#!/usr/bin/env python
# -*- coding: utf-8 -*-

from datetime import datetime, timezone
import time
import threading
import os
import sys
import os.path
from email.mime.multipart import MIMEMultipart
from email.mime.text import MIMEText
import smtplib
from smtplib import SMTPException, SMTPAuthenticationError, SMTPConnectError, SMTPRecipientsRefused
import psycopg2
import socket 
from socket import gaierror

###################################################################################
# write to database mailing status of inactive users
###################################################################################

def write_db(now, id, username, email, emailed_at, emailed):

  insert_line = "INSERT INTO " + mailing_db_table + "(datetime, account_id, username, email, emailed_at, emailed) VALUES(%s,%s,%s,%s,%s,%s) ON CONFLICT DO NOTHING"

  conn = None

  try:

    conn = psycopg2.connect(database = mailing_db, user = mailing_db_user, password = "", host = "/var/run/postgresql", port = "5432")

    cur = conn.cursor()

    cur.execute("SELECT account_id FROM " + mailing_db_table + " where account_id=(%s)", (id,))

    row = cur.fetchone()

    if row == None:

      cur.execute(insert_line, (now, id, username, email, now, emailed))

    else:

      if emailed == True:

        cur.execute("SELECT datetime FROM " + mailing_db_table + " where account_id=(%s)", (id,))

        row = cur.fetchone()
        delta = now-row[0]

        cur.execute("UPDATE " + mailing_db_table + " SET elapsed_days=(%s), email=(%s), emailed=(%s) where account_id=(%s)", (delta, email, emailed, id))
     
    conn.commit()

    cur.close()

  except (Exception, psycopg2.DatabaseError) as error:

    print(error)

  finally:

    if conn is not None:

      conn.close()

###############################################################################
# check if inactive user had been already emailed
###############################################################################

def email_sent(id):

  try:

    conn = psycopg2.connect(database = mailing_db, user = mailing_db_user, password = "", host = "/var/run/postgresql", port = "5432")

    cur = conn.cursor()

    cur.execute("SELECT emailed FROM " + mailing_db_table + " where account_id=(%s)", (id,))

    row = cur.fetchone()

    if row == None:

      been_emailed = False

    else:
 
      been_emailed = row[0]

    cur.close()

    return been_emailed

  except (Exception, psycopg2.DatabaseError) as error:

    print(error)

  finally:

    if conn is not None:

      conn.close() 

###############################################################################
# Connect to Mastodon's Postgres DB to check if any inactive user is back online 
###############################################################################

def check_alive(id):

  try:

    conn = psycopg2.connect(database = mastodon_db, user = mastodon_db_user, password = "", host = "/var/run/postgresql", port = "5432")

    cur = conn.cursor()

    cur.execute("select last_sign_in_at from users where account_id=(%s)", (id,))

    row = cur.fetchone()
    seen = row[0]

    cur.close()

    return seen

  except (Exception, psycopg2.DatabaseError) as error:

    print(error)

###############################################################################
# INITIALISATION
###############################################################################

# Returns the parameter from the specified file
def get_parameter( parameter, file_path ):
    # Check if secrets file exists
    if not os.path.isfile(file_path):
        if file_path == "secrets/secrets.txt":
          print("File %s not found, exiting. Run setup.py."%file_path)
        elif file_path == "config.txt":
          print("File %s not found, exiting. Run db-setup.py."%file_path)
        sys.exit(0)

    # Find parameter in file
    with open( file_path ) as f:
        for line in f:
            if line.startswith( parameter ):
                return line.replace(parameter + ":", "").strip()

    # Cannot find parameter, exit
    print(file_path + "  Missing parameter %s "%parameter)
    print("Run setup.py")
    sys.exit(0)

# Load secrets from secrets file
secrets_filepath = "secrets/secrets.txt"
smtp_host = get_parameter("smtp_host", secrets_filepath)
smtp_user_login = get_parameter("smtp_user_login", secrets_filepath)
smtp_user_password = get_parameter("smtp_user_password", secrets_filepath)
email_subject = get_parameter("email_subject", secrets_filepath)

# Load configuration from config file
config_filepath = "config.txt"
mastodon_db = get_parameter("mastodon_db", config_filepath)
mastodon_db_user = get_parameter("mastodon_db_user", config_filepath)
mailing_db = get_parameter("mailing_db", config_filepath)
mailing_db_user = get_parameter("mailing_db_user", config_filepath)
mailing_db_table = get_parameter("mailing_db_table", config_filepath)

