added windows interaction test

adding more variant stuff

variant_manager.py

@@ -35,19 +35,39 @@ class VariantManager:
         """Load variants from JSON file"""
         if self.variants_file.exists():
             with open(self.variants_file, 'r', encoding='utf-8') as f:
-                return json.load(f)
+                data = json.load(f)
+
+            # Migrate from version 2 to version 3
+            if data.get("meta", {}).get("version", 1) < 3:
+                print(f"Migrating variant file from version {data.get('meta', {}).get('version', 1)} to 3")
+                if "base_values" not in data:
+                    data["base_values"] = {}
+                for variant in data.get("variants", {}).values():
+                    if "part_overrides" not in variant:
+                        variant["part_overrides"] = {}
+                data["meta"]["version"] = 3
+                # Save migrated version
+                with open(self.variants_file, 'w', encoding='utf-8') as f:
+                    json.dump(data, f, indent=2)
+
+            return data
         else:
             # Default structure
             return {
                 "meta": {
-                    "version": 2,  # Version 2 uses UUIDs instead of references
+                    "version": 3,  # Version 3 adds base_values and part_overrides
                     "active_variant": "default"
                 },
+                "base_values": {
+                    # UUID -> {property_name: value}
+                    # Stores the base/default values for parts that vary between variants
+                },
                 "variants": {
                     "default": {
                         "name": "default",
                         "description": "Default variant - all parts fitted",
-                        "dnp_parts": []  # List of UUIDs that are DNP (Do Not Place)
+                        "dnp_parts": [],  # List of UUIDs that are DNP (Do Not Place)
+                        "part_overrides": {}  # UUID -> {property_name: override_value}
                     }
                 }
             }
@@ -194,6 +214,88 @@ class VariantManager:
 
         return uuid in self.variants["variants"][variant_name]["dnp_parts"]
 
+    def get_part_properties(self, variant_name: str, uuid: str) -> Dict[str, str]:
+        """
+        Get effective property values for a part in a variant.
+        Merges base_values with variant-specific overrides.
+
+        Args:
+            variant_name: Variant name
+            uuid: Component UUID
+
+        Returns:
+            Dict of property_name -> value (merged base + overrides)
+        """
+        if variant_name not in self.variants["variants"]:
+            return {}
+
+        # Start with base values
+        properties = self.variants.get("base_values", {}).get(uuid, {}).copy()
+
+        # Apply variant overrides
+        overrides = self.variants["variants"][variant_name].get("part_overrides", {}).get(uuid, {})
+        properties.update(overrides)
+
+        return properties
+
+    def set_part_property(self, variant_name: str, uuid: str, property_name: str, value: str) -> bool:
+        """
+        Set a property override for a part in a variant.
+
+        Args:
+            variant_name: Variant name
+            uuid: Component UUID
+            property_name: Property to set (e.g., "Value", "MPN")
+            value: New value
+
+        Returns:
+            True if successful, False if variant doesn't exist
+        """
+        if variant_name not in self.variants["variants"]:
+            return False
+
+        # Ensure part_overrides exists for this variant
+        if "part_overrides" not in self.variants["variants"][variant_name]:
+            self.variants["variants"][variant_name]["part_overrides"] = {}
+
+        # Get or create override dict for this UUID
+        if uuid not in self.variants["variants"][variant_name]["part_overrides"]:
+            self.variants["variants"][variant_name]["part_overrides"][uuid] = {}
+
+        # Check if this matches base value - if so, remove override (keep it sparse)
+        base_value = self.variants.get("base_values", {}).get(uuid, {}).get(property_name)
+        if value == base_value:
+            # Remove from overrides since it matches base
+            if property_name in self.variants["variants"][variant_name]["part_overrides"][uuid]:
+                del self.variants["variants"][variant_name]["part_overrides"][uuid][property_name]
+                # Clean up empty override dicts
+                if not self.variants["variants"][variant_name]["part_overrides"][uuid]:
+                    del self.variants["variants"][variant_name]["part_overrides"][uuid]
+        else:
+            # Store override
+            self.variants["variants"][variant_name]["part_overrides"][uuid][property_name] = value
+
+        self._save_variants()
+        return True
+
+    def set_base_value(self, uuid: str, property_name: str, value: str):
+        """
+        Set a base property value for a part.
+
+        Args:
+            uuid: Component UUID
+            property_name: Property name
+            value: Value to set
+        """
+        if "base_values" not in self.variants:
+            self.variants["base_values"] = {}
+
+        if uuid not in self.variants["base_values"]:
+            self.variants["base_values"][uuid] = {}
+
+        self.variants["base_values"][uuid][property_name] = value
+        self._save_variants()
+
 
 if __name__ == "__main__":
     if len(sys.argv) < 2: