerror("not green at ", i)
                return False
        for i in range(self.pegs+1,self.size) :
            if board[i] != "Red" :
                return False
        showerror("", "You solved it!!") 
        return True

    def draw(self) :
        canvas.delete(ALL)
        X = 40   # position of center of first cell of board
        Y = 40
        cellRad = 25
        holeRad = 10
        pegRad = 15
        for cell in self.cells :
            canvas.create_rectangle(X-cellRad, Y-cellRad, 
                                    X+cellRad, Y+cellRad, 
                                    fill="orange", outline="black")
            canvas.create_oval(X-pegRad, Y-pegRad, 
                               X+pegRad, Y+pegRad, 
                               fill=cell)
            X = X + 2 * cellRad
        canvas.update()
            
    def print(self) :
        print()
        print("board:       ")
        for cell in board :
            print(cell)
        print()
        print()

# -------------------------------------------

print("where does this go")
main()