/**
 * /api/gamelines/:sport (Session 23)
 *
 * Today's game-level betting odds from Tank01 — book-by-book moneylines,
 * run/point spreads, and totals. Separate budget from odds-api player
 * props: this uses the RAPID_API_KEY quota via the Tank01 adapters.
 *
 * Chrome Claude confirmed (2026-06-12) Tank01 MLB serves LIVE lines from
 * bet365 / betmgm / caesars. NBA carries the same in-season — an empty
 * result off-season is correct, not an error.
 *
 * Response shape:
 * {
 *   sport: 'mlb',
 *   date: '2026-06-12',
 *   games: {
 *     '20260612_ARI@CIN': {
 *       homeTeam: 'CIN', awayTeam: 'ARI',
 *       books: {
 *         bet365:  { homeML, awayML, total, overOdds, underOdds,
 *                    homeSpread, awaySpread },
 *         betmgm:  { ... },
 *       },
 *     },
 *   },
 *   source: 'tank01',
 * }
 */

const express = require('express');
const nbaAdapter = require('../services/adapters/tank01NbaAdapter');
const mlbAdapter = require('../services/adapters/tank01MlbAdapter');
const scheduleService = require('../services/scheduleService');
const { createRateLimit } = require('../middleware/rateLimit');

const router = express.Router();
// Session 32 — public throttle (60/min; Tank01, cached).
router.use(createRateLimit({ windowMs: 60_000, max: 60 }));

const MISSION_HEADER = { 'X-VYNDR-Mission': 'Lines keep the slate alive' };

// Sports that have a Tank01 game-lines feed wired up.
const FETCHERS = {
  nba: (date) => nbaAdapter.getNBABettingOdds(date),
  mlb: (date) => mlbAdapter.getMLBBettingOdds(date),
};

const HAS_KEY = {
  nba: () => nbaAdapter.hasApiKey(),
  mlb: () => mlbAdapter.hasApiKey(),
};

/**
 * Parse `YYYYMMDD_AWAY@HOME` → { awayTeam, homeTeam }. Tank01 keys every
 * game this way. Falls back to nulls on an unexpected key.
 */
function teamsFromGameId(gameId) {
  const m = String(gameId || '').match(/_([A-Za-z0-9]+)@([A-Za-z0-9]+)/);
  if (!m) return { awayTeam: null, homeTeam: null };
  return { awayTeam: m[1], homeTeam: m[2] };
}

// Session 25 — Tank01's real shape (traced 2026-06-12) puts each
// sportsbook as a TOP-LEVEL key inside the game object, NOT inside a
// `sportsBooks` array:
//   { "20260612_ARI@CIN": {
//       awayTeam: "ARI", homeTeam: "CIN", gameID: "...",
//       bet365:  { homeTeamML: "-110", totalOver: "9.5", ... },
//       betmgm:  { ... }, caesars: { ... } } }
// These non-book keys must be excluded so they don't get treated as books.
const NON_BOOK_KEYS = new Set([
  'awayTeam', 'homeTeam', 'gameID', 'gameId', 'gameDate', 'gameTime',
  'gameStatus', 'gameStatusCode', 'teamIDAway', 'teamIDHome',
  'season', 'seasonType', 'last_updated_e_time', 'espnID', 'espnLink',
  'cbsLink', 'sportsBooks', 'books',
]);

