feat: fieldset as tabs (#249)

README.md

@@ -30,7 +30,8 @@ Did you decide to start using Unfold but you don't have time to make the switch
 - **WYSIWYG:** built-in support for WYSIWYG (Trix)
 - **Custom filters:** widgets for filtering number & datetime values
 - **Dashboard:** custom components for rapid dashboard development
-- **Tabs:** define custom tab navigations for models
+- **Model tabs:** define custom tab navigations for models
+- **Fieldset tabs:** merge several fielsets into tabs in change form
 - **Colors:** possibility to override default color scheme
 - **Third party packages:** default support for multiple popular applications
 - **Environment label**: distinguish between environments by displaying a label
@@ -50,6 +51,7 @@ Did you decide to start using Unfold but you don't have time to make the switch
   - [Numeric filters](#numeric-filters)
   - [Date/time filters](#datetime-filters)
 - [Display decorator](#display-decorator)
+- [Change form tabs](#change-form-tabs)
 - [Third party packages](#third-party-packages)
   - [django-celery-beat](#django-celery-beat)
   - [django-guardian](#django-guardian)
@@ -582,6 +584,55 @@ class UserAdmin(ModelAdmin):
         return "First main heading", "Smaller additional description", "AB"
 ```
 
+## Change form tabs
+
+When the change form contains a lot of fieldsets, sometimes it is better to group them into tabs so it will not be needed to scroll. To mark a fieldset for tab navigation it is required to add a `tab` CSS class to the fieldset. Once the fieldset contains `tab` class it will be recognized in a template and grouped into tab navigation. Each tab must contain its name. If the name is not available, it will be not included in the tab navigation.
+
+```python
+# admin.py
+
+from django.contrib import admin
+from django.utils.translation import gettext_lazy as _
+from unfold.admin import ModelAdmin
+
+from .models import MyModel
+
+
+@admin.register(MyModel)
+class MyModelAdmin(ModelAdmin):
+    fieldsets = (
+        (
+            None,
+            {
+                "fields": [
+                    "field_1",
+                    "field_2",
+                ],
+            },
+        ),
+        (
+            _("Tab 1"),
+            {
+                "classes": ["tab"],
+                "fields": [
+                    "field_3",
+                    "field_4",
+                ],
+            },
+        ),
+        (
+            _("Tab 2"),
+            {
+                "classes": ["tab"],
+                "fields": [
+                    "field_5",
+                    "field_6",
+                ],
+            },
+        ),
+    )
+```
+
 ## Third party packages
 
 ### django-celery-beat

src/unfold/templates/admin/change_form.html

@@ -95,8 +95,12 @@
 
                 {% block field_sets %}
                     {% for fieldset in adminform %}
-                        {% include 'admin/includes/fieldset.html' %}
+                        {% if "tab" not in fieldset.classes %}
+                            {% include 'admin/includes/fieldset.html' %}
+                        {% endif %}
                     {% endfor %}
+
+                    {% include "unfold/helpers/fieldsets_tabs.html" %}
                 {% endblock %}
 
                 {% block after_field_sets %}{% endblock %}

src/unfold/templates/admin/includes/fieldset.html

@@ -1,8 +1,8 @@
 {% load unfold %}
 
-<fieldset class="module {{ fieldset.classes }}">
-    {% if fieldset.name %}
-        <h2 class="bg-gray-100 border border-transparent font-semibold mb-6 px-4 py-3 rounded-md text-gray-900 text-sm lg:-mx-4 dark:bg-white/[.02] dark:border dark:border-gray-800 dark:text-gray-200">
+<fieldset class="module{% if fieldset.classes %} {{ fieldset.classes }}{% endif %}">
+    {% if fieldset.name and "tab" not in fieldset.classes %}
+        <h2 class="bg-gray-100 border border-transparent font-semibold mb-6 px-4 py-3 rounded-md text-gray-700 text-sm lg:-mx-4 dark:bg-white/[.02] dark:border dark:border-gray-800 dark:text-gray-200">
             {{ fieldset.name }}
         </h2>
     {% endif %}

src/unfold/templates/unfold/helpers/fieldsets_tabs.html

@@ -0,0 +1,26 @@
+{% load unfold %}
+
+{% with tabs=adminform|tabs %}
+    {% if tabs %}
+        <div x-data="{openTab: null}">
+            <ul class="bg-gray-100 border border-transparent flex gap-10 mb-6 px-4 py-3 rounded-md text-gray-400 text-sm lg:-mx-4 dark:bg-white/[.02] dark:border dark:border-gray-800 dark:text-gray-400">
+                {% for fieldset in tabs %}
+                    <li>
+                        <a class="cursor-pointer font-semibold hover:text-gray-700 dark:hover:text-white"
+                        x-on:click="openTab = '{{ fieldset.name|slugify }}'"
+                        x-bind:class="openTab == '{{ fieldset.name|slugify }}'{% if forloop.first %} || openTab == null{% endif %} ? 'text-gray-700 dark:text-white' : ''">
+                            {{ fieldset.name }}
+                        </a>
+                    </li>
+                {% endfor %}
+            </ul>
+
+            {% for fieldset in tabs %}
+                <div class="tab-wrapper{% if fieldset.name %} fieldset-{{ fieldset.name|slugify }}{% endif %}"
+                    x-show="openTab == '{{ fieldset.name|slugify }}'{% if forloop.first %} || openTab == null{% endif %}">
+                    {% include 'admin/includes/fieldset.html' %}
+                </div>
+            {% endfor %}
+        </div>
+    {% endif %}
+{% endwith %}

src/unfold/templatetags/unfold.py

@@ -1,6 +1,7 @@
-from typing import Any, Dict, Mapping, Optional, Union
+from typing import Any, Dict, List, Mapping, Optional, Union
 
 from django import template
+from django.contrib.admin.helpers import AdminForm, Fieldset
 from django.forms import Field
 from django.template import Library, Node, RequestContext, TemplateSyntaxError
 from django.template.base import NodeList, Parser, Token, token_kwargs
@@ -42,6 +43,17 @@ def index(indexable: Mapping[int, Any], i: int) -> Any:
     return indexable[i]
 
 
+@register.filter
+def tabs(adminform: AdminForm) -> List[Fieldset]:
+    result = []
+
+    for fieldset in adminform:
+        if "tab" in fieldset.classes and fieldset.name:
+            result.append(fieldset)
+
+    return result
+
+
 class CaptureNode(Node):
     def __init__(self, nodelist: NodeList, varname: str, silent: bool) -> None:
         self.nodelist = nodelist