reflex_copy/reflex/utils/pyi_generator.py

"""The pyi generator module."""

from __future__ import annotations

import ast
import contextlib
import importlib
import inspect
import logging
import re
import subprocess
import textwrap
import typing
from inspect import getfullargspec
from multiprocessing import Pool, cpu_count
from pathlib import Path
from types import ModuleType, SimpleNamespace
from typing import Any, Callable, Iterable, Type, get_args

try:
    import black
    import black.mode
except ImportError:
    black = None

from reflex.components.component import Component
from reflex.utils import types as rx_types
from reflex.vars import Var

logger = logging.getLogger("pyi_generator")

INIT_FILE = Path("reflex/__init__.pyi").resolve()
PWD = Path(".").resolve()

EXCLUDED_FILES = [
    "__init__.py",
    # "app.py",
    "component.py",
    "bare.py",
    "foreach.py",
    "cond.py",
    "match.py",
    "multiselect.py",
    "literals.py",
]

# These props exist on the base component, but should not be exposed in create methods.
EXCLUDED_PROPS = [
    "alias",
    "children",
    "event_triggers",
    "library",
    "lib_dependencies",
    "tag",
    "is_default",
    "special_props",
    "_invalid_children",
    "_memoization_mode",
    "_rename_props",
    "_valid_children",
    "_valid_parents",
    "State",
]

DEFAULT_TYPING_IMPORTS = {
    "overload",
    "Any",
    "Dict",
    # "List",
    "Literal",
    "Optional",
    "Union",
}


def _walk_files(path):
    """Walk all files in a path.
    This can be replaced with Path.walk() in python3.12.

    Args:
        path: The path to walk.

    Yields:
        The next file in the path.
    """
    for p in Path(path).iterdir():
        if p.is_dir():
            yield from _walk_files(p)
            continue
        yield p.resolve()


def _relative_to_pwd(path: Path) -> Path:
    """Get the relative path of a path to the current working directory.

    Args:
        path: The path to get the relative path for.

    Returns:
        The relative path.
    """
    if path.is_absolute():
        return path.relative_to(PWD)
    return path


def _get_type_hint(value, type_hint_globals, is_optional=True) -> str:
    """Resolve the type hint for value.

    Args:
        value: The type annotation as a str or actual types/aliases.
        type_hint_globals: The globals to use to resolving a type hint str.
        is_optional: Whether the type hint should be wrapped in Optional.

    Returns:
        The resolved type hint as a str.
    """
    res = ""
    args = get_args(value)

    if value is type(None):
        return "None"

    if rx_types.is_union(value):
        if type(None) in value.__args__:
            res_args = [
                _get_type_hint(arg, type_hint_globals, rx_types.is_optional(arg))
                for arg in value.__args__
                if arg is not type(None)
            ]
            if len(res_args) == 1:
                return f"Optional[{res_args[0]}]"
            else:
                res = f"Union[{', '.join(res_args)}]"
                return f"Optional[{res}]"

        res_args = [
            _get_type_hint(arg, type_hint_globals, rx_types.is_optional(arg))
            for arg in value.__args__
        ]
        return f"Union[{', '.join(res_args)}]"

    if args:
        inner_container_type_args = (
            [repr(arg) for arg in args]
            if rx_types.is_literal(value)
            else [
                _get_type_hint(arg, type_hint_globals, is_optional=False)
                for arg in args
                if arg is not type(None)
            ]
        )
        res = f"{value.__name__}[{', '.join(inner_container_type_args)}]"

        if value.__name__ == "Var":
            # For Var types, Union with the inner args so they can be passed directly.
            types = [res] + [
                _get_type_hint(arg, type_hint_globals, is_optional=False)
                for arg in args
                if arg is not type(None)
            ]
            if len(types) > 1:
                res = ", ".join(types)
                res = f"Union[{res}]"
    elif isinstance(value, str):
        ev = eval(value, type_hint_globals)
        if rx_types.is_optional(ev):
            # hints = {
            #     _get_type_hint(arg, type_hint_globals, is_optional=False)
            #     for arg in ev.__args__
            # }
            return _get_type_hint(ev, type_hint_globals, is_optional=False)
            # return f"Optional[{', '.join(hints)}]"

        if rx_types.is_union(ev):
            res = [
                _get_type_hint(arg, type_hint_globals, rx_types.is_optional(arg))
                for arg in ev.__args__
            ]
            return f"Union[{', '.join(res)}]"
        res = (
            _get_type_hint(ev, type_hint_globals, is_optional=False)
            if ev.__name__ == "Var"
            else value
        )
    else:
        res = value.__name__
    if is_optional and not res.startswith("Optional"):
        res = f"Optional[{res}]"
    return res


def _generate_imports(typing_imports: Iterable[str]) -> list[ast.ImportFrom]:
    """Generate the import statements for the stub file.

