fertig-classic-games/public/src/games/blackjack/BlackjackLogic.js

// Blackjack pure game logic — no Phaser dependencies

import { SUITS, RANKS } from '../cards/Deck.js';

// ─── Shoe ─────────────────────────────────────────────────────────────────────

const RANK_VALUE = {
  '2':2,'3':3,'4':4,'5':5,'6':6,'7':7,'8':8,'9':9,'T':10,'J':10,'Q':10,'K':10,'A':11,
};

function makeCard(rank, suit) {
  return {
    rank, suit,
    value: RANK_VALUE[rank],
    label: rank === 'T' ? '10' : rank,
    isRed: suit === 'h' || suit === 'd',
    suitSymbol: { s:'♠', h:'♥', d:'♦', c:'♣' }[suit],
    key: `${rank}${suit}`,
  };
}

export function buildShoe(numDecks = 6) {
  const cards = [];
  for (let d = 0; d < numDecks; d++) {
    for (const suit of SUITS) {
      for (const rank of RANKS) {
        cards.push(makeCard(rank, suit));
      }
    }
  }
  for (let i = cards.length - 1; i > 0; i--) {
    const j = Math.floor(Math.random() * (i + 1));
    [cards[i], cards[j]] = [cards[j], cards[i]];
  }
  return cards;
}

// ─── Hand evaluation ──────────────────────────────────────────────────────────

export function handValue(cards) {
  let total = 0;
  let aces = 0;
  for (const c of cards) {
    if (c.rank === 'A') { aces++; total += 11; }
    else total += Math.min(c.value, 10);
  }
  while (total > 21 && aces > 0) { total -= 10; aces--; }
  return { score: total, soft: aces > 0 && total <= 21 };
}

export function isBlackjack(hand) {
  return hand.length === 2 && handValue(hand).score === 21;
}

export function isBust(hand) {
  return handValue(hand).score > 21;
}

export function canDouble(player) {
  const hand = player.activeHand === 1 ? player.hand2 : player.hand;
  return (hand ?? []).length === 2;
}

export function canSplit(player) {
  return (
    player.hand.length === 2 &&
    player.hand[0].rank === player.hand[1].rank &&
    !player.hand2
  );
}

// ─── State creation ───────────────────────────────────────────────────────────

export function createInitialState(opponents, chips) {
  const players = [
    {
      seat: 0, name: 'You', isHuman: true, active: true, opponent: null,
      chips, bet: 0, bet2: null,
      hand: [], hand2: null,
      doubled: false, doubled2: false,
      insuranceBet: 0,
      activeHand: 0,
      status: 'waiting', status2: null,
      result: null, result2: null, chipsWon: 0,
    },
  ];

  for (let i = 0; i < 6; i++) {
    const opp = opponents[i] ?? null;
    players.push({
      seat: i + 1, name: opp?.name ?? '', isHuman: false, active: !!opp, opponent: opp,
      chips: 1000, bet: 0, bet2: null,
      hand: [], hand2: null,
      doubled: false, doubled2: false,
      insuranceBet: 0,
      activeHand: 0,
      status: 'waiting', status2: null,
      result: null, result2: null, chipsWon: 0,
    });
  }

  return {
    phase: 'betting',
    dealer: { hand: [], revealed: false },
    players,
    currentSeat: 0,
    insurancePending: false,
    roundNumber: 0,
  };
}

// ─── Round start ──────────────────────────────────────────────────────────────

export function prepareRound(gs) {
  const players = gs.players.map(p => ({
    ...p,
    bet: 0, bet2: null,
    hand: [], hand2: null,
    doubled: false, doubled2: false,
    insuranceBet: 0,
    activeHand: 0,
    status: p.active ? 'waiting' : 'waiting',
    status2: null,
    result: null, result2: null, chipsWon: 0,
  }));
  return {
    ...gs,
    phase: 'betting',
    dealer: { hand: [], revealed: false },
    players,
    currentSeat: 0,
    insurancePending: false,
    roundNumber: gs.roundNumber + 1,
  };
}

export function applyBet(gs, seat, amount) {
  const players = gs.players.map(p => p.seat === seat ? { ...p, bet: amount } : p);
  return { ...gs, players };
}

