/**
 * Copyright (c) 2014-2018 Enzien Audio Ltd.
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
 * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
 * OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
 * PERFORMANCE OF THIS SOFTWARE.
 */

#include "HvSignalBiquad.h"

// http://reanimator-web.appspot.com/articles/simdiir
// http://musicdsp.org/files/Audio-EQ-Cookbook.txt

hv_size_t sBiquad_init(SignalBiquad *o) {
#if HV_SIMD_AVX
  o->x = _mm256_setzero_ps();
#elif HV_SIMD_SSE
  o->x = _mm_setzero_ps();
#elif HV_SIMD_NEON
  o->x = vdupq_n_f32(0.0f);
#else // HV_SIMD_NONE
  o->xm1 = 0.0f;
  o->xm2 = 0.0f;
#endif
  o->ym1 = 0.0f;
  o->ym2 = 0.0f;
  return 0;
}

#if _WIN32 && !_WIN64
void __hv_biquad_f_win32(SignalBiquad *o, hv_bInf_t *_bIn, hv_bInf_t *_bX0, hv_bInf_t *_bX1, hv_bInf_t *_bX2, hv_bInf_t *_bY1, hv_bInf_t *_bY2, hv_bOutf_t bOut) {
  hv_bInf_t bIn = *_bIn;
  hv_bInf_t bX0 = *_bX0;
  hv_bInf_t bX1 = *_bX1;
  hv_bInf_t bX2 = *_bX2;
  hv_bInf_t bY1 = *_bY1;
  hv_bInf_t bY2 = *_bY2;
#else
void __hv_biquad_f(SignalBiquad *o, hv_bInf_t bIn, hv_bInf_t bX0, hv_bInf_t bX1, hv_bInf_t bX2, hv_bInf_t bY1, hv_bInf_t bY2, hv_bOutf_t bOut) {
#endif
#if HV_SIMD_AVX
  __m256 x = _mm256_permute_ps(bIn, _MM_SHUFFLE(2,1,0,3));  // [3 0 1 2 7 4 5 6]
  __m256 y = _mm256_permute_ps(o->x, _MM_SHUFFLE(2,1,0,3)); // [d a b c h e f g]
  __m256 n = _mm256_permute2f128_ps(y,x,0x21);              // [h e f g 3 0 1 2]
  __m256 xm1 = _mm256_blend_ps(x, n, 0x11);                 // [h 0 1 2 3 4 5 6]

  x = _mm256_permute_ps(bIn, _MM_SHUFFLE(1,0,3,2));  // [2 3 0 1 6 7 4 5]
  y = _mm256_permute_ps(o->x, _MM_SHUFFLE(1,0,3,2)); // [c d a b g h e f]
  n = _mm256_permute2f128_ps(y,x,0x21);              // [g h e f 2 3 0 1]
  __m256 xm2 = _mm256_blend_ps(x, n, 0x33);          // [g h 0 1 2 3 4 5]

  __m256 a = _mm256_mul_ps(bIn, bX0);
  __m256 b = _mm256_mul_ps(xm1, bX1);
  __m256 c = _mm256_mul_ps(xm2, bX2);
  __m256 d = _mm256_add_ps(a, b);
  __m256 e = _mm256_add_ps(c, d); // bIn*bX0 + o->x1*bX1 + o->x2*bX2

  float y0 = e[0] - o->ym1*bY1[0] - o->ym2*bY2[0];
  float y1 = e[1] - y0*bY1[1] - o->ym1*bY2[1];
  float y2 = e[2] - y1*bY1[2] - y0*bY2[2];
  float y3 = e[3] - y2*bY1[3] - y1*bY2[3];
  float y4 = e[4] - y3*bY1[4] - y2*bY2[4];
  float y5 = e[5] - y4*bY1[5] - y3*bY2[5];
  float y6 = e[6] - y5*bY1[6] - y4*bY2[6];
  float y7 = e[7] - y6*bY1[7] - y5*bY2[7];

  o->x = bIn;
  o->ym1 = y7;
  o->ym2 = y6;

  *bOut = _mm256_set_ps(y7, y6, y5, y4, y3, y2, y1, y0);
#elif HV_SIMD_SSE
  __m128 n = _mm_blend_ps(o->x, bIn, 0x7); // [a b c d] [e f g h] = [e f g d]
  __m128 xm1 = _mm_shuffle_ps(n, n, _MM_SHUFFLE(2,1,0,3)); // [d e f g]
  __m128 xm2 = _mm_shuffle_ps(o->x, bIn, _MM_SHUFFLE(1,0,3,2)); // [c d e f]