    Args:
        typing_imports: The typing imports to include.

    Returns:
        The list of import statements.
    """
    return [
        ast.ImportFrom(
            module="typing",
            names=[ast.alias(name=imp) for imp in sorted(typing_imports)],
        ),
        *ast.parse(  # type: ignore
            textwrap.dedent(
                """
                from reflex.vars import Var, BaseVar, ComputedVar
                from reflex.event import EventChain, EventHandler, EventSpec
                from reflex.style import Style"""
            )
        ).body,
        # *[
        #     ast.ImportFrom(module=name, names=[ast.alias(name=val) for val in values])
        #     for name, values in EXTRA_IMPORTS.items()
        # ],
    ]


def _generate_docstrings(clzs: list[Type[Component]], props: list[str]) -> str:
    """Generate the docstrings for the create method.

    Args:
        clzs: The classes to generate docstrings for.
        props: The props to generate docstrings for.

    Returns:
        The docstring for the create method.
    """
    props_comments = {}
    comments = []
    for clz in clzs:
        for line in inspect.getsource(clz).splitlines():
            reached_functions = re.search("def ", line)
            if reached_functions:
                # We've reached the functions, so stop.
                break

            # Get comments for prop
            if line.strip().startswith("#"):
                comments.append(line)
                continue

            # Check if this line has a prop.
            match = re.search("\\w+:", line)
            if match is None:
                # This line doesn't have a var, so continue.
                continue

            # Get the prop.
            prop = match.group(0).strip(":")
            if prop in props:
                if not comments:  # do not include undocumented props
                    continue
                props_comments[prop] = [
                    comment.strip().strip("#") for comment in comments
                ]
            comments.clear()
    clz = clzs[0]
    new_docstring = []
    for line in (clz.create.__doc__ or "").splitlines():
        if "**" in line:
            indent = line.split("**")[0]
            for nline in [
                f"{indent}{n}:{' '.join(c)}" for n, c in props_comments.items()
            ]:
                new_docstring.append(nline)
        new_docstring.append(line)
    return "\n".join(new_docstring)


def _extract_func_kwargs_as_ast_nodes(
    func: Callable,
    type_hint_globals: dict[str, Any],
) -> list[tuple[ast.arg, ast.Constant | None]]:
    """Get the kwargs already defined on the function.

    Args:
        func: The function to extract kwargs from.
        type_hint_globals: The globals to use to resolving a type hint str.

    Returns:
        The list of kwargs as ast arg nodes.
    """
    spec = getfullargspec(func)
    kwargs = []

    for kwarg in spec.kwonlyargs:
        arg = ast.arg(arg=kwarg)
        if kwarg in spec.annotations:
            arg.annotation = ast.Name(
                id=_get_type_hint(spec.annotations[kwarg], type_hint_globals)
            )
        default = None
        if spec.kwonlydefaults is not None and kwarg in spec.kwonlydefaults:
            default = ast.Constant(value=spec.kwonlydefaults[kwarg])
        kwargs.append((arg, default))
    return kwargs


def _extract_class_props_as_ast_nodes(
    func: Callable,
    clzs: list[Type],
    type_hint_globals: dict[str, Any],
    extract_real_default: bool = False,
) -> list[tuple[ast.arg, ast.Constant | None]]:
    """Get the props defined on the class and all parents.

    Args:
        func: The function that kwargs will be added to.
        clzs: The classes to extract props from.
        type_hint_globals: The globals to use to resolving a type hint str.
        extract_real_default: Whether to extract the real default value from the
            pydantic field definition.

