/* ScummVM - Graphic Adventure Engine
 *
 * ScummVM is the legal property of its developers, whose names
 * are too numerous to list here. Please refer to the COPYRIGHT
 * file distributed with this source distribution.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

#include "sci/engine/features.h"
#include "sci/engine/hoyle5poker.h"
#include "sci/engine/kernel.h"
#include "sci/engine/script.h"
#include "sci/engine/selector.h"
#include "sci/engine/vm.h"

namespace Sci {

#ifdef ENABLE_SCI32

//#define DEBUG_POKER_LOGIC

// The logic for the poker game in Hoyle Classic Games (Hoyle 5) is hardcoded
// in PENGIN16.DLL, which is then loaded and invoked via the kWinDLL kernel call.
// Note that the first player is the left one.

enum Hoyle5PokerSuits {
	kSuitSpades = 0,
	kSuitClubs = 1,
	kSuitDiamonds = 2,
	kSuitHearts = 3
};

enum Hoyle5Operations {
	kCheckPlayerAction = 1, // localproc_0df8
	kCheckWinner = 2,       // localproc_3020
	kCheckDiscard = 3,      // PokerHand::think
	kCheckHand = 4          // PokerHand::whatAmI
};

enum Hoyle5PlayerActions {
	kPlayerActionCheck = -2,
	kPlayerActionFold = -1,
	kPlayerActionCall = 0,
	kPlayerActionRaise = 1
};

enum Hoyle5DiscardActions {
	kDiscardActionKeep = 0,
	kDiscardActionDiscard = 1
};

enum Hoyle5HandType {
	kHandTypeFiveOfAKind = 1 << 8,   // 256, five of a kind
	kHandTypeStraightFlush = 1 << 7, // 128, straight flush
	kHandTypeFourOfAKind = 1 << 6,   //  64, four of a kind
	kHandTypeFullHouse = 1 << 5,     //  32, full house
	kHandTypeFlush = 1 << 4,         //  16, flush
	kHandTypeStraight = 1 << 3,      //   8, straight
	kHandTypeThreeOfAKind = 1 << 2,  //   4, three of a kind
	kHandTypeTwoPairs = 1 << 1,      //   2, two pairs
	kHandTypeOnePair = 1 << 0,       //   1, one pair
	kHandTypeHighCard = 0            //   0, high card
};

enum Hoyle5PokerData {
	kOperation = 0,
	kTotalChips = 1,
	kCurrentPot = 2,
	kCurrentBet = 3,
	kTotalChipsPlayer1 = 4,
	kTotalChipsPlayer2 = 5,
	kTotalChipsPlayer3 = 6,
	kTotalChipsPlayer4 = 7,
	kStatusPlayer1 = 8,
	kStatusPlayer2 = 9,
	kStatusPlayer3 = 10,
	kStatusPlayer4 = 11,
	kTotalBetPlayer1 = 12,
	kTotalBetPlayer2 = 13,
	kTotalBetPlayer3 = 14,
	kTotalBetPlayer4 = 15,
	// 16: related to the current bet
	kCurrentPlayer = 17, // hand number
	kCurrentStage = 18,  // Stage 1: Card changes, 2: Betting
	kCard0 = 19,
	kSuit0 = 20,
	kCard1 = 21,
	kSuit1 = 22,
	kCard2 = 23,
	kSuit2 = 24,
	kCard3 = 25,
	kSuit3 = 26,
	kCard4 = 27,
	kSuit4 = 28,
	// 19 - 28: current player's cards (number + suit)
	// 29 - 38: next clockwise player's cards (number + suit)
	// 39 - 48: next clockwise player's cards (number + suit)
	// 49 - 58: next clockwise player's cards (number + suit)
	kUnkVar = 59, // set by localproc_0df8 to global 906
	// ---- Return values - start ---------------------------
	kPlayerAction = 60,   // flag, checked by localproc_0df8
	kWhatAmIResult = 61,  // bitmask, 0 - 128, checked by PokerHand::whatAmI. Determines what kind of card each player has
	kWinningPlayers = 62, // bitmask, winning players (0000 - 1111 binary), checked by localproc_3020
	kDiscardCard0 = 63,   // flag, checked by PokerHand::think
	kDiscardCard1 = 64,   // flag, checked by PokerHand::think
	kDiscardCard2 = 65,   // flag, checked by PokerHand::think
	kDiscardCard3 = 66,   // flag, checked by PokerHand::think
	kDiscardCard4 = 67,   // flag, checked by PokerHand::think
	// ---- Return values - end -----------------------------
	// 77 is a random number (0 - 32767)
	kLastRaise1 = 78,
	kLastRaise2 = 79,
	kLastRaise3 = 80,
	kLastRaise4 = 81,
	kLastSaw1 = 82,
	kLastSaw2 = 83,
	kLastSaw3 = 84,
	kLastSaw4 = 85,
	kTookCard1 = 86,
	kTookCard2 = 87,
	kTookCard3 = 88,
	kTookCard4 = 89
	// 90 is a number
};

