"""Price advisor — wraps the existing presow_v4 model with loud failure on
   missing artefacts. Dead branches (weekly, district_v2, sellhold_v4, presow_v3)
   no longer pretend to work; they return a structured "model_unavailable" error
   instead of silently degrading to v4.
"""
from __future__ import annotations
import logging
import sys
from pathlib import Path
from typing import Optional

_MANDI_DIR = Path(__file__).resolve().parents[1] / "data"
sys.path.insert(0, str(_MANDI_DIR))

logger = logging.getLogger(__name__)


def get_presow_signal(crop: str, state: str,
                       sowing_month: Optional[int] = None) -> dict:
    """Return harvest-price quantile forecast for crop+state.

    Quotes presow_v4 (P25/P50/P75) which IS present and validated at MAPE 7.6%.
    """
    try:
        from mandi_advisor.enterprise_engine_v2 import get_presow_signal as _impl
        return _impl(crop, state, sowing_month=sowing_month) if sowing_month \
               else _impl(crop, state)
    except FileNotFoundError as e:
        return {"error": "model_unavailable",
                "detail": f"presow_v4 artefacts missing: {e}",
                "remediation": "Run pipelines/check_artefacts.py to verify model files."}
    except Exception as e:
        logger.exception("[price] presow signal failed")
        return {"error": "internal", "detail": str(e)}


def get_signal(crop: str, state: str, district: str = "",
                current_price: Optional[float] = None) -> dict:
    """Sell/Hold signal — currently only the v4 fallback is reachable until the
    weekly/district_v2 models are restored.

    If you call this for a perishable crop (Tomato, Onion, Potato) we explicitly
    return model_unavailable so callers know the answer is a degraded fallback,
    not a confident weekly forecast.
    """
    PERISHABLES = {"tomato", "onion", "potato", "cabbage", "cauliflower",
                   "spinach", "okra", "chilli", "leafy"}
    try:
        from mandi_advisor.enterprise_engine_v2 import get_signal as _impl
        result = _impl(crop, state, district, current_price)
    except Exception as e:
        return {"error": "internal", "detail": str(e)}

    if crop.lower() in PERISHABLES and "weekly" not in (result.get("model_version") or ""):
        result["warning"] = (
            "Perishable crop without a weekly model — using state-level fallback. "
            "Re-run pipelines/build_weekly_perishable.py to restore weekly resolution."
        )
        result["confidence"] = "LOW"
    return result


def check_artefacts() -> dict:
    """Liveness check — which model files are actually on disk?"""
    md = _MANDI_DIR / "mandi_advisor"
    expected = {
        "presow_v4_model.pkl":          True,
        "presow_v4_meta.pkl":           True,
        "feature_store.parquet":        True,
        "weekly_perishable_model.pkl":  False,
        "weekly_perishable_meta.pkl":   False,
        "district_sellhold_v2_model.pkl": False,
        "sellhold_v4_model.pkl":        False,
        "presow_v3_model.pkl":          False,
        "mandi_data_clean.parquet":     False,
    }
    out = {"present": {}, "missing": {}}
    for name, must_have in expected.items():
        p = md / name
        bucket = "present" if p.exists() else "missing"
        out[bucket][name] = {"required": must_have, "size_mb":
                              round(p.stat().st_size / 1e6, 1) if p.exists() else 0}
    out["healthy"] = not any(d["required"] for n, d in out["missing"].items()
                              if d["required"])
    return out