"""
Context manager for Dana execution.

This module provides the ContextManager class, which manages variable scopes
and state during Dana program execution.

Copyright © 2025 Aitomatic, Inc.
MIT License

Community Values:
    1. Attribution: Please maintain attribution to Aitomatic and Dana/Dana in derivative works.
    2. Contributions: If you find Dana/Dana valuable, consider contributing improvements back rather than creating separate, similar implementations.
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Learn more: https://aitomatic.com
GitHub: https://github.com/aitomatic/dana
Discord: https://discord.gg/6jGD4PYk
"""

from typing import Any

from dana.common.exceptions import StateError
from dana.common.runtime_scopes import RuntimeScopes
from dana.core.lang.sandbox_context import SandboxContext


class ContextManager:
    """Context manager for Dana execution.

    This class manages variable scopes and state during Dana program execution.
    It provides methods for getting and setting variables in different scopes.
    """

    def __init__(self, context: SandboxContext | None = None):
        """Initialize the context manager.

        Args:
            context: Optional initial context
        """
        self.context = context or SandboxContext()
        self.context.manager = self
        self._registry = None  # Will be set by the interpreter

    def get(self, key: str, default: Any = None) -> Any:
        """Get a value from the context.

        Args:
            key: The key to get
            default: Default value if key not found

        Returns:
            The value associated with the key
        """
        return self.context.get(key, default)

    def set(self, key: str, value: Any) -> None:
        """Set a value in the context.

        Args:
            key: The key to set
            value: The value to set
        """
        self.context.set(key, value)

    def set_in_context(self, var_name: str, value: Any, scope: str = "local") -> None:
        """Set a value in a specific scope.

        Args:
            var_name: The variable name
            value: The value to set
            scope: The scope to set in (defaults to local)

        Raises:
            StateError: If the scope is unknown
        """
        if scope not in RuntimeScopes.ALL:
            raise StateError(f"Unknown scope: {scope}")

        # For global scopes, set in root context
        if scope in RuntimeScopes.GLOBALS:
            root = self.context
            while root._parent is not None:
                root = root._parent
            root._state[scope][var_name] = value
            return

        # For local scope, set in current context
        self.context._state[scope][var_name] = value

    def get_from_scope(self, identifier: str, scope: str, from_parent: bool = True) -> Any:
        """Get a variable from a specific scope.

        Args:
            identifier: The variable name
            scope: The scope to search in
            from_parent: Whether to search in parent contexts

        Returns:
            The variable value

        Raises:
            StateError: If the variable is not found
        """
        # Ensure scope exists
        if not scope or scope not in self.context._state:
            raise StateError(f"Unknown scope: {scope}")

        # Direct access for private:foo, public:bar, system:baz
        if identifier in self.context._state[scope]:
            return self.context._state[scope][identifier]

        if from_parent and self.context.parent_context:
            # TODO: Be careful: security risk
            return self.context.parent_context.get_from_scope(identifier, scope)

        # Not found anywhere, raise error
        raise StateError(f"Variable '{identifier}' not found in scope '{scope}'")

    def get_sanitized_context(self) -> SandboxContext:
        """Get a sandboxed copy of the current context without sensitive scopes.

        This method creates a copy of the current context with the private and system
        scopes removed to prevent access to sensitive information.

        Returns:
            A sanitized copy of the sandbox context
        """
        return self.context.sanitize()

    def has(self, key: str) -> bool:
        """Check if a key exists in the context.

        Args:
            key: The key to check

        Returns:
            True if the key exists, False otherwise
        """
        return self.context.has(key)

    def delete(self, key: str) -> None:
        """Delete a key from the context.

        Args:
            key: The key to delete
        """
        self.context.delete(key)

    def clear(self, scope: str | None = None) -> None:
        """Clear all variables in a scope or all scopes.

        Args:
            scope: Optional scope to clear (if None, clears all scopes)
        """
        self.context.clear(scope)

    def get_state(self) -> dict[str, dict[str, Any]]:
        """Get a copy of the current state.

        Returns:
            A copy of the state dictionary
        """
        return self.context.get_state()

    def set_state(self, state: dict[str, dict[str, Any]]) -> None:
        """Set the state from a dictionary.

        Args:
            state: The state dictionary to set
        """
        self.context.set_state(state)

    def merge(self, other: "ContextManager") -> None:
        """Merge another context manager into this one.

        Args:
            other: The context manager to merge from
        """
        self.context.merge(other.context)

    def copy(self) -> "ContextManager":
        """Create a copy of this context manager.

        Returns:
            A new ContextManager with the same state
        """
        return ContextManager(self.context.copy())

    def __str__(self) -> str:
        """Get a string representation of the context manager.

        Returns:
            A string representation of the context manager state
        """
        return str(self.context)

    def __repr__(self) -> str:
        """Get a detailed string representation of the context manager.

        Returns:
            A detailed string representation of the context manager
        """
        return f"ContextManager(context={self.context})"
