import { AudioDocument } from "@suaveplan/audio-core/document/document";

const PAGE_SIZE = 1024 * 1024;

/** Build an `AudioDocument` from a flat mono `Float32Array`. */
export function makeDoc(
    samples: Float32Array,
    sampleRate = 48_000
): AudioDocument {
    const pages: { channelData: Float32Array[]; startSample: number }[] = [];
    let offset = 0;
    while (offset < samples.length) {
        const end = Math.min(offset + PAGE_SIZE, samples.length);
        pages.push({
            channelData: [samples.slice(offset, end)],
            startSample: offset,
        });
        offset = end;
    }
    if (pages.length === 0) {
        pages.push({ channelData: [new Float32Array(0)], startSample: 0 });
    }
    return new AudioDocument({
        sampleRate,
        channels: 1,
        sourceLength: samples.length,
        pages,
    });
}

export function sineWave(
    durationSec: number,
    freqHz: number,
    sampleRate = 48_000
): Float32Array {
    const n = Math.floor(durationSec * sampleRate);
    const out = new Float32Array(n);
    for (let i = 0; i < n; i++)
        out[i] = Math.sin((2 * Math.PI * freqHz * i) / sampleRate);
    return out;
}

export function whiteNoise(length: number, seed = 12345): Float32Array {
    let s = seed >>> 0;
    const out = new Float32Array(length);
    for (let i = 0; i < length; i++) {
        s = (1_664_525 * s + 1_013_904_223) >>> 0;
        out[i] = (s / 0xffff_ffff) * 2 - 1;
    }
    return out;
}