import smtplib
import time

from string import Template

from email.mime.multipart import MIMEMultipart
from email.mime.text import MIMEText

import pandas as pd

from vars import *


def get_contacts(filename):
    """
    Return the lists containing the infos
    read from a file specified by filename.
    """

    return pd.read_csv(filename)


def read_template(filename):
    """
    Returns a Template object comprising the contents of the
    file specified by filename.
    """

    with open(filename, 'r', encoding='utf-8') as template_file:
        template_file_content = template_file.read()
    return Template(template_file_content)


def main():
    contacts = get_contacts('contacts.csv')
    message_template = read_template('message.html')

    # set up the SMTP server
    s = smtplib.SMTP(HOST, PORT)
    s.starttls()
    s.login(MY_ADDRESS, PASSWORD)

    # For each contact, send the email:
    for i in contacts.index:
        print(f"Sending email {i+1}\n")
        msg = MIMEMultipart()       # create a message

        # add in the actual person name to the message template
        contact_dict = {col: contacts[col][i] for col in contacts.columns}
        message = message_template.substitute(contact_dict)

        # Prints out the message body for our sake
        print(f"{message}\n")

        # setup the parameters of the message
        msg['From'] = MY_ADDRESS
        msg['To'] = contacts[MAIL_COLUMN][i]
        msg['Subject'] = SUBJECT

        # add in the message body
        msg.attach(MIMEText(message, 'html'))

        # send the message via the server set up earlier.
        s.send_message(msg)
        del msg

        if (i + 1) % WAIT_EVERY == 0:
            time.sleep(DELAY_SEC)

    # Terminate the SMTP session and close the connection
    s.quit()


if __name__ == '__main__':
    main()