#ifdef DEBUG_POKER_LOGIC
Common::String getCardDescription(int16 card, int16 suit) {
	Common::String result;

	if (card >= 2 && card <= 10)
		result += Common::String::format("%d", card);
	else if (card == 11)
		result = "Jack";
	else if (card == 12)
		result = "Queen";
	else if (card == 13)
		result = "King";
	else if (card == 14)
		result = "Ace";
	else
		result = "Unknown";

	switch (suit) {
	case kSuitSpades:
		return result + " of spades";
	case kSuitClubs:
		return result + " of clubs";
	case kSuitDiamonds:
		return result + " of diamonds";
	case kSuitHearts:
		return result + " of hearts";
	default:
		return result + " of unknown";
	}
}

void debugInputData(SciArray* data) {
	debug("Player %d's turn", data->getAsInt16(kCurrentPlayer));

	debug("Pot: %d, bet: %d", data->getAsInt16(kCurrentPot), data->getAsInt16(kCurrentBet));

	debug("Chips: %d %d %d %d - %d in total",
		data->getAsInt16(kTotalChipsPlayer1),
		data->getAsInt16(kTotalChipsPlayer2),
		data->getAsInt16(kTotalChipsPlayer3),
		data->getAsInt16(kTotalChipsPlayer4),
		data->getAsInt16(kTotalChips)
	);

	debug("Player status: %d %d %d %d",
		data->getAsInt16(kStatusPlayer1),
		data->getAsInt16(kStatusPlayer2),
		data->getAsInt16(kStatusPlayer3),
		data->getAsInt16(kStatusPlayer4)
	);

	for (int player = 0; player < 4; player++) {
		debug("Player %d cards:", player);
		for (int i = 19 + player * 10; i < 29 + player * 10; i += 2) {
			if (data->getAsInt16(i) > 0)
				debug("- %s", getCardDescription(data->getAsInt16(i), data->getAsInt16(i + 1)).c_str());
		}
	}

	for (int i = 0; i < data->size(); i++) {
		if (i >= kTotalChipsPlayer1 && i <= kTotalChipsPlayer4)
			continue;
		if (i >= 8 && i <= 11)
			continue;
		if (i >= 19 && i <= 58)
			continue;

		if (data->getAsInt16(i) != 0)
			debug("%d: %d", i, data->getAsInt16(i));
	}
}

#endif

int getCardValue(int card) {
	return card == 1 ? 14 : card; // aces are the highest valued cards
}

int getCardTotal(SciArray *data, int player) {
	int result = 0;

	int cards[5] = {
		getCardValue(data->getAsInt16(kCard0 + 10 * player)),
		getCardValue(data->getAsInt16(kCard1 + 10 * player)),
		getCardValue(data->getAsInt16(kCard2 + 10 * player)),
		getCardValue(data->getAsInt16(kCard3 + 10 * player)),
		getCardValue(data->getAsInt16(kCard4 + 10 * player)),
	};

	Common::sort(cards, cards + 5, Common::Less<int>());

	int sameRank = 0;
	int sameSuit = 0;
	int orderedCards = 0;

	for (int i = 0; i < 4; i++) {
		if (cards[i] == cards[i + 1]) {
			if (sameRank == 0) {
				result += cards[i] + cards[i + 1];
				sameRank += 2;
			} else {
				result += cards[i + 1];
				sameRank++;
			}
		}
		if (cards[i] == cards[i + 1] - 1)
			orderedCards == 0 ? orderedCards += 2 : orderedCards++;
	}

	bool isFullHouse =
		(cards[0] == cards[1] && cards[1] == cards[2] && cards[3] == cards[4]) ||
		(cards[0] == cards[1] && cards[2] == cards[3] && cards[3] == cards[4]);

	if (isFullHouse || sameSuit == 5 || orderedCards == 5) {
		result = 0;

		for (int i = 0; i < 5; i++)
			result += cards[i];
	}

	return result;
}

// Checks a player's hand, and returns its type using a bitmask
int checkHand(SciArray *data, int player = 0) {
	int cards[5] = {
		data->getAsInt16(kCard0 + 10 * player),
		data->getAsInt16(kCard1 + 10 * player),
		data->getAsInt16(kCard2 + 10 * player),
		data->getAsInt16(kCard3 + 10 * player),
		data->getAsInt16(kCard4 + 10 * player),
	};

	int suits[5] = {
		data->getAsInt16(kSuit0 + 10 * player),
		data->getAsInt16(kSuit1 + 10 * player),
		data->getAsInt16(kSuit2 + 10 * player),
		data->getAsInt16(kSuit3 + 10 * player),
		data->getAsInt16(kSuit4 + 10 * player),
	};

