====== Django Admin ======

===== Basic =====

To create a super user: ''$ python manage.py createsuperuser''


==== Registrar clases ====
<code>
from django.contrib import admin
from catalog.models import Author, Genre, Book, BookInstance

admin.site.register(Book)
admin.site.register(Author)
admin.site.register(Genre)
admin.site.register(BookInstance)
</code>

**También puedes hacerlo con clases** (permite añadir varios admins):
<code>
class CoopolisAdmin(AdminSite):
    site_header = "Coópolis Backoffice"
    site_title = "Coópolis backoffice"
    index_title = "Benvingut!"


coopolis_admin_site = CoopolisAdmin(name='coopolis_admin')
coopolis_admin_site.register(User)
coopolis_admin_site.register(Project)
coopolis_admin_site.register(Course)
coopolis_admin_site.register(Activity)
</code>
Las url estarían en ''coopolis_admin_site.urls'':
<code>
urlpatterns = [
    path('entity-admin/', admin.site.urls),
    path('event-admin/', coopolis_admin_site.urls),
]
</code>

Puedes registrar también ModelAdmins:
<code>
class AuthorAdmin(admin.ModelAdmin):
    pass

admin.site.register(Author, AuthorAdmin)
</code>

O con un decorador:
<code>
@admin.register(Book)
class BookAdmin(admin.ModelAdmin):
    pass
</code>

==== List views ====
Indicar los **campos** que se verán:
<code>
class AuthorAdmin(admin.ModelAdmin):
    list_display = ('last_name', 'first_name', 'date_of_birth', 'date_of_death')
</code>

Los **ManyToMany** no se verán en la lista. Aún así podemos sacar un campo como tal:
<code>
    def display_genre(self):
        """Create a string for the Genre. This is required to display genre in Admin."""
        return ', '.join(genre.name for genre in self.genre.all()[:3])
        
    display_genre.short_description = 'Genre'
</code>

Los filtros pueden indicarse también:
<code>
class BookInstanceAdmin(admin.ModelAdmin):
    list_filter = ('status', 'due_back')
</code>

:!: **Important**:_ To tell Django we want to perform a join instead of fetching the names of the categories one by one,we can use list_select_related
<code>
@admin.register(models.Product)
class ProductAdmin(admin.ModelAdmin):
    list_display = (
        'id',
        'name',
        'category',
    )
    list_select_related = (
        'category',
    )
</code>

=== Add a link into the list ===
<code python>
from django.contrib import admin
from django.utils.html import format_html


class CourseAdmin(admin.ModelAdmin):
    list_display = ('title', 'my_url_field',)

    def my_url_field(self, obj):
        return format_html('<a href="%s%s">%s</a>' % ('http://url-to-prepend.com/', obj.title, obj.title))
    my_url_field.allow_tags = True
    my_url_field.short_description = 'Column description'
</code>
==== Changing the layout ====
To put several fields in a row:
<code>
class AuthorAdmin(admin.ModelAdmin):
    list_display = ('last_name', 'first_name', 'date_of_birth', 'date_of_death')
    fields = ['first_name', 'last_name', ('date_of_birth', 'date_of_death')]
</code>

Add fieldsets (sections):
<code>
@admin.register(BookInstance)
class BookInstanceAdmin(admin.ModelAdmin):
    list_filter = ('status', 'due_back')
    
    fieldsets = (
        (None, {
            'fields': ('book', 'imprint', 'id')
        }),
        ('Availability', {
            'fields': ('status', 'due_back')
        }),
    )
</code>

You can do this by declaring inlines, of type TabularInline (horizonal layout) or StackedInline (vertical layout, just like the default model layout).
<code>
class BooksInstanceInline(admin.TabularInline):
    model = BookInstance

@admin.register(Book)
class BookAdmin(admin.ModelAdmin):
    list_display = ('title', 'author', 'display_genre')
    inlines = [BooksInstanceInline]
</code>

===== Admin templates =====
==== Overriding them ====
  * https://docs.djangoproject.com/en/2.0/ref/contrib/admin/#admin-overriding-templates


===== JS y CSS en el Admin =====

==== Usando jQuery en el Django Admin ====
<code>
(function($) {
    // < start of closure
    // within this block, $ = django.jQuery
    $(document).ready(function() {
      // Your JavaScript
    });
})(django.jQuery);
</code>

==== Add static snippets ====
<code>
# admin.py
class MyModelAdmin(admin.ModelAdmin):
    # admin additions

    class Media:
        css = {
            "all": ("css/my_style.css",)
        }
        js = ("js/my_script.js",)
</code>
===== Gotchas =====

==== Basic ====
=== Change the title and pages ===
<code>
admin.site.site_header = "UMSRA Admin"
admin.site.site_title = "UMSRA Admin Portal"
admin.site.index_title = "Welcome to UMSRA Researcher Portal"
</code>

=== Change the name of a class in the Admin ===
<code>
class Category(models.Model):
    ...

    class Meta:
        verbose_name_plural = "Categories"
</code>

=== Unregister a class ===
<code>
from django.contrib.auth.models import Group

admin.site.unregister(Group)
</code>

=== Add new page to the admin ===
<code python>
class CourseAdmin(admin.ModelAdmin):
    list_display = ('title', 'my_url_field',)

    def get_urls(self):
        urls = super().get_urls()
        custom_urls = [
            path(
                r'attendee-list/',
                self.admin_site.admin_view(self.attendee_list),
                name='attendee-list',
            ),
        ]
        return custom_urls + urls

    def my_url_field(self, obj):
        return format_html('<a href="%s" target="_new">Llista d\'assistencia</a>' % reverse('admin:attendee-list'))
    my_url_field.allow_tags = True
    my_url_field.short_description = 'Column description'

    def attendee_list(self, request):
        import weasyprint
        import django.template.loader as loader
        temp = loader.get_template('admin/attendee_list.html')
        html = temp.render()
        pdf = weasyprint.HTML(string=html.encode('utf-8'))
        response = HttpResponse(pdf.write_pdf(), content_type='application/pdf')
        # response['Content-Disposition'] = 'attachment; filename="llista_assistencia.pdf"'
        response['Content-Disposition'] = 'filename="llista_assistencia.pdf"'
        return response
</code>

=== Dynamically hide fields ===
<code>
class BookAdmin(admin.ModelAdmin):
    list_display = ("pk", "get_title_or_nothing")

    def get_form(self, request, obj=None, **kwargs):
        if obj.type == "1":
            self.exclude = ("title", )
        form = super(BookAdmin, self).get_form(request, obj, **kwargs)
        return form
</code>