secret_santa_gui.py

"""
Contains the logic of building GUI for
the Secret Santa Generator application.
"""

import random
from datetime import datetime
from tkinter import Tk, Label, Button, Entry, messagebox

from PIL import ImageTk, Image
from send_email import Email

NO_OF_ENTITIES = 8


class SecretSantaGUI:
    """
    Creates the GUI using tkinter module.
    """

    txt_name = [None] * NO_OF_ENTITIES
    txt_email = [None] * NO_OF_ENTITIES
    txt_date = None
    txt_budget = None

    def __init__(self, root_obj):
        self.root_obj = root_obj

    def construct(self):
        """
        Constructs the form as required.
        :return:
        """
        self.root_obj.title("Welcome to Secret Santa")
        self.root_obj.geometry("600x700")

        img = ImageTk.PhotoImage(Image.open("SecretSantaLogo_300px.png"))
        panel = Label(self.root_obj, image=img)
        panel.grid(column=0, row=0)
        panel.img = img  # You need to keep a reference to the photo.

        lbl_message = Label(
            self.root_obj,
            text="Enter the names and email addresses for the gift exchange."
                 "\nThe Secret Santa Generator will handle the rest!",
            padx=20,
            pady=10
        )
        lbl_message.grid(column=0, row=1)

        lbl_name = Label(self.root_obj, text="Name")
        lbl_name.grid(column=0, row=2)
        lbl_email = Label(self.root_obj, text="Email")
        lbl_email.grid(column=1, row=2)

        for idx in range(NO_OF_ENTITIES):
            self.txt_name[idx] = Entry(self.root_obj, width=30)
            self.txt_name[idx].grid(column=0, row=3 + idx, padx=5, pady=5)
            self.txt_email[idx] = Entry(self.root_obj, width=30)
            self.txt_email[idx].grid(column=1, row=3 + idx, padx=5, pady=5)

        lbl_date = Label(self.root_obj, text="Date of gift exchange: (mm/dd/yyyy)")
        lbl_date.grid(column=0, row=3 + NO_OF_ENTITIES, padx=20, pady=20)
        self.txt_date = Entry(self.root_obj, width=20)
        self.txt_date.grid(column=1, row=3 + NO_OF_ENTITIES, padx=20, pady=20)

        lbl_budget = Label(self.root_obj, text="Budget: (US$)")
        lbl_budget.grid(column=0, row=4 + NO_OF_ENTITIES, padx=5, pady=5)
        self.txt_budget = Entry(self.root_obj, width=20)
        self.txt_budget.grid(column=1, row=4 + NO_OF_ENTITIES, padx=5, pady=5)

        btn = Button(
            self.root_obj,
            width=15,
            text="Send Invitations",
            font=("Arial Bold", 10),
            command=self.send_invitations
        )
        btn.grid(
            column=0,
            row=5 + NO_OF_ENTITIES,
            padx=10,
            pady=30
        )

    def send_invitations(self):
        """
        Assigns secret santa to every participant and sends an email
        invite to respective members informing the same.
        :return:
        """

        event_date_str = self.txt_date.get()
        if event_date_str:
            try:
                event_date = datetime.strptime(event_date_str, "%m/%d/%Y")
            except ValueError:
                messagebox.showerror("Error", "Invalid date format.")
                return

            event_date_str = datetime.strftime(event_date, "%A - %d %b, %Y")
        else:
            event_date_str = "-"

        budget = self.txt_budget.get()
        try:
            budget = int(budget)
        except ValueError:
            messagebox.showerror("Error", "Invalid budget value.")
            return

        email_dict = {}
        participants = []
        for idx in range(NO_OF_ENTITIES):
            email = self.txt_email[idx].get()
            name = self.txt_name[idx].get()
            if name and email:
                email_dict[email] = name
                participants.append(email)
            else:
                if email and not name:
                    messagebox.showerror("Error", f"Name not found for entity no. {idx + 1}.")
                    return

                if name and not email:
                    messagebox.showerror("Error", f"Email mandatory for entity no. {idx + 1}.")
                    return

        if len(participants) < 2:
            messagebox.showerror("Error", "Insufficient participants.")
            return

        random.shuffle(participants)

        for i, _ in enumerate(participants):
            giver = participants[i]
            receiver = participants[(i + 1) % (len(participants))]
            Email().send(
                from_name="Secret Santa Generator",
                to_address=[giver],
                subject=EmailFormatter.subject(
                    email_dict[giver]
                ),
                body=EmailFormatter.body(
                    email_dict[giver],
                    email_dict[receiver],
                    event_date_str,
                    budget
                )
            )

        messagebox.showinfo("Success", "Invitations sent.")


class EmailFormatter:
    """
    Specifies the email subject and body content for invitations.
    """

    @staticmethod
    def subject(name):
        return f"{name}, you have drawn a name for Secret Santa!"

    @staticmethod
    def body(name1, name2, date_, budget):
        email_content = f"Hi {name1},\n\n"
        email_content += "The names have been drawn using the Python Secret Santa Generator. "
        email_content += "Find below your drawn name.\n\n"
        email_content += f"{name2}\n\n"
        email_content += f"Date of gift exchange: {date_}\n"
        email_content += f"Budget: US$ {budget}\n\n"
        email_content += "Have Fun!\n\n"
        email_content += "- Powered by Python"

        return email_content


def main():
    root = Tk()
    SecretSantaGUI(root).construct()
    root.mainloop()


if __name__ == "__main__":
    main()