API: improve type & class construction

pkgs/clan-app/clan_app/views/webview.py

@@ -4,9 +4,11 @@ import logging
 import sys
 import threading
 from collections.abc import Callable
+from dataclasses import fields, is_dataclass
 from pathlib import Path
 from threading import Lock
-from typing import Any
+from types import UnionType
+from typing import Any, get_args
 
 import gi
 from clan_cli.api import API
@@ -37,7 +39,7 @@ def dataclass_to_dict(obj: Any) -> Any:
     elif isinstance(obj, dict):
         return {k: dataclass_to_dict(v) for k, v in obj.items()}
     else:
-        return obj
+        return str(obj)
 
 
 # Implement the abstract open_file function
@@ -135,6 +137,58 @@ def open_file(file_request: FileRequest) -> str | None:
     return selected_path
 
 
+def is_union_type(type_hint: type) -> bool:
+    return type(type_hint) is UnionType
+
+
+def get_inner_type(type_hint: type) -> type:
+    if is_union_type(type_hint):
+        # Return the first non-None type
+        return next(t for t in get_args(type_hint) if t is not type(None))
+    return type_hint
+
+
+def from_dict(t: type, data: dict[str, Any] | None) -> Any:
+    """
+    Dynamically instantiate a data class from a dictionary, handling nested data classes.
+    """
+    if not data:
+        return None
+
+    try:
+        # Attempt to create an instance of the data_class
+        field_values = {}
+        for field in fields(t):
+            field_value = data.get(field.name)
+            field_type = get_inner_type(field.type)
+            if field_value is not None:
+                # If the field is another dataclass, recursively instantiate it
+                if is_dataclass(field_type):
+                    field_value = from_dict(field_type, field_value)
+                elif isinstance(field_type, Path | str) and isinstance(
+                    field_value, str
+                ):
+                    field_value = (
+                        Path(field_value) if field_type == Path else field_value
+                    )
+
+            if (
+                field.default is not dataclasses.MISSING
+                or field.default_factory is not dataclasses.MISSING
+            ):
+                # Field has a default value. We cannot set the value to None
+                if field_value is not None:
+                    field_values[field.name] = field_value
+            else:
+                field_values[field.name] = field_value
+
+        return t(**field_values)
+
+    except (TypeError, ValueError) as e:
+        print(f"Failed to instantiate {t.__name__}: {e}")
+        return None
+
+
 class WebView:
     def __init__(self, methods: dict[str, Callable]) -> None:
         self.method_registry: dict[str, Callable] = methods
@@ -216,14 +270,13 @@ class WebView:
                     # But the js api returns dictionaries.
                     # Introspect the function and create the expected dataclass from dict dynamically
                     # Depending on the introspected argument_type
-                    arg_type = API.get_method_argtype(method_name, k)
-                    if dataclasses.is_dataclass(arg_type):
-                        reconciled_arguments[k] = arg_type(**v)
+                    arg_class = API.get_method_argtype(method_name, k)
+                    if dataclasses.is_dataclass(arg_class):
+                        reconciled_arguments[k] = from_dict(arg_class, v)
                     else:
                         reconciled_arguments[k] = v
 
                 result = handler_fn(**reconciled_arguments)
-
             serialized = json.dumps(dataclass_to_dict(result))
 
             # Use idle_add to queue the response call to js on the main GTK thread