brackt/app/lib/draft-order.ts

/**
 * Returns the draft slot for a given pick number in a snake draft.
 */
export function getTeamForPick<T extends { draftOrder: number }>(
  pickNumber: number,
  draftSlots: T[]
): T | undefined {
  const totalTeams = draftSlots.length;
  if (totalTeams === 0) return undefined;

  const round = Math.ceil(pickNumber / totalTeams);
  const isEvenRound = round % 2 === 0;
  let pickInRound = ((pickNumber - 1) % totalTeams) + 1;
  if (isEvenRound) {
    pickInRound = totalTeams - pickInRound + 1;
  }
  return draftSlots.find((slot) => slot.draftOrder === pickInRound);
}

export interface ProjectedPick {
  round: number;
  pickNumber: number;
  picksFromNow: number;
}

export function getProjectedPicks(options: {
  draftSlots: Array<{ draftOrder: number; teamId: string }>;
  userTeamId: string;
  currentPick: number;
  totalRounds: number;
  existingPicks: Array<{ pickNumber: number; teamId: string }>;
}): ProjectedPick[] {
  const { draftSlots, userTeamId, currentPick, totalRounds, existingPicks } = options;
  const totalTeams = draftSlots.length;
  if (totalTeams === 0) return [];

  const userSlot = draftSlots.find((slot) => slot.teamId === userTeamId);
  if (!userSlot) return [];

  const userDraftOrder = userSlot.draftOrder;
  const pickedNumbersForTeam = new Set(
    existingPicks
      .filter((p) => p.teamId === userTeamId)
      .map((p) => p.pickNumber)
  );

  const result: ProjectedPick[] = [];

  for (let round = 1; round <= totalRounds; round++) {
    const isEvenRound = round % 2 === 0;
    const pickInRound = isEvenRound
      ? totalTeams - userDraftOrder + 1
      : userDraftOrder;
    const pickNumber = (round - 1) * totalTeams + pickInRound;

    if (pickNumber < currentPick) continue;
    if (pickedNumbersForTeam.has(pickNumber)) continue;

    result.push({
      round,
      pickNumber,
      picksFromNow: pickNumber - currentPick,
    });
  }

  return result;
}