/**
 * highscore.js
 * High-score screen: displays final score(s), persists top-10 to localStorage,
 * shows leaderboard, offers back-to-start button.
 *
 * show(names, scores, playerCount)
 *   names  — string (1P) or array of strings (2P)
 *   scores — number (1P) or array of numbers (2P)
 *   playerCount — 1 or 2
 */

const HighScoreScreen = (() => {

  const STORAGE_KEY = 'kidneylab_scores';

  /* ── Persistence ─────────────────────────────────────────────── */

  function loadScores() {
    try {
      return JSON.parse(localStorage.getItem(STORAGE_KEY)) || [];
    } catch {
      return [];
    }
  }

  function saveScore(name, score) {
    const scores = loadScores();
    scores.push({ name: name.toUpperCase().slice(0, 12), score, date: new Date().toLocaleDateString() });
    scores.sort((a, b) => b.score - a.score);
    const top10 = scores.slice(0, 10);
    localStorage.setItem(STORAGE_KEY, JSON.stringify(top10));
    return top10;
  }

  /* ── Helpers ─────────────────────────────────────────────────── */

  function rankLabel(rank) {
    if (rank === 1) return '🏆 NEW HIGH SCORE!';
    if (rank === 2) return '🥈 2nd place!';
    if (rank === 3) return '🥉 3rd place!';
    return `Rank #${rank}`;
  }

  function resultCardHTML(playerName, finalScore, scores, myRank) {
    const isTop = myRank === 1;
    return `
      <div class="hs-result ${isTop ? 'hs-gold' : ''}">
        <div class="hs-rank-label">${rankLabel(myRank)}</div>
        <div class="hs-player">${playerName.toUpperCase()}</div>
        <div class="hs-score-display">${finalScore >= 0 ? finalScore : 0}</div>
        <div class="hs-score-label">POINTS</div>
      </div>`;
  }

  function tableHTML(scores, highlightNames, highlightScores) {
    const rowsHTML = scores.map((s, i) => {
      // highlight any entry that matches one of the just-played players
      const isMe = highlightNames.some((n, ni) =>
        s.name === n.toUpperCase().slice(0, 12) && s.score === highlightScores[ni]
      );
      return `<tr class="${isMe ? 'my-row' : ''}">
        <td class="rank-col">${i + 1}</td>
        <td class="name-col">${s.name}</td>
        <td class="score-col">${s.score}</td>
        <td class="date-col">${s.date}</td>
      </tr>`;
    }).join('');

    return `
      <div class="hs-table-wrap">
        <h2 class="hs-heading">HALL OF FAME</h2>
        <table class="hs-table">
          <thead><tr><th>#</th><th>NAME</th><th>SCORE</th><th>DATE</th></tr></thead>
          <tbody>${rowsHTML}</tbody>
        </table>
      </div>`;
  }

  /* ── Public show ─────────────────────────────────────────────── */

  function show(names, scores, playerCount) {
    // Normalise to arrays
    const nameArr  = Array.isArray(names)  ? names  : [names];
    const scoreArr = Array.isArray(scores) ? scores : [scores];
    const count    = playerCount || nameArr.length;

    // Switch screen
    document.querySelectorAll('.screen').forEach(s => s.classList.remove('active'));
    document.getElementById('highscore-screen').classList.add('active');

    // Save all players' scores; last save wins for the leaderboard table
    let leaderboard;
    nameArr.forEach((n, i) => {
      leaderboard = saveScore(n, scoreArr[i]);
    });

    // Build rank info for each player
    const rankInfo = nameArr.map((n, i) => {
      const rank = leaderboard.findIndex(
        s => s.name === n.toUpperCase().slice(0, 12) && s.score === scoreArr[i]
      ) + 1;
      return { name: n, score: scoreArr[i], rank };
    });

    render(rankInfo, leaderboard, nameArr, scoreArr);
  }

  function render(rankInfo, leaderboard, nameArr, scoreArr) {
    const el = document.getElementById('highscore-screen');

    // One result card per player
    const cardsHTML = rankInfo.map(r =>
      resultCardHTML(r.name, r.score, leaderboard, r.rank)
    ).join('');

    // Cards side-by-side for 2P, centred for 1P
    const cardsWrap = rankInfo.length > 1
      ? `<div style="display:flex;gap:16px;justify-content:center;flex-wrap:wrap;">${cardsHTML}</div>`
      : cardsHTML;

    el.innerHTML = `
      <div class="hs-inner">
        <div class="hs-logo">
          <span class="logo-gw">GAME &amp; WATCH</span>
          <span class="logo-title">KIDNEY LAB</span>
        </div>

        ${cardsWrap}

        ${tableHTML(leaderboard, nameArr, scoreArr)}

        <div class="hs-actions">
          <button id="back-btn" class="btn-primary">PLAY AGAIN</button>
        </div>
      </div>
    `;

    el.querySelector('#back-btn').addEventListener('click', () => {
      IntroScreen.show();
    });
  }

  return { show };
})();