# coding=utf-8
import StringIO
from wsgiref.util import FileWrapper

from django.contrib import messages
from django.http import HttpResponse
from django.shortcuts import get_object_or_404
from django.urls import reverse_lazy
from django.views.generic import CreateView
from django.views.generic import DeleteView
from django.views.generic import ListView
from django.views.generic import UpdateView

from . import WrappedView
from ..models import StudySubject, Visit, Appointment, MailTemplate
from ..models.constants import MAIL_TEMPLATE_CONTEXT_SUBJECT, MAIL_TEMPLATE_CONTEXT_VISIT, \
    MAIL_TEMPLATE_CONTEXT_APPOINTMENT

MIMETYPE_DOCX = 'application/vnd.openxmlformats-officedocument.wordprocessingml.document'

CONTEXT_TYPES_MAPPING = {
    MAIL_TEMPLATE_CONTEXT_SUBJECT: StudySubject,
    MAIL_TEMPLATE_CONTEXT_VISIT: Visit,
    MAIL_TEMPLATE_CONTEXT_APPOINTMENT: Appointment
}


class MailTemplatesListView(ListView, WrappedView):
    model = MailTemplate
    context_object_name = "mail_templates"
    template_name = 'mail_templates/list.html'

    def get_context_data(self, **kwargs):
        context = super(MailTemplatesListView, self).get_context_data()
        context['explanations'] = {"generic": MailTemplate.MAILS_TEMPLATE_GENERIC_TAGS,
                                   "subject": MailTemplate.MAILS_TEMPLATE_SUBJECT_TAGS,
                                   "visit": MailTemplate.MAILS_TEMPLATE_VISIT_TAGS,
                                   "appointment": MailTemplate.MAILS_TEMPLATE_APPOINTMENT_TAGS,
                                   }
        return context


class MailTemplatesCreateView(CreateView, WrappedView):
    model = MailTemplate
    template_name = "mail_templates/add.html"
    fields = '__all__'
    success_url = reverse_lazy('web.views.mail_templates')
    success_message = "Template created"


class MailTemplatesDeleteView(DeleteView, WrappedView):
    model = MailTemplate
    success_url = reverse_lazy('web.views.mail_templates')
    template_name = 'mail_templates/confirm_delete.html'

    def delete(self, request, *args, **kwargs):
        messages.success(request, "Template deleted")
        return super(MailTemplatesDeleteView, self).delete(request, *args, **kwargs)


class MailTemplatesEditView(UpdateView, WrappedView):
    model = MailTemplate
    success_url = reverse_lazy('web.views.mail_templates')
    fields = '__all__'
    success_message = "Template edited"
    template_name = "mail_templates/edit.html"
    context_object_name = "mail_template"


def generate(request, mail_template_id, instance_id):
    mail_template = get_object_or_404(MailTemplate, id=mail_template_id)
    instance = get_object_or_404(CONTEXT_TYPES_MAPPING[mail_template.context], id=instance_id)
    stream = StringIO.StringIO()
    stream = mail_template.apply(instance, request.user, stream)
    file_size = stream.tell()
    stream.seek(0)
    response = HttpResponse(FileWrapper(stream), content_type=MIMETYPE_DOCX)
    response['Content-Length'] = file_size
    response['Content-Disposition'] = 'attachment; filename={}.docx'.format(mail_template.name)
    return response