"""Helpers for bounded tool responses."""

from __future__ import annotations

from typing import Any

from aegis_gitea_mcp.config import get_settings


class ResponseLimitError(RuntimeError):
    """Raised when response processing exceeds configured safety limits."""


def limit_items(
    items: list[dict[str, Any]], configured_limit: int | None = None
) -> tuple[list[dict[str, Any]], int]:
    """Trim a list of result items to configured maximum length.

    Args:
        items: List of result dictionaries.
        configured_limit: Optional explicit item limit.

    Returns:
        Tuple of trimmed list and omitted count.
    """
    settings = get_settings()
    max_items = configured_limit or settings.max_tool_response_items
    if max_items <= 0:
        raise ResponseLimitError("max_tool_response_items must be greater than zero")

    if len(items) <= max_items:
        return items, 0

    trimmed = items[:max_items]
    omitted = len(items) - max_items
    return trimmed, omitted


def limit_text(text: str, configured_limit: int | None = None) -> str:
    """Trim text output to configured maximum characters.

    Args:
        text: Untrusted text output.
        configured_limit: Optional explicit character limit.

    Returns:
        Trimmed text.
    """
    settings = get_settings()
    max_chars = configured_limit or settings.max_tool_response_chars
    if max_chars <= 0:
        raise ResponseLimitError("max_tool_response_chars must be greater than zero")

    if len(text) <= max_chars:
        return text
    return text[:max_chars]