from __future__ import absolute_import

from django.contrib.contenttypes.models import ContentType
from django.core.exceptions import PermissionDenied
from django.db.models.loading import get_model
from django.http import Http404
from django.shortcuts import get_object_or_404, render_to_response
from django.template import RequestContext
from django.utils.translation import ugettext_lazy as _

from acls.models import AccessEntry
from common.utils import encapsulate
from permissions.models import Permission

from .forms import HistoryDetailForm
from .models import History, HistoryType
from .permissions import PERMISSION_HISTORY_VIEW
from .widgets import history_entry_object_link


def history_list(request, object_list=None, title=None, extra_context=None):
    pre_object_list = object_list if not (object_list is None) else History.objects.all()

    try:
        Permission.objects.check_permissions(request.user, [PERMISSION_HISTORY_VIEW])
    except PermissionDenied:
        # If user doesn't have global permission, get a list of document
        # for which he/she does hace access use it to filter the
        # provided object_list
        final_object_list = AccessEntry.objects.filter_objects_by_access(PERMISSION_HISTORY_VIEW, request.user, pre_object_list, related='content_object')
    else:
        final_object_list = pre_object_list

    context = {
        'object_list': final_object_list,
        'title': title if title else _(u'History events'),
        'extra_columns': [
            {
                'name': _(u'Object link'),
                'attribute': encapsulate(lambda x: history_entry_object_link(x))
            },
        ],
        'hide_object': True,
    }

    if extra_context:
        context.update(extra_context)

    return render_to_response('main/generic_list.html', context,
        context_instance=RequestContext(request))


def history_for_object(request, app_label, module_name, object_id):
    model = get_model(app_label, module_name)
    if not model:
        raise Http404
    content_object = get_object_or_404(model, pk=object_id)
    content_type = ContentType.objects.get_for_model(model)

    try:
        Permission.objects.check_permissions(request.user, [PERMISSION_HISTORY_VIEW])
    except PermissionDenied:
        AccessEntry.objects.check_access(PERMISSION_HISTORY_VIEW, request.user, content_object)

    context = {
        'object_list': History.objects.filter(content_type=content_type, object_id=object_id),
        'title': _(u'History events for: %s') % content_object,
        'object': content_object,
        'hide_object': True,
    }

    return render_to_response('main/generic_list.html', context,
        context_instance=RequestContext(request))


def history_view(request, object_id):
    history = get_object_or_404(History, pk=object_id)

    try:
        Permission.objects.check_permissions(request.user, [PERMISSION_HISTORY_VIEW])
    except PermissionDenied:
        AccessEntry.objects.check_access(PERMISSION_HISTORY_VIEW, request.user, history.content_object)

    form = HistoryDetailForm(instance=history, extra_fields=[
        {'label': _(u'Date'), 'field': lambda x: x.datetime.date()},
        {'label': _(u'Time'), 'field': lambda x: unicode(x.datetime.time()).split('.')[0]},
        {'label': _(u'Object'), 'field': 'content_object'},
        {'label': _(u'Event type'), 'field': lambda x: x.get_label()},
        {'label': _(u'Additional details'), 'field': lambda x: x.get_processed_details() or _(u'None')},
    ])

    return render_to_response('main/generic_detail.html', {
        'title': _(u'Details for: %s') % history.get_processed_summary(),
        'form': form,
    }, context_instance=RequestContext(request))


def history_type_list(request, history_type_pk):
    history_type = get_object_or_404(HistoryType, pk=history_type_pk)

    return history_list(
        request,
        object_list=History.objects.filter(history_type=history_type),
        title=_(u'History events of type: %s') % history_type,
    )