__author__ = "Akshen Doke"

import hashlib
import logging
import logging.config
import yaml
import re
from django.core.mail import send_mail
from textwrap import dedent
from random import randint
from smtplib import SMTP
from django.utils.crypto import get_random_string
from string import punctuation, digits
try:
    from string import letters
except ImportError:
    from string import ascii_letters as letters
from nccps2018.config import (
    EMAIL_HOST,
    EMAIL_PORT,
    EMAIL_HOST_USER,
    EMAIL_HOST_PASSWORD,
    EMAIL_USE_TLS,
    PRODUCTION_URL,
    SENDER_EMAIL,
    ADMIN_EMAIL
)
from django.core.mail import EmailMultiAlternatives
from django.conf import settings
from os import listdir, path
from email.mime.multipart import MIMEMultipart
from email.mime.text import MIMEText
from email.mime.base import MIMEBase
from email import encoders
from time import sleep
from nccps2018.settings import LOG_FOLDER


def validateEmail(email):
    if len(email) > 7:
        if re.match("^.+\\@(\\[?)[a-zA-Z0-9\\-\\.]+\\.([a-zA-Z]{2,3}|[0-9]{1,3})(\\]?)$",
                    email) != None:
            return 1
        return 0


def generate_activation_key(username):
    """Generates hashed secret key for email activation"""
    chars = letters + digits + punctuation
    secret_key = get_random_string(randint(10, 40), chars)
    return hashlib.sha256((secret_key + username).encode('utf-8')).hexdigest()


def send_smtp_email(request=None, subject=None, message=None,
                    user_position=None, workshop_date=None,
                    workshop_title=None, user_name=None,
                    other_email=None, phone_number=None,
                    institute=None, attachment=None):
    '''
        Send email using SMTPLIB
    '''

    msg = MIMEMultipart()
    msg['From'] = EMAIL_HOST_USER
    msg['To'] = other_email
    msg['Subject'] = subject
    body = message
    msg.attach(MIMEText(body, 'plain'))

    if attachment:
        from django.conf import settings
        from os import listdir, path
        files = listdir(settings.MEDIA_ROOT)
        for f in files:
            attachment = open(path.join(settings.MEDIA_ROOT, f), 'rb')
            part = MIMEBase('application', 'octet-stream')
            part.set_payload((attachment).read())
            encoders.encode_base64(part)
            part.add_header('Content-Disposition',
                            "attachment; filename= %s " % f)
            msg.attach(part)

    server = SMTP(EMAIL_HOST, EMAIL_PORT)
    server.ehlo()
    server.starttls()
    server.ehlo()
    server.esmtp_features['auth'] = 'LOGIN DIGEST-MD5 PLAIN'
    server.login(EMAIL_HOST_USER, EMAIL_HOST_PASSWORD)
    text = msg.as_string()
    server.sendmail(EMAIL_HOST_USER, other_email, text)
    server.close()


def send_email(request, call_on,
               user_position=None, workshop_date=None,
               new_workshop_date=None,
               workshop_title=None, user_name=None,
               other_email=None, phone_number=None,
               institute=None, key=None
               ):
    '''
    Email sending function while registration and
    booking confirmation.
    '''
    try:
        with open(path.join(LOG_FOLDER, 'emailconfig.yaml'), 'r') as configfile:
            config_dict = yaml.load(configfile)
        logging.config.dictConfig(config_dict)
    except:
        print('File Not Found and Configuration Error')
        print(LOG_FOLDER)
    if call_on == "Registration":
        message = dedent("""\
                    Thank you for registering with us.

                    Please click on the below link to
                    activate your account
                    {0}/activate_user/{1}

                    After activation you can proceed to book your ticket for
                    the conference/ propose a paper.

                    In case of queries regarding ticket booking and proposing a paper,
                    revert to this email.""".format(PRODUCTION_URL, key))

        logging.info("New Registration from: %s", request.user.email)
        try:
            send_mail(
                "NCCPS-2018 Registration at FOSSEE, IIT Bombay", message, SENDER_EMAIL,
                [request.user.email], fail_silently=True
            )

        except Exception:
            send_smtp_email(request=request,
                            subject="NCCPS-2018 Registration - FOSSEE, IIT Bombay",
                            message=message, other_email=request.user.email,
                            )

    elif call_on == "Booking":
        if user_position == "instructor":
            message = dedent("""\
                    Coordinator name:{0}
                    Coordinator email: {1}
                    Contact number:{2}
                    Institute:{3}
                    Workshop date:{4}
                    Workshop title:{5}

