"""Langfuse LLM tracing - opt-in via env vars.

Safe no-op when LANGFUSE_PUBLIC_KEY / LANGFUSE_SECRET_KEY are unset
or the `langfuse` package is not installed.
"""

import os

LANGFUSE_ENABLED = bool(
    os.getenv("LANGFUSE_PUBLIC_KEY", "") and os.getenv("LANGFUSE_SECRET_KEY", "")
)
LANGFUSE_HOST = os.getenv("LANGFUSE_HOST", "https://cloud.langfuse.com")

_initialized = False


def init_langfuse() -> bool:
    """Initialize the Langfuse client. Returns True on success."""
    global _initialized
    if not LANGFUSE_ENABLED:
        return False
    try:
        from langfuse import Langfuse  # noqa: F401

        Langfuse(
            public_key=os.getenv("LANGFUSE_PUBLIC_KEY"),
            secret_key=os.getenv("LANGFUSE_SECRET_KEY"),
            host=LANGFUSE_HOST,
        )
        _initialized = True
        return True
    except ImportError:
        return False
    except Exception:
        return False


def flush_langfuse() -> None:
    """Flush any pending Langfuse events. Safe to call on shutdown."""
    if not _initialized:
        return
    try:
        from langfuse import Langfuse

        Langfuse().flush()
    except ImportError:
        pass
    except Exception:
        pass