4 files changed, 103 insertions, 41 deletions

diff --git a/tools/cru-py/cru/_iter.py b/tools/cru-py/cru/_iter.py
index 5d3766a..8f58561 100644
--- a/tools/cru-py/cru/_iter.py
+++ b/tools/cru-py/cru/_iter.py
@@ -63,7 +63,7 @@ class _Generic:
 
         @staticmethod
         def aggregate(
-            *results: _Generic.StepAction[_V, _R]
+            *results: _Generic.StepAction[_V, _R],
         ) -> _Generic.StepAction[_V, _R]:
             return _Generic.StepAction(results, _Generic.StepActionKind.AGGREGATE)
 
@@ -255,7 +255,6 @@ class _Helpers:
 
 
 class _Creators:
-
     class Raw:
         @staticmethod
         def empty() -> Iterator[Never]:
@@ -313,7 +312,7 @@ class CruIterator(Generic[_T]):
 
     @staticmethod
     def _wrap(
-        f: Callable[Concatenate[CruIterator[_T], _P], Iterable[_O]]
+        f: Callable[Concatenate[CruIterator[_T], _P], Iterable[_O]],
     ) -> Callable[Concatenate[CruIterator[_T], _P], CruIterator[_O]]:
         def _wrapped(
             self: CruIterator[_T], *args: _P.args, **kwargs: _P.kwargs
@@ -435,11 +434,33 @@ class CruIterator(Generic[_T]):
         value_set = set(old_values)
         return self.transform(lambda v: new_value if v in value_set else v)
 
+    def group_by(self, key_getter: Callable[[_T], _O]) -> dict[_O, list[_T]]:
+        result: dict[_O, list[_T]] = {}
+
+        for item in self:
+            key = key_getter(item)
+            if key not in result:
+                result[key] = []
+            result[key].append(item)
+
+        return result
+
+
+class CruIterMixin(Generic[_T]):
+    def cru_iter(self: Iterable[_T]) -> CruIterator[_T]:
+        return CruIterator(self)
+
+
+class CruIterList(list[_T], CruIterMixin[_T]):
+    pass
+
 
 class CruIterable:
     Generic: TypeAlias = _Generic
-    Iterator: TypeAlias = CruIterator
+    Iterator: TypeAlias = CruIterator[_T]
     Helpers: TypeAlias = _Helpers
+    Mixin: TypeAlias = CruIterMixin[_T]
+    IterList: TypeAlias = CruIterList[_T]
 
 
 CRU.add_objects(CruIterable, CruIterator)
diff --git a/tools/cru-py/cru/config.py b/tools/cru-py/cru/config.py
index 926ed6a..497eb01 100644
--- a/tools/cru-py/cru/config.py
+++ b/tools/cru-py/cru/config.py
@@ -82,11 +82,20 @@ class ConfigItem(Generic[_T]):
     def can_generate_default(self) -> bool:
         return self.default is not None
 
-    def set_value(self, v: _T | str, /, allow_convert_from_str=False):
-        if allow_convert_from_str:
-            self._value = self.value_type.check_value(v)
-        else:
+    def set_value(
+        self, v: _T | str, *, empty_is_default=True, allow_convert_from_str=True
+    ):
+        if empty_is_default and v == "":
+            self._value = None
+        elif allow_convert_from_str:
             self._value = self.value_type.check_value_or_try_convert_from_str(v)
+        else:
+            self._value = self.value_type.check_value(v)
+
+    def reset(self, clear_default_cache=False):
+        if clear_default_cache:
+            self._default_value = None
+        self._value = None
 
     def generate_default_value(self) -> _T:
         if self.default is None:
@@ -140,3 +149,7 @@ class Configuration(CruUniqueKeyList[ConfigItem, str]):
         item = ConfigItem(name, description, INTEGER_VALUE_TYPE, value, default)
         self.add(item)
         return item
+
+    def reset_all(self, clear_default_cache=False) -> None:
+        for item in self:
+            item.reset(clear_default_cache)
diff --git a/tools/cru-py/cru/parsing.py b/tools/cru-py/cru/parsing.py
index a9eee04..5049a33 100644
--- a/tools/cru-py/cru/parsing.py
+++ b/tools/cru-py/cru/parsing.py
@@ -1,20 +1,34 @@
+from __future__ import annotations
+
 from abc import ABCMeta, abstractmethod
-from typing import TypeVar, Generic, NoReturn, Callable
+from typing import NamedTuple, TypeAlias, TypeVar, Generic, NoReturn, Callable
 
 from ._error import CruException
+from ._iter import  CruIterable
 
 _T = TypeVar("_T")
 
