/*
 * Copyright (c) 2013 Cisco Systems, Inc. and others.  All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v1.0 which accompanies this distribution,
 * and is available at http://www.eclipse.org/legal/epl-v10.html
 */
package org.opendaylight.protocol.pcep.ietf.stateful07;

import com.google.common.base.Preconditions;
import io.netty.buffer.ByteBuf;
import java.util.ArrayList;
import java.util.List;
import java.util.Optional;
import org.opendaylight.protocol.pcep.parser.message.PCEPErrorMessageParser;
import org.opendaylight.protocol.pcep.spi.ObjectRegistry;
import org.opendaylight.protocol.pcep.spi.PCEPDeserializerException;
import org.opendaylight.protocol.pcep.spi.PCEPErrors;
import org.opendaylight.protocol.pcep.spi.UnknownObject;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.ietf.stateful.rev181109.pcerr.pcerr.message.error.type.StatefulCase;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.ietf.stateful.rev181109.pcerr.pcerr.message.error.type.StatefulCaseBuilder;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.ietf.stateful.rev181109.pcerr.pcerr.message.error.type.stateful._case.StatefulBuilder;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.ietf.stateful.rev181109.pcerr.pcerr.message.error.type.stateful._case.stateful.Srps;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.ietf.stateful.rev181109.pcerr.pcerr.message.error.type.stateful._case.stateful.SrpsBuilder;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.ietf.stateful.rev181109.srp.object.Srp;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.message.rev181109.PcerrBuilder;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.types.rev181109.Message;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.types.rev181109.Object;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.types.rev181109.PcerrMessage;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.types.rev181109.open.object.Open;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.types.rev181109.pcep.error.object.ErrorObject;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.types.rev181109.pcerr.message.PcerrMessageBuilder;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.types.rev181109.pcerr.message.pcerr.message.Errors;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.types.rev181109.pcerr.message.pcerr.message.ErrorsBuilder;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.types.rev181109.pcerr.message.pcerr.message.error.type.RequestCase;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.types.rev181109.pcerr.message.pcerr.message.error.type.RequestCaseBuilder;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.types.rev181109.pcerr.message.pcerr.message.error.type.SessionCaseBuilder;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.types.rev181109.pcerr.message.pcerr.message.error.type.request._case.RequestBuilder;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.types.rev181109.pcerr.message.pcerr.message.error.type.request._case.request.Rps;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.types.rev181109.pcerr.message.pcerr.message.error.type.request._case.request.RpsBuilder;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.types.rev181109.pcerr.message.pcerr.message.error.type.session._case.SessionBuilder;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.types.rev181109.rp.object.Rp;

/**
 * Parser for {@link PcerrMessage}
 */
public final class Stateful07ErrorMessageParser extends PCEPErrorMessageParser {

    public Stateful07ErrorMessageParser(final ObjectRegistry registry) {
        super(registry);
    }

    @Override
    protected void serializeCases(final org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.types.rev181109.pcerr.message.PcerrMessage err, final ByteBuf buffer) {
        if (err.getErrorType() instanceof RequestCase) {
            final List<Rps> rps = ((RequestCase) err.getErrorType()).getRequest().getRps();
            for (final Rps r : rps) {
                serializeObject(r.getRp(), buffer);
            }
        }
        if (err.getErrorType() instanceof StatefulCase) {
            final List<Srps> srps = ((StatefulCase) err.getErrorType()).getStateful().getSrps();
            for (final Srps s : srps) {
                serializeObject(s.getSrp(), buffer);
            }
        }
    }

    @Override
    protected PcerrMessage validate(final List<Object> objects, final List<Message> errors) throws PCEPDeserializerException {
        Preconditions.checkArgument(objects != null, "Passed list can't be null.");
        if (objects.isEmpty()) {
            throw new PCEPDeserializerException("Error message is empty.");
        }
        final List<Rps> requestParameters = new ArrayList<>();
        final List<Srps> srps = new ArrayList<>();
        final List<Errors> errorObjects = new ArrayList<>();
        final PcerrMessageBuilder b = new PcerrMessageBuilder();
        Object obj = objects.get(0);
        State state = State.INIT;
        if (obj instanceof ErrorObject) {
            final ErrorObject o = (ErrorObject) obj;
            errorObjects.add(new ErrorsBuilder().setErrorObject(o).build());
            state = State.ERROR_IN;
        } else if (obj instanceof Rp) {
            final Rp o = (Rp) obj;
            if (o.isProcessingRule()) {
                errors.add(createErrorMsg(PCEPErrors.P_FLAG_NOT_SET, Optional.empty()));
                return null;
            }
            requestParameters.add(new RpsBuilder().setRp(o).build());
            state = State.RP_IN;
        } else if (obj instanceof Srp) {
            final Srp s = (Srp) obj;
            srps.add(new SrpsBuilder().setSrp(s).build());
            state = State.SRP_IN;
        }
        if (!state.equals(State.INIT)) {
            objects.remove(0);
        }
        while (!objects.isEmpty() && !state.equals(State.END)) {
            obj = objects.get(0);
            if (obj instanceof UnknownObject) {
                return new PcerrBuilder().setPcerrMessage(b.setErrors(((UnknownObject) obj).getErrors()).build()).build();
            }
            state = insertObject(state, obj, errorObjects, requestParameters, srps, b);
            if (!state.equals(State.END)) {
                objects.remove(0);
            }
        }
        if (errorObjects.isEmpty()) {
            throw new PCEPDeserializerException("At least one PCEPErrorObject is mandatory.");
        }
        if (!objects.isEmpty()) {
            throw new PCEPDeserializerException("Unprocessed Objects: " + objects);
        }
        if (!requestParameters.isEmpty()) {
            b.setErrorType(new RequestCaseBuilder().setRequest(new RequestBuilder().setRps(requestParameters).build()).build());
        }
        if (!srps.isEmpty()) {
            b.setErrorType(new StatefulCaseBuilder().setStateful(new StatefulBuilder().setSrps(srps).build()).build());
        }
        return new PcerrBuilder().setPcerrMessage(b.setErrors(errorObjects).build()).build();
    }

    private static State insertObject(final State state, final Object obj, final List<Errors> errorObjects,
            final List<Rps> requestParameters, final List<Srps> srps, final PcerrMessageBuilder b){
        switch (state) {
        case ERROR_IN:
            if (obj instanceof ErrorObject) {
                final ErrorObject o = (ErrorObject) obj;
                errorObjects.add(new ErrorsBuilder().setErrorObject(o).build());
                return State.ERROR_IN;
            }
        case RP_IN:
            if (obj instanceof Rp) {
                final Rp o = (Rp) obj;
                requestParameters.add(new RpsBuilder().setRp(o).build());
                return State.RP_IN;
            }
        case SRP_IN:
            if (obj instanceof Srp) {
                final Srp o = (Srp) obj;
                srps.add(new SrpsBuilder().setSrp(o).build());
                return State.SRP_IN;
            }
        case OPEN:
            if (obj instanceof Open) {
                b.setErrorType(new SessionCaseBuilder().setSession(new SessionBuilder().setOpen((Open) obj).build()).build());
                return State.OPEN_IN;
            }
        case ERROR:
            if (obj instanceof ErrorObject) {
                final ErrorObject o = (ErrorObject) obj;
                errorObjects.add(new ErrorsBuilder().setErrorObject(o).build());
                return State.ERROR;
            }
        case OPEN_IN:
        case END:
            return State.END;
        default:
            return state;
        }
    }

    private enum State {
        INIT, ERROR_IN, RP_IN, SRP_IN, OPEN, ERROR, OPEN_IN, END
    }
}