src/config.py

"""
Central configuration loaded from environment variables.

All tunables live here — no magic numbers scattered across modules.
Override any of these via a .env file (see .env.example) or real env vars.
"""
import os
from pathlib import Path

try:
    from dotenv import load_dotenv
    # Load .env from project root if present (safe to call even if missing)
    load_dotenv(Path(__file__).resolve().parent.parent / ".env")
except ImportError:
    pass  # python-dotenv is optional; env vars still work


def _bool(v: str, default: bool = False) -> bool:
    if v is None:
        return default
    return v.strip().lower() in ("1", "true", "yes", "on")


# ── Model ──────────────────────────────────────────────────────────
MODEL_NAME = os.getenv("HF_MODEL_NAME", "deepset/bert-base-cased-squad2")
MAX_CONTEXT_CHARS = int(os.getenv("MAX_CONTEXT_CHARS", "2500"))
MAX_SEQ_LENGTH = int(os.getenv("MAX_SEQ_LENGTH", "512"))
WARMUP_ON_START = _bool(os.getenv("WARMUP_ON_START"), default=True)

# ── Scraper ────────────────────────────────────────────────────────
SCRAPE_TIMEOUT = int(os.getenv("SCRAPE_TIMEOUT", "20"))
SCRAPE_MAX_RETRIES = int(os.getenv("SCRAPE_MAX_RETRIES", "3"))

# ── Rate limiting ──────────────────────────────────────────────────
RATE_LIMIT_ENABLED = _bool(os.getenv("RATE_LIMIT_ENABLED"), default=True)
RATE_LIMIT_SCRAPE = os.getenv("RATE_LIMIT_SCRAPE", "10 per minute")
RATE_LIMIT_PREDICT = os.getenv("RATE_LIMIT_PREDICT", "30 per minute")
RATE_LIMIT_DEFAULT = os.getenv("RATE_LIMIT_DEFAULT", "200 per hour")

# ── Persistence (SQLite) ───────────────────────────────────────────
# HF Spaces persistent storage lives under /data when enabled; fallback to local file otherwise
_default_db = "/data/history.db" if Path("/data").exists() and os.access("/data", os.W_OK) else "history.db"
DB_PATH = os.getenv("DB_PATH", _default_db)
HISTORY_LIMIT = int(os.getenv("HISTORY_LIMIT", "100"))

# ── Server ─────────────────────────────────────────────────────────
# HF Spaces Docker SDK defaults to 7860; honor $PORT if set (Render/Railway/etc.)
PORT = int(os.getenv("PORT", "7860"))
DEBUG = _bool(os.getenv("FLASK_DEBUG"), default=False)