import { sfbkstream } from './sfbkstream.js';
import { PDTA } from './pdta.js';
import { generatorNames, Pbag, Shdr } from './sf.types.js';
import { readAB } from './aba.js';

export async function streamSF2File(file: string) {
  const { pdtaBuffer, sdtaStream, nsamples, infos } = await sfbkstream(file);
  const pdta = new PDTA(readAB(pdtaBuffer));

  const samplesData = pdta.shdr.map((sh, idx) => ({
    ...sh,
    sid: idx,
    izones: pdta.ibag.filter((ib) => ib.izone.sampleID == idx),
  }));
  const readable = new ReadableStream<string>({
    async start(controller) {
      controller.enqueue(JSON.stringify(infos));
    },
  });

  let sampleIdx;

  const reader = sdtaStream.getReader();
  const floats = new Float32Array(nsamples);

  let sampleOffset = 0;
  const sampleData: { ab: AudioBuffer; loop: [number, number] }[] = [];
  function createSamplebuffer(): [Float32Array, number] {
    const sample = pdta.shdr[sampleOffset];
    sampleData[sampleOffset].ab = new AudioBuffer({
      numberOfChannels: 1,
      length: sample.end - sample.start,
      sampleRate: sample.sampleRate,
    });
    sampleData[sampleOffset].loop = [
      sample.startLoop - sample.start,
      sample.end - sample.end,
    ];
    const floatss = sampleData[sampleOffset].ab.getChannelData(0);
    return [floatss, floatss.length];
  }
  let [floatss, nsample] = createSamplebuffer();
  var offset = 0;
  while (true) {
    const { done, value } = await reader.read();
    if (done) break;
    const dv = new DataView(value.buffer);
    for (let i = 0; i < value.byteLength / 2 - 1; i++) {
      floatss[offset++] = dv.getInt16(2 * i, true) / 0x7fff; // / 0x7fff;
      if (offset >= nsample) {
        if (sampleOffset >= pdta.shdr.length) return;
        [floatss, nsample] = createSamplebuffer();
        offset = 0;
      }
    }
  }
}