from tkinter import *
import random


class Converter:
    """
    Currency Converter GUI
    """

    def __init__(self, parent):
        self.converter_frame = Frame(padx=10, pady=10)
        self.converter_frame.grid()

        self.converter_heading = Label(self.converter_frame,
                                       text="Temperature Converter",
                                       font=("Arial", "16", "bold")
                                       )
        self.converter_heading.grid(row=0)

        instructions = ("Please enter a temperature below and then press "
                        "one of the buttons to convert it from Centigrade "
                        "to Fahrenheit.")
        self.converter_instructions = Label(self.converter_frame,
                                            text=instructions,
                                            wraplength=250, width=40,
                                            justify="left")
        self.converter_instructions.grid(row=1)

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

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

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

        # button list (button text | bg colour | command | row | column)
        button_details_list = [
            ["To NZD", "#990099", "", 0, 0],
            ["To USD", "#009900", "", 0, 1],
            ["Help / Info", "#CC6600", "", 1, 0],
            ["History / Export", "#004C99", "", 1, 1],
        ]

        # List to hold buttons once they have been made
        self.button_ref_list = []

        for item in button_details_list:
            self.make_button = Button(self.button_frame,
                                      text=item[0], bg=item[1],
                                      fg="#FFFFFF", font=("Arial", "12", "bold"),
                                      width=12, command=item[2])
            self.make_button.grid(row=item[3], column=item[4], padx=5, pady=5)

            self.button_ref_list.append(self.make_button)

        # retrieve 'history / export' and disable it at the start
        self.to_history_button = self.button_ref_list[3]
        self.to_history_button.config(state=DISABLED)

    # main routine


if __name__ == "__main__":
    root = Tk()
    root.title("Temperature converter")
    something = Converter(root)
    root.mainloop()