/**
 * @param {Buffer | Uint8Array | number[]} data
 * @param {number} offset
 */
function readUInt16LE(data, offset) {
    return data[offset] + data[offset + 1] * 0x100;
}

/**
 * Rip specified BRR sample from a SPC file chunk.
 * @param {Buffer | Uint8Array | number[]} chunk Chunk data
 * @param {number} id Sample ID
 * @returns {Uint8Array | null} Ripped BRR sample with AddMusicM loop header
 */
function getBRR(chunk, id) {
    const offset = 0x100;
    const sampleIndexPtr = chunk[0x1015D] * 0x100 + offset;
    const samplePtr = readUInt16LE(chunk, sampleIndexPtr + id * 4);
    if (samplePtr === 0x0000 || samplePtr === 0xFFFF) {
        return null;
    }
    const sampleLoop = readUInt16LE(chunk, sampleIndexPtr + id * 4 + 2) - samplePtr;
    let sampleCurrentPtr = samplePtr + offset;
    while (sampleCurrentPtr < (0xFFFF + offset)) {
        sampleCurrentPtr += 9;
        if (chunk[sampleCurrentPtr - 9] % 2 === 1) {
            break;
        }
    }
    const sampleLength = sampleCurrentPtr - (samplePtr + offset);
    const brr = new Uint8Array(sampleLength + 2);
    brr[0] = sampleLoop & 0xFF;
    brr[1] = sampleLoop >> 8;
    for (let i = 0; i < sampleLength; i++) {
        brr[i + 2] = chunk[(samplePtr + offset) + i];
    }
    return brr;
};