feat: add ModelMapper with folder_paths introspection

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

mapper.py

@@ -66,3 +66,116 @@ class NodePackageMapper:
     def invalidate(self):
         """Force rebuild on next access (e.g. after node reload)."""
         self._map = None
+
+
+# Folder types that are not model files and should not be tracked
+EXCLUDED_FOLDER_TYPES = {
+    "loras",
+    "configs",
+    "custom_nodes",
+    "temp",
+    "output",
+    "input",
+    "annotators",
+    "assets",
+}
+
+
+class ModelMapper:
+    """Tracks which folder_paths model types exist and resolves filenames to types."""
+
+    def __init__(self):
+        self._folder_files = None   # {folder_type: frozenset(filenames)}
+        self._reverse = None        # {filename: folder_type}
+
+    def _build(self):
+        try:
+            import folder_paths
+
+            self._folder_files = {}
+            for folder_type in folder_paths.folder_names_and_paths:
+                if folder_type in EXCLUDED_FOLDER_TYPES:
+                    continue
+                try:
+                    files = folder_paths.get_filename_list(folder_type)
+                except Exception:
+                    files = []
+                if files:
+                    self._folder_files[folder_type] = frozenset(files)
+
+            # Reverse map: filename -> folder_type (last write wins on collision)
+            self._reverse = {}
+            for folder_type, files in self._folder_files.items():
+                for f in files:
+                    self._reverse[f] = folder_type
+
+        except Exception:
+            logger.warning("ModelMapper: failed to build model map", exc_info=True)
+            self._folder_files = {}
+            self._reverse = {}
+
+    def _ensure(self):
+        if self._folder_files is None:
+            self._build()
+
+    def get_model_type(self, filename):
+        """Return the folder type for a filename, or None if not tracked."""
+        self._ensure()
+        return self._reverse.get(filename)
+
+    def get_all_models(self):
+        """Return {folder_type: [filename, ...]} for all tracked types."""
+        self._ensure()
+        return {k: sorted(v) for k, v in self._folder_files.items()}
+
+    def extract_models_from_prompt(self, prompt):
+        """Scan a prompt dict and return (model_name, model_type) pairs.
+
+        For each node, inspects INPUT_TYPES() to find list-type (folder dropdown)
+        inputs, then resolves the selected value against the folder_paths reverse map.
+        """
+        self._ensure()
+        try:
+            import nodes as comfy_nodes
+        except ImportError:
+            return []
+
+        seen = set()
+        results = []
+
+        for node_data in prompt.values():
+            class_type = node_data.get("class_type")
+            node_inputs = node_data.get("inputs", {})
+            if not class_type or not node_inputs:
+                continue
+
+            node_cls = comfy_nodes.NODE_CLASS_MAPPINGS.get(class_type)
+            if node_cls is None:
+                continue
+
+            try:
+                input_types = node_cls.INPUT_TYPES()
+            except Exception:
+                continue
+
+            for category in ("required", "optional"):
+                for input_name, input_def in input_types.get(category, {}).items():
+                    if not isinstance(input_def, (list, tuple)) or not input_def:
+                        continue
+                    # ComfyUI folder dropdowns have a list as their type
+                    if not isinstance(input_def[0], list):
+                        continue
+                    value = node_inputs.get(input_name)
+                    if not isinstance(value, str) or value in seen:
+                        continue
+                    model_type = self.get_model_type(value)
+                    if model_type:
+                        seen.add(value)
+                        results.append((value, model_type))
+
+        return results
+
+    def invalidate(self):
+        """Force rebuild on next access."""
+        self._folder_files = None
+        self._reverse = None