# -*- encoding: utf-8 -*-
##############################################################################
#
#    OpenERP, Open Source Management Solution
#    This module copyright (C) 2014 Savoir-faire Linux
#    (<http://www.savoirfairelinux.com>).
#
#    This program is free software: you can redistribute it and/or modify
#    it under the terms of the GNU Affero General Public License as
#    published by the Free Software Foundation, either version 3 of the
#    License, or (at your option) any later version.
#
#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU Affero General Public License for more details.
#
#    You should have received a copy of the GNU Affero General Public License
#    along with this program.  If not, see <http://www.gnu.org/licenses/>.
#
##############################################################################

from datetime import datetime
import logging
_logger = logging.getLogger(__name__)

import pytz
from jinja2 import contextfilter

from openerp.tools import (
    DEFAULT_SERVER_DATETIME_FORMAT as DTFMT,
    DEFAULT_SERVER_DATE_FORMAT as DFMT,
)
from openerp.addons.email_template import email_template


@contextfilter
def format_date(context, dtstr, new_format, tz=None):
    if not dtstr:
        return dtstr

    try:
        date = datetime.strptime(dtstr, DTFMT)
    except ValueError:
        # Maybe this is a date, not datetime
        date = datetime.strptime(dtstr, DFMT)

    if tz:
        tz_name = tz
    elif context.get("user") and context["user"].tz:
        tz_name = context["user"].tz
    else:
        tz_name = context.get("ctx", {}).get("tz")

    if tz_name:
        try:
            utc = pytz.timezone('UTC')
            context_tz = pytz.timezone(tz_name)
            utc_timestamp = utc.localize(date, is_dst=False)  # UTC = no DST
            date = utc_timestamp.astimezone(context_tz)
        except Exception:
            _logger.debug("failed to compute context/client-specific timestamp, "
                          "using the UTC value",
                          exc_info=True)

    return date.strftime(new_format)


email_template.mako_template_env.filters.update(
    format_date=format_date,
)