"""Python backend adapter for molting-cli."""
from __future__ import annotations
import shutil
from typing import Any
from mcp_refactoring.adapters.base import BackendAdapter
from mcp_refactoring.config import get_config
from mcp_refactoring.models import (
RefactoringCategory,
RefactoringParam,
RefactoringSpec,
PreviewResult,
RefactoringResult,
FileChange,
StructureInfo,
ClassInfo,
MethodInfo,
)
from mcp_refactoring.utils import run_command
class PythonAdapter(BackendAdapter):
"""Adapter for the molting-cli Python refactoring tool."""
def __init__(self, command: str | None = None) -> None:
"""Initialize the adapter.
Args:
command: Override for the CLI command (uses config default if None)
"""
if command is None:
config = get_config()
command = config.backends.get("python", {}).command
self._command = command or "molting"
@property
def language(self) -> str:
return "python"
@property
def cli_command(self) -> str:
return self._command
def is_available(self) -> bool:
return shutil.which(self._command) is not None
def list_refactorings(self) -> list[RefactoringSpec]:
"""Return the catalog of supported Python refactorings."""
return PYTHON_REFACTORINGS
def build_command(
self,
refactoring: str,
target: str,
params: dict[str, Any],
preview: bool = True,
) -> list[str]:
cmd = [self._command, refactoring, target]
# Add refactoring-specific params
for key, value in params.items():
if isinstance(value, bool):
if value:
cmd.append(f"--{key.replace('_', '-')}")
elif isinstance(value, list):
# Handle list params (e.g., --fields a,b,c)
cmd.extend([f"--{key.replace('_', '-')}", ",".join(str(v) for v in value)])
else:
cmd.extend([f"--{key.replace('_', '-')}", str(value)])
if preview:
cmd.append("--dry-run")
return cmd
async def preview_refactoring(
self,
refactoring: str,
target: str,
params: dict[str, Any],
) -> PreviewResult:
cmd = self.build_command(refactoring, target, params, preview=True)
result = await run_command(cmd)
if not result.success:
return PreviewResult(
refactoring=refactoring,
status="error",
error=result.stderr or f"Command failed with exit code {result.returncode}",
)
# Parse the output to extract changes
# Note: This will need to be updated when molting-cli adds --output=toon
changes = self._parse_diff_output(result.stdout, target)
return PreviewResult(
refactoring=refactoring,
status="success",
files_affected=len(changes),
changes=changes,
)
async def apply_refactoring(
self,
refactoring: str,
target: str,
params: dict[str, Any],
) -> RefactoringResult:
cmd = self.build_command(refactoring, target, params, preview=False)
result = await run_command(cmd)
if not result.success:
return RefactoringResult(
refactoring=refactoring,
status="error",
error=result.stderr or f"Command failed with exit code {result.returncode}",
)
# Extract the file path from target
file_path = target.split("::")[0].split("#")[0]
return RefactoringResult(
refactoring=refactoring,
status="success",
files_modified=1,
files=[FileChange(path=file_path, action="modified")],
)
async def inspect_structure(
self,
path: str,
depth: str = "class",
) -> StructureInfo:
"""Inspect Python code structure using AST.
Note: This is a basic implementation. A full implementation would
use molting-cli's inspect command once available.
"""
# For now, return a basic structure
# TODO: Implement using molting inspect command or Python AST
return StructureInfo(
path=path,
language="python",
classes=[],
methods=[],
total_lines=0,
)
def _parse_diff_output(self, output: str, target: str) -> list[FileChange]:
"""Parse the CLI output to extract file changes.
Note: This is a placeholder. Once molting-cli supports --output=toon,
this will parse the TOON output format.
