#include "fn529fe0.hpp"
#include <cmath>
#include <algorithm>
#include <cstring>

// Structural mask-apply chain FUN_180529fe0 (mono path). Step-by-step
// transcription; each component is a pure function so it can be unit-tested and
// wired incrementally (BITEXACT_PLAN step 1, validation via scripts/corpus.py).

namespace fn529fe0 {

void iir1(float* x, const double* A, const double* B, size_t nbin, double /*acc0*/) {
    // leaky first-order: y = A*acc + B*x ;  acc = y  (B = 1-A from live tables)
    double acc = 0.0;
    for (size_t i = 0; i < nbin; i++) {
        double y = A[i] * acc + B[i] * static_cast<double>(x[i]);
        acc = y;
        x[i] = static_cast<float>(y);
    }
}

void blend_exp2(float* mask, const float* x, const float* freqaxis,
                float mix, size_t nbin) {
    for (size_t i = 0; i < nbin; i++) {
        double blend = static_cast<double>(freqaxis[i]) * (1.0 - mix) + mix * 0.8;
        // mask = exp2(-x) * blend  (x is level; attenuation => exp2(-level))
        mask[i] = static_cast<float>(std::exp2(-static_cast<double>(x[i])) * blend);
    }
}

void combine_acc(double* acc, const float* band, const float* f6f8,
                 const float* wAtt, const float* wRel, size_t nfft) {
    const size_t half = nfft / 2;
    // acc = band - f6f8 (0x8d60 sub), over full nfft (mirrored halves)
    for (size_t i = 0; i < half; i++) {
        acc[i] = static_cast<double>(band[i]) - static_cast<double>(f6f8[i]);
        acc[nfft - 1 - i] = acc[i];
    }
    // += wAtt*upper + wRel*lower (weights indexed by bin, applied to mirrored halves)
    for (size_t i = 0; i < half; i++) {
        acc[i] += static_cast<double>(wAtt[i]) * static_cast<double>(f6f8[i]);
        acc[i] += static_cast<double>(wRel[i]) * static_cast<double>(f6f8[i]);
    }
    // += band (0x5a20), full nfft
    for (size_t i = 0; i < half; i++) {
        acc[i] += static_cast<double>(band[i]);
        acc[nfft - 1 - i] += static_cast<double>(band[i]);
    }
}

void warp_mask(float* mask, const float* kBand768, const float* kWarp, size_t nbin) {
    for (size_t i = 0; i < nbin; i++) {
        mask[i] *= kBand768[i] * kWarp[i];
    }
}

void dry_wet(float* mask, float fVar30, float wet, size_t nbin) {
    if (fVar30 == 1.0f && wet == 1.0f) return;  // identity default
    for (size_t i = 0; i < nbin; i++) {
        mask[i] = mask[i] * (fVar30 * wet) + (1.0f - fVar30);
    }
}

}  // namespace fn529fe0