/**
 * Normalize one sportsbook's raw odds object into a flat, UI-ready row.
 * Tank01 field names are verbose and vary across feeds — pull defensively,
 * tolerating both the MLB run-line and NBA spread spellings.
 */
function normalizeBook(odds) {
  if (!odds || typeof odds !== 'object' || Array.isArray(odds)) return null;
  const pick = (...keys) => {
    for (const k of keys) {
      if (odds[k] !== undefined && odds[k] !== null && odds[k] !== '') return odds[k];
    }
    return null;
  };
  return {
    homeML: pick('homeTeamML', 'homeTeamMLOdds', 'homeML', 'moneyLineHome'),
    awayML: pick('awayTeamML', 'awayTeamMLOdds', 'awayML', 'moneyLineAway'),
    total: pick('totalOver', 'totalUnder', 'total', 'overUnder'),
    overOdds: pick('totalOverOdds', 'overOdds'),
    underOdds: pick('totalUnderOdds', 'underOdds'),
    homeSpread: pick('homeTeamRunLine', 'homeTeamSpread', 'homeSpread'),
    awaySpread: pick('awayTeamRunLine', 'awayTeamSpread', 'awaySpread'),
    homeSpreadOdds: pick('homeTeamSpreadOdds', 'homeTeamRunLineOdds'),
    awaySpreadOdds: pick('awayTeamSpreadOdds', 'awayTeamRunLineOdds'),
  };
}

/**
 * Extract the books map from a single game object. Handles BOTH shapes:
 *   1. (current) sportsbooks as top-level keys on the game object
 *   2. (legacy) a `sportsBooks` array of { sportsBook, odds } entries
 * A book is only counted if it yields at least one real odds field, so a
 * stray non-book object key can't pollute the result.
 */
function extractBooks(game) {
  const books = {};

  // Shape 1 — top-level book keys.
  for (const [key, val] of Object.entries(game)) {
    if (NON_BOOK_KEYS.has(key)) continue;
    if (!val || typeof val !== 'object' || Array.isArray(val)) continue;
    const row = normalizeBook(val);
    if (row && Object.values(row).some((v) => v !== null)) {
      books[String(key).toLowerCase()] = row;
    }
  }

  // Shape 2 — legacy sportsBooks array (kept for backward compatibility).
  const sbList = game.sportsBooks || game.books;
  if (Array.isArray(sbList)) {
    for (const sb of sbList) {
      const name = sb?.sportsBook || sb?.book || sb?.name;
      const row = normalizeBook(sb?.odds || sb);
      if (name && row && Object.values(row).some((v) => v !== null)) {
        books[String(name).toLowerCase()] = row;
      }
    }
  }

  return books;
}

/**
 * Normalize the Tank01 betting-odds body (a map keyed by gameID) into the
 * route's `games` shape. Defensive against both the documented map form
 * and a bare array of game objects.
 */
function normalizeGameLines(body) {
  const games = {};
  if (!body || typeof body !== 'object') return games;

  const entries = Array.isArray(body)
    ? body.map((g) => [g.gameID || g.gameId, g])
    : Object.entries(body);

  for (const [gameId, game] of entries) {
    if (!gameId || !game || typeof game !== 'object') continue;
    const { awayTeam, homeTeam } = teamsFromGameId(gameId);
    games[gameId] = {
      homeTeam: game.homeTeam || homeTeam,
      awayTeam: game.awayTeam || awayTeam,
      books: extractBooks(game),
    };
  }
  return games;
}

router.get('/:sport', async (req, res) => {
  const sport = String(req.params.sport || '').toLowerCase();
  const date = req.query.date || scheduleService.todayET();

  const fetcher = FETCHERS[sport];
  if (!fetcher) {
    return res.status(404).set(MISSION_HEADER).json({ error: `No game lines for sport: ${sport}` });
  }

  // Missing RAPID_API_KEY → graceful empty, never a crash.
  if (HAS_KEY[sport] && !HAS_KEY[sport]()) {
    return res.set(MISSION_HEADER).json({ sport, date, games: {}, source: 'tank01', configured: false });
  }

  try {
    const body = await fetcher(date);
    const games = normalizeGameLines(body);
    return res.set(MISSION_HEADER).json({ sport, date, games, source: 'tank01' });
  } catch (err) {
    console.error(`[gamelines/${sport}]`, err.message);
    return res.set(MISSION_HEADER).json({ sport, date, games: {}, source: 'tank01' });
  }
});

module.exports = router;
module.exports.__internals = { teamsFromGameId, normalizeBook, normalizeGameLines, extractBooks };