# chrono - agendas system
# Copyright (C) 2016  Entr'ouvert
#
# 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 __future__ import unicode_literals

import csv
import datetime

from django import forms
from django.contrib.auth.models import Group
from django.forms import ValidationError
from django.utils import six
from django.utils.encoding import force_text
from django.utils.timezone import make_aware
from django.utils.translation import ugettext_lazy as _

from chrono.agendas.models import (Agenda, Event, MeetingType, TimePeriod, Desk,
                                   TimePeriodException, WEEKDAYS_LIST)

from . import widgets


DATETIME_OPTIONS = {
        'weekStart': 1,
        'autoclose': True,
        }


class DateTimeWidget(widgets.DateTimeWidget):
    def __init__(self, *args, **kwargs):
        super(DateTimeWidget, self).__init__(*args, options=DATETIME_OPTIONS, **kwargs)


class AgendaAddForm(forms.ModelForm):
    class Meta:
        model = Agenda
        fields = ['label', 'kind', 'edit_role', 'view_role']

    edit_role = forms.ModelChoiceField(
            label=_('Edit Role'), required=False,
            queryset=Group.objects.all().order_by('name'))
    view_role = forms.ModelChoiceField(
            label=_('View Role'), required=False,
            queryset=Group.objects.all().order_by('name'))


class AgendaEditForm(AgendaAddForm):
    class Meta:
        model = Agenda
        fields = ['label', 'slug', 'edit_role', 'view_role', 'minimal_booking_delay', 'maximal_booking_delay']


class EventForm(forms.ModelForm):
    class Meta:
        model = Event
        widgets = {
                'agenda': forms.HiddenInput(),
                'start_datetime': DateTimeWidget(),
        }
        exclude = ['full', 'meeting_type', 'desk']


class NewMeetingTypeForm(forms.ModelForm):
    class Meta:
        model = MeetingType
        widgets = {
                'agenda': forms.HiddenInput(),
        }
        exclude = ['slug']


class MeetingTypeForm(forms.ModelForm):
    class Meta:
        model = MeetingType
        widgets = {
                'agenda': forms.HiddenInput(),
        }
        exclude = []


class TimePeriodAddForm(forms.Form):
    weekdays = forms.MultipleChoiceField(
            label=_('Days'),
            widget=widgets.WeekdaysWidget(),
            choices=WEEKDAYS_LIST)
    start_time = forms.TimeField(label=_('Start Time'), widget=widgets.TimeWidget())
    end_time = forms.TimeField(label=_('End Time'), widget=widgets.TimeWidget())

    def clean_end_time(self):
        if self.cleaned_data['end_time'] <= self.cleaned_data['start_time']:
            raise ValidationError(_('End time must come after start time.'))
        return self.cleaned_data['end_time']


class TimePeriodForm(forms.ModelForm):
    class Meta:
        model = TimePeriod
        widgets = {
                'start_time': widgets.TimeWidget(),
                'end_time': widgets.TimeWidget(),
                'desk': forms.HiddenInput(),
        }
        exclude = []

    def clean_end_time(self):
        if self.cleaned_data['end_time'] <= self.cleaned_data['start_time']:
            raise ValidationError(_('End time must come after start time.'))
        return self.cleaned_data['end_time']


class NewDeskForm(forms.ModelForm):
    class Meta:
        model = Desk
        widgets = {
            'agenda': forms.HiddenInput(),
        }
        exclude = ['slug', 'timeperiod_exceptions_remote_url']


class DeskForm(forms.ModelForm):
    class Meta:
        model = Desk
        widgets = {
            'agenda': forms.HiddenInput(),
        }
        exclude = ['timeperiod_exceptions_remote_url']


class TimePeriodExceptionForm(forms.ModelForm):
    class Meta:
        model = TimePeriodException
        fields = ['desk', 'start_datetime', 'end_datetime', 'label']
        widgets = {
            'desk': forms.HiddenInput(),
            'start_datetime': DateTimeWidget(),
            'end_datetime': DateTimeWidget(),
        }

    def clean_end_datetime(self):
        if self.cleaned_data['end_datetime'] <= self.cleaned_data['start_datetime']:
            raise ValidationError(_('End datetime must be greater than start datetime.'))
        return self.cleaned_data['end_datetime']


class ImportEventsForm(forms.Form):
    events_csv_file = forms.FileField(
            label=_('Events File'),
            required=True,
            help_text=_('CSV file with date, time, number of places, '
                        'number of places in waiting list, and label '
                        'as columns.'))
    events = None

    def clean_events_csv_file(self):
        content = self.cleaned_data['events_csv_file'].read()
        if b'\0' in content:
            raise ValidationError(_('Invalid file format.'))

        if six.PY3:
            content = content.decode('utf-8')
        try:
            dialect = csv.Sniffer().sniff(content)
        except csv.Error:
            dialect = None

        events = []
        for i, csvline in enumerate(csv.reader(content.splitlines(), dialect=dialect)):
            if not csvline:
                continue
            if len(csvline) < 3:
                raise ValidationError(_('Invalid file format. (line %d)') % (i+1))
            if i == 0 and csvline[0].strip('#') in ('date', 'Date', _('date'), _('Date')):
                continue
            event = Event()
            for datetime_fmt in ('%Y-%m-%d %H:%M', '%d/%m/%Y %H:%M',
                    '%d/%m/%Y %Hh%M', '%Y-%m-%d %H:%M:%S', '%d/%m/%Y %H:%M:%S'):
                try:
                    event_datetime = datetime.datetime.strptime(
                            '%s %s' % tuple(csvline[:2]), datetime_fmt)
                except ValueError:
                    continue
                event.start_datetime = make_aware(event_datetime)
                break
            else:
                raise ValidationError(_('Invalid file format. (date/time format, line %d)') % (i+1))
            try:
                event.places = int(csvline[2])
            except ValueError:
                raise ValidationError(_('Invalid file format. (number of places, line %d)') % (i+1))
            if len(csvline) >= 4:
                try:
                    event.waiting_list_places = int(csvline[3])
                except ValueError:
                    raise ValidationError(_('Invalid file format. (number of places in waiting list, line %d)') % (i+1))
            if len(csvline) >= 5:
                event.label = ' '.join([force_text(x) for x in csvline[4:]])
            events.append(event)
        self.events = events


class ExceptionsImportForm(forms.ModelForm):
    class Meta:
        model = Desk
        fields = []

    ics_file = forms.FileField(label=_('ICS File'), required=False,
            help_text=_('ICS file containing events which will be considered as exceptions.'))
    ics_url = forms.URLField(label=_('URL'), required=False,
            help_text=_('URL to remote calendar which will be synchronised hourly.'))


class AgendasImportForm(forms.Form):
    agendas_json = forms.FileField(label=_('Agendas Export File'))