"""
file_path = target.split("::")[0].split("#")[0]
# For now, just indicate the file was affected
if output.strip():
return [
FileChange(
path=file_path,
action="modified",
diff=output,
)
]
return []
# Catalog of Python refactorings supported by molting-cli
PYTHON_REFACTORINGS: list[RefactoringSpec] = [
# Composing Methods
RefactoringSpec(
name="extract-method",
category=RefactoringCategory.COMPOSING_METHODS,
description="Extract code block into new method",
params=[
RefactoringParam(name="target", param_type="string", description="Target with line range (e.g., file.py::Class::method#L10-L15)"),
RefactoringParam(name="name", param_type="string", description="Name for the new method"),
],
),
RefactoringSpec(
name="extract-function",
category=RefactoringCategory.COMPOSING_METHODS,
description="Extract code into module-level function",
params=[
RefactoringParam(name="target", param_type="string", description="Target with line range"),
RefactoringParam(name="name", param_type="string", description="Name for the new function"),
],
),
RefactoringSpec(
name="inline-method",
category=RefactoringCategory.COMPOSING_METHODS,
description="Replace method calls with method body",
params=[
RefactoringParam(name="target", param_type="string", description="Method to inline (e.g., file.py::Class::method)"),
],
),
RefactoringSpec(
name="inline-temp",
category=RefactoringCategory.COMPOSING_METHODS,
description="Replace temporary variable with its value",
params=[
RefactoringParam(name="target", param_type="string", description="Variable to inline (e.g., file.py::Class::method::var_name)"),
],
),
RefactoringSpec(
name="replace-temp-with-query",
category=RefactoringCategory.COMPOSING_METHODS,
description="Replace temp variable with method call",
params=[
RefactoringParam(name="target", param_type="string", description="Variable to replace"),
RefactoringParam(name="name", param_type="string", description="Name for the query method"),
],
),
RefactoringSpec(
name="introduce-explaining-variable",
category=RefactoringCategory.COMPOSING_METHODS,
description="Extract expression into named variable",
params=[
RefactoringParam(name="target", param_type="string", description="Target file or method"),
RefactoringParam(name="expression", param_type="string", description="Expression to extract", required=False),
RefactoringParam(name="name", param_type="string", description="Name for the new variable"),
RefactoringParam(name="in_", param_type="string", description="Method to search in", required=False),
RefactoringParam(name="replace_all", param_type="bool", description="Replace all occurrences", required=False, default=False),
],
),
RefactoringSpec(
name="split-temporary-variable",
category=RefactoringCategory.COMPOSING_METHODS,
description="Separate variables for different purposes",
params=[
RefactoringParam(name="target", param_type="string", description="Variable to split"),
],
),
RefactoringSpec(
name="remove-assignments-to-parameters",
category=RefactoringCategory.COMPOSING_METHODS,
description="Use temp variable instead of parameter modification",
params=[
RefactoringParam(name="target", param_type="string", description="Parameter to protect"),
],
),
RefactoringSpec(
name="replace-method-with-method-object",
category=RefactoringCategory.COMPOSING_METHODS,
description="Convert method into its own object",
params=[
RefactoringParam(name="target", param_type="string", description="Method to extract"),
RefactoringParam(name="name", param_type="string", description="Name for the new class"),
],
),
RefactoringSpec(
name="substitute-algorithm",
category=RefactoringCategory.COMPOSING_METHODS,
description="Replace algorithm with clearer implementation",
params=[
RefactoringParam(name="target", param_type="string", description="Method containing algorithm"),
],
),
# Moving Features Between Objects
RefactoringSpec(
name="move-method",
category=RefactoringCategory.MOVING_FEATURES,
description="Move method between classes",
params=[
RefactoringParam(name="target", param_type="string", description="Method to move"),
RefactoringParam(name="to", param_type="string", description="Destination class name"),
],
multi_file=True,
),
RefactoringSpec(
name="move-field",
category=RefactoringCategory.MOVING_FEATURES,