  __m128 a = _mm_mul_ps(bIn, bX0);
  __m128 b = _mm_mul_ps(xm1, bX1);
  __m128 c = _mm_mul_ps(xm2, bX2);
  __m128 d = _mm_add_ps(a, b);
  __m128 e = _mm_add_ps(c, d);

  const float *const bbe = (float *) &e;
  const float *const bbY1 = (float *) &bY1;
  const float *const bbY2 = (float *) &bY2;

  float y0 = bbe[0] - o->ym1*bbY1[0] - o->ym2*bbY2[0];
  float y1 = bbe[1] - y0*bbY1[1] - o->ym1*bbY2[1];
  float y2 = bbe[2] - y1*bbY1[2] - y0*bbY2[2];
  float y3 = bbe[3] - y2*bbY1[3] - y1*bbY2[3];

  o->x = bIn;
  o->ym1 = y3;
  o->ym2 = y2;

  *bOut = _mm_set_ps(y3, y2, y1, y0);
#elif HV_SIMD_NEON
  float32x4_t xm1 = vextq_f32(o->x, bIn, 3);
  float32x4_t xm2 = vextq_f32(o->x, bIn, 2);

  float32x4_t a = vmulq_f32(bIn, bX0);
  float32x4_t b = vmulq_f32(xm1, bX1);
  float32x4_t c = vmulq_f32(xm2, bX2);
  float32x4_t d = vaddq_f32(a, b);
  float32x4_t e = vaddq_f32(c, d);

  float y0 = e[0] - o->ym1*bY1[0] - o->ym2*bY2[0];
  float y1 = e[1] - y0*bY1[1] - o->ym1*bY2[1];
  float y2 = e[2] - y1*bY1[2] - y0*bY2[2];
  float y3 = e[3] - y2*bY1[3] - y1*bY2[3];

  o->x = bIn;
  o->ym1 = y3;
  o->ym2 = y2;

  *bOut = (float32x4_t) {y0, y1, y2, y3};
#else
  const float y = bIn*bX0 + o->xm1*bX1 + o->xm2*bX2 - o->ym1*bY1 - o->ym2*bY2;
  o->xm2 = o->xm1; o->xm1 = bIn;
  o->ym2 = o->ym1; o->ym1 = y;
  *bOut = y;
#endif
}

static void sBiquad_k_updateCoefficients(SignalBiquad_k *const o) {
#if DEBUG
  // inspect the filter coefficients to ensure that the filter is stable
  // 1/((1-a*z^-1) * (1-b*z^-1))
  float k = (o->a1*o->a1) - (4.0f*o->a2);
  float l = hv_sqrt_f(hv_abs_f(k));

  float m_alpha = 0.0f;
  float m_beta = 0.0f;
  if (k < 0.0f) {
    // alpha is complex
    float r_alpha = o->a1 * 0.5f;
    float i_alpha = l * 0.5f;
    m_alpha = (r_alpha*r_alpha + i_alpha*i_alpha); // |alpha|^2

    float r_beta = (o->a2 * r_alpha) / m_alpha;
    float i_beta = (o->a2 * -i_alpha) / m_alpha;
    m_alpha = hv_sqrt_f(m_alpha);
    m_beta = hv_sqrt_f(r_beta*r_beta + i_beta*i_beta);
  } else {
    // alpha is real
    float alpha = (o->a1 + l) * 0.5f;
    float beta = o->a2 / alpha;
    m_alpha = hv_abs_f(alpha);
    m_beta = hv_abs_f(beta);
  }

  hv_assert(m_alpha < 1.0f);
  hv_assert(m_beta < 1.0f);
#endif

  // calculate all filter coefficients in the double domain
#if HV_SIMD_AVX || HV_SIMD_SSE || HV_SIMD_NEON
  double b0 = (double) o->b0;
  double b1 = (double) o->b1;
  double b2 = (double) o->b2;
  double a1 = (double) -o->a1;
  double a2 = (double) -o->a2;

  double coeffs[4][8] =
  {
    { 0,  0,  0,  b0, b1, b2, a1, a2 },
    { 0,  0,  b0, b1, b2, 0,  a2, 0  },
    { 0,  b0, b1, b2, 0,  0,  0,  0  },
    { b0, b1, b2, 0,  0,  0,  0,  0  },
  };

  for (int i = 0; i < 8; i++) {
    coeffs[1][i] += a1*coeffs[0][i];
    coeffs[2][i] += a1*coeffs[1][i] + a2*coeffs[0][i];
    coeffs[3][i] += a1*coeffs[2][i] + a2*coeffs[1][i];
  }

