/*
 * Copyright 2014-2016 Open Networking Laboratory
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.onosproject.yangutils.parser.impl.listeners;

/*
 * Reference: RFC6020 and YANG ANTLR Grammar
 *
 * ABNF grammar as per RFC6020
 * type-body-stmts     = numerical-restrictions /
 *                       decimal64-specification /
 *                      string-restrictions /
 *                       enum-specification /
 *                       leafref-specification /
 *                       identityref-specification /
 *                       instance-identifier-specification /
 *                       bits-specification /
 *                       union-specification
 *
 * bits-specification  = 1*(bit-stmt stmtsep)
 *
 * ANTLR grammar rule
 *
 * typeBodyStatements : numericalRestrictions | stringRestrictions | enumSpecification
 *                 | leafrefSpecification | identityrefSpecification | instanceIdentifierSpecification
 *                 | bitsSpecification | unionSpecification;
 *
 * bitsSpecification : bitStatement+;
 */

import org.onosproject.yangutils.datamodel.YangBits;
import org.onosproject.yangutils.datamodel.YangLeaf;
import org.onosproject.yangutils.datamodel.YangLeafList;
import org.onosproject.yangutils.datamodel.YangType;
import org.onosproject.yangutils.parser.Parsable;
import static org.onosproject.yangutils.parser.ParsableDataType.BITS_DATA;
import static org.onosproject.yangutils.parser.ParsableDataType.TYPE_DATA;
import org.onosproject.yangutils.parser.antlrgencode.GeneratedYangParser;
import org.onosproject.yangutils.parser.exceptions.ParserException;
import org.onosproject.yangutils.parser.impl.TreeWalkListener;
import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorLocation.ENTRY;
import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorLocation.EXIT;
import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorMessageConstruction.constructListenerErrorMessage;
import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorType.INVALID_HOLDER;
import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorType.MISSING_CURRENT_HOLDER;
import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorType.MISSING_HOLDER;
import static org.onosproject.yangutils.parser.impl.parserutils.ListenerValidation.checkStackIsNotEmpty;

/**
 * Implements listener based call back function corresponding to the "bits"
 * rule defined in ANTLR grammar file for corresponding ABNF rule in RFC 6020.
 */
public final class BitsListener {

    /**
     * Creates a new bits listener.
     */
    private BitsListener() {
    }

    /**
     * It is called when parser enters grammar rule (bits), it perform
     * validations and updates the data model tree.
     *
     * @param listener listener's object.
     * @param ctx context object of the grammar rule.
     */
    public static void processBitsEntry(TreeWalkListener listener,
                                               GeneratedYangParser.BitsSpecificationContext ctx) {

        // Check for stack to be non empty.
        checkStackIsNotEmpty(listener, MISSING_HOLDER, BITS_DATA, "", ENTRY);

        if (listener.getParsedDataStack().peek() instanceof YangType) {
            YangBits bitsNode = new YangBits();
            Parsable typeData = listener.getParsedDataStack().pop();

            // Check for stack to be non empty.
            checkStackIsNotEmpty(listener, MISSING_HOLDER, BITS_DATA, "", ENTRY);

            Parsable tmpData = listener.getParsedDataStack().peek();

            switch (tmpData.getParsableDataType()) {
                case LEAF_DATA:
                    bitsNode.setBitsName(((YangLeaf) tmpData).getLeafName());
                    break;
                case LEAF_LIST_DATA:
                    bitsNode.setBitsName(((YangLeafList) tmpData).getLeafName());
                    break;
                // TODO typedef, union, deviate.
                default:
                    throw new ParserException(constructListenerErrorMessage(INVALID_HOLDER, TYPE_DATA,
                            ((YangType) typeData).getDataTypeName(), ENTRY));
            }
            listener.getParsedDataStack().push(typeData);
            listener.getParsedDataStack().push(bitsNode);
        } else {
            throw new ParserException(constructListenerErrorMessage(INVALID_HOLDER, BITS_DATA, "", ENTRY));
        }
    }

    /**
     * It is called when parser exits from grammar rule (bits), it perform
     * validations and update the data model tree.
     *
     * @param listener Listener's object.
     * @param ctx      context object of the grammar rule.
     */
    public static void processBitsExit(TreeWalkListener listener,
                                              GeneratedYangParser.BitsSpecificationContext ctx) {

        // Check for stack to be non empty.
        checkStackIsNotEmpty(listener, MISSING_HOLDER, BITS_DATA, "", EXIT);

        Parsable tmpBitsNode = listener.getParsedDataStack().peek();
        if (tmpBitsNode instanceof YangBits) {
            listener.getParsedDataStack().pop();

            // Check for stack to be non empty.
            checkStackIsNotEmpty(listener, MISSING_HOLDER, BITS_DATA, "", EXIT);

            Parsable tmpNode = listener.getParsedDataStack().peek();
            switch (tmpNode.getParsableDataType()) {
                case TYPE_DATA: {
                    YangType typeNode = (YangType) tmpNode;
                    typeNode.setDataTypeExtendedInfo((YangBits) tmpBitsNode);
                    break;
                }
                default:
                    throw new ParserException(
                            constructListenerErrorMessage(INVALID_HOLDER, BITS_DATA, "", EXIT));
            }
        } else {
            throw new ParserException(
                    constructListenerErrorMessage(MISSING_CURRENT_HOLDER, BITS_DATA, "", EXIT));
        }
    }
}