From e8cc67a546df3e9fd0e0e1d970a23cd25fcdca4f Mon Sep 17 00:00:00 2001
From: Parashara Shamaprasad <p.shama@vanderbilt.edu>
Date: Thu, 31 Oct 2019 17:38:59 -0500
Subject: [PATCH 1/2] Add initial attempt at a plugin detector.

---
 foyer/__init__.py |  1 +
 foyer/plugins.py  | 39 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 40 insertions(+)
 create mode 100644 foyer/plugins.py

diff --git a/foyer/__init__.py b/foyer/__init__.py
index c310b99c..a4c8ac90 100644
--- a/foyer/__init__.py
+++ b/foyer/__init__.py
@@ -1,3 +1,4 @@
 from foyer.forcefield import Forcefield
 from foyer.forcefields import forcefields
 from foyer.version import version
+from foyer.plugins import collect_plugins
diff --git a/foyer/plugins.py b/foyer/plugins.py
new file mode 100644
index 00000000..8dfb0118
--- /dev/null
+++ b/foyer/plugins.py
@@ -0,0 +1,39 @@
+import foyer
+import glob
+
+def collect_plugins(plugin_names=None):
+    """
+    Detects which plugins are installed
+
+    Arguments
+    ---------
+    plugin_names: list, default=None
+        A list of non-standard plugin names (strings) to additionally
+        check for.
+    """
+
+    plugin_funcs = [func for func in dir(foyer.forcefields)
+                    if "load" in func and "__" not in func]
+
+    if plugin_names:
+        plugin_funcs += plugin_names
+
+    plugins = dict()
+    for plugin_func in plugin_funcs:
+        plugin_loader_func = eval("foyer.forcefields.{}".format(plugin_func))
+        # Assumes all plugins are named "load_{plugin_name}"
+        plugin_name = "_".join(plugin_func.split("_")[1:])
+        # TODO: plugin_version = get_version_info
+        plugin_dir = eval("foyer.forcefields.{}.__globals__['__file__']".format(plugin_func))
+        # TODO: plugin_xml_path = get_xml_path
+        # This assumes that plugin directory tree is consistent.
+        # Does not consider versioned FFs.
+        plugin_xml_path = glob.glob("{}/xml/*xml".format(plugin_dir))
+
+        plugin = {plugin_name : {"version"       : None,
+                                 "load_function" : plugin_loader_func,
+                                 "xml_path"      : plugin_xml_path
+                                 }}
+        plugins.update(plugin)
+
+    return plugins

From 2678a39614c338cc2cbeab2619a905e90c7195e1 Mon Sep 17 00:00:00 2001
From: Parashara Shamaprasad <p.shama@vanderbilt.edu>
Date: Fri, 22 Nov 2019 12:04:22 -0600
Subject: [PATCH 2/2] Make plugin_dir reference the directory instead of a
 file.

---
 foyer/plugins.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/foyer/plugins.py b/foyer/plugins.py
index 8dfb0118..2ca779ad 100644
--- a/foyer/plugins.py
+++ b/foyer/plugins.py
@@ -1,5 +1,6 @@
 import foyer
 import glob
+import os
 
 def collect_plugins(plugin_names=None):
     """
@@ -25,6 +26,7 @@ def collect_plugins(plugin_names=None):
         plugin_name = "_".join(plugin_func.split("_")[1:])
         # TODO: plugin_version = get_version_info
         plugin_dir = eval("foyer.forcefields.{}.__globals__['__file__']".format(plugin_func))
+        plugin_dir = os.path.dirname(plugin_dir)
         # TODO: plugin_xml_path = get_xml_path
         # This assumes that plugin directory tree is consistent.
         # Does not consider versioned FFs.