    Returns:
        The list of props as ast arg nodes
    """
    spec = getfullargspec(func)
    all_props = []
    kwargs = []
    for target_class in clzs:
        # Import from the target class to ensure type hints are resolvable.
        exec(f"from {target_class.__module__} import *", type_hint_globals)
        for name, value in target_class.__annotations__.items():
            if (
                name in spec.kwonlyargs
                or name in EXCLUDED_PROPS
                or name in all_props
                or (isinstance(value, str) and "ClassVar" in value)
            ):
                continue
            all_props.append(name)

            default = None
            if extract_real_default:
                # TODO: This is not currently working since the default is not type compatible
                #       with the annotation in some cases.
                with contextlib.suppress(AttributeError, KeyError):
                    # Try to get default from pydantic field definition.
                    default = target_class.__fields__[name].default
                    if isinstance(default, Var):
                        default = default._decode()  # type: ignore

            kwargs.append(
                (
                    ast.arg(
                        arg=name,
                        annotation=ast.Name(
                            id=_get_type_hint(value, type_hint_globals)
                        ),
                    ),
                    ast.Constant(value=default),
                )
            )
    return kwargs


def _get_parent_imports(func):
    _imports = {"reflex.vars": ["Var"]}
    for type_hint in inspect.get_annotations(func).values():
        try:
            match = re.match(r"\w+\[([\w\d]+)\]", type_hint)
        except TypeError:
            continue
        if match:
            type_hint = match.group(1)
            if type_hint in importlib.import_module(func.__module__).__dir__():
                _imports.setdefault(func.__module__, []).append(type_hint)
    return _imports


def _generate_component_create_functiondef(
    node: ast.FunctionDef | None,
    clz: type[Component] | type[SimpleNamespace],
    type_hint_globals: dict[str, Any],
) -> ast.FunctionDef:
    """Generate the create function definition for a Component.

    Args:
        node: The existing create functiondef node from the ast
        clz: The Component class to generate the create functiondef for.
        type_hint_globals: The globals to use to resolving a type hint str.

    Returns:
        The create functiondef node for the ast.

    Raises:
        TypeError: If clz is not a subclass of Component.
    """
    if not issubclass(clz, Component):
        raise TypeError(f"clz must be a subclass of Component, not {clz!r}")

    # add the imports needed by get_type_hint later
    type_hint_globals.update(
        {name: getattr(typing, name) for name in DEFAULT_TYPING_IMPORTS}
    )

    if clz.__module__ != clz.create.__module__:
        _imports = _get_parent_imports(clz.create)
        for name, values in _imports.items():
            exec(f"from {name} import {','.join(values)}", type_hint_globals)

    kwargs = _extract_func_kwargs_as_ast_nodes(clz.create, type_hint_globals)

    # kwargs associated with props defined in the class and its parents
    all_classes = [c for c in clz.__mro__ if issubclass(c, Component)]
    prop_kwargs = _extract_class_props_as_ast_nodes(
        clz.create, all_classes, type_hint_globals
    )
    all_props = [arg[0].arg for arg in prop_kwargs]
    kwargs.extend(prop_kwargs)

    # event handler kwargs
    kwargs.extend(
        (
            ast.arg(
                arg=trigger,
                annotation=ast.Name(
                    id="Optional[Union[EventHandler, EventSpec, list, function, BaseVar]]"
                ),
            ),
            ast.Constant(value=None),
        )
        for trigger in sorted(clz().get_event_triggers().keys())
    )
    logger.debug(f"Generated {clz.__name__}.create method with {len(kwargs)} kwargs")
    create_args = ast.arguments(
        args=[ast.arg(arg="cls")],
        posonlyargs=[],
        vararg=ast.arg(arg="children"),
        kwonlyargs=[arg[0] for arg in kwargs],
        kw_defaults=[arg[1] for arg in kwargs],
        kwarg=ast.arg(arg="props"),
        defaults=[],
    )
    definition = ast.FunctionDef(
        name="create",
        args=create_args,
        body=[
            ast.Expr(
                value=ast.Constant(value=_generate_docstrings(all_classes, all_props))
            ),
            ast.Expr(
                value=ast.Ellipsis(),
            ),
        ],
        decorator_list=[
            ast.Name(id="overload"),
            *(
                node.decorator_list
                if node is not None
                else [ast.Name(id="classmethod")]
            ),
        ],
        lineno=node.lineno if node is not None else None,
        returns=ast.Constant(value=clz.__name__),
    )
    return definition


def _generate_staticmethod_call_functiondef(
    node: ast.FunctionDef | None,
    clz: type[Component] | type[SimpleNamespace],
    type_hint_globals: dict[str, Any],
) -> ast.FunctionDef | None:
    ...

