"""
Lightweight event emitter for the GPU inference server.

Pushes debug logs to the same Redis stream as the pipeline orchestrator,
so GPU-side details (model load, VRAM, inference timing) appear in the
same log panel.

Only active when the request includes X-Job-Id header.
No dependency on the detect package.
"""

from __future__ import annotations

import json
import os
from datetime import datetime, timezone

import redis

REDIS_URL = os.environ.get("REDIS_URL", "redis://localhost:6379/0")
EVENTS_PREFIX = "detect_events"

_LEVEL_ORDER = {"DEBUG": 0, "INFO": 1, "WARN": 2, "ERROR": 3}

_redis_client = None


def _get_redis():
    global _redis_client
    if _redis_client is None:
        _redis_client = redis.from_url(REDIS_URL, decode_responses=True)
    return _redis_client


def log(job_id: str, stage: str, level: str, msg: str, log_level: str = "INFO"):
    """Push a log event to Redis if the level meets the threshold."""
    if not job_id:
        return
    if _LEVEL_ORDER.get(level.upper(), 1) < _LEVEL_ORDER.get(log_level.upper(), 1):
        return

    r = _get_redis()
    key = f"{EVENTS_PREFIX}:{job_id}"
    event = json.dumps({
        "event": "log",
        "level": level,
        "stage": stage,
        "msg": msg,
        "ts": datetime.now(timezone.utc).isoformat(),
    })
    r.rpush(key, event)
    r.expire(key, 3600)