#!/usr/bin/env python
# -*- coding: utf-8 -*-
"""
    openslides.utils.views
    ~~~~~~~~~~~~~~~~~~~~~~

    Views for utils.

    :copyright: 2011 by the OpenSlides team, see AUTHORS.
    :license: GNU GPL, see LICENSE for more details.
"""

try:
    import json
except ImportError:
    import simplejson as json

try:
    from cStringIO import StringIO
except ImportError:
    from StringIO import StringIO

from reportlab.platypus import SimpleDocTemplate, Paragraph, Frame, PageBreak, Spacer, Table, LongTable, TableStyle, Image
from reportlab.lib.units import cm

from django.conf import settings
from django.contrib import messages
from django.utils.translation import ugettext as _
from django.http import HttpResponseServerError, HttpResponse, HttpResponseRedirect
from django.core.urlresolvers import reverse
from django.template import loader, RequestContext
from django.template.loader import render_to_string
from django.contrib.auth.decorators import login_required
from django.utils.decorators import method_decorator
from django.dispatch import receiver
from django.views.generic import (
    TemplateView as _TemplateView,
    RedirectView as _RedirectView,
    UpdateView as _UpdateView,
    CreateView as _CreateView,
    View as _View,
    FormView as _FormView,
    ListView as _ListView,
)
from django.views.generic.detail import SingleObjectMixin
from django.views.generic.list import TemplateResponseMixin
from django.utils.importlib import import_module
from django.core.context_processors import csrf
import settings

from utils import render_to_forbitten
from openslides.utils.signals import template_manipulation
from pdf import firstPage, laterPages

NO_PERMISSION_REQUIRED = 'No permission required'

View = _View


class SetCookieMixin(object):
    def render_to_response(self, context, **response_kwargs):
        response = TemplateResponseMixin.render_to_response(self, context, **response_kwargs)
        if 'cookie' in context:
            response.set_cookie(context['cookie'][0], context['cookie'][1])
        return response


class LoginMixin(object):
    @method_decorator(login_required)
    def dispatch(self, request, *args, **kwargs):
        return super(LoginMixin, self).dispatch(request, *args, **kwargs)


class PermissionMixin(object):
    permission_required = NO_PERMISSION_REQUIRED

    def dispatch(self, request, *args, **kwargs):
        if self.permission_required == NO_PERMISSION_REQUIRED:
            has_permission = True
        else:
            has_permission = request.user.has_perm(self.permission_required)

        if not has_permission:
            if not request.user.is_authenticated():
                path = request.get_full_path()
                return HttpResponseRedirect("%s?next=%s" % (settings.LOGIN_URL, path))
            else:
                return render_to_forbitten(request)
        return _View.dispatch(self, request, *args, **kwargs)


class TemplateView(PermissionMixin, _TemplateView):
    def get_context_data(self, **kwargs):
        context = super(TemplateView, self).get_context_data(**kwargs)
        template_manipulation.send(sender=self, request=self.request, context=context)
        return context


class ListView(PermissionMixin, SetCookieMixin, _ListView):
    def get_context_data(self, **kwargs):
        context = super(ListView, self).get_context_data(**kwargs)
        template_manipulation.send(sender=self, request=self.request, context=context)
        return context


class AjaxView(PermissionMixin, View):
    def get(self, request, *args, **kwargs):
        return HttpResponse(json.dumps(self.get_ajax_context(**kwargs)))

    def get_ajax_context(self, **kwargs):
        return {}


class RedirectView(PermissionMixin, _RedirectView):
    permanent = False
    allow_ajax = False

    def pre_redirect(self, request, *args, **kwargs):
        pass

    def pre_post_redirect(self, request, *args, **kwargs):
        pass

    def get(self, request, *args, **kwargs):
        if request.method == 'GET':
            self.pre_redirect( request, *args, **kwargs)
        elif request.method == 'POST':
            self.pre_post_redirect(request, *args, **kwargs)

        if self.request.is_ajax() and self.allow_ajax:
            return HttpResponse(json.dumps(self.get_ajax_context(**kwargs)))
        return super(RedirectView, self).get(request, *args, **kwargs)

    def get_redirect_url(self, **kwargs):
        return reverse(super(RedirectView, self).get_redirect_url(**kwargs))

