"""
Local Langfuse client wrapper with enriched error handling.

The get_prompt_from_langfuse() method from agent_framework.prompts silently
captures all exceptions without indicating the root cause of the failure.
This module replaces that function with a wrapper that:
  - Distinguishes between authentication errors, prompt not found, and network errors.
  - Logs the root cause in a structured way.
  - Supports retrieval by label (e.g. "production") instead of version "latest".
"""

import langfuse
from typing import Optional, Tuple
from src.core.logging import get_logger
from src.core.config import settings

logger = get_logger(__name__)


def _build_httpx_client():
    """Mirror setup_observer's behavior: honor settings.OTEL_EXPORTER_OTLP_TRACES_CERTIFICATE."""
    cert_path = settings.OTEL_EXPORTER_OTLP_TRACES_CERTIFICATE
    if not cert_path:
        return None
    try:
        import httpx
        return httpx.Client(verify=cert_path)
    except Exception as exc:
        logger.warning("Failed to build httpx client for Langfuse provider: %s", exc)
        return None


def get_prompt_with_config_from_langfuse(
    prompt_name: str,
    label: str = "production",
) -> Tuple[Optional[str], dict]:
    """
    Fetches a text prompt + its `config` dict from Langfuse.

    Langfuse permite anexar um objeto JSON `config` ao lado do corpo do
    prompt (editável pela mesma UI). Usamos isso para guardar tuning
    parameters que o squad de prompt-engineering pode ajustar sem deploy
    (ex.: tamanho de janelas de histórico, thresholds, flags).

    Args:
        prompt_name: Nome do prompt registrado no Langfuse.
        label: Label a recuperar (default: "production").

    Returns:
        Tupla `(content, config)`. `content=None` quando o prompt não foi
        encontrado ou houve erro de rede/auth — nesses casos o caller deve
        cair em fallback local. `config` é `{}` quando o prompt não tem
        config setado.
    """

    try:
        client_kwargs = {
            "public_key": settings.LANGFUSE_PUBLIC_KEY,
            "secret_key": settings.LANGFUSE_SECRET_KEY,
            "host": settings.LANGFUSE_BASE_URL,
        }
        httpx_client = _build_httpx_client()
        if httpx_client is not None:
            client_kwargs["httpx_client"] = httpx_client
        client = langfuse.Langfuse(**client_kwargs)
    except Exception as e:
        logger.error(
            "Failed to initialize the Langfuse client. Check LANGFUSE_PUBLIC_KEY, LANGFUSE_SECRET_KEY and LANGFUSE_BASE_URL. "
            f"Error: {e}"
        )
        return None, {}

    try:
        prompt_obj = client.get_prompt(name=prompt_name, label=label)
    except Exception as e:
        logger.error(
            f"Unexpected error while fetching prompt '{prompt_name}' from Langfuse: "
            f"{type(e).__name__}: {e}"
        )
        return None, {}

    # The Langfuse v3 SDK returns different types depending on the prompt type.
    # For text prompts (type="text"), the content is in the .prompt attribute.
    if prompt_obj is None:
        logger.warning(f"Langfuse returned None for prompt '{prompt_name}'.")
        return None, {}

    # Try both known SDK attributes to ensure version compatibility.
    content = getattr(prompt_obj, "prompt", None) or getattr(prompt_obj, "content", None)

    if not content:
        logger.warning(
            f"Prompt '{prompt_name}' found but has no content. "
            f"Available attributes: {[a for a in dir(prompt_obj) if not a.startswith('_')]}"
        )
        return None, {}

    # `config` é opcional no Langfuse. Normalizamos para dict para que o
    # caller possa sempre fazer `config.get(...)` sem checar tipo.
    raw_config = getattr(prompt_obj, "config", None)
    config = raw_config if isinstance(raw_config, dict) else {}

    return content, config


def get_prompt_from_langfuse(
    prompt_name: str,
    label: str = "production",
) -> Optional[str]:
    """Backwards-compatible wrapper que ignora o `config` do prompt."""
    content, _config = get_prompt_with_config_from_langfuse(prompt_name, label)
    return content