import json

from django import forms
from django.contrib.auth.mixins import LoginRequiredMixin, PermissionRequiredMixin, UserPassesTestMixin
from django.http import HttpResponse, HttpResponseRedirect

DAISYUI_WIDGET_CLASSES = (
    (forms.CheckboxInput, 'checkbox'),
    (forms.CheckboxSelectMultiple, 'checkbox'),
    (forms.ClearableFileInput, 'file-input file-input-bordered w-full'),
    (forms.Textarea, 'textarea textarea-bordered w-full'),
    (forms.Select, 'select select-bordered w-full'),
)
DAISYUI_DEFAULT_WIDGET_CLASS = 'input input-bordered w-full'


class BackofficeSectionMixin:
    section = None

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        context['section'] = self.section
        return context


class BackofficeAccessMixin(BackofficeSectionMixin, LoginRequiredMixin, UserPassesTestMixin):
    login_url = 'users:login'

    def test_func(self):
        return self.request.user.is_staff


class BackofficeCRUDMixin(BackofficeAccessMixin, PermissionRequiredMixin):
    raise_exception = True


class BackofficeStyledFormMixin:
    """Aplica clases de DaisyUI a los widgets del formulario según su tipo,
    sin necesitar declarar un ModelForm explícito por modelo (a diferencia de
    web.mixins.StylingMixin, que requiere listar `styled_fields` a mano)."""

    def get_form(self, form_class=None):
        form = super().get_form(form_class)

        for field in form.fields.values():
            css_class = DAISYUI_DEFAULT_WIDGET_CLASS

            for widget_type, widget_css_class in DAISYUI_WIDGET_CLASSES:
                if isinstance(field.widget, widget_type):
                    css_class = widget_css_class
                    break

            existing = field.widget.attrs.get('class', '')
            field.widget.attrs['class'] = f'{existing} {css_class}'.strip()

        return form


class BackofficeHtmxMixin:
    """Toda vista de backoffice puede responder con la página completa (navegación
    directa) o con un fragmento (carga en el modal, o autorefresco de una lista/detalle)."""

    fragment_template_name = None

    def is_htmx(self):
        return self.request.headers.get('HX-Request') == 'true'

    def get_template_names(self):
        if self.is_htmx() and self.fragment_template_name:
            return [self.fragment_template_name]
        return super().get_template_names()


class BackofficeModalFormMixin(BackofficeStyledFormMixin, BackofficeHtmxMixin):
    """Create/Update pensadas para abrirse en modal. Al guardar con éxito vía htmx
    no redirige (un <dialog> no navega): responde 204 + HX-Trigger para cerrar el
    modal y avisar a quien lo abrió (lista o detalle) de que se refresque."""

    trigger_event = 'backoffice:list-changed'

    def form_valid(self, form):
        self.object = form.save()

        if self.is_htmx():
            response = HttpResponse(status=204)
            response['HX-Trigger'] = json.dumps({'backoffice:modal-close': True, self.trigger_event: True})
            return response

        return HttpResponseRedirect(self.get_success_url())


class BackofficeModalDeleteMixin(BackofficeHtmxMixin):
    trigger_event = 'backoffice:list-changed'

    def perform_delete(self):
        self.object.delete()

    def form_valid(self, form):
        success_url = self.get_success_url()
        self.perform_delete()

        if self.is_htmx():
            response = HttpResponse(status=204)
            response['HX-Trigger'] = json.dumps({'backoffice:modal-close': True, self.trigger_event: True})
            return response

        return HttpResponseRedirect(success_url)