package geniusweb.voting;

import com.fasterxml.jackson.annotation.JsonAutoDetect;
import com.fasterxml.jackson.annotation.JsonAutoDetect.Visibility;
import com.fasterxml.jackson.annotation.JsonSubTypes;
import com.fasterxml.jackson.annotation.JsonTypeInfo;
import com.fasterxml.jackson.annotation.JsonTypeInfo.As;

import geniusweb.inform.Agreements;
import geniusweb.voting.evaluatorwithvalue.LargestAgreementWithValue;

/**
 * Evaluates the {@link CollectedVotes}, determining the agreements and if the
 * negotiation should continue.
 * 
 * Implementations should be immutable and not serialize internal variables (eg
 * @JsonIgnore them).
 */
@JsonAutoDetect(fieldVisibility = Visibility.ANY, getterVisibility = Visibility.NONE, setterVisibility = Visibility.NONE, isGetterVisibility = Visibility.NONE)
@JsonTypeInfo(use = JsonTypeInfo.Id.NAME, include = As.WRAPPER_OBJECT)
@JsonSubTypes({ @JsonSubTypes.Type(value = LargestAgreementWithValue.class) })
public interface VotingEvaluatorWithValue {
	/**
	 * This function is the effective constructor. This mechanism serves several
	 * purposes:
	 * <ul>
	 * <li>It defines the constructor at interface level, so that we can ensure
	 * it's available and can call it given an instance,
	 * <li>We can use a (typically blank) instance of this to make more
	 * instances
	 * <li>You can cache intermediate results in the object for caching
	 * </ul>
	 * 
	 * @param votes the Votes made by parties in the round to be evaluated.. All
	 *              active parties in the negotiation must be available, even if
	 *              they did not vote, to ensure that {@link #isFinished()} can
	 *              work properly.
	 * 
	 * @return new VotingEvaluation object containing the given votes.
	 */
	VotingEvaluatorWithValue create(CollectedVotesWithValue votes);

	/**
	 * 
	 * @return the agreements that is contained in the current available votes.
	 *         The exact procedure varies with the implementation.
	 */
	Agreements getAgreements();

	/**
	 * 
	 * @return true iff the negotiation is finished after taking the agreement
	 *         returned by {@link #getAgreements()}
	 */
	boolean isFinished();
}