from tkinter import *

#  lets the user place and rearrange tables in a room 

#Global constants
room_width=500
room_height=450
table_size = 90

# Represents a table with four chairs around it.
class Table() :
    def __init__(self, x, y) :
        self.xPos = x
        self.yPos = y
        self.table_rad = table_size/3
        self.chair_rad = table_size/6
                  
    #Is the position (x, y) on top of this table
    def posOn(self, x, y) :
        left = self.xPos - self.table_rad
        right= self.xPos + self.table_rad
        top  = self.yPos - self.table_rad
        bot  = self.yPos + self.table_rad
        return (left <= x and x <= right and top <= y and y <= bot)       

    #Set the position of this table to be (x, y)
    def setPos(self, x, y) :
        self.xPos = x
        self.yPos = y
        
    #Draw the table on the canvas
    def draw(self, canvas) :
        left = self.xPos - self.table_rad
        right= self.xPos + self.table_rad
        top  = self.yPos - self.table_rad
        bot  = self.yPos + self.table_rad
        self.__draw_chair(canvas, left, self.yPos)
        self.__draw_chair(canvas, right, self.yPos)
        self.__draw_chair(canvas, self.xPos, top)
        self.__draw_chair(canvas, self.xPos, bot)
        canvas.create_rectangle(left, top, right, bot, fill="brown")
    
    def __draw_chair(self, canvas, x, y) :
        left = x - self.chair_rad
        right= x + self.chair_rad
        top  = y - self.chair_rad
        bot  = y + self.chair_rad
        canvas.create_oval(left, top, right, bot, fill="black")
        
#-----------------------------------------------------------------------------
class Room :
    #Create a new room, with the canvas it should draw itself on.
    def __init__(self, canv) :
        self.canvas = canv
        self.reset()
        
    # reset the room to have no tables.
    def reset(self) :
        self.tables = []
        self.canvas.delete(ALL)
        self.canvas.update()

    # remember the table that the position (x, y) is on, if any
    def select_table(self, x, y) :
        self.selected_table = None 
        for table in self.tables :
            if table.posOn(x, y) :
                self.selected_table = table
                return

    # either create a new table at the mouse position, or
    # move the selected table to the mouse position
    def create_or_move_table(self, x, y) :
        left = x - table_size/2
        right= x + table_size/2
        top  = y - table_size/2
        bot  = y + table_size/2
        if left < 0  or right > room_width or top < 0 or bot > room_height :
            print("too close to edge", end='\n')
        else :
            if self.selected_table is None :
                self.tables.append(Table(x, y))
            else :
                self.selected_table.setPos(x, y)
            self.redraw_tables()

    #redraw all the tables
    def redraw_tables(self) :
        self.canvas.delete(ALL)
        for table in self.tables :
            table.draw(self.canvas)
        self.canvas.update()

#-----------------------------------------------------------------------------
# set up the window with a canvas and the  room
class Gui :

    def __init__(self):
        window= Tk()
        Label(window, text="Click mouse to move or place tables").pack()
        button = Button(window, text="Restart", command = self.do_restart)
        button.pack()
        canvas = Canvas(window, width=room_width, height=room_height, bg = 'white')
        canvas.bind("<Button-1>", self.mousepress)
        canvas.bind("<ButtonRelease-1>", self.mouserelease)
        canvas.pack()
        self.room = Room(canvas)
        window.mainloop()

    def do_restart(self):
        self.room.reset()
    
    def mousepress(self, event):
        self.room.select_table(event.x, event.y)
        
    def mouserelease(self,event):
        self.room.create_or_move_table(event.x, event.y)

#------------------------------------------------------------------
# Create the gui.
Gui()