description="Move field between classes",
params=[
RefactoringParam(name="target", param_type="string", description="Field to move"),
RefactoringParam(name="to", param_type="string", description="Destination class name"),
],
multi_file=True,
),
RefactoringSpec(
name="extract-class",
category=RefactoringCategory.MOVING_FEATURES,
description="Split class into two classes",
params=[
RefactoringParam(name="target", param_type="string", description="Class to split"),
RefactoringParam(name="name", param_type="string", description="Name for new class"),
RefactoringParam(name="fields", param_type="list", description="Fields to move"),
RefactoringParam(name="methods", param_type="list", description="Methods to move", required=False),
],
),
RefactoringSpec(
name="inline-class",
category=RefactoringCategory.MOVING_FEATURES,
description="Merge class into another class",
params=[
RefactoringParam(name="target", param_type="string", description="Class to inline"),
RefactoringParam(name="into", param_type="string", description="Target class to merge into"),
],
),
RefactoringSpec(
name="hide-delegate",
category=RefactoringCategory.MOVING_FEATURES,
description="Create delegating methods to hide delegation",
params=[
RefactoringParam(name="target", param_type="string", description="Class with delegate"),
RefactoringParam(name="delegate", param_type="string", description="Delegate field name"),
],
),
RefactoringSpec(
name="remove-middle-man",
category=RefactoringCategory.MOVING_FEATURES,
description="Call delegate directly instead of through wrapper",
params=[
RefactoringParam(name="target", param_type="string", description="Class with delegating methods"),
],
),
RefactoringSpec(
name="introduce-foreign-method",
category=RefactoringCategory.MOVING_FEATURES,
description="Add method to class you can't modify",
params=[
RefactoringParam(name="target", param_type="string", description="Class to extend"),
RefactoringParam(name="name", param_type="string", description="Name for new method"),
],
),
RefactoringSpec(
name="introduce-local-extension",
category=RefactoringCategory.MOVING_FEATURES,
description="Create subclass or wrapper for extensions",
params=[
RefactoringParam(name="target", param_type="string", description="Class to extend"),
RefactoringParam(name="name", param_type="string", description="Name for extension class"),
],
),
# Simplifying Conditional Expressions
RefactoringSpec(
name="decompose-conditional",
category=RefactoringCategory.SIMPLIFYING_CONDITIONALS,
description="Extract condition and branches into methods",
params=[
RefactoringParam(name="target", param_type="string", description="Conditional to decompose"),
],
),
RefactoringSpec(
name="consolidate-conditional-expression",
category=RefactoringCategory.SIMPLIFYING_CONDITIONALS,
description="Combine conditions with same result",
params=[
RefactoringParam(name="target", param_type="string", description="Conditionals to consolidate"),
],
),
RefactoringSpec(
name="consolidate-duplicate-conditional-fragments",
category=RefactoringCategory.SIMPLIFYING_CONDITIONALS,
description="Move common code outside conditionals",
params=[
RefactoringParam(name="target", param_type="string", description="Conditional with duplicate code"),
],
),
RefactoringSpec(
name="remove-control-flag",
category=RefactoringCategory.SIMPLIFYING_CONDITIONALS,
description="Use break/return instead of control flag",
params=[
RefactoringParam(name="target", param_type="string", description="Method with control flag"),
],
),
RefactoringSpec(
name="replace-nested-conditional-with-guard-clauses",
category=RefactoringCategory.SIMPLIFYING_CONDITIONALS,
description="Use guard clauses instead of nested conditionals",
params=[
RefactoringParam(name="target", param_type="string", description="Method with nested conditionals"),
],
),
RefactoringSpec(
name="replace-conditional-with-polymorphism",
category=RefactoringCategory.SIMPLIFYING_CONDITIONALS,
description="Use polymorphic dispatch instead of conditionals",
params=[
RefactoringParam(name="target", param_type="string", description="Conditional to replace"),
],
),
RefactoringSpec(
name="introduce-null-object",
category=RefactoringCategory.SIMPLIFYING_CONDITIONALS,
description="Replace null checks with null object pattern",
