import ast
import difflib
import importlib
import typing
from typing import Any, ClassVar, Dict, List, Optional

from .base import BaseInterpreter
from .interpreter_error import InterpreterError


class InternalPythonInterpreter(BaseInterpreter):
    r"""A customized python interpreter to control the execution of
    LLM-generated codes. The interpreter makes sure the code can only execute
    functions given in action space and import white list. It also supports
    fuzzy variable matching to retrieve uncertain input variable name.

    .. highlight:: none

    This class is adapted from the hugging face implementation
    `python_interpreter.py <https://github.com/huggingface/transformers/blob/8f
    093fb799246f7dd9104ff44728da0c53a9f67a/src/transformers/tools/python_interp
    reter.py>`_. The original license applies::

        Copyright 2023 The HuggingFace Inc. team. All rights reserved.

        Licensed under the Apache License, Version 2.0 (the "License");
        you may not use this file except in compliance with the License.
        You may obtain a copy of the License at

            http://www.apache.org/licenses/LICENSE-2.0

        Unless required by applicable law or agreed to in writing, software
        distributed under the License is distributed on an "AS IS" BASIS,
        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
        implied. See the License for the specific language governing
        permissions and limitations under the License.

    We have modified the original code to suit our requirements. We have
    encapsulated the original functions within a class and saved the
    interpreter state after execution. We have added support for "import"
    statements, "for" statements, and several binary and unary operators. We
    have added import white list to keep `import` statement safe. Additionally,
    we have modified the variable matching logic and introduced the
    :obj:`fuzz_state` for fuzzy matching.

    Modifications copyright (C) 2023 CAMEL-AI.org

    Args:
        action_space (Dict[str, Any], optional): A dictionary that maps action
            names to their corresponding functions or objects. The interpreter
            can only execute functions that are either directly listed in this
            dictionary or are member functions of objects listed in this
            dictionary. The concept of :obj:`action_space` is derived from
            EmbodiedAgent, representing the actions that an agent is capable of
            performing. If `None`, set to empty dict. (default: :obj:`None`)
        import_white_list (List[str], optional): A list that stores
            the Python modules or functions that can be imported in the code.
            All submodules and functions of the modules listed in this list are
            importable. Any other import statements will be rejected. The
            module and its submodule or function name are separated by a period
            (:obj:`.`). (default: :obj:`None`)
        unsafe_mode (bool, optional): If `True`, the interpreter runs the code
            by `eval()` or `exec()` without any security check.
            (default: :obj:`False`)
        raise_error (bool, optional): Raise error if the interpreter fails.
            (default: :obj:`False`)
    """

    _CODE_TYPES: ClassVar[List[str]] = ["python", "py", "python3", "python2"]


    _DEFAULT_BUILTINS = {
        "range": range,
        "len": len,
        "print": print,
    }

    # ➋ 默认允许 import 的模块（按需增删）
    _DEFAULT_IMPORTS = [
        "math",
        "sympy",            # 整个 sympy
        "astor",
        "sympy.core",       # ——如果想更细粒度可拆分
        "sympy.symbols",
    ]

    def __init__(
        self,
        action_space: Optional[Dict[str, Any]] = None,
        import_white_list: Optional[List[str]] = None,
        unsafe_mode: bool = False,
        raise_error: bool = False,
    ) -> None:
        # self.action_space = action_space or dict()
        self.action_space = {**self._DEFAULT_BUILTINS, **(action_space or {})}
        self.state = self.action_space.copy()
        self.fuzz_state: Dict[str, Any] = dict()
        # self.import_white_list = import_white_list or list()
        self.import_white_list = list(
            {*(import_white_list or []), *self._DEFAULT_IMPORTS}
        )
        self.raise_error = raise_error
        self.unsafe_mode = unsafe_mode

    def run(self, code: str, code_type: str) -> str:
        r"""Executes the given code with specified code type in the
        interpreter.

        This method takes a string of code and its type, checks if the code
        type is supported, and then executes the code. If `unsafe_mode` is
        set to `False`, the code is executed in a controlled environment using
        the `execute` method. If `unsafe_mode` is `True`, the code is executed
        using `eval()` or `exec()` with the action space as the global context.
        An `InterpreterError` is raised if the code type is unsupported or if
        any runtime error occurs during execution.

        Args:
            code (str): The python code to be executed.
            code_type (str): The type of the code, which should be one of the
            supported code types (`python`, `py`, `python3`, `python2`).


        Returns:
            str: The string representation of the output of the executed code.