    fullspec = getfullargspec(clz.__call__)

    call_args = ast.arguments(
        args=[
            ast.arg(
                name,
                annotation=ast.Name(
                    id=_get_type_hint(
                        anno := fullspec.annotations[name],
                        type_hint_globals,
                        is_optional=rx_types.is_optional(anno),
                    )
                ),
            )
            for name in fullspec.args
        ],
        posonlyargs=[],
        kwonlyargs=[],
        kw_defaults=[],
        kwarg=ast.arg(arg="props"),
        defaults=[],
    )
    definition = ast.FunctionDef(
        name="__call__",
        args=call_args,
        body=[
            ast.Expr(value=ast.Constant(value=clz.__call__.__doc__)),
            ast.Expr(
                value=ast.Constant(...),
            ),
        ],
        decorator_list=[ast.Name(id="staticmethod")],
        lineno=node.lineno if node is not None else None,
        returns=ast.Constant(
            value=_get_type_hint(
                typing.get_type_hints(clz.__call__).get("return", None),
                type_hint_globals,
            )
        ),
    )
    return definition


def _generate_namespace_call_functiondef(
    node: ast.ClassDef | None,
    clz_name: str,
    classes: dict[str, type[Component] | type[SimpleNamespace]],
    type_hint_globals: dict[str, Any],
) -> ast.FunctionDef | None:
    """Generate the __call__ function definition for a SimpleNamespace.

    Args:
        node: The existing __call__ classdef parent node from the ast
        clz_name: The name of the SimpleNamespace class to generate the __call__ functiondef for.
        classes: Map name to actual class definition.
        type_hint_globals: The globals to use to resolving a type hint str.

    Returns:
        The create functiondef node for the ast.
    """
    # add the imports needed by get_type_hint later
    type_hint_globals.update(
        {name: getattr(typing, name) for name in DEFAULT_TYPING_IMPORTS}
    )

    clz = classes[clz_name]

    if not hasattr(clz.__call__, "__self__"):
        return _generate_staticmethod_call_functiondef(node, clz, type_hint_globals)  # type: ignore

    # Determine which class is wrapped by the namespace __call__ method
    component_clz = clz.__call__.__self__

    if clz.__call__.__func__.__name__ != "create":
        return None

    definition = _generate_component_create_functiondef(
        node=None,
        clz=component_clz,  # type: ignore
        type_hint_globals=type_hint_globals,
    )
    definition.name = "__call__"

    # Turn the definition into a staticmethod
    del definition.args.args[0]  # remove `cls` arg
    definition.decorator_list = [ast.Name(id="staticmethod")]

    return definition


class StubGenerator(ast.NodeTransformer):
    """A node transformer that will generate the stubs for a given module."""

    def __init__(
        self, module: ModuleType, classes: dict[str, Type[Component | SimpleNamespace]]
    ):
        """Initialize the stub generator.

        Args:
            module: The actual module object module to generate stubs for.
            classes: The actual Component class objects to generate stubs for.
        """
        super().__init__()
        # Dict mapping class name to actual class object.
        self.classes = classes
        # Track the last class node that was visited.
        self.current_class = None
        # These imports will be included in the AST of stub files.
        self.typing_imports = DEFAULT_TYPING_IMPORTS
        # Whether those typing imports have been inserted yet.
        self.inserted_imports = False
        # Collected import statements from the module.
        self.import_statements: list[str] = []
        # This dict is used when evaluating type hints.
        self.type_hint_globals = module.__dict__.copy()

    @staticmethod
    def _remove_docstring(
        node: ast.Module | ast.ClassDef | ast.FunctionDef,
    ) -> ast.Module | ast.ClassDef | ast.FunctionDef:
        """Removes any docstring in place.

        Args:
            node: The node to remove the docstring from.

        Returns:
            The modified node.
        """
        if (
            node.body
            and isinstance(node.body[0], ast.Expr)
            and isinstance(node.body[0].value, ast.Constant)
        ):
            node.body.pop(0)
        return node

    def _current_class_is_component(self) -> bool:
        """Check if the current class is a Component.

        Returns:
            Whether the current class is a Component.
        """
        return (
            self.current_class is not None
            and self.current_class in self.classes
            and issubclass(self.classes[self.current_class], Component)
        )

    def visit_Module(self, node: ast.Module) -> ast.Module:
        """Visit a Module node and remove docstring from body.

        Args:
            node: The Module node to visit.

        Returns:
            The modified Module node.
        """
        self.generic_visit(node)
        return self._remove_docstring(node)  # type: ignore

    def visit_Import(
        self, node: ast.Import | ast.ImportFrom
    ) -> ast.Import | ast.ImportFrom | list[ast.Import | ast.ImportFrom]:
        """Collect import statements from the module.