                    You may accept or reject this booking
                    {6}/my_workshops/ .""".format(
                user_name, request.user.email,
                request.user.profile.phone_number,
                request.user.profile.institute,
                workshop_date, workshop_title,
                PRODUCTION_URL
            ))

            logging.info("Booking Done by{0} for {1} ".format(request.user.email,
                                                              other_email))
            try:
                send_mail(
                    "New FOSSEE Workshop booking on {0}".format(workshop_date),
                    message, SENDER_EMAIL, [other_email],
                    fail_silently=True
                )
            except Exception:
                send_smtp_email(request=request,
                                subject="New FOSSEE Workshop booking on {0}"
                                .format(workshop_date),
                                message=message, other_email=other_email,
                                )
        else:
            message = dedent("""\
                    Thank You for New FOSSEE Workshop booking.

                    Workshop date:{0}
                    Workshop title:{1}

                    Your request has been received and is awaiting instructor
                    approval/disapproval. You will be notified about the status
                    via email and on {2}/my_workshops/

                    Please Note: Unless you get a confirmation email for this workshop with
                    the list of instructions, your workshop shall be in the waiting list.

                    In case of queries regarding workshop booking(s), revert
                    to this email.""".format(
                workshop_date, workshop_title, PRODUCTION_URL
            ))

            try:
                send_mail(
                    "Pending Request for New FOSSEE Workshop booking on {0}"
                    .format(workshop_date), message, SENDER_EMAIL,
                    [request.user.email], fail_silently=True
                )
            except Exception:
                send_smtp_email(request=request,
                                subject="Pending Request for New FOSSEE Workshop booking \
                    on {0}".format(workshop_date),
                                message=message, other_email=request.user.email,
                                )

    elif call_on == "Booking Confirmed":
        if user_position == "instructor":
            message = dedent("""\
            Coordinator name:{0}
            Coordinator email: {1}
            Contact number:{2}
            Institute:{3}
            Workshop date:{4}
            Workshop title:{5}

            You have accepted this booking.  Detailed instructions have
            been sent to the coordinator. 
            
            This is a auto-generated mail.
            """.format(user_name, other_email,
                       phone_number, institute, workshop_date, workshop_title))

            logging.info("Booking Confirmed by {0} for {1} ".format(request.user.email,
                                                                    other_email))

            subject = "FOSSEE Workshop booking confirmation  on {0}".\
                format(workshop_date)
            msg = EmailMultiAlternatives(
                subject, message, SENDER_EMAIL, [request.user.email])
            attachment_paths = path.join(
                settings.MEDIA_ROOT, workshop_title.replace(" ", "_"))
            files = listdir(attachment_paths)
            for f in files:
                attachment = open(path.join(attachment_paths, f), 'rb')
                part = MIMEBase('application', 'octet-stream')
                part.set_payload((attachment).read())
                encoders.encode_base64(part)
                part.add_header('Content-Disposition',
                                "attachment; filename= %s " % f)
                msg.attach(part)
                sleep(1)
            msg.send()

        else:
            message = dedent("""\
                Instructor name:{0}
                Instructor email: {1}
                Contact number:{2}
                Workshop date:{3}
                Workshop title:{4}

                Your workshop booking has been accepted. Detailed
                instructions are attached below.

                In case of queries regarding the workshop
                instructions/schedule revert to this email.""".format(
                request.user.username, request.user.email,
                phone_number, workshop_date, workshop_title
            ))

            subject = "FOSSEE Workshop booking confirmation  on {0}".\
                format(workshop_date)
            msg = EmailMultiAlternatives(
                subject, message, SENDER_EMAIL, [other_email])
            attachment_paths = path.join(
                settings.MEDIA_ROOT, workshop_title.replace(" ", "_"))
            files = listdir(attachment_paths)
            for f in files:
                attachment = open(path.join(attachment_paths, f), 'rb')
                part = MIMEBase('application', 'octet-stream')
                part.set_payload((attachment).read())
                encoders.encode_base64(part)
                part.add_header('Content-Disposition',
                                "attachment; filename= %s " % f)
                msg.attach(part)
            msg.send()

    elif call_on == "Booking Request Rejected":
        if user_position == "instructor":
            message = dedent("""\
                    Coordinator name: {0}
                    Coordinator email: {1}
                    Contact number: {2}
                    Institute: {3}
                    Workshop date: {4}
                    Workshop title: {5}

                    You have rejected this booking.  The coordinator has
                    been notified.
                    
