export const generateOffsets = ({
  sliderWidth,
  itemWidth,
  itemCount,
  horizontalPadding,
}: {
  sliderWidth: number;
  itemWidth: number;
  itemCount: number;
  horizontalPadding: number;
}) => {
  const padding = (sliderWidth - itemWidth) / 2;
  const result: number[] = [];
  for (let i = 0; i < itemCount; i++) {
    if (i === 0) {
      result.push(0);
    } else if (i === itemCount - 1) {
      result.push(i * itemWidth + 2 * (horizontalPadding - padding));
    } else {
      result.push(i * itemWidth + horizontalPadding - padding);
    }
  }
  return result;
};

export const findNearestPage = (offset: number, offsets: number[]): number => {
  'worklet';
  let lo = 0;
  let hi = offsets.length - 1;
  while (hi - lo > 1) {
    const mid = Math.floor((lo + hi) / 2);
    if (offsets[mid] < offset) {
      lo = mid;
    } else {
      hi = mid;
    }
  }
  return offset - offsets[lo] <= offsets[hi] - offset ? lo : hi;
};

export function getLogicalPage(
  renderIndex: number,
  totalItems: number,
  additionalPagesPerSide: number,
  loop: boolean
): number {
  'worklet';
  if (!loop) {
    return renderIndex;
  }
  return (renderIndex - additionalPagesPerSide + totalItems) % totalItems;
}

export function getLoopBoundaryTarget(
  renderPage: number,
  totalPages: number,
  additionalPagesPerSide: number
): number {
  'worklet';
  const totalRenderPages = totalPages + additionalPagesPerSide * 2;
  if (renderPage <= 0) {
    return totalPages;
  }
  if (renderPage >= totalRenderPages - 1) {
    return renderPage - totalPages;
  }
  return -1;
}