"""
History GUI button component.
"""

from tkinter import *
from functools import partial  # To prevent unwanted windows

class Converter:
    """
    Temperature conversion tool (C to F or F to C)
    """
    def __init__(self):
        """
        Temperature converter GUI
        """

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

        self.to_history_button = Button(self.temp_frame,
                                        text="Help / Info",
                                        bg="#CC6600",
                                        fg="#FFFFFF",
                                        font=("Arial", "14", "bold"), width=12,
                                        command=self.to_history)
        self.to_history_button.grid(row=1, padx=5, pady=5)

    def to_history(self):
        """
        Opens help dialogue box and disables help button
        (so that users can't create multiple help boxes).
        """
        HistoryExport(self)

class HistoryExport:
    """
    Displays help window
    """
    def __init__(self, partner):
        # setup dialogue box and background colour
        background = "#ffe6cc"
        self.history_box = Toplevel()

        # disable help button
        partner.to_history_button.config(state=DISABLED)

        self.history_box.protocol('WM_DELETE_WINDOW',
                                  partial(self.close_history, partner))

        self.history_frame = Frame(self.history_box, width=300,
                                   height=200)
        self.history_frame.grid()

        self.history_heading_label = Label(self.history_frame,
                                           text="History / Export",
                                           font=("Arial", "14", "bold"))
        self.history_heading_label.grid(row=0)

        history_text = "Below are your recent calculations - showing 3 / 3 calculations. " \
                       "All calculations are shown to the nearest degree."

        self.history_text_label = Label(self.history_frame,
                                        text=history_text, wraplength=350,
                                        justify="left")
        self.history_text_label.grid(row=1, padx=10)

        # calculation list goes here

        history_instructions_text = "Please push the Export button to save your calculations in a text file. " \
                                    "If the file name already exists, it will be overwritten!"

        self.history_instructions_label = Label(self.history_frame,
                                                text=history_instructions_text, wraplength=350,
                                                justify="left")
        self.history_instructions_label.grid(row=2, padx=10)

        self.history_button_frame = Frame(self.history_frame)
        self.history_button_frame.grid(row=4)

        self.dismiss_button = Button(self.history_button_frame,
                                     font=("Arial", "12", "bold"),
                                     text="Export", bg="#0000FF",
                                     fg="#FFFFFF",
                                     command=partial(self.close_history, partner))
        self.dismiss_button.grid(row=3, column=0, padx=0, pady=0)

        self.dismiss_button = Button(self.history_button_frame,
                                     font=("Arial", "12", "bold"),
                                     text="Dismiss", bg="#808080",
                                     fg="#FFFFFF",
                                     command=partial(self.close_history, partner))
        self.dismiss_button.grid(row=3, column=1, padx=5, pady=5)

        # List and loop to set background colour on
        # everything except the buttons.
        recolour_list = [self.history_frame, self.history_heading_label, self.history_text_label,
                         self.history_instructions_label, self.history_button_frame]

        for item in recolour_list:
            item.config(bg=background)

    def close_history(self, partner):
        partner.to_history_button.config(state=NORMAL)
        self.history_box.destroy()


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