	Common::sort(cards, cards + 5, Common::Less<int>());

	int lastCard = -1;
	int pairs = 0;
	int sameRank = 0;
	int sameSuit = 0;
	int orderedCards = 0;

	for (int i = 0; i < 4; i++) {
		if (cards[i] == cards[i + 1] && cards[i] != lastCard)
			pairs++;
		if (cards[i] == cards[i + 1])
			sameRank == 0 ? sameRank += 2 : sameRank++;
		if (suits[i] == suits[i + 1])
			sameSuit == 0 ? sameSuit += 2 : sameSuit++;
		if (cards[i] == cards[i + 1] - 1)
			orderedCards == 0 ? orderedCards += 2 : orderedCards++;

		lastCard = cards[i];
	}

	bool isFullHouse =
		(cards[0] == cards[1] && cards[1] == cards[2] && cards[3] == cards[4]) ||
		(cards[0] == cards[1] && cards[2] == cards[3] && cards[3] == cards[4]);

	if (pairs == 1 && sameRank == 2)
		return kHandTypeOnePair;
	else if (pairs == 2 && !isFullHouse)
		return kHandTypeTwoPairs;
	else if (sameRank == 3 && !isFullHouse)
		return kHandTypeThreeOfAKind;
	else if (orderedCards == 5 && sameSuit < 5)
		return kHandTypeStraight;
	else if (orderedCards < 5 && sameSuit == 5)
		return kHandTypeFlush;
	else if (isFullHouse)
		return kHandTypeFullHouse;
	else if (sameRank == 4)
		return kHandTypeFourOfAKind;
	else if (orderedCards == 5 && sameSuit == 5)
		return kHandTypeStraightFlush;
	else if (sameRank == 5)
		return kHandTypeFiveOfAKind;

	return kHandTypeHighCard;
}

struct Hand {
	int player;
	int handTotal;

	Hand(int p, int h) : player(p), handTotal(h) {}
};

struct WinningHand : public Common::BinaryFunction<Hand, Hand, bool> {
	bool operator()(const Hand &x, const Hand &y) const { return x.handTotal > y.handTotal; }
};

int getWinner(SciArray *data) {
	Hand playerHands[4] = {
		Hand(0, checkHand(data, 0)),
		Hand(1, checkHand(data, 1)),
		Hand(2, checkHand(data, 2)),
		Hand(3, checkHand(data, 3))
	};

	Common::sort(playerHands, playerHands + 4, WinningHand());

	if (playerHands[0].handTotal > playerHands[1].handTotal)
		return playerHands[0].player;
	else
		return getCardTotal(data, 0) > getCardTotal(data, 1) ? playerHands[0].player : playerHands[1].player;
}

int16 findMostFrequentCard(int *cards, int16 ignoreCard = -1) {
	int16 mostFrequentCard = 0;
	int16 maxCount = 0;

	for (int16 i = 0; i <= 4; ++i) {
		int16 count = 0;
		for (int j = 0; j <= 4; ++j) {
			if (cards[i] == cards[j])
				count++;
		}

		if (count > maxCount && cards[i] != ignoreCard) {
			maxCount = count;
			mostFrequentCard = cards[i];
		}
	}

	return mostFrequentCard;
}

void handleDiscard(SciArray *data) {
	int16 player = data->getAsInt16(kCurrentPlayer);

	int cards[5] = {
		data->getAsInt16(kCard0 + 10 * player),
		data->getAsInt16(kCard1 + 10 * player),
		data->getAsInt16(kCard2 + 10 * player),
		data->getAsInt16(kCard3 + 10 * player),
		data->getAsInt16(kCard4 + 10 * player),
	};

	int hand = checkHand(data, player);
	int16 cardToKeep = findMostFrequentCard(cards);
	int16 cardToKeep2 = -1;
	if (hand != kHandTypeFiveOfAKind) {
		cardToKeep2 = findMostFrequentCard(cards, cardToKeep);
	}

