"""
feature_builder.py — Converts raw rule-engine output dicts into a clean
feature vector for the ML model. Single responsibility: no model logic here.

Design decisions:
- All bool features cast to int (0/1) — LGBM handles natively but this
  keeps the matrix dtype homogeneous.
- Engineered interaction terms computed here, not in regime/volume modules,
  to keep those modules free of ML concerns.
- Returns a dict (for inference) or DataFrame row (for training).
- FEATURE_COLUMNS from ml_config defines the canonical order — any missing
  feature raises KeyError immediately rather than silently producing NaN.
"""

import math
from typing import Dict, Any

import numpy as np
import pandas as pd

from ml_config import FEATURE_COLUMNS


def build_feature_dict(
    regime_data: Dict[str, Any],
    volume_data: Dict[str, Any],
    scores: Dict[str, Any],
) -> Dict[str, float]:
    """
    Build the canonical feature dict from rule-engine outputs.
    All values are Python floats or ints — no pandas/numpy scalars.
    """
    adx       = float(regime_data.get("adx", 0.0))
    di_plus   = float(regime_data.get("di_plus", 0.0))
    di_minus  = float(regime_data.get("di_minus", 0.0))
    di_sum    = di_plus + di_minus + 1e-9
    di_diff   = di_plus - di_minus
    di_ratio  = di_plus / di_sum

    atr_pct               = float(regime_data.get("atr_pct", 0.0))
    vol_ratio             = float(regime_data.get("vol_ratio", 1.0))
    vol_compressed        = int(bool(regime_data.get("vol_compressed", False)))
    vol_expanding         = int(bool(regime_data.get("vol_expanding", False)))
    vol_expanding_from_base = int(bool(regime_data.get("vol_expanding_from_base", False)))

    absorption          = int(bool(volume_data.get("absorption", False)))
    failed_breakout     = int(bool(volume_data.get("failed_breakout", False)))
    recent_failed_count = int(volume_data.get("recent_failed_count", 0))
    obv_slope_norm      = float(volume_data.get("obv_slope_norm", 0.0))
    delta_sign          = int(volume_data.get("delta_sign", 0))
    spike               = int(bool(volume_data.get("spike", False)))
    climax              = int(bool(volume_data.get("climax", False)))

    dist_atr     = float(regime_data.get("dist_atr", 0.0))
    dist_atr_abs = abs(dist_atr)

    regime_confidence = float(regime_data.get("regime_confidence", 0.0))
    regime_score      = float(scores.get("regime_score", 0.0))
    volume_score      = float(scores.get("volume_score", 0.0))
    structure_score   = float(scores.get("structure_score", 0.0))
    confidence_score  = float(scores.get("confidence_score", 0.0))
    total_score       = float(scores.get("total_score", 0.0))

    # Interaction terms — multiplicative combinations reduce model depth needed
    adx_x_regime = adx * regime_score
    vol_x_obv    = vol_ratio * obv_slope_norm
    score_x_conf = total_score * regime_confidence

    raw = {
        "adx":                    adx,
        "di_plus":                di_plus,
        "di_minus":               di_minus,
        "di_diff":                di_diff,
        "di_ratio":               di_ratio,
        "atr_pct":                atr_pct,
        "vol_ratio":              vol_ratio,
        "vol_compressed":         vol_compressed,
        "vol_expanding":          vol_expanding,
        "vol_expanding_from_base": vol_expanding_from_base,
        "absorption":             absorption,
        "failed_breakout":        failed_breakout,
        "recent_failed_count":    recent_failed_count,
        "obv_slope_norm":         obv_slope_norm,
        "delta_sign":             delta_sign,
        "spike":                  spike,
        "climax":                 climax,
        "dist_atr":               dist_atr,
        "dist_atr_abs":           dist_atr_abs,
        "regime_confidence":      regime_confidence,
        "regime_score":           regime_score,
        "volume_score":           volume_score,
        "structure_score":        structure_score,
        "confidence_score":       confidence_score,
        "total_score":            total_score,
        "adx_x_regime":           adx_x_regime,
        "vol_x_obv":              vol_x_obv,
        "score_x_conf":           score_x_conf,
    }

    # Validate all expected columns are present
    missing = set(FEATURE_COLUMNS) - set(raw.keys())
    if missing:
        raise KeyError(f"Missing features: {missing}")

    # Return in canonical column order
    return {k: raw[k] for k in FEATURE_COLUMNS}


def feature_dict_to_row(feat: Dict[str, float]) -> pd.Series:
    """Convert feature dict to a pandas Series with canonical column order."""
    return pd.Series({k: feat[k] for k in FEATURE_COLUMNS})


def feature_dict_to_matrix(feat: Dict[str, float]) -> np.ndarray:
    """
    Convert single feature dict to (1, n_features) numpy array for inference.
    Preserves canonical column order from FEATURE_COLUMNS.
    """
    return np.array([[feat[k] for k in FEATURE_COLUMNS]], dtype=np.float64)


def validate_features(feat: Dict[str, float]) -> bool:
    """Return True if all features are finite and present."""
    for k in FEATURE_COLUMNS:
        v = feat.get(k)
        if v is None or (isinstance(v, float) and not math.isfinite(v)):
            return False
    return True