/**
* Get legal plays per straight game play. Needs played cards for the round.
*/
Cards Player::getLegalPlays(Cards cardsOnTable) const {
Cards legalPlays;
Card firstCard = Card(SPADE, SEVEN);
// Outer loop: current cards in hand
for (int i = 0; i < getCurrentCards().size(); i++) {
bool isLegalPlay = false;
// Only legal card is 7S if there is a 7S on your hand
if (*getCurrentCards().at(i) == firstCard) {
legalPlays.clear();
legalPlays.push_back(getCurrentCards().at(i));
return legalPlays;
// Legal if card is a 7
} else if (getCurrentCards().at(i)->getRank() == SEVEN) {
isLegalPlay = true;
// If card in hand has same suit and is +/- 1 rank of a played card, then it is legal
} else {
for (int j = 0; j < cardsOnTable.size(); j++) {
if (cardsOnTable.at(j)->getSuit() == getCurrentCards().at(i)->getSuit()
&& abs((int) cardsOnTable.at(j)->getRank() - (int) getCurrentCards().at(i)->getRank()) <= 1) {
isLegalPlay = true;
}
}
}
if (isLegalPlay) {
legalPlays.push_back(getCurrentCards().at(i));
}
}
return legalPlays;
}
Card NoddyAi::play_card() {
Cards legal = legal_plays();
assert(!legal.empty());
std::uniform_int_distribution<size_t> card_chooser(0, legal.size()-1);
size_t which = card_chooser(random_engine_);
Cards::iterator i = legal.begin();
std::advance(i, which);
return *i;
}
Card DefenceAi::play_card(FateAi const& ai) {
// TODO: Rethink this function for partnership contracts
Trick const& trick = ai.tricks().back();
//Cards const& hand = ai.hand();
Cards const plays = ai.legal_plays();
boost::optional<Card> bird = ai.relevant_bird();
// If there's only one legal play, play it
if (plays.size() == 1) {
return *plays.begin();
}
if (trick.played() == 0) {
// We're leading
if (guess_master_defender_) {
// Lead a long suit
for (SuitProfiles::reverse_iterator it = suit_profiles_.rbegin();
it != suit_profiles_.rend(); ++it) {
if (it->suit == Suit::trumps) continue;
auto playable = plays.equal_range(it->suit);
if (!boost::empty(playable)) {
return *playable.first;
}
}
} else {
// Lead a short suit
for (SuitProfiles::iterator it = suit_profiles_.begin();
it != suit_profiles_.end(); ++it) {
if (it->suit == Suit::trumps) continue;
auto playable = plays.equal_range(it->suit);
if (!boost::empty(playable)) {
return *playable.first;
}
}
}
// At this point we must be playing trumps; play low
assert(plays.begin()->trump());
auto candidate = plays.begin();
// Avoid leading a bird that might cause us to lose game points
if (bird && *candidate == *bird) ++candidate;
return *candidate;
} else {
// We're following
Suit s = trick.suit();
bool const playing_trump = plays.begin()->trump();
bool const roughing = playing_trump && s != Suit::trump;
const int declarers_position_in_trick =
(ai.declarer() - trick.leader() + 4)%4;
const bool declarer_has_played =
trick.played() > declarers_position_in_trick;
if (declarer_has_played) {
bool const declarer_is_winning =
trick.winner() == ai.declarer();
if (declarer_is_winning) {
auto winning_play = plays.lower_bound(trick.winning_card());
if (winning_play != plays.end() && !winning_play->trump() &&
winning_play->suit() != s) {
winning_play = plays.end();
}
if (roughing) {
// If I'm last to play then make an effort to win
if (trick.played() == 3 && winning_play != plays.end()) {
return *winning_play;
}
// Otherwise just play low
return *plays.begin();
} else if (playing_trump) {
// Following in trumps
if (winning_play != plays.end()) {
// Win minimally
return *winning_play;
} else {
// Can't win; play low
return *plays.begin();
}
} else {
// Declarer is winning and I'm following suit or discarding
if (winning_play != plays.end()) {
// We can win in a side suit; play card worth most points, or least
// valuable winning pip card
auto most_points = std::max_element(
winning_play, plays.end(), Card::CompareRanksReversePips()
);
return *most_points;
}
// Can't win, so play low
/** \bug Discarding something valuable sometimes under these
* circumstances is pretty vital */
auto smallest_rank = std::min_element(
plays.begin(), plays.end(), Card::CompareSuitRanks()
);
return *smallest_rank;
}
} else {
if (roughing) {
// Play smallest trump
return *plays.begin();
} else if (playing_trump) {
// I'm following in trumps, but the defense is already going to win,
// so just play low
/** \bug Really person before declarer should deliberately beat
* the other defenders sometimes */
return *plays.begin();
} else {
// Play card worth most points, or least valuable pip card
auto most_points = std::max_element(
plays.begin(), plays.end(), Card::CompareRanksReversePips()
);
return *most_points;
}
}
} else {
// Declarer hasn't played yet.
bool const defence_will_win =
ai.guaranteed_to_win_against(trick.winning_card(), ai.declarer());
if (defence_will_win) {
if (playing_trump) {
// We're winning anyway, so play a low trump
return *plays.begin();
} else {
// Play something worth points
auto most_points = std::max_element(
plays.begin(), plays.end(), Card::CompareRanksReversePips()
);
return *most_points;
}
} else {
// Defence not guaranteed to win, so declarer probably will. Play
// something worthless
if (playing_trump) {
return *plays.begin();
} else {
return *boost::range::min_element(
plays, Card::CompareSuitRanks()
);
}
}
}
}
KONIG_FATAL("unimplimented (" << ai.tricks().size() << "): " << trick);
}