source: src/main/java/agents/ai2014/group11/OpponentBidHistory.java@ 161

package agents.ai2014.group11;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map.Entry;

import genius.core.Bid;
import genius.core.issue.Issue;
import genius.core.issue.Value;

/**
 * This class saves the history of bids done by a single opponent.
 */
public class OpponentBidHistory {

        private ArrayList<BidSequence> bids;

        public OpponentBidHistory() {
                bids = new ArrayList<OpponentBidHistory.BidSequence>();
        }

        /**
         * Save a sequence of bids
         * @param previousBid
         * @param newBid
         */
        public void add(Bid previousBid, Bid newBid) {
                bids.add(new BidSequence(previousBid, newBid));
        }

        /**
         * @return the amount of bids in this history
         */
        public int getSize() {
                return bids.size();
        }

        /**
         * Try to determine what kind of strategy the opponent is using.
         * 
         * This is done by checking the difference in values between the 
         * opponent's current and the opponent's own last offer, 
         * and between the opponent's current and the overall last offer.
         * 
         * @return the strategy the opponent is most likely using.
         */
        public BidModificationStrategy getMostLikelyStrategy() {
                HashMap<BidModificationStrategy, Integer> counts = new HashMap<OpponentBidHistory.BidModificationStrategy, Integer>();

                if (bids.size() < 2) {
                        return BidModificationStrategy.UNKNOWN;
                } else {
                        for (int i = 1; i < bids.size(); i++) {
                                BidSequence bsCurrent = bids.get(i);
                                BidSequence bsPrevious = bids.get(i - 1);

                                double currentDistance = getBidDifference(bsCurrent.previous,
                                                bsCurrent.current);
                                double previousDistance = getBidDifference(bsPrevious.current,
                                                bsCurrent.current);

                                if (currentDistance == previousDistance) {
                                        Integer c = counts.get(BidModificationStrategy.UNKNOWN);
                                        int currentCount = c == null ? 0 : c;
                                        counts.put(BidModificationStrategy.UNKNOWN, currentCount++);
                                } else if (currentDistance < previousDistance) {
                                        Integer c = counts
                                                        .get(BidModificationStrategy.MODIFY_PREVIOUS);
                                        int currentCount = c == null ? 0 : c;
                                        counts.put(BidModificationStrategy.MODIFY_PREVIOUS,
                                                        currentCount++);
                                } else {
                                        Integer c = counts.get(BidModificationStrategy.MODIFY_SELF);
                                        int currentCount = c == null ? 0 : c;
                                        counts.put(BidModificationStrategy.MODIFY_SELF,
                                                        currentCount++);
                                }
                        }

                        int maxCount = 0;
                        BidModificationStrategy maxStrategy = BidModificationStrategy.UNKNOWN;

                        for (Entry<BidModificationStrategy, Integer> e : counts.entrySet()) {
                                if (e.getValue() > maxCount) {
                                        maxStrategy = e.getKey();
                                        maxCount = e.getValue();
                                }
                        }
                        return maxStrategy;
                }
        }

        /**
         * Get the amount of different values between two bids
         * 
         * @param bid1 Bid
         * @param bid2 Bid
         * @return the amount of different values between bid1 and bid2
         */
        private double getBidDifference(Bid bid1, Bid bid2) {
                HashMap<Integer, Boolean> counts = new HashMap<Integer, Boolean>();
                for (Issue i : bid1.getIssues()) {
                        try {
                                Value value1 = bid1.getValue(i.getNumber());
                                Value value2 = bid2.getValue(i.getNumber());
                                counts.put(i.getNumber(), value1 == value2);
                        } catch (Exception e) {
                                e.printStackTrace();
                        }
                }

                double differenceCount = 0;

                for (Entry<Integer, Boolean> e : counts.entrySet()) {
                        if (!e.getValue())
                                differenceCount += 1;
                }

                return differenceCount;
        }

        /**
         * There are three strategies defined, 
         * UNKNOWN (everything unclassified), 
         * MODIFY_SELF (using own bids) and
         * MODIFY_PREVIOUS (modify opponent bids more to your liking)
         */
        enum BidModificationStrategy {
                UNKNOWN, MODIFY_SELF, MODIFY_PREVIOUS
        }

        /**
         * Wrapper for two following bids
         */
        class BidSequence {
                Bid previous;
                Bid current;
                
                /**
                 * Wrapper for two following bids
                 */
                BidSequence(Bid previous, Bid current) {
                        this.previous = previous;
                        this.current = current;
                }
        }
}