params=[
RefactoringParam(name="target", param_type="string", description="Class needing null object"),
RefactoringParam(name="name", param_type="string", description="Name for null object class"),
],
),
RefactoringSpec(
name="introduce-assertion",
category=RefactoringCategory.SIMPLIFYING_CONDITIONALS,
description="Make assumptions explicit with assertions",
params=[
RefactoringParam(name="target", param_type="string", description="Method needing assertion"),
],
),
# Simplifying Method Calls
RefactoringSpec(
name="rename-method",
category=RefactoringCategory.SIMPLIFYING_METHOD_CALLS,
description="Rename a method",
params=[
RefactoringParam(name="target", param_type="string", description="Method to rename"),
RefactoringParam(name="new_name", param_type="string", description="New method name"),
],
),
RefactoringSpec(
name="add-parameter",
category=RefactoringCategory.SIMPLIFYING_METHOD_CALLS,
description="Add a parameter to a method",
params=[
RefactoringParam(name="target", param_type="string", description="Method to modify"),
RefactoringParam(name="name", param_type="string", description="Parameter name"),
RefactoringParam(name="param_type", param_type="string", description="Parameter type", required=False),
RefactoringParam(name="default", param_type="string", description="Default value", required=False),
],
),
RefactoringSpec(
name="remove-parameter",
category=RefactoringCategory.SIMPLIFYING_METHOD_CALLS,
description="Remove a parameter from a method",
params=[
RefactoringParam(name="target", param_type="string", description="Method to modify"),
RefactoringParam(name="name", param_type="string", description="Parameter name to remove"),
],
),
RefactoringSpec(
name="separate-query-from-modifier",
category=RefactoringCategory.SIMPLIFYING_METHOD_CALLS,
description="Split method into query and modifier",
params=[
RefactoringParam(name="target", param_type="string", description="Method to split"),
],
),
RefactoringSpec(
name="parameterize-method",
category=RefactoringCategory.SIMPLIFYING_METHOD_CALLS,
description="Combine similar methods with parameter",
params=[
RefactoringParam(name="target", param_type="string", description="Methods to combine"),
],
),
RefactoringSpec(
name="replace-parameter-with-explicit-methods",
category=RefactoringCategory.SIMPLIFYING_METHOD_CALLS,
description="Create separate methods for parameter values",
params=[
RefactoringParam(name="target", param_type="string", description="Method to split"),
RefactoringParam(name="parameter", param_type="string", description="Parameter to eliminate"),
],
),
RefactoringSpec(
name="preserve-whole-object",
category=RefactoringCategory.SIMPLIFYING_METHOD_CALLS,
description="Pass entire object instead of extracted values",
params=[
RefactoringParam(name="target", param_type="string", description="Method to modify"),
],
),
RefactoringSpec(
name="replace-parameter-with-method-call",
category=RefactoringCategory.SIMPLIFYING_METHOD_CALLS,
description="Call method internally instead of receiving parameter",
params=[
RefactoringParam(name="target", param_type="string", description="Method to modify"),
RefactoringParam(name="parameter", param_type="string", description="Parameter to replace"),
],
),
RefactoringSpec(
name="introduce-parameter-object",
category=RefactoringCategory.SIMPLIFYING_METHOD_CALLS,
description="Group parameters into object",
params=[
RefactoringParam(name="target", param_type="string", description="Method with many parameters"),
RefactoringParam(name="name", param_type="string", description="Name for parameter object class"),
RefactoringParam(name="parameters", param_type="list", description="Parameters to group"),
],
),
RefactoringSpec(
name="remove-setting-method",
category=RefactoringCategory.SIMPLIFYING_METHOD_CALLS,
description="Remove setter for field set in constructor",
params=[
RefactoringParam(name="target", param_type="string", description="Setter to remove"),
],
),
RefactoringSpec(
name="hide-method",
category=RefactoringCategory.SIMPLIFYING_METHOD_CALLS,
description="Make method private",
params=[
RefactoringParam(name="target", param_type="string", description="Method to hide"),
],
),
RefactoringSpec(
name="replace-constructor-with-factory-function",
