"""
Context expansion utilities.
"""

from typing import Any


class SimilaritySearcher:
    """Search for similar content."""

    def __init__(self, config: dict[str, Any] | None = None):
        """Initialize the similarity searcher."""
        self.config = config or {}

    def search(self, query: str, candidates: list[str]) -> list[str]:
        """Search for similar content."""
        # Placeholder implementation
        return candidates[:3] if candidates else []

    def rank(self, query: str, candidates: list[str]) -> list[tuple[str, float]]:
        """Rank candidates by similarity."""
        # Placeholder implementation
        return [(candidate, 0.5) for candidate in candidates]


class ContextExpander:
    """Expand context with related information."""

    def __init__(self, config: dict[str, Any] | None = None):
        """Initialize the context expander."""
        self.config = config or {}
        self.searcher = SimilaritySearcher(config)

    def expand(self, context: str, knowledge_base: list[str]) -> list[str]:
        """Expand context with related knowledge."""
        # Placeholder implementation
        return self.searcher.search(context, knowledge_base)
