Source code for eav.admin

'''This module contains classes used for admin integration.'''

from django.contrib import admin
from django.contrib.admin.options import InlineModelAdmin, ModelAdmin
from django.forms.models import BaseInlineFormSet
from django.utils.safestring import mark_safe

from .models import Attribute, EnumGroup, EnumValue, Value


class BaseEntityAdmin(ModelAdmin):
    def render_change_form(self, request, context, *args, **kwargs):
        """
        Wrapper for `ModelAdmin.render_change_form`. Replaces standard static
        `AdminForm` with an EAV-friendly one. The point is that our form generates
        fields dynamically and fieldsets must be inferred from a prepared and
        validated form instance, not just the form class. Django does not seem
        to provide hooks for this purpose, so we simply wrap the view and
        substitute some data.
        """
        form = context['adminform'].form

        # Infer correct data from the form.
        fieldsets = self.fieldsets or [(None, {'fields': form.fields.keys()})]
        adminform = admin.helpers.AdminForm(form, fieldsets, self.prepopulated_fields)
        media = mark_safe(self.media + adminform.media)

        context.update(adminform=adminform, media=media)

        return super(BaseEntityAdmin, self).render_change_form(
            request, context, *args, **kwargs
        )


class BaseEntityInlineFormSet(BaseInlineFormSet):
    '''
    An inline formset that correctly initializes EAV forms.
    '''
    def add_fields(self, form, index):
        if self.instance:
            setattr(form.instance, self.fk.name, self.instance)
            form._build_dynamic_fields()

        super(BaseEntityInlineFormSet, self).add_fields(form, index)


class BaseEntityInline(InlineModelAdmin):
    '''
    Inline model admin that works correctly with EAV attributes. You should mix
    in the standard StackedInline or TabularInline classes in order to define
    formset representation, e.g.::

        class ItemInline(BaseEntityInline, StackedInline):
            model = Item
            form = forms.ItemForm

    .. warning:: TabularInline does *not* work out of the box. There is,
        however, a patched template `admin/edit_inline/tabular.html` bundled
        with EAV-Django. You can copy or symlink the `admin` directory to your
        templates search path (see Django documentation).
    '''
    formset = BaseEntityInlineFormSet

    def get_fieldsets(self, request, obj=None):
        if self.declared_fieldsets:
            return self.declared_fieldsets

        formset = self.get_formset(request)
        fk_name = self.fk_name or formset.fk.name
        kw = {fk_name: obj} if obj else {}
        instance = self.model(**kw)
        form = formset.form(request.POST, instance=instance)

        return [(None, {'fields': form.fields.keys()})]


class AttributeAdmin(ModelAdmin):
    list_display = ('name', 'slug', 'datatype', 'description')
    prepopulated_fields = {'slug': ('name',)}


admin.site.register(Attribute, AttributeAdmin)
admin.site.register(Value)
admin.site.register(EnumValue)
admin.site.register(EnumGroup)