package geniusweb.profile;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.Set;

import com.fasterxml.jackson.annotation.JsonAutoDetect;
import com.fasterxml.jackson.annotation.JsonAutoDetect.Visibility;
import com.fasterxml.jackson.annotation.JsonCreator;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.databind.DeserializationContext;
import com.fasterxml.jackson.databind.JsonSerializer;
import com.fasterxml.jackson.databind.KeyDeserializer;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializerProvider;
import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
import com.fasterxml.jackson.databind.annotation.JsonSerialize;

import geniusweb.issuevalue.Bid;
import geniusweb.issuevalue.Domain;

/**
 * Strange that we need to do this. Bid is completely standard. The complication
 * that this solves is that the keys are places as STRING in the json code
 * because json allows only strings as key.
 */
@SuppressWarnings("serial")
class BidDeserializer extends KeyDeserializer {
	private ObjectMapper jackson = new ObjectMapper();

	@Override
	public Bid deserializeKey(String key, DeserializationContext ctxt)
			throws IOException {
		return jackson.readValue(key, Bid.class);
	}

}

/**
 * Serializes a Bid to string. Unfortunately by default jackson uses
 * key.toString() for serializing (rather than
 * {@link ObjectMapper#writeValueAsString(Object)}).
 *
 */
class BidSerializer extends JsonSerializer<Bid> {
	private ObjectMapper jackson = new ObjectMapper();

	@Override
	public void serialize(Bid bid, JsonGenerator gen,
			SerializerProvider serializers) throws IOException {
		gen.writeFieldName(jackson.writeValueAsString(bid));
	}

}

/**
 * Default implementation of partial ordering that stores all is-better
 * relations explicitly in a map.
 * 
 * NOTICE this can handle profiles of max size Integer. This is because various
 * functions used here rely on basic java functions that can handle only int.
 * Besides, the size of partial maps grows very rapidly so this approach is
 * limited anyway.
 */
@JsonAutoDetect(fieldVisibility = Visibility.ANY, getterVisibility = Visibility.NONE, setterVisibility = Visibility.NONE, isGetterVisibility = Visibility.NONE)
public class DefaultPartialOrdering extends DefaultProfile
		implements PartialOrdering {

	/**
	 * Set is sparsely filled. If a Bid is not a key, it is not better than any
	 * other bid.
	 */
	//#PY # not needed in pyson, has fallback for key (de)serialization 
	@JsonDeserialize(keyUsing = BidDeserializer.class)
	//#PY # not needed in pyson, has fallback for key (de)serialization 
	@JsonSerialize(keyUsing = BidSerializer.class)
	private final Map<Bid, Set<Bid>> better;

	/**
	 * @param name           the name for the profile
	 * @param domain         the {@link Domain} description
	 * @param reservationBid the reservation {@link Bid}
	 * @param better         a map with keys = a better bid and value=a less
	 *                       good bid.
	 */
	@JsonCreator
	public DefaultPartialOrdering(@JsonProperty("name") String name,
			@JsonProperty("domain") Domain domain,
			@JsonProperty("reservationBid") Bid reservationBid,
			@JsonProperty("better") Map<Bid, Set<Bid>> better) {
		super(name, domain, reservationBid);
		this.better = better;
	}

	@Override
	public boolean isPreferredOrEqual(Bid bid1, Bid bid2) {
		if (!better.containsKey(bid1))
			return false;
		return better.get(bid1).contains(bid2);
	}

	/**
	 * 
	 * @return a list with all the bids that are referred to, either as better
	 *         or as worse than another bid
	 */
	public List<Bid> getBids() {
		// FIXME the iteration order may not be guaranteed!
		Set<Bid> bids = new HashSet<>();
		for (Bid bid : better.keySet()) {
			bids.add(bid);
			bids.addAll(better.get(bid));
		}
		return new ArrayList<Bid>(bids);
	}

	/**
	 * 
	 * @return a list of tuples [bid1index, bid2index]. It indicates that
	 *         bids[bid1index] isbetterthan bids[bid2index].
	 */
	public List<List<Integer>> getBetter() {
		List<List<Integer>> betterlist = new LinkedList<>();
		List<Bid> bidslist = getBids();

		for (Bid bid : bidslist) {
			if (better.containsKey(bid)) {
				for (Bid worsebid : better.get(bid)) {
					betterlist.add(Arrays.asList(bidslist.indexOf(bid),
							bidslist.indexOf(worsebid)));
				}
			}
		}

		return betterlist;
	}

	@Override
	public String toString() {
		return "DefaultPartialOrdering[" + getValuesString() + "," + better
				+ "]";
	}

	@Override
	public int hashCode() {
		final int prime = 31;
		int result = super.hashCode();
		result = prime * result + ((better == null) ? 0 : better.hashCode());
		return result;
	}

	@Override
	public boolean equals(Object obj) {
		if (this == obj)
			return true;
		if (!super.equals(obj))
			return false;
		if (getClass() != obj.getClass())
			return false;
		DefaultPartialOrdering other = (DefaultPartialOrdering) obj;
		if (better == null) {
			if (other.better != null)
				return false;
		} else if (!better.equals(other.better))
			return false;
		return true;
	}

}