import cStringIO as StringIO
import re
import urllib2
from io import BytesIO

import reversion
from PyPDF2 import PdfFileReader, PdfFileMerger
from django.conf import settings
from django.core.mail import EmailMessage
from django.template.loader import get_template
from z3c.rml import rml2pdf

from RIGS import models


def send_eventauthorisation_success_email(instance):
    # Generate PDF first to prevent context conflicts
    context = {
        'object': instance.event,
        'fonts': {
            'opensans': {
                'regular': 'RIGS/static/fonts/OPENSANS-REGULAR.TTF',
                'bold': 'RIGS/static/fonts/OPENSANS-BOLD.TTF',
            }
        },
        'receipt': True,
        'current_user': False,
    }

    template = get_template('RIGS/event_print.xml')
    merger = PdfFileMerger()

    rml = template.render(context)

    buffer = rml2pdf.parseString(rml)
    merger.append(PdfFileReader(buffer))
    buffer.close()

    terms = urllib2.urlopen(settings.TERMS_OF_HIRE_URL)
    merger.append(StringIO.StringIO(terms.read()))

    merged = BytesIO()
    merger.write(merged)

    # Produce email content
    context = {
        'object': instance,
    }

    subject = "N%05d | %s - Event Authorised" % (instance.event.pk, instance.event.name)

    client_email = EmailMessage(
        subject,
        get_template("RIGS/eventauthorisation_client_success.txt").render(context),
        to=[instance.email],
        reply_to=[settings.AUTHORISATION_NOTIFICATION_ADDRESS],
    )

    escapedEventName = re.sub('[^a-zA-Z0-9 \n\.]', '', instance.event.name)

    client_email.attach('N%05d - %s - RECEIPT.pdf' % (instance.event.pk, escapedEventName),
                        merged.getvalue(),
                        'application/pdf'
                        )

    if instance.event.mic:
        mic_email_address = instance.event.mic.email
    else:
        mic_email_address = settings.AUTHORISATION_NOTIFICATION_ADDRESS

    mic_email = EmailMessage(
        subject,
        get_template("RIGS/eventauthorisation_mic_success.txt").render(context),
        to=[mic_email_address]
    )

    # Now we have both emails successfully generated, send them out
    client_email.send()
    mic_email.send()


def on_revision_commit(instances, **kwargs):
    for instance in instances:
        if isinstance(instance, models.EventAuthorisation):
            send_eventauthorisation_success_email(instance)


reversion.post_revision_commit.connect(on_revision_commit)