###############################################################################
# check if inactive user is back online
###############################################################################

try:

  conn = psycopg2.connect(database = mailing_db, user = mailing_db_user, password = "", host = "/var/run/postgresql", port = "5432")

  cur = conn.cursor()

  cur.execute("SELECT account_id FROM " + mailing_db_table)

  rows = cur.fetchall()
  if rows != []:

    inactive_users_id = []

    for row in rows:

      inactive_users_id.append(row[0])

  else:
   
    inactive_users_id = []

  cur.close()

except (Exception, psycopg2.DatabaseError) as error:

  print(error)

finally:

  if conn is not None:

    conn.close()

i = 0
while i < len(inactive_users_id):
 
  seen = check_alive(inactive_users_id[i])

  try:

    conn = psycopg2.connect(database = mailing_db, user = mailing_db_user, password = "", host = "/var/run/postgresql", port = "5432")

    cur = conn.cursor()

    cur.execute("SELECT emailed_at FROM " + mailing_db_table + " where account_id=(%s)", (inactive_users_id[i],))

    row = cur.fetchone()
    email_datetime = row[0]
    email_datetime = email_datetime.replace(tzinfo=None)

    if email_datetime < seen:
     
      cur.execute("DELETE FROM " + mailing_db_table + " where account_id=(%s)", (inactive_users_id[i],))

      conn.commit()

    cur.close()

    i += 1

  except (Exception, psycopg2.DatabaseError) as error:

    print(error)

  finally:

    if conn is not None:

      conn.close()
  
###############################################################################

now = datetime.now(timezone.utc)

###############################################################################
# Connect to Mastodon's Postgres DB to get last year inactive users 
###############################################################################

try:

  conn = psycopg2.connect(database = mastodon_db, user = mastodon_db_user, password = "", host = "/var/run/postgresql", port = "5432")

  cur = conn.cursor()

  cur.execute("select account_id, email from users where last_sign_in_at < now() - interval '365 days' and disabled=False and approved=True order by last_sign_in_at desc;")
  rows = cur.fetchall()

  inactive_account_id = []
  inactive_email = []

  for row in rows:
    inactive_account_id.append(row[0])
    inactive_email.append(row[1])

  cur.close()

except (Exception, psycopg2.DatabaseError) as error:

  print(error)

########################################################################################################
# get related usernames                                                                                #
########################################################################################################

inactive_usernames = []

i = 0
while i < len(inactive_account_id):

  try:

    conn = psycopg2.connect(database = mastodon_db, user = mastodon_db_user, password = "", host = "/var/run/postgresql", port = "5432")

    cur = conn.cursor()

    inactive_id = inactive_account_id[i]
    cur.execute("select username from accounts where id = '%s';", [inactive_id])

    row = cur.fetchone()
    new_username = row[0]
    inactive_usernames.append(new_username)

    i += 1

    cur.close()

  except (Exception, psycopg2.DatabaseError) as error:

    print(error)

  finally:

    if conn is not None:

      conn.close()

###########################################################################################################
# email inactive users
###########################################################################################################

try:

  fp = open('message.txt')
  text = fp.read()
  message = MIMEText(text)
  print(type(message))
  print(message)

except:

  print("message.txt file not found! Create it and write in the message you want for your inactive users.")

finally:

  fp.close()

i = 0
while i < len(inactive_email):

  been_emailed = email_sent(inactive_account_id[i])

  if been_emailed == False:

    # Create message object instance
    msg = MIMEMultipart()

    # Declare message elements
    msg['From'] = smtp_user_login
    msg['To'] = inactive_email[i]
    msg['Subject'] = inactive_usernames[i] + " " + email_subject

    # Add the message body to the object instance
    msg.attach(message)

    try:

      # Create the server connection 
      server = smtplib.SMTP(smtp_host)
      # Switch the connection over to TLS encryption
      server.starttls() 
      # Authenticate with the server
      server.login(smtp_user_login, smtp_user_password)
      # Send the message
      server.sendmail(msg['From'], msg['To'], msg.as_string())
      # Disconnect 
      server.quit()

      print("Successfully sent email message to %s" % msg['To'])
      emailed = True
      write_db(now, inactive_account_id[i], inactive_usernames[i], inactive_email[i], now, emailed) 

      i += 1
      time.sleep(5)
   
    except SMTPAuthenticationError as auth_error:
 
      print(auth_error)
      sys.exit(":-(")

    except socket.gaierror as socket_error:

      print(socket_error)
      print("Unknown SMTP server") 
      sys.exit(":-(")

    except SMTPRecipientsRefused as recip_error:

      print(recip_error)
      emailed = False
      write_db(now, inactive_account_id[i], inactive_usernames[i], inactive_email[i], now, emailed)
      i += 1

  else:

    emailed = True
    write_db(now, inactive_account_id[i], inactive_usernames[i], inactive_email[i], now, emailed)
    i += 1