category=RefactoringCategory.SIMPLIFYING_METHOD_CALLS,
description="Use factory function instead of constructor",
params=[
RefactoringParam(name="target", param_type="string", description="Class with constructor"),
RefactoringParam(name="name", param_type="string", description="Factory function name"),
],
),
RefactoringSpec(
name="replace-error-code-with-exception",
category=RefactoringCategory.SIMPLIFYING_METHOD_CALLS,
description="Throw exception instead of returning error code",
params=[
RefactoringParam(name="target", param_type="string", description="Method returning error code"),
],
),
RefactoringSpec(
name="replace-exception-with-test",
category=RefactoringCategory.SIMPLIFYING_METHOD_CALLS,
description="Use conditional check instead of exception",
params=[
RefactoringParam(name="target", param_type="string", description="Code with exception to replace"),
],
),
# Dealing with Generalization
RefactoringSpec(
name="pull-up-field",
category=RefactoringCategory.DEALING_WITH_GENERALIZATION,
description="Move field to superclass",
params=[
RefactoringParam(name="target", param_type="string", description="Field to pull up"),
],
),
RefactoringSpec(
name="pull-up-method",
category=RefactoringCategory.DEALING_WITH_GENERALIZATION,
description="Move method to superclass",
params=[
RefactoringParam(name="target", param_type="string", description="Method to pull up"),
],
),
RefactoringSpec(
name="pull-up-constructor-body",
category=RefactoringCategory.DEALING_WITH_GENERALIZATION,
description="Move constructor logic to superclass",
params=[
RefactoringParam(name="target", param_type="string", description="Subclass constructor"),
],
),
RefactoringSpec(
name="push-down-method",
category=RefactoringCategory.DEALING_WITH_GENERALIZATION,
description="Move method to subclass",
params=[
RefactoringParam(name="target", param_type="string", description="Method to push down"),
RefactoringParam(name="to", param_type="string", description="Target subclass"),
],
),
RefactoringSpec(
name="push-down-field",
category=RefactoringCategory.DEALING_WITH_GENERALIZATION,
description="Move field to subclass",
params=[
RefactoringParam(name="target", param_type="string", description="Field to push down"),
RefactoringParam(name="to", param_type="string", description="Target subclass"),
],
),
RefactoringSpec(
name="extract-subclass",
category=RefactoringCategory.DEALING_WITH_GENERALIZATION,
description="Create subclass for subset of features",
params=[
RefactoringParam(name="target", param_type="string", description="Class to extract from"),
RefactoringParam(name="name", param_type="string", description="Name for new subclass"),
],
),
RefactoringSpec(
name="extract-superclass",
category=RefactoringCategory.DEALING_WITH_GENERALIZATION,
description="Create superclass from common features",
params=[
RefactoringParam(name="target", param_type="string", description="Classes to extract from"),
RefactoringParam(name="name", param_type="string", description="Name for new superclass"),
],
),
RefactoringSpec(
name="extract-interface",
category=RefactoringCategory.DEALING_WITH_GENERALIZATION,
description="Create interface for common methods",
params=[
RefactoringParam(name="target", param_type="string", description="Class to extract from"),
RefactoringParam(name="name", param_type="string", description="Name for new interface"),
],
),
RefactoringSpec(
name="collapse-hierarchy",
category=RefactoringCategory.DEALING_WITH_GENERALIZATION,
description="Merge subclass into superclass",
params=[
RefactoringParam(name="target", param_type="string", description="Subclass to collapse"),
],
),
RefactoringSpec(
name="form-template-method",
category=RefactoringCategory.DEALING_WITH_GENERALIZATION,
description="Extract algorithm to superclass with varying steps",
params=[
RefactoringParam(name="target", param_type="string", description="Methods to templatize"),
],
),
RefactoringSpec(
name="replace-inheritance-with-delegation",
category=RefactoringCategory.DEALING_WITH_GENERALIZATION,
description="Use composition instead of inheritance",
params=[
RefactoringParam(name="target", param_type="string", description="Subclass to convert"),
],
),
RefactoringSpec(
name="replace-delegation-with-inheritance",