                    This is a auto-generated mail.
                    """.format(user_name, other_email,
                               phone_number, institute,
                               workshop_date, workshop_title))

            logging.info("Booking Rejected by {0} for {1} ".format(request.user.email,
                                                                   other_email))

            try:
                send_mail("FOSSEE Workshop booking rejected for {0}"
                          .format(workshop_date), message, SENDER_EMAIL,
                          [request.user.email], fail_silently=True)
            except Exception:
                send_smtp_email(request=request,
                                subject="FOSSEE Workshop booking rejected for {0}".
                                format(workshop_date), message=message,
                                other_email=request.user.email
                                )
        else:
            message = dedent("""\
                    Workshop date:{0}
                    Workshop title:{1}

                    We regret to inform you that your workshop booking
                    has been rejected due to unavailability of the
                    instructor. You may try booking other available
                    slots {2}/book/ or you can also Propose a workshop
                    based on your available date.
                    
                    This is a auto-generated mail.
                    """
                             .format(workshop_date, workshop_title, PRODUCTION_URL))

            try:
                send_mail("FOSSEE Workshop booking rejected for {0}".
                          format(workshop_date), message, SENDER_EMAIL,
                          [other_email], fail_silently=True)
            except Exception:
                send_smtp_email(request=request,
                                subject="FOSSEE Workshop booking rejected for {0}".
                                format(workshop_date), message=message,
                                other_email=other_email
                                )

    elif call_on == 'Workshop Deleted':
        message = dedent("""\
                You have deleted a Workshop.

                Workshop date:{0}
                Workshop title:{1}
                
                This is a auto-generated mail.
                """
                         .format(workshop_date, workshop_title))

        logging.info("Workshop Deleted by {0} for {1} ".format(request.user.email,
                                                               workshop_date))
        try:
            send_mail("FOSSEE workshop deleted for {0}".format(workshop_date),
                      message, SENDER_EMAIL, [request.user.email],
                      fail_silently=True)
        except Exception:
            send_smtp_email(request=request,
                            subject="FOSSEE Workshop deleted for {0}".
                            format(workshop_date), message=message,
                            other_email=request.user.email
                            )

    elif call_on == 'Proposed Workshop':
        if user_position == "instructor":
            message = dedent("""\
                    A coordinator has proposed a workshop. The details are 
                    given below:

                    Coordinator name: {0}
                    Coordinator email: {1}
                    Contact number: {2}
                    Institute: {3}
                    Workshop date: {4}
                    Workshop title: {5}

                    Please Accept only if you are willing to take the workshop.
                    {6}/my_workshops/ 

                    This is a auto-generated mail.
                    """
                             .format(user_name, request.user.email,
                                     phone_number, institute,
                                     workshop_date, workshop_title,
                                     PRODUCTION_URL))

            logging.info("Workshop Proposed by {0} for {1} ".format(request.user.email,
                                                                    workshop_date))

            send_mail("Proposed Workshop on {0}".
                      format(workshop_date), message, SENDER_EMAIL,
                      [other_email], fail_silently=False)

    elif call_on == 'Change Date':
        if user_position == "instructor":
            message = dedent("""\
                    Dear Instructor,

                    Your workshop date has been changed from {0} to {1}.
                    
                    This is a auto-generated mail.
                    """
                             .format(
                                 workshop_date, new_workshop_date))

            logging.info("Workshop Date Changed Done by {0} from {1} to {2}"
                         .format(request.user.email,
                                 new_workshop_date, workshop_date))
            try:
                send_mail(
                    "FOSSEE Python Workshop Date Changed",
                    message, SENDER_EMAIL, [request.user.email],
                    fail_silently=True
                )
            except Exception:
                send_smtp_email(request=request,
                                subject="FOSSEE Python Workshop Date Changed",
                                message=message, other_email=other_email,
                                )
        else:
            message = dedent("""\
                    Dear Coordinator,

                    Your workshop has been rescheduled from {0} to {1}.
                    
                    This is a auto-generated mail.
                    """
                             .format(
                                 workshop_date, new_workshop_date
                             ))

            try:
                send_mail(
                    "FOSSEE Python Workshop Date Changed",
                    message, SENDER_EMAIL,
                    [other_email], fail_silently=True
                )
            except Exception:
                send_smtp_email(request=request,
                                subject="FOSSEE Python Workshop Date Changed",
                                message=message, other_email=request.user.email,
                                )