package geniusweb.profile.utilityspace;

import java.math.BigDecimal;
import java.util.Collections;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;

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 geniusweb.issuevalue.Value;
import geniusweb.issuevalue.ValueSet;

/**
 * Contains utilities of a ProductOfValue of a {@link SumOfGroupsUtilitySpace}.
 * So this is similar to a {@link DiscreteValueSetUtilities} but instead of
 * issues this contains an (ordered) list of issues. This object serializes to
 * something like <code> 
 * {"partsutils":
 * {"issues":["issue1","issue2"],
 * "utilslist":[{"values":["low","low"],"util":0.3},{"values":["high","high"],"util":0.9}]}}
 </code> The issues field contains a list of N issues in the domain, The
 * utilslist contains a list of dictionaries, with "values" containing a list of
 * N issue values, in the same order as the issues list and with "util"
 * containng the utility value of that set of values.
 */
@JsonAutoDetect(fieldVisibility = Visibility.ANY, getterVisibility = Visibility.NONE, setterVisibility = Visibility.NONE, isGetterVisibility = Visibility.NONE)
public class PartsUtilities implements ValueSetUtilities {
	private final List<String> issues;
	// the real but not-serializable values (because Map can only have String
	// keys in jackson)
	private transient final Map<ProductOfValue, BigDecimal> utilities = new HashMap<>();
	// copy only for serializing
	private final List<PartUtil> utilslist = new LinkedList<>();

	/**
	 * 
	 * @param issues list of issues
	 * @param utils  with keys: list of values and value: utility value for that
	 *               list of values. All list-of-values missing from the map are
	 *               assumed to have utility 0. This includes partial bids where
	 *               list-of-values contain null objects.
	 */
	public PartsUtilities(List<String> issues,
			Map<ProductOfValue, BigDecimal> utils) {
		if (issues == null || utils == null) {
			throw new IllegalArgumentException(
					"issues and utils must be not null");
		}

		this.issues = issues;
		this.utilities.putAll(utils);

		checkUtilities();
		for (ProductOfValue pval : utils.keySet()) {
			utilslist.add(new PartUtil(pval.getValues(), utils.get(pval)));
		}
	}

	@JsonCreator
	public PartsUtilities(@JsonProperty("issues") List<String> issues,
			@JsonProperty("utilslist") List<PartUtil> utilslist) {
		this(issues, list2map(utilslist));
	}

	/**
	 * 
	 * @param pval the {@link ProductOfValue} value
	 * @return the utility of the value, in the same order as
	 *         {@link #getIssues()}. Returns 0 if there is no utility set for
	 *         the given combination of values. Notice, partial bids will
	 *         usually have utility 0.
	 * 
	 */
	@Override
	public BigDecimal getUtility(Value pval) {
		BigDecimal val = utilities.get(pval);
		if (val == null)
			return BigDecimal.ZERO;
		return val;
	}

	@Override
	public String isFitting(ValueSet valueset) {
		return null; // what can we tests here?
	}

	/**
	 * @return the issues that are contained here.
	 */
	public List<String> getIssues() {
		return issues;
	}

	/**
	 * 
	 * @return map with all available values and their utilities. The map and
	 *         its contents should all be immutable.
	 */
	public Map<ProductOfValue, BigDecimal> getUtilities() {
		return Collections.unmodifiableMap(utilities);
	}

	/**
	 * 
	 * @param other another {@link PartsUtilities} map. The issues in the other
	 *              map must be different from {@link #issues}.
	 * @return new PartsUtils, with the powermap of all combinations of one
	 *         element from this and one from the other map, and with the
	 *         utilities computed as the sum of thisvalue + othervalue.
	 */
	public PartsUtilities add(PartsUtilities other) {
		for (String issue : issues) {
			if (other.issues.contains(issue)) {
				throw new IllegalArgumentException(
						"Issue " + issue + " exists already");
			}
		}

		List<String> combinedissues = new LinkedList<String>(issues);
		combinedissues.addAll(other.issues);

		Map<ProductOfValue, BigDecimal> combinedvalues = new HashMap<>();
		for (ProductOfValue productOfValue : this.utilities.keySet()) {
			for (ProductOfValue otherProductOfValue : other.utilities
					.keySet()) {
				BigDecimal combinedutil = getUtility(productOfValue)
						.add(other.getUtility(otherProductOfValue));
				combinedvalues.put(productOfValue.merge(otherProductOfValue),
						combinedutil);
			}
		}
		return new PartsUtilities(combinedissues, combinedvalues);

	}

	@Override
	public int hashCode() {
		final int prime = 31;
		int result = 1;
		result = prime * result + ((issues == null) ? 0 : issues.hashCode());
		result = prime * result
				+ ((utilities == null) ? 0 : utilities.hashCode());
		return result;
	}

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

	@Override
	public String toString() {
		return "PartsUtilities[" + issues + "," + utilities + "]";
	}

	private void checkUtilities() {
		if (utilities.values().stream()
				.anyMatch(v -> v == null || v.compareTo(BigDecimal.ZERO) < 0
						|| v.compareTo(BigDecimal.ONE) > 0)) {
			throw new IllegalArgumentException(
					"part weights must all be in [0,1]");
		}
	}

	private static Map<ProductOfValue, BigDecimal> list2map(
			List<PartUtil> list) {
		Map<ProductOfValue, BigDecimal> map = new HashMap<>();
		for (PartUtil partutil : list) {
			map.put(new ProductOfValue(partutil.getValues()),
					partutil.getUtil());
		}
		return map;
	}

	/**
	 * 
	 * @return the max utility of all values contained here.
	 */
	public BigDecimal getMaxUtility() {
		BigDecimal maxutil = BigDecimal.ZERO;
		for (ProductOfValue vakye : utilities.keySet()) {
			if (utilities.get(vakye).compareTo(maxutil) > 0) {
				maxutil = utilities.get(vakye);
			}

		}
		return maxutil;
	}

}

/**
 * contains list of values, and the utility for this combi of values. The values
 * make only sense with a corresponding list of issues, but that is managed in
 * (see {@link PartsUtilities}.
 * <p>
 * immutable.
 */
@JsonAutoDetect(fieldVisibility = Visibility.ANY, getterVisibility = Visibility.NONE, setterVisibility = Visibility.NONE, isGetterVisibility = Visibility.NONE)
class PartUtil {
	private final List<Value> values;

	private final BigDecimal util;

	@JsonCreator
	public PartUtil(@JsonProperty("values") List<Value> values,
			@JsonProperty("util") BigDecimal util) {
		this.values = values;
		this.util = util;
	}

	public List<Value> getValues() {
		return values;
	}

	public BigDecimal getUtil() {
		return util;
	}
}