"""Redis-backed live render log for streaming task progress.

Each order line gets a Redis list keyed by render:log:{order_line_id}.
Entries are JSON objects with timestamp, level, and message.
Lists auto-expire after 1 hour.
"""
import json
import time
import logging

import redis

from app.config import settings

logger = logging.getLogger(__name__)

_LOG_TTL = 3600  # 1 hour
_MAX_ENTRIES = 500


def _redis() -> redis.Redis:
    return redis.from_url(settings.redis_url, decode_responses=True)


def _key(order_line_id: str) -> str:
    return f"render:log:{order_line_id}"


def emit(order_line_id: str, message: str, level: str = "info") -> None:
    """Push a log entry for a render job."""
    entry = json.dumps({
        "ts": time.time(),
        "t": time.strftime("%H:%M:%S", time.gmtime()),
        "level": level,
        "msg": message,
    })
    try:
        r = _redis()
        key = _key(order_line_id)
        r.rpush(key, entry)
        r.ltrim(key, -_MAX_ENTRIES, -1)
        r.expire(key, _LOG_TTL)
    except Exception as exc:
        logger.debug(f"render_log emit failed: {exc}")


def get_entries(order_line_id: str, after_index: int = 0) -> list[dict]:
    """Get log entries starting from after_index."""
    try:
        r = _redis()
        raw = r.lrange(_key(order_line_id), after_index, -1)
        return [json.loads(e) for e in raw]
    except Exception:
        return []


def count(order_line_id: str) -> int:
    """Get the number of log entries."""
    try:
        r = _redis()
        return r.llen(_key(order_line_id))
    except Exception:
        return 0


def clear(order_line_id: str) -> None:
    """Clear log entries for a render job."""
    try:
        r = _redis()
        r.delete(_key(order_line_id))
    except Exception:
        pass