        If this is the first import statement, insert the typing imports before it.

        Args:
            node: The import node to visit.

        Returns:
            The modified import node(s).
        """
        self.import_statements.append(ast.unparse(node))
        if not self.inserted_imports:
            self.inserted_imports = True
            return _generate_imports(self.typing_imports) + [node]
        return node

    def visit_ImportFrom(
        self, node: ast.ImportFrom
    ) -> ast.Import | ast.ImportFrom | list[ast.Import | ast.ImportFrom] | None:
        """Visit an ImportFrom node.

        Remove any `from __future__ import *` statements, and hand off to visit_Import.

        Args:
            node: The ImportFrom node to visit.

        Returns:
            The modified ImportFrom node.
        """
        if node.module == "__future__":
            return None  # ignore __future__ imports
        return self.visit_Import(node)

    def visit_ClassDef(self, node: ast.ClassDef) -> ast.ClassDef:
        """Visit a ClassDef node.

        Remove all assignments in the class body, and add a create functiondef
        if one does not exist.

        Args:
            node: The ClassDef node to visit.

        Returns:
            The modified ClassDef node.
        """
        exec("\n".join(self.import_statements), self.type_hint_globals)
        self.current_class = node.name
        self._remove_docstring(node)

        # Define `__call__` as a real function so the docstring appears in the stub.
        call_definition = None
        for child in node.body[:]:
            found_call = False
            if isinstance(child, ast.Assign):
                for target in child.targets[:]:
                    if isinstance(target, ast.Name) and target.id == "__call__":
                        child.targets.remove(target)
                        found_call = True
                if not found_call:
                    continue
                if not child.targets[:]:
                    node.body.remove(child)
                call_definition = _generate_namespace_call_functiondef(
                    node,
                    self.current_class,
                    self.classes,
                    type_hint_globals=self.type_hint_globals,
                )
                break

        self.generic_visit(node)  # Visit child nodes.

        if (
            not any(
                isinstance(child, ast.FunctionDef) and child.name == "create"
                for child in node.body
            )
            and self._current_class_is_component()
        ):
            # Add a new .create FunctionDef since one does not exist.
            node.body.append(
                _generate_component_create_functiondef(
                    node=None,
                    clz=self.classes[self.current_class],
                    type_hint_globals=self.type_hint_globals,
                )
            )
        if call_definition is not None:
            node.body.append(call_definition)
        if not node.body:
            # We should never return an empty body.
            node.body.append(ast.Expr(value=ast.Ellipsis()))
        self.current_class = None
        return node

    def visit_FunctionDef(self, node: ast.FunctionDef) -> Any:
        """Visit a FunctionDef node.

        Special handling for `.create` functions to add type hints for all props
        defined on the component class.

        Remove all private functions and blank out the function body of the
        remaining public functions.

        Args:
            node: The FunctionDef node to visit.

        Returns:
            The modified FunctionDef node (or None).
        """
        if node.name == "create" and self.current_class in self.classes:
            node = _generate_component_create_functiondef(
                node, self.classes[self.current_class], self.type_hint_globals
            )
        else:
            if node.name.startswith("_") and node.name != "__call__":
                return None  # remove private methods

            if node.body[-1] != ast.Expr(value=ast.Ellipsis()):
                # Blank out the function body for public functions.
                node.body = [ast.Expr(value=ast.Ellipsis())]
        return node

    def visit_Assign(self, node: ast.Assign) -> ast.Assign | None:
        """Remove non-annotated assignment statements.

        Args:
            node: The Assign node to visit.

        Returns:
            The modified Assign node (or None).
        """
        # Special case for assignments to `typing.Any` as fallback.
        if (
            node.value is not None
            and isinstance(node.value, ast.Name)
            and node.value.id == "Any"
        ):
            return node

        if self._current_class_is_component():
            # Remove annotated assignments in Component classes (props)
            return None

        return node

    def visit_AnnAssign(self, node: ast.AnnAssign) -> ast.AnnAssign | None:
        """Visit an AnnAssign node (Annotated assignment).

        Remove private target and remove the assignment value in the stub.

        Args:
            node: The AnnAssign node to visit.