	data->setFromInt16(kDiscardCard0, kDiscardActionKeep);
	data->setFromInt16(kDiscardCard1, kDiscardActionKeep);
	data->setFromInt16(kDiscardCard2, kDiscardActionKeep);
	data->setFromInt16(kDiscardCard3, kDiscardActionKeep);
	data->setFromInt16(kDiscardCard4, kDiscardActionKeep);

	switch (hand) {
	case kHandTypeFiveOfAKind:
	case kHandTypeStraightFlush:
	case kHandTypeFullHouse:
	case kHandTypeFlush:
	case kHandTypeStraight:
		// Nothing is discarded
		break;
	case kHandTypeThreeOfAKind:
	case kHandTypeFourOfAKind:
	case kHandTypeOnePair:
	case kHandTypeTwoPairs:
		// Discard the odd ones out. We don't have a full house case in this branch
		for (int i = 0; i <= 4; ++i) {
			if (cards[i] == cardToKeep && hand != kHandTypeTwoPairs)
				data->setFromInt16(kDiscardCard0 + i, kDiscardActionKeep);
			else if ((cards[i] == cardToKeep || cards[i] == cardToKeep2) && hand == kHandTypeTwoPairs)
				data->setFromInt16(kDiscardCard0 + i, kDiscardActionKeep);
			else
				data->setFromInt16(kDiscardCard0 + i, kDiscardActionDiscard);
		}
		break;
	case kHandTypeHighCard:
		// Everything is discarded
		data->setFromInt16(kDiscardCard0, kDiscardActionDiscard);
		data->setFromInt16(kDiscardCard1, kDiscardActionDiscard);
		data->setFromInt16(kDiscardCard2, kDiscardActionDiscard);
		data->setFromInt16(kDiscardCard3, kDiscardActionDiscard);
		data->setFromInt16(kDiscardCard4, kDiscardActionDiscard);
		break;
	}
}

void handleRaiseOrCall(SciArray *data) {
	// Raise if the player has money, call otherwise
	int16 player = data->getAsInt16(kCurrentPlayer);
	int16 bet = data->getAsInt16(kCurrentBet);
	int16 playerBet = data->getAsInt16(kTotalBetPlayer1 + player);
	int16 chips = data->getAsInt16(kTotalChipsPlayer1 + player);
	
	if (playerBet < bet && chips > bet)
		data->setFromInt16(kPlayerAction, kPlayerActionRaise);
	else
		data->setFromInt16(kPlayerAction, kPlayerActionCall);
}

void handlePlayerAction(SciArray *data) {
	// TODO: This implementation is somewhat better than completely
	// random actions, but it's still severely lacking
	warning("The Poker player action logic has not been implemented yet");

	int16 player = data->getAsInt16(kCurrentPlayer);
	int hand = checkHand(data, player);
	bool shouldBluff = g_sci->getRNG().getRandomBit();

	if (shouldBluff) {
		handleRaiseOrCall(data);
		return;
	}

	switch (hand) {
	case kHandTypeFiveOfAKind:
	case kHandTypeStraightFlush:
	case kHandTypeFullHouse:
	case kHandTypeFlush:
	case kHandTypeStraight:
	case kHandTypeThreeOfAKind:
	case kHandTypeFourOfAKind:
	case kHandTypeTwoPairs:
		handleRaiseOrCall(data);
		break;
	case kHandTypeOnePair:
		data->setFromInt16(kPlayerAction, kPlayerActionCall);
		break;
	case kHandTypeHighCard:
		data->setFromInt16(kPlayerAction, kPlayerActionFold);
		// TODO: kPlayerActionCheck
		break;
	}
}

reg_t hoyle5PokerEngine(SciArray *data) {
	int16 operation = data->getAsInt16(kOperation);

#ifdef DEBUG_POKER_LOGIC
	debug("*** Before running operation %d", operation);
	debugInputData(data);
#endif

	switch (operation) {
	case kCheckPlayerAction:
		handlePlayerAction(data);
		break;
	case kCheckWinner:
		data->setFromInt16(kWinningPlayers, 1 << getWinner(data));
		break;
	case kCheckDiscard:
		handleDiscard(data);
		break;
	case kCheckHand:
		data->setFromInt16(kWhatAmIResult, checkHand(data));
		break;
	default:
		error("Unknown Poker logic operation: %d", operation);
		break;
	}

#ifdef DEBUG_POKER_LOGIC
	debug("*** After running operation %d", operation);
	debugInputData(data);
#endif

	return TRUE_REG;
}

#endif

}