#include "spectral.hpp"
#include <cmath>
#include <cstring>
#include <vector>

SpectralProcessor::SpectralProcessor(size_t nfft, size_t hop)
    : nfft_(nfft), hop_(hop), frame_count_(0), output_pos_(0) {
    window_ = new double[nfft_];
    computeWindow();
    fft::init_plan(&plan_, static_cast<uint32_t>(std::log2(nfft_)));
    buf_ = new std::complex<double>[nfft_];
    tmp_buf_ = new std::complex<double>[nfft_];
    overlap_.resize(nfft_, 0.0f);
}

SpectralProcessor::~SpectralProcessor() {
    delete[] window_;
    delete[] buf_;
    delete[] tmp_buf_;
}

void SpectralProcessor::computeWindow() {
    for (size_t i = 0; i < nfft_; i++) {
        window_[i] = 0.5 * (1.0 - std::cos(2.0 * M_PI * i / (nfft_ - 1)));
    }
}

void SpectralProcessor::stftFrame(const float* in, std::complex<double>* out) {
    for (size_t i = 0; i < nfft_; i++) {
        out[i] = std::complex<double>(static_cast<double>(in[i]) * window_[i], 0.0);
    }
    fft::execute(&plan_, out);
}

void SpectralProcessor::istftFrame(std::complex<double>* in, float* out, float* overlap) {
    memcpy(tmp_buf_, in, nfft_ * sizeof(std::complex<double>));
    fft::execute_inverse(&plan_, tmp_buf_);
    for (size_t i = 0; i < nfft_; i++) {
        overlap[i] += static_cast<float>(tmp_buf_[i].real() * window_[i]);
    }
    for (size_t i = 0; i < hop_; i++) {
        out[i] = overlap[i];
    }
    for (size_t i = 0; i < nfft_ - hop_; i++) {
        overlap[i] = overlap[i + hop_];
    }
    for (size_t i = nfft_ - hop_; i < nfft_; i++) {
        overlap[i] = 0.0f;
    }
}

void SpectralProcessor::updateDetector() {
}

void SpectralProcessor::processBlock(float* in, float* out, size_t num_samples, size_t num_channels) {
    memset(out, 0, num_samples * sizeof(float));
    if (num_samples == 0 || num_samples < nfft_) {
        return;
    }
    
    size_t nframes = (num_samples - nfft_) / hop_ + 1;
    
    for (size_t f = 0; f < nframes; f++) {
        size_t offset = f * hop_;
        if (offset + nfft_ > num_samples) break;
        stftFrame(in + offset, buf_);
        updateDetector();
        istftFrame(buf_, out + offset, overlap_.data());
    }
}