mmday-firebase/src/services/predictionService.ts

import { HttpError } from "../middleware/errors";
import { getGame, listByDate, type GameWithId } from "../repositories/gameRepository";
import {
  getUserVote,
  submitVote,
  changeVote,
  getCounts,
  getUserDateVotes,
} from "../repositories/voteRepository";
import type { Game, VoteEntry } from "../types/panit";
import { fromTimestamp, parseDateString, type DateString } from "../types/dateString";
import { MemCache } from "../lib/memCache";

type SummaryCounts = { homeCount: number; awayCount: number };

const summaryCache = new MemCache<SummaryCounts>(5_000);

function gameDate(game: Game): DateString {
  return fromTimestamp(game.time);
}

function sideOf(game: Game, teamCode: string): "home" | "away" {
  if (teamCode === game.homeTeamCode) return "home";
  if (teamCode === game.awayTeamCode) return "away";
  throw new HttpError(400, `teamCode ${teamCode} not in game ${game.homeTeamCode}/${game.awayTeamCode}`);
}

async function loadWaitingGame(gameId: string): Promise<Game> {
  const game = await getGame(gameId);
  if (!game) throw new HttpError(404, `game not found: ${gameId}`);
  if (game.status !== "scheduled") {
    throw new HttpError(409, `game status is ${game.status}, voting closed`);
  }
  return game;
}

export async function createPrediction(
  uid: string,
  body: { gameId?: string; selectedTeamCode?: string }
): Promise<{ ok: true }> {
  if (!body.gameId || !body.selectedTeamCode) {
    throw new HttpError(400, "gameId and selectedTeamCode required");
  }
  const game = await loadWaitingGame(body.gameId);
  const side = sideOf(game, body.selectedTeamCode);

  const existing = await getUserVote(body.gameId, uid);
  if (existing) throw new HttpError(409, "already voted; use PUT to change");

  await submitVote({
    gameId: body.gameId,
    uid,
    date: gameDate(game),
    side,
    team: body.selectedTeamCode,
  });
  summaryCache.delete(body.gameId);
  return { ok: true };
}

export async function updatePrediction(
  uid: string,
  body: { gameId?: string; selectedTeamCode?: string }
): Promise<{ ok: true; changed: boolean }> {
  if (!body.gameId || !body.selectedTeamCode) {
    throw new HttpError(400, "gameId and selectedTeamCode required");
  }
  const game = await loadWaitingGame(body.gameId);
  const newSide = sideOf(game, body.selectedTeamCode);

  const existing = await getUserVote(body.gameId, uid);
  if (!existing) throw new HttpError(400, "no prior vote; use POST");

  if (existing.team === body.selectedTeamCode) return { ok: true, changed: false };

  const oldSide = sideOf(game, existing.team);
  await changeVote({
    gameId: body.gameId,
    uid,
    date: gameDate(game),
    oldSide,
    newSide,
    newTeam: body.selectedTeamCode,
  });
  summaryCache.delete(body.gameId);
  return { ok: true, changed: true };
}

export async function getMyVotes(
  uid: string,
  date: string
): Promise<Record<string, VoteEntry>> {
  try {
    return getUserDateVotes(uid, parseDateString(date));
  } catch (err) {
    throw new HttpError(400, (err as Error).message);
  }
}

export async function listGamesByDate(date: string): Promise<GameWithId[]> {
  try {
    return await listByDate(parseDateString(date));
  } catch (err) {
    throw new HttpError(400, (err as Error).message);
  }
}

export async function getSummary(
  gameId: string
): Promise<{ homeCount: number; awayCount: number }> {
  if (!gameId) throw new HttpError(400, "gameId required");
  return summaryCache.getOrFetch(gameId, () => getCounts(gameId));
}