export interface GroupConfig {
  num_groups: number;
  advance_per_group: number;
}

export function getGroupLabel(
  seed: number | undefined,
  groupConfig: GroupConfig | undefined
): string | undefined {
  if (!seed || !groupConfig) return undefined;

  const groupNames = ["A", "B", "C", "D", "E", "F", "G", "H"];
  const numGroups = groupConfig.num_groups;
  const advancePerGroup = groupConfig.advance_per_group;

  const totalQualifiedTeams = numGroups * advancePerGroup;
  const nextPowerOf2 = Math.pow(2, Math.ceil(Math.log2(totalQualifiedTeams)));
  const wildcardsNeeded = nextPowerOf2 - totalQualifiedTeams;

  if (seed > totalQualifiedTeams && wildcardsNeeded > 0) {
    const wildcardNumber = seed - totalQualifiedTeams;
    return `Wildcard ${wildcardNumber}`;
  }

  const pairIndex = Math.floor((seed - 1) / 2);
  const isFirstInPair = (seed - 1) % 2 === 0;

  if (isFirstInPair) {
    const groupIndex = pairIndex % numGroups;
    const rankIndex = Math.floor(pairIndex / numGroups);

    const rank = rankIndex + 1;
    const groupName = groupNames[groupIndex] || `${groupIndex + 1}`;
    const rankSuffix =
      rank === 1 ? "1st" : rank === 2 ? "2nd" : rank === 3 ? "3rd" : `${rank}th`;

    return `${groupName} ${rankSuffix}`;
  } else {
    const groupIndex = (pairIndex + 1) % numGroups;
    const rankIndex = advancePerGroup - 1 - Math.floor(pairIndex / numGroups);

    const rank = rankIndex + 1;
    const groupName = groupNames[groupIndex] || `${groupIndex + 1}`;
    const rankSuffix =
      rank === 1 ? "1st" : rank === 2 ? "2nd" : rank === 3 ? "3rd" : `${rank}th`;

    return `${groupName} ${rankSuffix}`;
  }
}