        Raises:
            InterpreterError: If the `code_type` is not supported or if any
                runtime error occurs during the execution of the code.
        """
        if code_type not in self._CODE_TYPES:
            raise InterpreterError(
                f"Unsupported code type {code_type}. "
                f"`{self.__class__.__name__}` only supports "
                f"{', '.join(self._CODE_TYPES)}."
            )
        if self.unsafe_mode:
            import contextlib
            import io

            # Try to execute first and capture stdout
            output_buffer = io.StringIO()
            with contextlib.redirect_stdout(output_buffer):
                exec(code, self.action_space)
            result = output_buffer.getvalue()

            # If no output was captured, try to evaluate the code
            if not result:
                try:
                    result = str(eval(code, self.action_space))
                except (SyntaxError, NameError):
                    result = ""  # If eval fails, return empty string

            return result
        else:
            return str(self.execute(code))

    def update_action_space(self, action_space: Dict[str, Any]) -> None:
        r"""Updates action space for *python* interpreter."""
        self.action_space.update(action_space)

    def supported_code_types(self) -> List[str]:
        r"""Provides supported code types by the interpreter."""
        return self._CODE_TYPES

    def execute(
        self,
        code: str,
        state: Optional[Dict[str, Any]] = None,
        fuzz_state: Optional[Dict[str, Any]] = None,
        keep_state: bool = True,
    ) -> Any:
        r"""Execute the input python codes in a security environment.

        Args:
            code (str): Generated python code to be executed.
            state (Optional[Dict[str, Any]], optional): External variables that
                may be used in the generated code. (default: :obj:`None`)
            fuzz_state (Optional[Dict[str, Any]], optional): External variables
                that do not have certain variable names. The interpreter will
                use fuzzy matching to access these variables. For example, if
                :obj:`fuzz_state` has a variable :obj:`image`, the generated
                code can use :obj:`input_image` to access it. (default:
                :obj:`None`)
            keep_state (bool, optional):  If :obj:`True`, :obj:`state` and
                :obj:`fuzz_state` will be kept for later execution. Otherwise,
                they will be cleared. (default: :obj:`True`)

        Returns:
            Any: The value of the last statement (excluding "import") in the
                code. For this interpreter, the value of an expression is its
                value, the value of an "assign" statement is the assigned
                value, and the value of an "if" and "for" block statement is
                the value of the last statement in the block.
        """

        if state is not None:
            self.state.update(state)
        if fuzz_state is not None:
            self.fuzz_state.update(fuzz_state)

        try:
            expression = ast.parse(code)
        except SyntaxError as e:
            if self.raise_error:
                raise InterpreterError(f"Syntax error in code: {e}")
            else:
                import traceback

                return traceback.format_exc()

        result = None
        for idx, node in enumerate(expression.body):
            try:
                line_result = self._execute_ast(node)
            except InterpreterError as e:
                if not keep_state:
                    self.clear_state()
                msg = (
                    f"Evaluation of the code stopped at node {idx}. "
                    f"See:\n{e}"
                )
                # More information can be provided by `ast.unparse()`,
                # which is new in python 3.9.
                if self.raise_error:
                    raise InterpreterError(msg)
                else:
                    import traceback

                    return traceback.format_exc()
            if line_result is not None:
                result = line_result

        if not keep_state:
            self.clear_state()

        return result

    def clear_state(self) -> None:
        r"""Initialize :obj:`state` and :obj:`fuzz_state`."""
        self.state = self.action_space.copy()
        self.fuzz_state = {}

