from tkinter import *


class Converter():

    def __init__(self):

        self.dist_frame = Frame(padx=10, pady=10)
        self.dist_frame.grid()

        self.dist_heading = Label(self.dist_frame,
                                  text="Distance Converter",
                                  font=("Arial", "16", "bold"))
        self.dist_heading.grid(row=0, columnspan=2)

        instructions = ("Please enter a distance below, choose the units "
                        "to convert from and to, then press Convert.")
        self.dist_instructions = Label(self.dist_frame,
                                       text=instructions,
                                       wraplength=250, width=40,
                                       justify="left")
        self.dist_instructions.grid(row=1, columnspan=2)

        self.dist_entry = Entry(self.dist_frame,
                                font=("Arial", "14"))
        self.dist_entry.grid(row=2, padx=10, pady=10)

        error = "Please enter a number"
        self.dist_error = Label(self.dist_frame, text=error,
                                fg="#9C0000")
        self.dist_error.grid(row=3)

        # Conversion, help and history / export buttons
        self.button_frame = Frame(self.dist_frame)
        self.button_frame.grid(row=4)

        self.convert_button = Button(self.button_frame,
                                     text="Convert",
                                     bg="#009900",
                                     fg="#ffffff",
                                     font=("Arial", "12", "bold"), width=12)
        self.convert_button.grid(row=0, column=0, padx=5, pady=5)

        self.clear_button = Button(self.button_frame,
                                   text="Clear",
                                   bg="#666666",
                                   fg="#ffffff",
                                   font=("Arial", "12", "bold"), width=12)
        self.clear_button.grid(row=0, column=1, padx=5, pady=5)

        self.help_button = Button(self.button_frame,
                                  text="Help / Info",
                                  bg="#CC6600",
                                  fg="#ffffff",
                                  font=("Arial", "12", "bold"), width=12)
        self.help_button.grid(row=1, column=0, padx=5, pady=5)

        self.history_button = Button(self.button_frame,
                                     text="History / Export",
                                     bg="#004C99",
                                     fg="#ffffff",
                                     font=("Arial", "12", "bold"), width=12)
        self.history_button.grid(row=1, column=1, padx=5, pady=5)


# main routine
if __name__ == "__main__":
    root = Tk()
    root.title("Distance Converter")
    Converter()
    root.mainloop()