"""agent_49_adx_dir — Trend-strength (ADX-like) GATED directional position.

ANGLE [family=mix, slug=adx_dir]:
  Build a causal ADX (Average Directional Index) from directional movement and ATR.
  ADX measures TREND STRENGTH (not direction). We take a directional position ONLY
  when trend strength is HIGH (ADX above an adaptive, past-only threshold); otherwise
  flat. Direction is the directional-movement sign (+DI vs -DI). Size is vol-targeted
  so a calm strong trend and a violent one carry comparable risk.

  Long-only: on these strongly up-trending overlaid curves, shorting "strong"
  down-moves (which are mostly sharp counter-trend dips that snap back) was net-
  negative and added drawdown in the train sweep — the honest result is that the
  ADX gate adds value as a LONG participation filter, lifting risk-adjusted return
  (train combined Sharpe ~1.1 at ~10% DD vs buy&hold ~1.0 at ~77% DD), not by
  catching the declines short.

Everything is causal: +DM/-DM, ATR (Wilder EWM), DI, DX, ADX (EWM of DX) all use
only data up to bar i. The ADX gate threshold is an EXPANDING quantile (past-only),
so the strength bar adapts to each curve without peeking forward.

Tuned ONLY on split='train'. Params chosen on a broad plateau (win 10-20, gate
q 0.30-0.45 all positive at <15% DD), centered at win=14, q=0.38.
"""
import numpy as np
import pandas as pd
import blindlib as bl

ADX_WIN = 14          # directional-movement / ADX smoothing window
GATE_Q = 0.38         # expanding-quantile threshold on ADX (trend-strength gate)
GATE_MINP = 120       # warmup bars before the gate can fire
TARGET_VOL = 0.20
VOL_WIN = 30
LEV_CAP = 1.0


def _wilder(x, win):
    """Wilder smoothing == EWM with alpha=1/win, adjust=False. Fully causal."""
    return pd.Series(x).ewm(alpha=1.0 / win, adjust=False).mean().values


def _adx(df, win):
    """Causal ADX + DI+ / DI-. value[i] uses only data <= i."""
    h = df["high"].values.astype(float)
    l = df["low"].values.astype(float)
    c = df["close"].values.astype(float)
    pc = np.roll(c, 1); pc[0] = c[0]
    ph = np.roll(h, 1); ph[0] = h[0]
    pl = np.roll(l, 1); pl[0] = l[0]

    up = h - ph                       # this bar's up extension
    dn = pl - l                       # this bar's down extension
    plus_dm = np.where((up > dn) & (up > 0), up, 0.0)
    minus_dm = np.where((dn > up) & (dn > 0), dn, 0.0)

    tr = np.maximum(h - l, np.maximum(np.abs(h - pc), np.abs(l - pc)))
    atr = _wilder(tr, win)
    atr_safe = np.where(atr > 0, atr, np.nan)

    di_plus = np.nan_to_num(100.0 * _wilder(plus_dm, win) / atr_safe, nan=0.0)
    di_minus = np.nan_to_num(100.0 * _wilder(minus_dm, win) / atr_safe, nan=0.0)

    di_sum = di_plus + di_minus
    dx = 100.0 * np.abs(di_plus - di_minus) / np.where(di_sum > 0, di_sum, np.nan)
    dx = np.nan_to_num(dx, nan=0.0)
    adx = _wilder(dx, win)
    return adx, di_plus, di_minus


def _expanding_quantile(x, q, min_periods):
    """Past-only expanding quantile. value[i] uses x[0..i] -> causal."""
    out = pd.Series(x).expanding(min_periods=min_periods).quantile(q).values
    return np.where(np.isfinite(out), out, np.inf)   # flat (inf thr) until warmed


def signal(df):
    c = df["close"].values.astype(float)

    adx, di_p, di_m = _adx(df, ADX_WIN)

    # Trend-STRENGTH gate: only act when ADX is in its upper regime (past-only thr).
    adx_thr = _expanding_quantile(adx, GATE_Q, GATE_MINP)
    strong = adx > adx_thr

    # Direction from directional movement: +DI dominant -> up, -DI dominant -> down.
    di_dir = np.sign(di_p - di_m)
    # Long-only on these up-trending curves (shorting strong dips was net-negative).
    raw_dir = np.where(di_dir > 0, 1.0, 0.0)

    direction = np.where(strong, raw_dir, 0.0).astype(float)

    # Vol-target so calm strong trends and wild ones carry comparable risk.
    pos = bl.vol_target(direction, df, target_vol=TARGET_VOL,
                        vol_win_days=VOL_WIN, leverage_cap=LEV_CAP)
    return np.clip(np.nan_to_num(pos, nan=0.0), -1.0, 1.0)