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

def smtp_config():

    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)

    return (smtp_host, smtp_user_login, smtp_user_password, email_subject)

def db_config():

    config_filepath = "config/db_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)
    inactive_days = get_parameter("inactive_days", config_filepath)

    return (mastodon_db, mastodon_db_user, mailing_db, mailing_db_user, mailing_db_table, inactive_days)

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/db_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)

class Inactives:

    name = "Inactives"

    def __init__(self):

        smtp_host, smtp_user_login, smtp_user_password, email_subject = smtp_config()
        
        mastodon_db, mastodon_db_user, mailing_db, mailing_db_user, mailing_db_table, inactive_days = db_config()

        self.smtp_host = smtp_host
        self.smtp_user_login = smtp_user_login
        self.smtp_user_password = smtp_user_password
        self.email_subject = email_subject
        self.mastodon_db = mastodon_db
        self.mastodon_db_user = mastodon_db_user
        self.mailing_db = mailing_db
        self.mailing_db_user = mailing_db_user
        self.mailing_db_table = mailing_db_table
        self.inactive_days = inactive_days
        self.now = datetime.now(timezone.utc)

    def id(self):

        ###############################################################################
        # get id of inactive users from inactive database

        conn = None

        try:

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

            cur = conn.cursor()

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

            return inactive_users_id

        except (Exception, psycopg2.DatabaseError) as error:

            print(error)

        finally:

            if conn is not None:

                conn.close()

    def delete(self,ids_lst):

        print(f'\nChecking {len(ids_lst)} ids to delete reactivated or deleted accounts...')
        
        i = 0

        while i < len(ids_lst):

            seen = self.check_alive(self, ids_lst[i])

            try:

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

                cur = conn.cursor()

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

                row = cur.fetchone()

                email_datetime = row[0]

                email_datetime = email_datetime.replace(tzinfo=None)

                if seen != None:

                    reactivated = email_datetime < seen

                    last_year = datetime.today() - timedelta(days=int(self.inactive_days))

                if reactivated == True or seen == None or seen > last_year: #if inactive user had reactivated its account or had deleted it we must delete related row from 'mailing_db_table'

                    cur.execute("DELETE FROM " + self.mailing_db_table + " where account_id=(%s)", (ids_lst[i],))

                    print(f"Deleting user {ids_lst[i]}")

                    conn.commit()

                cur.close()

                i += 1

            except (Exception, psycopg2.DatabaseError) as error:

                print(error)

            finally:

                if conn is not None:

                    conn.close()

    def get_inactives(self):

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

        conn = None

        try:

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

            cur = conn.cursor()

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

            inactive_account_id = []
            
            inactive_email = []

            current_sign_in_at = []

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

                inactive_email.append(row[1])

                current_sign_in_at.append(row[2])

            cur.close()
            
            print(f'inactive accounts found: {len(inactive_account_id)}')

            return (inactive_account_id, inactive_email, current_sign_in_at)

        except (Exception, psycopg2.DatabaseError) as error:

            print(error)

        finally:

            if conn is not None:

                conn.close()

    def usernames(self, account_ids):

        ########################################################################################################
        # get accounts usernames                                                                                #
        ########################################################################################################

        inactive_usernames = []

        i = 0
        while i < len(account_ids):

            conn = None

            try:

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

                cur = conn.cursor()

                inactive_id = account_ids[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()

        return inactive_usernames

    def mailing(self, account_ids, account_emails, account_usernames, account_current_sign_in_ats):

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

        try:

            fp = open('message.txt')
            text = fp.read()
            message = MIMEText(text)
            fp.close()
      
        except:

            print("message.txt file not found! Create it and write in the message you want for your inactive users.")
            sys.exit(0)

        i = 0
        while i < len(account_emails):

            been_emailed = self.email_sent(self, account_ids[i])

            if been_emailed == False:

                # Create message object instance
                msg = MIMEMultipart()

                # Declare message elements
                msg['From'] = self.smtp_user_login
                msg['To'] = account_emails[i]
                msg['Subject'] = account_usernames[i] + " " + self.email_subject

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

                try:

                    # Create the server connection
                    server = smtplib.SMTP(self.smtp_host)
                    # Switch the connection over to TLS encryption
                    server.starttls()
                    # Authenticate with the server
                    server.login(self.smtp_user_login, self.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

                    self.write_db(self, self.now, account_ids[i], account_usernames[i], account_emails[i], self.now, emailed, account_current_sign_in_ats[i]) 

                    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
                    self.write_db(self, self.now, account_ids[i], account_usernames[i], account_emails[i], self.now, emailed, account_current_sign_in_ats[i])
                    i += 1

            else:

                emailed = True
                self.write_db(self, self.now, account_ids[i], account_usernames[i], account_emails[i], self.now, emailed, account_current_sign_in_ats[i])
                i += 1

    @staticmethod
    def write_db(self, now, id, username, email, emailed_at, emailed, current_sign_in_at):
        
        ###################################################################################
        # write to mailing database the status of inactive users


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

        conn = None

        try:

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

            cur = conn.cursor()

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

            row = cur.fetchone()

            if row == None:

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

            else:

                if emailed == True:

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

                    row = cur.fetchone()

                    delta = now-row[0]

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

                    print(f"Updating user {str(id)}")

            conn.commit()

            cur.close()

        except (Exception, psycopg2.DatabaseError) as error:

            print(error)

        finally:

            if conn is not None:

                conn.close()

    @staticmethod
    def email_sent(self, account_id):

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

        been_emailed = False

        conn = None
        
        try:

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

            cur = conn.cursor()

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

            row = cur.fetchone()

            if row != None:

                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()

    @staticmethod
    def check_alive(self, id):

        conn = None

        try:

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

            cur = conn.cursor()

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

            row = cur.fetchone()

            if row != None:
                
                seen = row[0]
            else:
                
                seen = None
            
            cur.close()

            return seen

        except (Exception, psycopg2.DatabaseError) as error:

            print(error)