# -*- coding: utf-8 -*-
from __future__ import unicode_literals

import os
import hashlib
import binascii
import base64
import html2text
import re
import sys
from datetime import date, timedelta
from contextlib import contextmanager
from functools import wraps

from django.utils import translation
from django.core.mail import EmailMultiAlternatives
from django.core.files.storage import FileSystemStorage
from django.conf import settings
from django.template.loader import get_template
from django.template import Context, TemplateDoesNotExist
from django.contrib.sites.models import Site


# Stockage des fichiers privés (comme les factures par exemple)
private_files_storage = FileSystemStorage(location=settings.PRIVATE_FILES_ROOT)

# regexp which matches for ex irc://irc.example.tld/#channel
re_chat_url = re.compile(r'(?P<protocol>\w+://)(?P<server>[\w\.]+)/(?P<channel>.*)')

def str_or_none(obj):
    return str(obj) if obj else None

def rstrip_str(s, suffix):
    """Return a copy of the string [s] with the string [suffix] removed from
    the end (if [s] ends with [suffix], otherwise return s)."""
    if s.endswith(suffix):
        return s[:-len(suffix)]
    else:
        return s

def ldap_hash(password):
    """Hash a password for use with LDAP.  If the password is already hashed,
    do nothing.

    Implementation details: Django provides us with a unicode object, so
    we have to encode/decode it as needed to switch between unicode and
    bytes.  The code should work fine with both python2 and python3.
    """
    if password and not password.startswith('{SSHA}'):
        salt = binascii.hexlify(os.urandom(8))
        digest = hashlib.sha1(password.encode("utf-8") + salt).digest()
        return '{SSHA}' + base64.b64encode(digest + salt).decode("utf-8")
    else:
        return password


def send_templated_email(to, subject_template, body_template, context={}, attachements=[], **kwargs):
    """
    Send a multialternative email based on html and optional txt template.

    :param **kwargs: extra-args pased as-is to EmailMultiAlternatives()
    """

    # Ensure arrays when needed
    if not isinstance(to, list):
        to = [to]
    if not isinstance(attachements, list):
        attachements = [attachements]

    # Add domain in context
    context['domain'] = Site.objects.get_current()

    # If .html/.txt is specified in template name remove it
    body_template = body_template.split('.')[0]
    subject_template = subject_template.split('.')[0]

    # Get html template for body, fail if not exists
    template_html = get_template('%s.html' % (body_template,))
    html_content = template_html.render(Context(context))

    # Get txt template for subject, fail if not exists
    subject_template = get_template('%s.txt' % (subject_template,))
    subject = subject_template.render(Context(context))
    # Get rid of newlines
    subject = subject.strip().replace('\n', '')

    # Try to get a txt version, convert from html to markdown style
    # (using html2text) if fail
    try:
        template_txt = get_template('%s.txt' % (body_template,))
        text_content = template_txt.render_to_string(Context(context))
    except TemplateDoesNotExist:
        text_content = html2text.html2text(html_content)

    # make multipart email default : text, alternative : html
    msg = EmailMultiAlternatives(subject=subject, body=text_content, to=to, **kwargs)
    msg.attach_alternative(html_content, "text/html")

    # Set attachements
    for attachement in attachements:
        msg.attach_file(attachement)

    # Send email
    msg.send()


def delete_selected(modeladmin, request, queryset):
    """Overrides QuerySet's delete() function to remove objects one by one
    so, that they are deleted in the LDAP (Redmine issue #195)."""
    for obj in queryset:
        obj.delete()

delete_selected.short_description = "Supprimer tous les objets sélectionnés."

# Time-related functions


def in_one_year():
    return date.today() + timedelta(365)


def start_of_month():
    return date(date.today().year, date.today().month, 1)


def end_of_month():
    today = date.today()
    if today.month == 12:
        return date(today.year + 1, 1, 1) - timedelta(days=1)
    else:
        return date(today.year, today.month + 1, 1) - timedelta(days=1)

@contextmanager
def respect_language(language):
    """Context manager that changes the current translation language for
    all code inside the following block.
    Can be used like this::
        from amorce.utils import respect_language
        def my_func(language='fr'):
            with respect_language(language):
                pass
    """
    if language:
        prev = translation.get_language()
        translation.activate(language)
        try:
            yield
        finally:
            translation.activate(prev)
    else:
        yield


def respects_language(fun):
    """Associated decorator"""
    @wraps(fun)
    def _inner(*args, **kwargs):
        with respect_language(kwargs.pop('language', None)):
            return fun(*args, **kwargs)
    return _inner


def disable_for_loaddata(signal_handler):
    """Decorator for post_save events that disables them when loading
    data from fixtures."""
    @wraps(signal_handler)
    def wrapper(*args, **kwargs):
        if kwargs['raw']:
            return
        signal_handler(*args, **kwargs)
    return wrapper


def postgresql_regexp(regexp):
    """ Make a PCRE regexp PostgreSQL compatible (kinda)

    PostgreSQL forbids using capture-group names, this function removes them.
    :param regexp: a PCRE regexp or pattern
    :return a PostgreSQL regexp
    """
    try:
        original_pattern = regexp.pattern
    except AttributeError:
        original_pattern = regexp

    return re.sub(
        r'\?P<.*?>', '', original_pattern)


if __name__ == '__main__':
    # ldap_hash expects an unicode string
    print(ldap_hash(sys.argv[1].decode("utf-8")))