package geniusweb.protocol.session.saop;

import java.util.Arrays;
import java.util.Collections;
import java.util.HashSet;
import java.util.List;
import java.util.Map;

import com.fasterxml.jackson.annotation.JsonCreator;
import com.fasterxml.jackson.annotation.JsonProperty;

import geniusweb.actions.Accept;
import geniusweb.actions.Action;
import geniusweb.actions.EndNegotiation;
import geniusweb.actions.Offer;
import geniusweb.actions.PartyId;
import geniusweb.inform.Agreements;
import geniusweb.issuevalue.Bid;
import geniusweb.progress.Progress;
import geniusweb.progress.ProgressRounds;
import geniusweb.protocol.ProtocolException;
import geniusweb.protocol.session.DefaultSessionState;
import geniusweb.protocol.session.SessionResult;
import geniusweb.references.PartyWithProfile;

/**
 * Immutable.
 */
public class SAOPState extends DefaultSessionState<SAOPState, SAOPSettings> {

	/**
	 * 
	 * @param actions       the actions done by the parties
	 * @param connections   the existing party connections. If null, default
	 *                      empty list is used. Can be less than 2 parties in
	 *                      the first phases of the setup or after parties
	 *                      disconnected.
	 * @param progress      the {@link Progress} line. can be null
	 * @param settings      the {@link SAOPSettings}
	 * @param partyprofiles map with the {@link PartyWithProfile} for connected
	 *                      parties. null is equivalent to an empty map.
	 * @param error         the {@link ProtocolException}, or null if none
	 *                      occurred.
	 */
	@JsonCreator
	public SAOPState(@JsonProperty("actions") List<Action> actions,
			@JsonProperty("connections") List<PartyId> connections,
			@JsonProperty("progress") Progress progress,
			@JsonProperty("settings") SAOPSettings settings,
			@JsonProperty("partyprofiles") Map<PartyId, PartyWithProfile> partyprofiles,
			@JsonProperty("error") ProtocolException error) {
		super(actions, connections, progress, settings, partyprofiles, error);
	}

	@Override
	public SAOPState with(List<Action> actions, List<PartyId> conns,
			Progress progr, SAOPSettings settings,
			Map<PartyId, PartyWithProfile> partyprofiles, ProtocolException e) {
		return new SAOPState(actions, conns, progr, settings, partyprofiles, e);
	}

	/**
	 * Creates the initial state from the given settings and progress=null
	 * 
	 * @param settings the {@link SAOPSettings}
	 */
	public SAOPState(SAOPSettings settings) {
		this(Collections.emptyList(), Collections.emptyList(), null, settings,
				null, null);

	}

	@Override
	public Agreements getAgreements() {
		Agreements agree = new Agreements();
		List<Action> acts = getActions();
		int nparticipants = getConnections().size();
		if (nparticipants < 2 || acts.size() < nparticipants) {
			return agree;
		}
		Action offer = acts.get(acts.size() - nparticipants);
		if (!(offer instanceof Offer))
			return agree;
		Bid bid = ((Offer) offer).getBid();

		// check that the last n-1 are accepts.
		boolean allaccept = acts.stream().skip(acts.size() - nparticipants + 1)
				.allMatch(act -> act instanceof Accept
						&& bid.equals(((Accept) act).getBid()));
		if (allaccept)
			agree = agree
					.with(new Agreements(bid, new HashSet<>(getParties())));
		return agree;
	}

	/**
	 * 
	 * @return all currently connected parties.
	 */
	public List<PartyId> getParties() {
		return getConnections();
	}

	@Override
	public boolean isFinal(long currentTimeMs) {
		List<Action> acts = getActions();
		return super.isFinal(currentTimeMs)
				|| !getAgreements().getMap().isEmpty() || (!acts.isEmpty()
						&& acts.get(acts.size() - 1) instanceof EndNegotiation);
	}

	@Override
	public SAOPState with(PartyId actor, Action action) {
		return super.with(actor, action).with(advanceProgress());
	}

	@Override
	public String checkAction(PartyId actor, Action action) {
		String msg = super.checkAction(actor, action);
		if (msg != null)
			return msg;

		if (!actor.equals(getNextActor()))
			return "Party does not have the turn ";

		// check protocol is followed for specific actions
		if (action instanceof Accept) {
			Bid bid = getLastBid();
			if (bid == null)
				return "Accept without a recent offer";

			if (!bid.equals(((Accept) action).getBid()))
				return "Party accepts a bid differing from the last offer ="
						+ bid + ", action=" + action + ")";
			return null;
		} else if (action instanceof Offer) {
			return null;
		} else if (action instanceof EndNegotiation) {
			return null;
		}
		return "Action " + action + " is not allowed in SAOP";
	}

	/**
	 * Check up to nparticipants-1 steps back if there was an offer.
	 * 
	 * @return Bid from the most recent offer, or null if no such offer
	 */
	private Bid getLastBid() {
		int nparticipants = getConnections().size();
		List<Action> acts = getActions();
		for (int n = acts.size() - 1; n > acts.size() - nparticipants
				&& n >= 0; n--) {
			Action action = acts.get(n);
			if (action instanceof Offer) {
				return ((Offer) action).getBid();
			}
		}
		return null;

	}

	/**
	 * 
	 * @return the next actor in the current state. Assumes 1 action per actor
	 *         every time. NOTE if party disconnects this would jump wildly but
	 *         nego stops then anyway
	 */
	protected PartyId getNextActor() {
		return getConnections()
				.get(getActions().size() % getConnections().size());
	}

	/**
	 * @return new progress state
	 */
	public Progress advanceProgress() {
		Progress newprogress = getProgress();
		if (newprogress instanceof ProgressRounds && isLastActor()) {
			newprogress = ((ProgressRounds) newprogress).advance();
		}
		return newprogress;
	}

	/**
	 * @return true if the current actor is the last actor in the list
	 */
	private boolean isLastActor() {
		int nparticipants = getConnections().size();
		return getActions().size() % nparticipants == nparticipants - 1;
	}

	@Override
	public List<SessionResult> getResults() {
		return Arrays.asList(new SessionResult(getPartyProfiles(),
				getAgreements(), Collections.emptyMap(), getError()));
	}

}