"""Debug logging helpers for rp."""

from __future__ import annotations

import os
from collections.abc import Callable, Mapping

from rich.console import Console
from rich.text import Text

DEBUG_ENV_VAR = "RP_DEBUG"
_FALSE_DEBUG_VALUES = {"", "0", "false", "no", "off"}

type DebugLogger = Callable[[str], None]


def env_debug_enabled(env: Mapping[str, str] | None = None) -> bool:
    """Return whether debug logging is enabled via ``RP_DEBUG``."""
    source = os.environ if env is None else env
    value = source.get(DEBUG_ENV_VAR)
    if value is None:
        return False
    return value.strip().lower() not in _FALSE_DEBUG_VALUES


def make_debug_logger(console: Console, enabled: bool) -> DebugLogger | None:
    """Return a console-backed debug logger when debug mode is enabled."""
    if not enabled:
        return None

    def _log(message: str) -> None:
        console.print(Text.assemble(("[rp debug] ", "dim"), message))

    return _log


def log_debug(debug: DebugLogger | None, message: str) -> None:
    """Emit a debug line when a debug logger is configured."""
    if debug is not None:
        debug(message)