// Deal all cards into state from the shoe (shoe is mutated).
// Returns new gs with hands populated, phase set appropriately.
export function dealAllCards(gs, shoe) {
  const players = gs.players.map(p => ({ ...p }));
  const dealer = { hand: [], revealed: false };

  // Standard deal order: each player card 1, dealer upcard, each player card 2, dealer hole
  const activePlayers = players.filter(p => p.active);

  // Round 1
  for (const p of activePlayers) p.hand.push(shoe.pop());
  dealer.hand.push(shoe.pop()); // upcard (index 0)

  // Round 2
  for (const p of activePlayers) p.hand.push(shoe.pop());
  dealer.hand.push(shoe.pop()); // hole card (index 1)

  // Detect player blackjacks immediately
  for (const p of activePlayers) {
    if (isBlackjack(p.hand)) p.status = 'blackjack';
  }

  const firstActiveSeat = activePlayers[0]?.seat ?? 0;
  const dealerUpcard = dealer.hand[0];
  const insurancePending = dealerUpcard.rank === 'A';

  return {
    ...gs,
    phase: insurancePending ? 'insurance' : 'player_turn',
    dealer,
    players,
    currentSeat: firstActiveSeat,
    insurancePending,
  };
}

// ─── Insurance ────────────────────────────────────────────────────────────────

export function applyInsurance(gs, seat, accept) {
  const players = gs.players.map(p => {
    if (p.seat !== seat) return p;
    const insuranceBet = accept ? Math.floor(p.bet / 2) : 0;
    return { ...p, insuranceBet };
  });
  return { ...gs, players };
}

// After all insurance decisions: check dealer blackjack
export function resolveInsurance(gs) {
  const dealerBJ = isBlackjack(gs.dealer.hand);
  const players = gs.players.map(p => {
    if (!p.active || p.insuranceBet === 0) return p;
    // Insurance bet: pays 2:1 if dealer has BJ, else lost
    const insuranceResult = dealerBJ ? p.insuranceBet * 2 : -p.insuranceBet;
    return { ...p, chipsWon: (p.chipsWon ?? 0) + insuranceResult };
  });
  return { ...gs, players, insurancePending: false };
}

// ─── Player actions ───────────────────────────────────────────────────────────

export function applyHit(gs, seat, shoe) {
  const players = gs.players.map(p => {
    if (p.seat !== seat) return p;
    const isH2 = p.activeHand === 1;
    const newCard = shoe.pop();
    if (isH2) {
      const hand2 = [...p.hand2, newCard];
      const bust = isBust(hand2);
      return { ...p, hand2, status2: bust ? 'bust' : 'playing' };
    } else {
      const hand = [...p.hand, newCard];
      const bust = isBust(hand);
      return { ...p, hand, status: bust ? 'bust' : 'playing' };
    }
  });
  return { ...gs, players };
}

export function applyStand(gs, seat) {
  const players = gs.players.map(p => {
    if (p.seat !== seat) return p;
    if (p.activeHand === 1) return { ...p, status2: 'standing' };
    // If split exists and hand 1 not yet played, move to hand 2
    if (p.hand2 !== null && p.status2 === null) return { ...p, status: 'standing', activeHand: 1 };
    return { ...p, status: 'standing' };
  });
  return { ...gs, players };
}

export function applyDouble(gs, seat, shoe) {
  const players = gs.players.map(p => {
    if (p.seat !== seat) return p;
    const isH2 = p.activeHand === 1;
    const newCard = shoe.pop();
    if (isH2) {
      const hand2 = [...p.hand2, newCard];
      const bust = isBust(hand2);
      return { ...p, hand2, bet2: p.bet2 * 2, doubled2: true, status2: bust ? 'bust' : 'standing' };
    } else {
      const hand = [...p.hand, newCard];
      const bust = isBust(hand);
      const doubled = true;
      // If split exists and not yet played hand 2
      if (p.hand2 !== null && p.status2 === null) {
        return { ...p, hand, bet: p.bet * 2, doubled, status: bust ? 'bust' : 'standing', activeHand: 1 };
      }
      return { ...p, hand, bet: p.bet * 2, doubled, status: bust ? 'bust' : 'standing' };
    }
  });
  return { ...gs, players };
}