    def get_ajax_context(self, **kwargs):
        return {}


class FormView(PermissionMixin, _FormView):
    def get_success_url(self):
        if not self.success_url:
            return ''
        return reverse(super(FormView, self).get_success_url())

    def get_context_data(self, **kwargs):
        context = super(FormView, self).get_context_data(**kwargs)
        template_manipulation.send(sender=self, request=self.request, context=context)
        return context

    def form_invalid(self, form):
        messages.error(self.request, _('Please check the form for errors.'))
        return super(FormView, self).form_invalid(form)


class UpdateView(PermissionMixin, _UpdateView):
    def get_success_url(self):
        if 'apply' in self.request.POST:
            return ''
        return reverse(super(UpdateView, self).get_success_url())

    def get_context_data(self, **kwargs):
        context = super(UpdateView, self).get_context_data(**kwargs)
        template_manipulation.send(sender=self, request=self.request, context=context)
        return context


class CreateView(PermissionMixin, _CreateView):
    def get_success_url(self):
        if 'apply' in self.request.POST:
            return reverse(self.get_apply_url(), args=[self.object.id])
        return reverse(super(CreateView, self).get_success_url())

    def get_context_data(self, **kwargs):
        context = super(CreateView, self).get_context_data(**kwargs)
        template_manipulation.send(sender=self, request=self.request, context=context)
        return context

    def get_apply_url(self):
        #todo: Versuche apply url automatisch anhand on self.object herauszufindne
        return self.apply_url


class DeleteView(RedirectView, SingleObjectMixin):
    def pre_redirect(self, request, *args, **kwargs):
        self.confirm_form(request, self.object)

    def pre_post_redirect(self, request, *args, **kwargs):
        self.object.delete()
        messages.success(request, _("Item <b>%s</b> was successfully deleted.") % self.object)

    def get(self, request, *args, **kwargs):
        self.object = self.get_object()
        return super(DeleteView, self).get(request, *args, **kwargs)

    def confirm_form(self, request, object, name=None):
        if name is None:
            name = object
        self.gen_confirm_form(request, _('Do you really want to delete <b>%s</b>?') % name, object.get_absolute_url('delete'))

    def gen_confirm_form(self, request, message, url):
        messages.warning(request, '%s<form action="%s" method="post"><input type="hidden" value="%s" name="csrfmiddlewaretoken"><input type="submit" value="%s" /> <input type="button" value="%s"></form>' % (message, url, csrf(request)['csrf_token'], _("Yes"), _("No")))


class PDFView(PermissionMixin, View):
    filename = _('undefined-filename')
    top_space = 3
    document_title = None

    def get_top_space(self):
        return self.top_space

    def get_document_title(self):
        return self.document_title

    def render_to_response(self, filename):
        response = HttpResponse(mimetype='application/pdf')
        filename = u'filename=%s.pdf;' % filename
        response['Content-Disposition'] = filename.encode('utf-8')

        buffer = StringIO()
        pdf_document = SimpleDocTemplate(buffer)
        pdf_document.title = self.get_document_title()
        story = [Spacer(1, self.get_top_space()*cm)]

        self.append_to_pdf(story)

        pdf_document.build(story, onFirstPage=firstPage, onLaterPages=laterPages)

        pdf = buffer.getvalue()
        buffer.close()
        response.write(pdf)
        return response

    def append_to_pdf(self, story):
        pass

    def get_filename(self):
        return self.filename

    def get(self, request, *args, **kwargs):
        return self.render_to_response(self.get_filename())


def server_error(request, template_name='500.html'):
    """
    500 error handler.

    Templates: `500.html`
    Context:
        MEDIA_URL
            Path of static media (e.g. "media.example.org")
    """
    t = loader.get_template("500.html") # You need to create a 500.html template.
    return HttpResponseServerError(render_to_string('500.html', context_instance=RequestContext(request)))


@receiver(template_manipulation, dispatch_uid="send_register_tab")
def send_register_tab(sender, request, context, **kwargs):
    tabs = []
    for app in settings.INSTALLED_APPS:
        try:
            mod = import_module(app + '.views')
            tabs.append(mod.register_tab(request))
        except (ImportError, AttributeError):
            continue

    context.update({
        'tabs': tabs,
    })