"""V3d: base-sizer median-curve parity vs recorded BLUE (unit + @gate)."""

from __future__ import annotations

import json
import sys
from datetime import datetime, timezone
from pathlib import Path

sys.path.insert(0, "/mnt/dolphinng5_predict")

import pytest

from prod.clean_arch.violet.parity_harness import (
    ParityReport, base_curve_parity, live_blue_sizer, load_recorded_samples_from_ch,
)

REPORTS_DIR = Path("/mnt/dolphinng5_predict/prod/VIOLET_dev/reports")


def _base_samples(per_bin: int = 12):
    """Synthetic samples drawn exactly from the base curve (perfect parity)."""
    s = live_blue_sizer()
    out = []
    for k in range(2, 13):                     # vd = -0.02 .. -0.12, all on 0.01 bin centers
        vd = -k / 100.0
        base = s.calculate(capital=1.0, vel_div=vd, trade_direction=-1).conviction_leverage
        out.extend([(vd, base)] * per_bin)
    return out


def test_perfect_base_samples_pass():
    rep = base_curve_parity(_base_samples(), live_blue_sizer())
    assert rep.passed
    assert rep.max_abs_err == pytest.approx(0.0, abs=1e-6)
    assert rep.pearson_r == pytest.approx(1.0, abs=1e-6)


def test_median_tracks_base_under_minority_haircuts():
    # majority at base, minority haircut down -> median still tracks base -> passes.
    s = live_blue_sizer()
    samples = []
    for k in range(2, 13):                               # vd on 0.01 bin centers
        vd = -k / 100.0
        base = s.calculate(capital=1.0, vel_div=vd, trade_direction=-1).conviction_leverage
        samples.extend([(vd, base)] * 8)                 # 8 at base
        samples.extend([(vd, base * 0.3)] * 3)           # 3 haircut (minority)
    rep = base_curve_parity(samples, s)
    assert rep.passed


def test_decorrelated_noise_fails_gate():
    # leverage independent of vel_div -> low correlation -> gate fails (guard works).
    import random
    rng = random.Random(7)
    samples = [(vd / 1000.0, rng.uniform(0.5, 9.0))
               for vd in range(-60, -1) for _ in range(12)]
    rep = base_curve_parity(samples, live_blue_sizer())
    assert not rep.passed


@pytest.mark.gate
def test_base_curve_parity_vs_recorded_blue():
    """GATE (prod host): the V3a base sizer reproduces BLUE's recorded median curve."""
    samples = load_recorded_samples_from_ch(limit=5000)
    assert len(samples) >= 500, f"too few recorded samples: {len(samples)}"
    rep = base_curve_parity(samples, live_blue_sizer())

    REPORTS_DIR.mkdir(parents=True, exist_ok=True)
    ts = datetime.now(timezone.utc).strftime("%Y%m%d_%H%M%S")
    (REPORTS_DIR / f"violet_v3_parity_{ts}.json").write_text(
        json.dumps(rep.model_dump(), indent=2, default=str))

    assert isinstance(rep, ParityReport)
    assert rep.n_bins >= 5
    assert rep.passed, (
        f"base-curve parity FAILED: max_abs_err={rep.max_abs_err:.3f} "
        f"(budget {rep.max_abs_err_budget}), pearson={rep.pearson_r:.3f} "
        f"(budget {rep.pearson_budget})"
    )