#!/usr/bin/env python3
"""verify_lut.py — непараметрическая LUT-кривая, форма B.10. rmse."""
import numpy as np
from scipy.interpolate import PchipInterpolator

FS = 44100.0
DEPTH = 0.8639736175537109
QS = [0.1, 0.2, 0.3, 0.5, 0.7, 1.0, 1.5, 2.0, 3.0, 5.0, 10.0]
DUAL = np.array([(10.220, 15.224), (10.219, 13.963), (10.219, 12.947),
                 (10.219, 11.725), (10.218, 11.119), (10.216, 10.689),
                 (10.210, 10.412), (10.203, 10.305), (10.182, 10.225),
                 (10.113, 10.183), (9.822, 10.165)])
FCS = [800.0, 900.0, 950.0, 1000.0, 1050.0, 1100.0, 1200.0]
T1KQ = np.array([7.868, 8.536, 8.726, 8.788, 8.729, 8.575, 8.115])
T1K = np.array([14.548, 15.332, 15.553, 15.626, 15.557, 15.378, 14.840])
L_DUAL = 10 ** (-7.142 / 20)
L_T1KQ = 10 ** (-18.063 / 20)
L_T1K = 1.0
TILT = {500: 1.414, 1000: 1.454, 2000: 1.795}
Q, G = 0.900, 4.132

LUTX = np.array([-0.750, -0.500, -0.250, 0.000, 0.250, 0.500, 0.750, 1.000])
LUTY = np.array([0.4453, 0.4551, 0.4784, 0.5041, 0.5331, 0.5715, 0.6574, 0.6636])
lut = PchipInterpolator(LUTX, LUTY)


def res_at(ft, fc, Q, g):
    w0 = fc * 2 * np.pi / FS
    c, s = np.cos(w0), np.sin(w0)
    p = (s * 0.5) / Q
    a, a2 = p * g, p / g
    A = [a + 1, -2 * c, 1 - a]
    B = [a2 + 1, -2 * c, 1 - a2]
    w = 2 * np.pi * ft / FS
    z = np.exp(-1j * w)
    return np.abs(2.0 * (B[0] + B[1] * z + B[2] * z * z) /
                  (A[0] + A[1] * z + A[2] * z * z))


def red(x, tilt):
    C = DEPTH * tilt * lut(x)
    return -20 * np.log10(max(1 - C, 1e-9))


def run():
    preds = []
    meas = []
    print('--- dual_b1q ---')
    for i, q in enumerate(QS):
        for f, m in ((500, DUAL[i, 0]), (2000, DUAL[i, 1])):
            r = res_at(f, 500, q, G)
            p = red(np.log10(L_DUAL / r), TILT[f])
            preds.append(p); meas.append(m)
            print(f'q={q:5.1f} f={int(f)} {m:6.3f}/{p:6.3f}  ({p - m:+.3f})')
    print('--- t1kq -18dB ---')
    for i, fc in enumerate(FCS):
        r = res_at(1000, fc, 0.9999978, G)
        p = red(np.log10(L_T1KQ / r), TILT[1000])
        preds.append(p); meas.append(T1KQ[i])
        print(f'fc={fc:5.0f} {T1KQ[i]:6.3f}/{p:6.3f}  ({p - T1KQ[i]:+.3f})')
    print('--- t1k 0dB ---')
    for i, fc in enumerate(FCS):
        r = res_at(1000, fc, 0.9999978, G)
        p = red(np.log10(L_T1K / r), TILT[1000])
        preds.append(p); meas.append(T1K[i])
        print(f'fc={fc:5.0f} {T1K[i]:6.3f}/{p:6.3f}  ({p - T1K[i]:+.3f})')
    preds = np.array(preds); meas = np.array(meas)
    print(f'\nTOTAL rmse={np.sqrt(np.mean((preds - meas) ** 2)):.4f} dB')


if __name__ == '__main__':
    run()