#if HV_SIMD_AVX || HV_SIMD_SSE
  o->coeff_xp3 = _mm_set_ps((float) coeffs[3][0], (float) coeffs[2][0], (float) coeffs[1][0], (float) coeffs[0][0]);
  o->coeff_xp2 = _mm_set_ps((float) coeffs[3][1], (float) coeffs[2][1], (float) coeffs[1][1], (float) coeffs[0][1]);
  o->coeff_xp1 = _mm_set_ps((float) coeffs[3][2], (float) coeffs[2][2], (float) coeffs[1][2], (float) coeffs[0][2]);
  o->coeff_x0 =  _mm_set_ps((float) coeffs[3][3], (float) coeffs[2][3], (float) coeffs[1][3], (float) coeffs[0][3]);
  o->coeff_xm1 = _mm_set_ps((float) coeffs[3][4], (float) coeffs[2][4], (float) coeffs[1][4], (float) coeffs[0][4]);
  o->coeff_xm2 = _mm_set_ps((float) coeffs[3][5], (float) coeffs[2][5], (float) coeffs[1][5], (float) coeffs[0][5]);
  o->coeff_ym1 = _mm_set_ps((float) coeffs[3][6], (float) coeffs[2][6], (float) coeffs[1][6], (float) coeffs[0][6]);
  o->coeff_ym2 = _mm_set_ps((float) coeffs[3][7], (float) coeffs[2][7], (float) coeffs[1][7], (float) coeffs[0][7]);
#else // HV_SIMD_NEON
  o->coeff_xp3 = (float32x4_t) {(float) coeffs[0][0], (float) coeffs[1][0], (float) coeffs[2][0], (float) coeffs[3][0]};
  o->coeff_xp2 = (float32x4_t) {(float) coeffs[0][1], (float) coeffs[1][1], (float) coeffs[2][1], (float) coeffs[3][1]};
  o->coeff_xp1 = (float32x4_t) {(float) coeffs[0][2], (float) coeffs[1][2], (float) coeffs[2][2], (float) coeffs[3][2]};
  o->coeff_x0 =  (float32x4_t) {(float) coeffs[0][3], (float) coeffs[1][3], (float) coeffs[2][3], (float) coeffs[3][3]};
  o->coeff_xm1 = (float32x4_t) {(float) coeffs[0][4], (float) coeffs[1][4], (float) coeffs[2][4], (float) coeffs[3][4]};
  o->coeff_xm2 = (float32x4_t) {(float) coeffs[0][5], (float) coeffs[1][5], (float) coeffs[2][5], (float) coeffs[3][5]};
  o->coeff_ym1 = (float32x4_t) {(float) coeffs[0][6], (float) coeffs[1][6], (float) coeffs[2][6], (float) coeffs[3][6]};
  o->coeff_ym2 = (float32x4_t) {(float) coeffs[0][7], (float) coeffs[1][7], (float) coeffs[2][7], (float) coeffs[3][7]};
#endif
#endif
  // NOTE(mhroth): not necessary to calculate any coefficients for HV_SIMD_NONE case
}

hv_size_t sBiquad_k_init(SignalBiquad_k *o, float b0, float b1, float b2, float a1, float a2) {
  // initialise filter coefficients
  o->b0 = b0;
  o->b1 = b1;
  o->b2 = b2;
  o->a1 = a1;
  o->a2 = a2;
  sBiquad_k_updateCoefficients(o);

  // clear filter state
#if HV_SIMD_AVX || HV_SIMD_SSE
  o->xm1 = _mm_setzero_ps();
  o->xm2 = _mm_setzero_ps();
  o->ym1 = _mm_setzero_ps();
  o->ym2 = _mm_setzero_ps();
#elif HV_SIMD_NEON
  o->xm1 = vdupq_n_f32(0.0f);
  o->xm2 = vdupq_n_f32(0.0f);
  o->ym1 = vdupq_n_f32(0.0f);
  o->ym2 = vdupq_n_f32(0.0f);
#else // HV_SIMD_NONE
  o->xm1 = 0.0f;
  o->xm2 = 0.0f;
  o->ym1 = 0.0f;
  o->ym2 = 0.0f;
#endif
  return 0;
}

void sBiquad_k_onMessage(SignalBiquad_k *o, int letIn, const HvMessage *m) {
  if (msg_isFloat(m,0)) {
    switch (letIn) {
      case 1: o->b0 = msg_getFloat(m,0); break;
      case 2: o->b1 = msg_getFloat(m,0); break;
      case 3: o->b2 = msg_getFloat(m,0); break;
      case 4: o->a1 = msg_getFloat(m,0); break;
      case 5: o->a2 = msg_getFloat(m,0); break;
      default: return;
    }
    sBiquad_k_updateCoefficients(o);
  }
}