from tkinter import *
from functools import partial


class DisplayHelp:
    # displays help dialogue box

    def __init__(self, partner):
        background = "#ffe6cc"
        self.help_box = Toplevel()

        # disable help button while help is open
        partner.button_ref_list[5].config(state=DISABLED)

        self.help_box.protocol("WM_DELETE_WINDOW",
                               partial(self.close_help, partner))

        self.help_frame = Frame(self.help_box, bg=background)
        self.help_frame.grid()

        self.help_heading_label = Label(self.help_frame,
                                        text="Help / Info",
                                        font=("Arial", "14", "bold"),
                                        bg=background)
        self.help_heading_label.grid(row=0)

        help_text = ("To use the program, simply enter an amount "
                     "in New Zealand Dollars (NZD) and then press "
                     "one of the currency buttons to convert it.\n\n"
                     "The exchange rates used are approximate and "
                     "may not reflect live market rates.\n\n"
                     "To see your calculation history and export it "
                     "to a text file, please click the "
                     "'History / Export' button.")

        self.help_text_label = Label(self.help_frame,
                                     text=help_text,
                                     wraplength=350,
                                     justify="left",
                                     bg=background)
        self.help_text_label.grid(row=1, padx=10)

        self.dismiss_button = Button(self.help_frame,
                                     text="Dismiss",
                                     bg="#CC6600",
                                     fg="#FFFFFF",
                                     font=("Arial", "12", "bold"),
                                     command=partial(self.close_help, partner))
        self.dismiss_button.grid(row=2, padx=10, pady=10)

    def close_help(self, partner):
        # closes help window and re-enables help button
        partner.button_ref_list[5].config(state=NORMAL)
        self.help_box.destroy()


# main routine
if __name__ == "__main__":
    root = Tk()
    root.title("Help Info")
    DisplayHelp()
    root.mainloop()