category=RefactoringCategory.DEALING_WITH_GENERALIZATION,
description="Use inheritance instead of delegation",
params=[
RefactoringParam(name="target", param_type="string", description="Class using delegation"),
],
),
# Organizing Data
RefactoringSpec(
name="self-encapsulate-field",
category=RefactoringCategory.ORGANIZING_DATA,
description="Create getter/setter for field access",
params=[
RefactoringParam(name="target", param_type="string", description="Field to encapsulate"),
],
),
RefactoringSpec(
name="replace-data-value-with-object",
category=RefactoringCategory.ORGANIZING_DATA,
description="Convert data item into object",
params=[
RefactoringParam(name="target", param_type="string", description="Field to convert"),
RefactoringParam(name="name", param_type="string", description="Name for new class"),
],
),
RefactoringSpec(
name="change-value-to-reference",
category=RefactoringCategory.ORGANIZING_DATA,
description="Convert value object to reference",
params=[
RefactoringParam(name="target", param_type="string", description="Value class to convert"),
],
),
RefactoringSpec(
name="change-reference-to-value",
category=RefactoringCategory.ORGANIZING_DATA,
description="Convert reference to value object",
params=[
RefactoringParam(name="target", param_type="string", description="Reference class to convert"),
],
),
RefactoringSpec(
name="replace-array-with-object",
category=RefactoringCategory.ORGANIZING_DATA,
description="Replace array with object",
params=[
RefactoringParam(name="target", param_type="string", description="Array to replace"),
RefactoringParam(name="name", param_type="string", description="Name for new class"),
],
),
RefactoringSpec(
name="duplicate-observed-data",
category=RefactoringCategory.ORGANIZING_DATA,
description="Copy data to domain object",
params=[
RefactoringParam(name="target", param_type="string", description="Data to duplicate"),
],
),
RefactoringSpec(
name="change-unidirectional-to-bidirectional",
category=RefactoringCategory.ORGANIZING_DATA,
description="Add back pointers to association",
params=[
RefactoringParam(name="target", param_type="string", description="Association to modify"),
],
),
RefactoringSpec(
name="change-bidirectional-to-unidirectional",
category=RefactoringCategory.ORGANIZING_DATA,
description="Remove back pointers from association",
params=[
RefactoringParam(name="target", param_type="string", description="Association to modify"),
],
),
RefactoringSpec(
name="replace-magic-number-with-symbolic-constant",
category=RefactoringCategory.ORGANIZING_DATA,
description="Create named constant for magic number",
params=[
RefactoringParam(name="target", param_type="string", description="Location of magic number"),
RefactoringParam(name="name", param_type="string", description="Name for constant"),
RefactoringParam(name="value", param_type="string", description="Value to replace"),
],
),
RefactoringSpec(
name="encapsulate-field",
category=RefactoringCategory.ORGANIZING_DATA,
description="Add getter/setter accessors for public field",
params=[
RefactoringParam(name="target", param_type="string", description="Field to encapsulate"),
],
),
RefactoringSpec(
name="encapsulate-collection",
category=RefactoringCategory.ORGANIZING_DATA,
description="Add proper accessors for collection field",
params=[
RefactoringParam(name="target", param_type="string", description="Collection field to encapsulate"),
],
),
RefactoringSpec(
name="replace-type-code-with-class",
category=RefactoringCategory.ORGANIZING_DATA,
description="Replace type code with class",
params=[
RefactoringParam(name="target", param_type="string", description="Type code to replace"),
RefactoringParam(name="name", param_type="string", description="Name for new class"),
],
),
RefactoringSpec(
name="replace-type-code-with-subclasses",
category=RefactoringCategory.ORGANIZING_DATA,
description="Use inheritance to replace type code",
params=[
RefactoringParam(name="target", param_type="string", description="Class with type code"),
],
),
RefactoringSpec(
name="replace-type-code-with-state-strategy",
category=RefactoringCategory.ORGANIZING_DATA,
description="Use State/Strategy pattern for type code",
params=[
RefactoringParam(name="target", param_type="string", description="Class with type code"),
],
),
]
