from __future__ import annotations
from typing import Any, Callable, Optional
from string import whitespace

from core.primitives.symbol import symbolKey, isSymbol
from core.printer import Representation
from core.primitives.list import NIL

class Environment:
    """Environment for variable bindings with lexical scoping."""

    frame: dict[str, Any]
    parent: Environment | None

    def __init__(self, parent: Environment | None) -> None:
        self.frame: dict[str, Any] = {}
        self.parent: Environment | None = parent

    def add(self, symbol_key: Any, value: Any) -> None:
        """Add a new binding to the current environment frame."""
        self.frame[symbolKey(symbol_key)] = value

    def set(self, symbol_key: Any, value: Any) -> None:
        """Set a binding in the environment chain."""
        key: str = symbolKey(symbol_key)
        currentEnvironment: Environment = self
        while currentEnvironment is not None:
            if key in currentEnvironment.frame:
                currentEnvironment.frame[key] = value
                return
            assert currentEnvironment is Environment
            currentEnvironment = currentEnvironment.parent
        raise SyntaxError(f"no such symbol: {key}")

    def get(self, symbol_key: Any) -> Any:
        """Get a binding from the environment chain."""
        key: str = symbolKey(symbol_key)
        currentEnvironment: Environment | None = self
        while currentEnvironment is not None:
            if key in currentEnvironment.frame:
                return currentEnvironment.frame[key]
            currentEnvironment = currentEnvironment.parent
        return symbol_key

EVAL_NIL: Callable[[], Any] = lambda: NIL
ENV: Environment = Environment(None)

MEANINGFUL: str = "\"();'"
IGNORE: str = whitespace + ","

RepresentateAST: Callable[[Any], str] = lambda value: (
    value if type(value) is str and not isSymbol(value) else Representation(value)
)
TCO: bool = True