 
-class ParseException(CruException):
+class ParseException(CruException, Generic[_T]):
     def __init__(
-        self, message, text: str, line_number: int | None = None, *args, **kwargs
+        self,
+        message,
+        parser: Parser[_T],
+        text: str,
+        line_number: int | None = None,
+        *args,
+        **kwargs,
     ):
         super().__init__(message, *args, **kwargs)
+        self._parser = parser
         self._text = text
         self._line_number = line_number
 
     @property
+    def parser(self) -> Parser[_T]:
+        return self._parser
+
+    @property
     def text(self) -> str:
         return self._text
 
@@ -38,16 +52,34 @@ class Parser(Generic[_T], metaclass=ABCMeta):
     def raise_parse_exception(
         self, text: str, line_number: int | None = None
     ) -> NoReturn:
-        a = f" at line {line_number}" if line_number is not None else ""
-        raise ParseException(f"Parser {self.name} failed{a}.", text, line_number)
+        a = line_number and f" at line {line_number}" or ""
+        raise ParseException(f"Parser {self.name} failed{a}.", self, text, line_number)
+
+
+class SimpleLineConfigParserItem(NamedTuple):
+    key: str
+    value: str
+    line_number: int | None = None
 
 
-class SimpleLineConfigParser(Parser[list[tuple[str, str]]]):
+SimpleLineConfigParserResult: TypeAlias = CruIterable.IterList[
+    SimpleLineConfigParserItem
+]
+
+
+class SimpleLineConfigParser(Parser[SimpleLineConfigParserResult]):
+    """
+    The parsing result is a list of tuples (key, value, line number).
+    """
+
+    Item: TypeAlias = SimpleLineConfigParserItem
+    Result: TypeAlias = SimpleLineConfigParserResult
+
     def __init__(self) -> None:
         super().__init__(type(self).__name__)
 
-    def _parse(self, s: str, callback: Callable[[str, str], None]) -> None:
-        for ln, line in enumerate(s.splitlines()):
+    def _parse(self, text: str, callback: Callable[[Item], None]) -> None:
+        for ln, line in enumerate(text.splitlines()):
             line_number = ln + 1
             # check if it's a comment
             if line.strip().startswith("#"):
@@ -59,27 +91,9 @@ class SimpleLineConfigParser(Parser[list[tuple[str, str]]]):
             key, value = line.split("=", 1)
             key = key.strip()
             value = value.strip()
-            callback(key, value)
-
-    def parse(self, s: str) -> list[tuple[str, str]]:
-        items = []
-        self._parse(s, lambda key, value: items.append((key, value)))
-        return items
-
-    def parse_to_dict(
-        self, s: str, /, allow_override: bool = False
-    ) -> tuple[dict[str, str], list[tuple[str, str]]]:
-        result: dict[str, str] = {}
-        duplicate: list[tuple[str, str]] = []
-
-        def add(key: str, value: str) -> None:
-            if key in result:
-                if allow_override:
-                    duplicate.append((key, result[key]))
-                    result[key] = value
-                else:
-                    self.raise_parse_exception(f"Key '{key}' already exists!", None)
-            result[key] = value
-
-        self._parse(s, add)
-        return result, duplicate
+            callback(SimpleLineConfigParserItem(key, value, line_number))
+
+    def parse(self, text: str) -> Result:
+        result = SimpleLineConfigParserResult()
+        self._parse(text, lambda item: result.append(item))
+        return result
diff --git a/tools/cru-py/cru/service/_config.py b/tools/cru-py/cru/service/_config.py
index b5f3e7c..018b45b 100644
--- a/tools/cru-py/cru/service/_config.py
+++ b/tools/cru-py/cru/service/_config.py
@@ -5,6 +5,7 @@ from cru.value import (
     RandomStringValueGenerator,
     UuidValueGenerator,
 )
+from cru.parsing import SimpleLineConfigParser
 
 from ._base import AppFeaturePath, AppFeatureProvider, OWNER_NAME
 
@@ -83,7 +84,7 @@ class ConfigManager(AppFeatureProvider):
         )
 
     @property
-    def config_path(self) -> AppFeaturePath:
+    def config_file_path(self) -> AppFeaturePath:
         return self._config_path
 
     @property
@@ -91,5 +92,18 @@ class ConfigManager(AppFeatureProvider):
         return self._configuration
 
     @property
+    def config_keys(self) -> list[str]:
+        return [item.name for item in self.configuration]
+
+    @property
     def config_map(self) -> dict[str, str]:
         raise NotImplementedError()
+
+    def reload_config_file(self) -> bool:
+        self.configuration.reset_all()
+        if not self.config_file_path.check_self():
+            return False
+        parser = SimpleLineConfigParser()
+        parse_result = parser.parse(self.config_file_path.full_path.read_text())
+        config_dict = parse_result.cru_iter().group_by(lambda i: i.key)
+        return True