    # ast.Index is deprecated after python 3.9, which cannot pass type check,
    # but is still necessary for older versions.
    @typing.no_type_check
    def _execute_ast(self, expression: ast.AST) -> Any:
        if isinstance(expression, ast.Assign):
            # Assignment -> evaluate the assignment which should
            # update the state. We return the variable assigned as it may
            # be used to determine the final result.
            return self._execute_assign(expression)
        elif isinstance(expression, ast.Attribute):
            value = self._execute_ast(expression.value)
            return getattr(value, expression.attr)
        elif isinstance(expression, ast.BinOp):
            # Binary Operator -> return the result value
            return self._execute_binop(expression)
        elif isinstance(expression, ast.Call):
            # Function call -> return the value of the function call
            return self._execute_call(expression)
        elif isinstance(expression, ast.Compare):
            # Compare -> return True or False
            return self._execute_condition(expression)
        elif isinstance(expression, ast.Constant):
            # Constant -> just return the value
            return expression.value
        elif isinstance(expression, ast.Dict):
            # Dict -> evaluate all keys and values
            result: Dict = {}
            for k, v in zip(expression.keys, expression.values):
                if k is not None:
                    result[self._execute_ast(k)] = self._execute_ast(v)
                else:
                    result.update(self._execute_ast(v))
            return result
        elif isinstance(expression, ast.Expr):
            # Expression -> evaluate the content
            return self._execute_ast(expression.value)
        elif isinstance(expression, ast.For):
            return self._execute_for(expression)
        elif isinstance(expression, ast.FormattedValue):
            # Formatted value (part of f-string) -> evaluate the content
            # and return
            return self._execute_ast(expression.value)
        elif isinstance(expression, ast.If):
            # If -> execute the right branch
            return self._execute_if(expression)
        elif isinstance(expression, ast.Import):
            # Import -> add imported names in self.state and return None.
            self._execute_import(expression)
            return None
        elif isinstance(expression, ast.ImportFrom):
            self._execute_import_from(expression)
            return None
        elif hasattr(ast, "Index") and isinstance(expression, ast.Index):
            # cannot pass type check
            return self._execute_ast(expression.value)
        elif isinstance(expression, ast.JoinedStr):
            return "".join(
                [str(self._execute_ast(v)) for v in expression.values]
            )
        elif isinstance(expression, ast.List):
            # List -> evaluate all elements
            return [self._execute_ast(elt) for elt in expression.elts]
        elif isinstance(expression, ast.Name):
            # Name -> pick up the value in the state
            return self._execute_name(expression)
        elif isinstance(expression, ast.Subscript):
            # Subscript -> return the value of the indexing
            return self._execute_subscript(expression)
        elif isinstance(expression, ast.Tuple):
            return tuple([self._execute_ast(elt) for elt in expression.elts])
        elif isinstance(expression, ast.UnaryOp):
            # Binary Operator -> return the result value
            return self._execute_unaryop(expression)
        else:
            # For now we refuse anything else. Let's add things as we need
            # them.
            raise InterpreterError(
                f"{expression.__class__.__name__} is not supported."
            )

    def _execute_assign(self, assign: ast.Assign) -> Any:
        targets = assign.targets
        result = self._execute_ast(assign.value)

        for target in targets:
            self._assign(target, result)
        return result

    def _assign(self, target: ast.expr, value: Any):
        if isinstance(target, ast.Name):
            self.state[target.id] = value
        elif isinstance(target, ast.Tuple):
            if not isinstance(value, tuple):
                raise InterpreterError(
                    f"Expected type tuple, but got"
                    f"{value.__class__.__name__} instead."
                )
            if len(target.elts) != len(value):
                raise InterpreterError(
                    f"Expected {len(target.elts)} values but got"
                    f" {len(value)}."
                )
            for t, v in zip(target.elts, value):
                self.state[self._execute_ast(t)] = v
        else:
            raise InterpreterError(
                f"Unsupported variable type. Expected "
                f"ast.Name or ast.Tuple, got "
                f"{target.__class__.__name__} instead."
            )

    def _execute_call(self, call: ast.Call) -> Any:
        callable_func = self._execute_ast(call.func)

        # Todo deal with args
        args = [self._execute_ast(arg) for arg in call.args]
        kwargs = {
            keyword.arg: self._execute_ast(keyword.value)
            for keyword in call.keywords
        }
        return callable_func(*args, **kwargs)

    def _execute_subscript(self, subscript: ast.Subscript):
        index = self._execute_ast(subscript.slice)
        value = self._execute_ast(subscript.value)
        if not isinstance(subscript.ctx, ast.Load):
            raise InterpreterError(
                f"{subscript.ctx.__class__.__name__} is not supported for "
                "subscript."
            )
        if isinstance(value, (list, tuple)):
            return value[int(index)]
        if index in value:
            return value[index]
        if isinstance(index, str) and isinstance(value, dict):
            close_matches = difflib.get_close_matches(
                index,
                [key for key in list(value.keys()) if isinstance(key, str)],
            )
            if len(close_matches) > 0:
                return value[close_matches[0]]

        raise InterpreterError(f"Could not index {value} with '{index}'.")

    def _execute_name(self, name: ast.Name):
        if isinstance(name.ctx, ast.Store):
            return name.id
        elif isinstance(name.ctx, ast.Load):
            return self._get_value_from_state(name.id)
        else:
            raise InterpreterError(f"{name.ctx} is not supported.")