export function applySplit(gs, seat, shoe) {
  const players = gs.players.map(p => {
    if (p.seat !== seat) return p;
    const [c1, c2] = p.hand;
    const hand = [c1, shoe.pop()];
    const hand2 = [c2, shoe.pop()];
    const isAceSplit = c1.rank === 'A';
    // Ace splits: each hand gets one card only, immediately stands
    return {
      ...p,
      hand, hand2,
      bet2: p.bet,
      doubled: false, doubled2: false,
      status: isAceSplit ? 'standing' : 'playing',
      status2: isAceSplit ? 'standing' : null,
      activeHand: 0,
    };
  });
  return { ...gs, players };
}

// ─── Dealer turn ──────────────────────────────────────────────────────────────

// Returns new gs with dealer hand fully played out. shoe is mutated.
export function runDealerTurn(gs, shoe) {
  const dealer = { ...gs.dealer, revealed: true };
  while (true) {
    const { score } = handValue(dealer.hand);
    if (score >= 17) break;
    dealer.hand = [...dealer.hand, shoe.pop()];
  }
  return { ...gs, phase: 'resolved', dealer };
}

// ─── Resolve round ────────────────────────────────────────────────────────────

export function resolveRound(gs) {
  const { score: dealerScore } = handValue(gs.dealer.hand);
  const dealerBJ = isBlackjack(gs.dealer.hand);
  const dealerBust = dealerScore > 21;

  const players = gs.players.map(p => {
    if (!p.active) return p;

    function resolveHand(hand, bet, status, doubled) {
      if (!hand || hand.length === 0) return { result: null, net: 0 };
      const { score: playerScore } = handValue(hand);
      const playerBJ = isBlackjack(hand);

      if (status === 'bust') return { result: 'lose', net: -bet };
      if (playerBJ && dealerBJ) return { result: 'push', net: 0 };
      if (playerBJ) return { result: 'blackjack', net: Math.floor(bet * 1.5) }; // 3:2
      if (dealerBJ) return { result: 'lose', net: -bet };
      if (dealerBust) return { result: 'win', net: bet };
      if (playerScore > dealerScore) return { result: 'win', net: bet };
      if (playerScore === dealerScore) return { result: 'push', net: 0 };
      return { result: 'lose', net: -bet };
    }

    const h1 = resolveHand(p.hand, p.bet, p.status, p.doubled);
    const h2 = p.hand2 ? resolveHand(p.hand2, p.bet2, p.status2, p.doubled2) : { result: null, net: 0 };

    const totalNet = h1.net + h2.net + (p.chipsWon ?? 0); // chipsWon may have insurance delta
    const newChips = p.chips + totalNet;

    return {
      ...p,
      chips: newChips,
      result: h1.result,
      result2: h2.result,
      chipsWon: totalNet,
    };
  });

  return { ...gs, phase: 'resolved', players };
}

// ─── Turn advancement ─────────────────────────────────────────────────────────

// Returns the seat number of the next player who still needs to act, or null if done.
export function nextActiveSeat(gs) {
  const activePlayers = gs.players.filter(p => p.active);
  const currentIdx = activePlayers.findIndex(p => p.seat === gs.currentSeat);
  for (let i = currentIdx + 1; i < activePlayers.length; i++) {
    const p = activePlayers[i];
    if (p.status === 'playing' || p.status === 'waiting') return p.seat;
  }
  return null; // dealer's turn
}

export function isPlayerDone(player) {
  // Hand 1 is done
  const h1done = ['standing','bust','blackjack','done'].includes(player.status);
  // Hand 2 (if split): must also be done
  const h2done = player.hand2 === null || ['standing','bust','blackjack','done'].includes(player.status2);
  return h1done && h2done;
}