From d75d4d911929a2fd5902ccb9d83eaebd8c001484 Mon Sep 17 00:00:00 2001
From: Andreas Pelme <andreas@pelme.se>
Date: Thu, 25 Jul 2024 20:03:06 +0200
Subject: [PATCH] Experimental Django template loader.

---
 conftest.py          |  7 ++++++-
 htpy/django.py       | 30 ++++++++++++++++++++++++++++++
 tests/test_django.py | 30 ++++++++++++++++++++++++++++--
 3 files changed, 64 insertions(+), 3 deletions(-)
 create mode 100644 htpy/django.py

diff --git a/conftest.py b/conftest.py
index 4b33e2a..a32418b 100644
--- a/conftest.py
+++ b/conftest.py
@@ -6,5 +6,10 @@ def django_env() -> None:
     import django
     from django.conf import settings
 
-    settings.configure(TEMPLATES=[{"BACKEND": "django.template.backends.django.DjangoTemplates"}])
+    settings.configure(
+        TEMPLATES=[
+            {"BACKEND": "django.template.backends.django.DjangoTemplates"},
+            {"BACKEND": "htpy.django.HTPYTemplates", "NAME": "htpy"},
+        ]
+    )
     django.setup()
diff --git a/htpy/django.py b/htpy/django.py
new file mode 100644
index 0000000..707672d
--- /dev/null
+++ b/htpy/django.py
@@ -0,0 +1,30 @@
+from collections.abc import Callable
+from typing import Any
+
+from django.http import HttpRequest
+from django.template import Context, TemplateDoesNotExist
+
+from . import Element, render_node
+
+
+class _HTPYTemplate:
+    def __init__(self, func: Callable[[Context | None, HttpRequest | None], Element]) -> None:
+        self.func = func
+
+    def render(self, context: Context | None, request: HttpRequest | None) -> str:
+        return render_node(self.func(context, request))
+
+
+class HTPYTemplates:
+    def __init__(self, config: Any):
+        pass
+
+    def get_template(self, name: str) -> _HTPYTemplate:
+        from django.utils.module_loading import import_string
+
+        try:
+            func = import_string(name)
+        except ImportError:
+            raise TemplateDoesNotExist(name)
+
+        return _HTPYTemplate(func)
diff --git a/tests/test_django.py b/tests/test_django.py
index 93a2202..08327b2 100644
--- a/tests/test_django.py
+++ b/tests/test_django.py
@@ -1,10 +1,14 @@
+from typing import Any
+
 import pytest
 from django.forms.utils import ErrorList
-from django.template import Context, Template
+from django.http import HttpRequest
+from django.template import Context, Template, TemplateDoesNotExist
+from django.template.loader import render_to_string
 from django.utils.html import escape
 from django.utils.safestring import SafeString
 
-from htpy import div, li, ul
+from htpy import Element, Node, div, li, ul
 
 pytestmark = pytest.mark.usefixtures("django_env")
 
@@ -29,3 +33,25 @@ def test_explicit_escape() -> None:
 def test_errorlist() -> None:
     result = div[ErrorList(["my error"])]
     assert str(result) == """<div><ul class="errorlist"><li>my error</li></ul></div>"""
+
+
+def my_template(context: dict[str, Any], request: HttpRequest | None) -> Element:
+    return div[f"hey {context['name']}"]
+
+
+def my_template_fragment(context: dict[str, Any], request: HttpRequest | None) -> Node:
+    return [div[f"hey {context['name']}"]]
+
+
+class Test_custom_template_loader:
+    def test_render(self) -> None:
+        result = render_to_string(__name__ + ".my_template", {"name": "andreas"})
+        assert result == "<div>hey andreas</div>"
+
+    def test_list_fragment(self) -> None:
+        result = render_to_string(__name__ + ".my_template_fragment", {"name": "andreas"})
+        assert result == "<div>hey andreas</div>"
+
+    def test_template_does_not_exist(self) -> None:
+        with pytest.raises(TemplateDoesNotExist):
+            render_to_string(__name__ + ".fooasdf", {})