import { TestAudioBuffer } from "./TestAudioBuffer";
// eslint-disable-next-line @typescript-eslint/no-var-requires
const dsp = require("dsp.js");
// eslint-disable-next-line @typescript-eslint/no-var-requires
const windowing = require("fft-windowing");

export function analyse(buffer: TestAudioBuffer, fftSize = 256, hopSize = 128): Float64Array[] {
	const spectrogram: Float64Array[] = [];
	buffer.toMono().toArray().forEach(channel => {
		for (let index = 0; index < channel.length - fftSize; index += hopSize) {
			const FFT = new dsp.FFT(fftSize, buffer.sampleRate);
			const segment = windowing.blackman_harris(channel.slice(index, index + fftSize));
			FFT.forward(segment);
			spectrogram.push(FFT.spectrum);
		}
	});
	return spectrogram;
}