"""This file houses various core utility functions for GPP"""
import datetime
import re
import logging

import django.core.mail
from django.contrib.sites.models import Site
from django.conf import settings

import mailer


def send_mail(subject, message, from_email, recipient_list,
        fail_silently=False, auth_user=None, auth_password=None,
        expedite=False):
    """The main gpp send email function.
    Use this function to send email from the site. It will obey debug settings and
    log all emails. The expedite flag, when True, will bypass the mail queue.
    """
    recipient_list = [dest for dest in recipient_list if dest]
    if not recipient_list:
        logging.warning("Empty recipient_list in send_mail")
        return

    if settings.MAILER_ENQUEUE_MAIL and not expedite:
        mailer.enqueue_mail(subject, message, from_email, recipient_list)
    elif settings.GPP_SEND_EMAIL:
        django.core.mail.send_mail(subject, message, from_email, recipient_list,
                fail_silently, auth_user, auth_password)

    logging.debug('EMAIL:\nFrom: %s\nTo: %s\nSubject: %s\nMessage:\n%s',
        from_email, str(recipient_list), subject, message)


def email_admins(subject, message):
    """Emails the site admins. Goes through the site send_mail function."""
    site = Site.objects.get_current()
    subject = '[%s] %s' % (site.name, subject)
    send_mail(subject,
            message,
            '%s@%s' % (settings.GPP_NO_REPLY_EMAIL, site.domain),
            [mail_tuple[1] for mail_tuple in settings.ADMINS])


def email_managers(subject, message):
    """Emails the site managers. Goes through the site send_mail function."""
    site = Site.objects.get_current()
    subject = '[%s] %s' % (site.name, subject)
    send_mail(subject,
            msg,
            '%s@%s' % (settings.GPP_NO_REPLY_EMAIL, site.domain),
            [mail_tuple[1] for mail_tuple in settings.MANAGERS])


def get_full_name(user):
    """Returns the user's full name if available, otherwise falls back
    to the username."""
    full_name = user.get_full_name()
    if full_name:
        return full_name
    return user.username


BASE_YEAR = 2010

def copyright_str():
    curr_year = datetime.datetime.now().year
    if curr_year == BASE_YEAR:
        year_range = str(BASE_YEAR)
    else:
        year_range = "%d - %d" % (BASE_YEAR, curr_year)

    return 'Copyright (C) %s, SurfGuitar101.com' % year_range


IP_PAT = re.compile('(\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})')

def get_ip(request):
    """Returns the IP from the request or None if it cannot be retrieved."""
    ip = request.META.get('HTTP_X_FORWARDED_FOR',
            request.META.get('REMOTE_ADDR'))

    if ip:
        match = IP_PAT.match(ip)
        ip = match.group(1) if match else None

    return ip


def get_page(qdict):
    """Attempts to retrieve the value for "page" from the given query dict and
    return it as an integer. If the key cannot be found or converted to an
    integer, 1 is returned.
    """
    n = qdict.get('page', 1)
    try:
        n = int(n)
    except ValueError:
        n = 1
    return n