        Returns:
            The modified AnnAssign node (or None).
        """
        # skip ClassVars
        if (
            isinstance(node.annotation, ast.Subscript)
            and isinstance(node.annotation.value, ast.Name)
            and node.annotation.value.id == "ClassVar"
        ):
            return node
        if isinstance(node.target, ast.Name) and node.target.id.startswith("_"):
            return None
        if self.current_class in self.classes:
            # Remove annotated assignments in Component classes (props)
            return None
        # Blank out assignments in type stubs.
        node.value = None
        return node


class PyiGenerator:
    """A .pyi file generator that will scan all defined Component in Reflex and
    generate the approriate stub.
    """

    modules: list = []
    root: str = ""
    current_module: Any = {}

    def _write_pyi_file(self, module_path: Path, source: str):
        relpath = str(_relative_to_pwd(module_path)).replace("\\", "/")
        pyi_content = [
            f'"""Stub file for {relpath}"""',
            "# ------------------- DO NOT EDIT ----------------------",
            "# This file was generated by `reflex/utils/pyi_generator.py`!",
            "# ------------------------------------------------------",
            "",
        ]
        if black is not None:
            for formatted_line in black.format_file_contents(
                src_contents=source,
                fast=True,
                mode=black.mode.Mode(is_pyi=True),
            ).splitlines():
                # Bit of a hack here, since the AST cannot represent comments.
                if "def create(" in formatted_line or "Figure" in formatted_line:
                    pyi_content.append(formatted_line + "  # type: ignore")
                else:
                    pyi_content.append(formatted_line)
            pyi_content.append("")  # add empty line at the end for formatting
        else:
            pyi_content = source.splitlines()

        pyi_path = module_path.with_suffix(".pyi")
        pyi_path.write_text("\n".join(pyi_content))
        logger.info(f"Wrote {relpath}")

    def _scan_file(self, module_path: Path):
        module_import = (
            _relative_to_pwd(module_path)
            .with_suffix("")
            .as_posix()
            .replace("/", ".")
            .replace("\\", ".")
        )
        module = importlib.import_module(module_import)
        logger.debug(f"Read {module_path}")
        class_names = {
            name: obj
            for name, obj in vars(module).items()
            if inspect.isclass(obj)
            and (issubclass(obj, Component) or issubclass(obj, SimpleNamespace))
            and obj != Component
            and inspect.getmodule(obj) == module
        }
        if not class_names:
            return

        new_tree = StubGenerator(module, class_names).visit(
            ast.parse(inspect.getsource(module))
        )
        self._write_pyi_file(module_path, ast.unparse(new_tree))

    def _scan_files_multiprocess(self, files: list[Path]):
        with Pool(processes=cpu_count()) as pool:
            pool.map(self._scan_file, files)

    def _scan_files(self, files: list[Path]):
        for file in files:
            self._scan_file(file)

    def scan_all(self, targets, changed_files: list[Path] | None = None):
        """Scan all targets for class inheriting Component and generate the .pyi files.

        Args:
            targets: the list of file/folders to scan.
            changed_files (optional): the list of changed files since the last run.
        """
        file_targets = []
        for target in targets:
            target_path = Path(target)
            if (
                target_path.is_file()
                and target_path.suffix == ".py"
                and target_path.name not in EXCLUDED_FILES
            ):
                file_targets.append(target_path)
                continue
            if not target_path.is_dir():
                continue
            for file_path in _walk_files(target_path):
                relative = _relative_to_pwd(file_path)
                if relative.name in EXCLUDED_FILES or file_path.suffix != ".py":
                    continue
                if (
                    changed_files is not None
                    and _relative_to_pwd(file_path) not in changed_files
                ):
                    continue
                file_targets.append(file_path)

        # check if pyi changed but not the source
        if changed_files is not None:
            for changed_file in changed_files:
                if changed_file.suffix != ".pyi":
                    continue
                py_file_path = changed_file.with_suffix(".py")
                if not py_file_path.exists() and changed_file.exists():
                    changed_file.unlink()
                if py_file_path in file_targets:
                    continue
                subprocess.run(["git", "checkout", changed_file])

        if cpu_count() == 1 or len(file_targets) < 5:
            self._scan_files(file_targets)
        else:
            self._scan_files_multiprocess(file_targets)


def generate_init():
    """Generate a pyi file for the main __init__.py."""
    from reflex import _MAPPING  # type: ignore

    imports = [
        f"from {path if mod != path.rsplit('.')[-1] or mod == 'page' else '.'.join(path.rsplit('.')[:-1])} import {mod} as {mod}"
        for mod, path in _MAPPING.items()
    ]
    imports.append("")
    with contextlib.suppress(Exception):
        INIT_FILE.write_text("\n".join(imports))