/**
 * [Gitea #138] How many reaction chips fit on one row next to a "+N" chip.
 *
 * Returns `undefined` when every chip fits on the first row (nothing to
 * collapse). Otherwise returns the number of leading chips to show; the
 * caller renders a "+N" chip after them. Always at least 1 chip.
 */
export function fitReactionRow(
  chipWidths: number[],
  moreChipWidth: number,
  gap: number,
  rowWidth: number,
): number | undefined {
  const rowLength = (count: number, extra: number) => {
    let total = extra;
    for (let i = 0; i < count; i += 1) total += chipWidths[i] + (i > 0 || extra > 0 ? gap : 0);
    return total;
  };
  if (rowLength(chipWidths.length, 0) <= rowWidth) return undefined;
  let count = chipWidths.length - 1;
  while (count > 1 && rowLength(count, 0) + gap + moreChipWidth > rowWidth) count -= 1;
  return count;
}

/** Session-only memory of which messages have their reactions expanded. */
export const expandedReactionMessages = new Set<string>();