From c961bc4ec60e49a5ac62c793a8e8990ad30e066c Mon Sep 17 00:00:00 2001
From: Edan Bainglass <edan.bainglass@gmail.com>
Date: Thu, 11 Jul 2024 09:54:13 +0000
Subject: [PATCH] Add css loader utility

---
 aiidalab_widgets_base/utils/loaders.py | 38 ++++++++++++++++++++++++++
 tests/test_loaders.py                  |  8 ++++++
 2 files changed, 46 insertions(+)
 create mode 100644 aiidalab_widgets_base/utils/loaders.py
 create mode 100644 tests/test_loaders.py

diff --git a/aiidalab_widgets_base/utils/loaders.py b/aiidalab_widgets_base/utils/loaders.py
new file mode 100644
index 000000000..4d00fc908
--- /dev/null
+++ b/aiidalab_widgets_base/utils/loaders.py
@@ -0,0 +1,38 @@
+from importlib.resources import Package, files
+
+from IPython.display import Javascript, display
+
+
+def load_css_stylesheet(package: Package, filename=""):
+    """Load a CSS stylesheet from a package and inject it into the DOM.
+
+    Parameters
+    ----------
+    `package` : `Package`
+        The package where the CSS file is located.
+    `filename` : `str`, optional
+        The name of the CSS file to load.
+        If not provided, all CSS files in the package will be loaded.
+    """
+    root = files(package)
+
+    filenames = []
+    if filename:
+        filenames.append(filename)
+    else:
+        filenames.extend(
+            path.name
+            for path in root.iterdir()
+            if path.is_file() and path.name.endswith(".css")
+        )
+
+    for filename in filenames:
+        stylesheet = (root / filename).read_text()
+        display(
+            Javascript(f"""
+                var style = document.createElement('style');
+                style.type = 'text/css';
+                style.innerHTML = `{stylesheet}`;
+                document.head.appendChild(style);
+            """)
+        )
diff --git a/tests/test_loaders.py b/tests/test_loaders.py
new file mode 100644
index 000000000..21caa9186
--- /dev/null
+++ b/tests/test_loaders.py
@@ -0,0 +1,8 @@
+from aiidalab_widgets_base.utils.loaders import load_css_stylesheet
+
+
+def test_load_css_stylesheet():
+    """Test `load_css_stylesheet` function."""
+    package = "aiidalab_widgets_base.static.styles"
+    load_css_stylesheet(package=package, filename="global.css")
+    load_css_stylesheet(package=package)