# combo - content management system
# Copyright (C) 2014-2017  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 django.conf import settings
from django.utils.translation import ugettext_lazy as _
from django import template
from django.http import HttpResponse
from django.core.exceptions import PermissionDenied
from django.core.urlresolvers import reverse
from django.utils.http import quote
from django.template import Context, Template

from jsonfield import JSONField

from combo.utils import requests
from combo.data.models import CellBase
from combo.data.library import register_cell_class
from combo.utils import get_templated_url

from . import engines


@register_cell_class
class SearchCell(CellBase):
    template_name = 'combo/search-cell.html'

    _search_services = JSONField(_('Search Services'), default=dict, blank=True)

    class Meta:
        verbose_name = _('Search')

    def is_visible(self, user=None):
        if not self.search_services:
            return False
        return super(SearchCell, self).is_visible(user=user)

    def get_default_form_class(self):
        from .forms import SearchCellForm
        return SearchCellForm

    @property
    def varname(self):
        if self.slug:
            # no hyphen in varname, could be used in context and templates
            return self.slug.replace('-', '_')
        return ''

    @property
    def search_services(self):
        services = []
        for service_slug in self._search_services.get('data') or []:
            service = engines.get(service_slug)
            if service and service.get('url'):
                service['slug'] = service_slug
                services.append(service)
        return services

    @property
    def has_multiple_search_services(self):
        return len(self._search_services.get('data') or []) > 1

    @classmethod
    def get_cells_by_search_service(cls, search_service):
        for cell in cls.objects.all():
            if search_service in (cell._search_services.get('data') or []):
                yield cell

    def modify_global_context(self, context, request):
        # if self.varname is in the query string (of the page),
        # add it to the global context; so it can be used by others cells
        # for example by a JsonCell with ...[self.varname]... in its URL
        if self.varname and self.varname in request.GET:
            context[self.varname] = request.GET.get(self.varname)

    def get_cell_extra_context(self, context):
        extra_context = super(SearchCell, self).get_cell_extra_context(context)
        # if there is a q_<slug> in query_string, send it to the template (to be
        # used as an initial query) and remove it from query_string
        initial_q = None
        initial_query_string = None
        if context.get('request'):
            request_get = context['request'].GET.copy()
            if self.varname and context.get('request'):
                q_varname = 'q_%s' % self.varname
                if q_varname in request_get:
                    initial_q = request_get[q_varname]
                    del request_get[q_varname]
            initial_query_string = request_get.urlencode()
        extra_context.update({
            'initial_q': initial_q,
            'initial_query_string': initial_query_string
        })
        return extra_context

    @classmethod
    def ajax_results_view(cls, request, cell_pk, service_slug):
        cell = cls.objects.get(pk=cell_pk)
        if not cell.is_visible(request.user) or not cell.page.is_visible(request.user):
            raise PermissionDenied

        query = request.GET.get('q')

        def render_response(service={}, results={'err': 0, 'data': []}):
            template_names = ['combo/search-cell-results.html']
            if cell.slug:
                template_names.insert(0, 'combo/cells/%s/search-cell-results.html' % cell.slug)
            tmpl = template.loader.select_template(template_names)
            context = {
                'cell': cell,
                'results': results,
                'search_service': service,
                'query': query
            }
            return HttpResponse(tmpl.render(context, request), content_type='text/html')

        for service in cell.search_services:
            if service.get('slug') == service_slug:
                break
        else:
            return render_response()

        if not query:
            return render_response(service)

        url = get_templated_url(service['url'],
                context={'request': request, 'q': query, 'search_service': service})
        url = url % {'q': quote(query.encode('utf-8'))}  # if url contains %(q)s
        if url.startswith('/'):
            url = request.build_absolute_uri(url)

        if not url:
            return render_response(service)

        kwargs = {}
        kwargs['cache_duration'] = service.get('cache_duration', 0)
        kwargs['remote_service'] = 'auto' if service.get('signature') else None
        # don't automatically add user info to query string, if required it can
        # be set explicitely in the URL template in the engine definition (via
        # {{user_nameid}} or {{user_email}}).
        kwargs['without_user'] = True
        results = requests.get(url, **kwargs).json()
        if service.get('data_key'):
            results['data'] = results.get(service['data_key']) or []
        hit_templates = {}
        if service.get('hit_url_template'):
            hit_templates['url'] = Template(service['hit_url_template'])
        if service.get('hit_label_template'):
            hit_templates['text'] = Template(service['hit_label_template'])
        if service.get('hit_description_template'):
            hit_templates['description'] = Template(service['hit_description_template'])
        if hit_templates:
            for hit in results.get('data') or []:
                for k, v in hit_templates.items():
                    hit[k] = v.render(Context(hit))
        return render_response(service, results)