    def _execute_condition(self, condition: ast.Compare):
        if len(condition.ops) > 1:
            raise InterpreterError(
                "Cannot evaluate conditions with multiple operators"
            )

        left = self._execute_ast(condition.left)
        comparator = condition.ops[0]
        right = self._execute_ast(condition.comparators[0])

        if isinstance(comparator, ast.Eq):
            return left == right
        elif isinstance(comparator, ast.NotEq):
            return left != right
        elif isinstance(comparator, ast.Lt):
            return left < right
        elif isinstance(comparator, ast.LtE):
            return left <= right
        elif isinstance(comparator, ast.Gt):
            return left > right
        elif isinstance(comparator, ast.GtE):
            return left >= right
        elif isinstance(comparator, ast.Is):
            return left is right
        elif isinstance(comparator, ast.IsNot):
            return left is not right
        elif isinstance(comparator, ast.In):
            return left in right
        elif isinstance(comparator, ast.NotIn):
            return left not in right
        else:
            raise InterpreterError(f"Unsupported operator: {comparator}")

    def _execute_if(self, if_statement: ast.If):
        result = None
        if not isinstance(if_statement.test, ast.Compare):
            raise InterpreterError(
                "Only Compare expr supported in if statement, get"
                f" {if_statement.test.__class__.__name__}"
            )
        if self._execute_condition(if_statement.test):
            for line in if_statement.body:
                line_result = self._execute_ast(line)
                if line_result is not None:
                    result = line_result
        else:
            for line in if_statement.orelse:
                line_result = self._execute_ast(line)
                if line_result is not None:
                    result = line_result
        return result

    def _execute_for(self, for_statement: ast.For):
        result = None
        for value in self._execute_ast(for_statement.iter):
            self._assign(for_statement.target, value)
            for line in for_statement.body:
                line_result = self._execute_ast(line)
                if line_result is not None:
                    result = line_result

        return result

    def _execute_import(self, import_module: ast.Import) -> None:
        for module in import_module.names:
            self._validate_import(module.name)
            alias = module.asname or module.name
            self.state[alias] = importlib.import_module(module.name)

    def _execute_import_from(self, import_from: ast.ImportFrom):
        if import_from.module is None:
            raise InterpreterError("\"from . import\" is not supported.")
        for import_name in import_from.names:
            full_name = import_from.module + f".{import_name.name}"
            self._validate_import(full_name)
            imported_module = importlib.import_module(import_from.module)
            alias = import_name.asname or import_name.name
            self.state[alias] = getattr(imported_module, import_name.name)

    def _validate_import(self, full_name: str):
        tmp_name = ""
        found_name = False
        for name in full_name.split("."):
            tmp_name += name if tmp_name == "" else f".{name}"
            if tmp_name in self.import_white_list:
                found_name = True
                return

        if not found_name:
            raise InterpreterError(
                f"It is not permitted to import modules "
                f"than module white list (try to import "
                f"{full_name})."
            )

    def _execute_binop(self, binop: ast.BinOp):
        left = self._execute_ast(binop.left)
        operator = binop.op
        right = self._execute_ast(binop.right)

        if isinstance(operator, ast.Add):
            return left + right
        elif isinstance(operator, ast.Sub):
            return left - right
        elif isinstance(operator, ast.Mult):
            return left * right
        elif isinstance(operator, ast.Div):
            return left / right
        elif isinstance(operator, ast.FloorDiv):
            return left // right
        elif isinstance(operator, ast.Mod):
            return left % right
        elif isinstance(operator, ast.Pow):
            return left**right
        elif isinstance(operator, ast.LShift):
            return left << right
        elif isinstance(operator, ast.RShift):
            return left >> right
        elif isinstance(operator, ast.MatMult):
            return left @ right
        else:
            raise InterpreterError(f"Operator not supported: {operator}")

    def _execute_unaryop(self, unaryop: ast.UnaryOp):
        operand = self._execute_ast(unaryop.operand)
        operator = unaryop.op

        if isinstance(operator, ast.UAdd):
            return +operand
        elif isinstance(operator, ast.USub):
            return -operand
        elif isinstance(operator, ast.Not):
            return not operand
        else:
            raise InterpreterError(f"Operator not supported: {operator}")

    def _get_value_from_state(self, key: str) -> Any:
        if key in self.state:
            return self.state[key]
        else:
            close_matches = difflib.get_close_matches(
                key, list(self.fuzz_state.keys()), n=1
            )
            if close_matches:
                return self.fuzz_state[close_matches[0]]
            else:
                raise InterpreterError(f"The variable `{key}` is not defined.")
