/*
 * Copyright 2016-present 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;

import java.util.List;

import org.onosproject.yangutils.datamodel.YangAugment;
import org.onosproject.yangutils.datamodel.YangModule;
import org.onosproject.yangutils.datamodel.YangNode;
import org.onosproject.yangutils.datamodel.YangNodeIdentifier;
import org.onosproject.yangutils.datamodel.YangSubModule;
import org.onosproject.yangutils.datamodel.YangUses;
import org.onosproject.yangutils.datamodel.exceptions.DataModelException;
import org.onosproject.yangutils.datamodel.utils.Parsable;
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.datamodel.utils.GeneratedLanguage.JAVA_GENERATION;
import static org.onosproject.yangutils.datamodel.utils.YangConstructType.AUGMENT_DATA;
import static org.onosproject.yangutils.datamodel.utils.YangConstructType.CASE_DATA;
import static org.onosproject.yangutils.datamodel.utils.YangConstructType.DATA_DEF_DATA;
import static org.onosproject.yangutils.datamodel.utils.YangConstructType.DESCRIPTION_DATA;
import static org.onosproject.yangutils.datamodel.utils.YangConstructType.REFERENCE_DATA;
import static org.onosproject.yangutils.datamodel.utils.YangConstructType.STATUS_DATA;
import static org.onosproject.yangutils.datamodel.utils.YangConstructType.WHEN_DATA;
import static org.onosproject.yangutils.parser.impl.parserutils.AugmentListenerUtil.generateNameForAugmentNode;
import static org.onosproject.yangutils.parser.impl.parserutils.AugmentListenerUtil.getParentsPrefix;
import static org.onosproject.yangutils.parser.impl.parserutils.AugmentListenerUtil.parserException;
import static org.onosproject.yangutils.parser.impl.parserutils.AugmentListenerUtil.validateNodeInTargetPath;
import static org.onosproject.yangutils.parser.impl.parserutils.ListenerCollisionDetector.detectCollidingChildUtil;
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
        .constructExtendedListenerErrorMessage;
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.ListenerErrorType.UNHANDLED_PARSED_DATA;
import static org.onosproject.yangutils.parser.impl.parserutils.ListenerUtil.getValidAbsoluteSchemaNodeId;
import static org.onosproject.yangutils.parser.impl.parserutils.ListenerValidation.checkStackIsNotEmpty;
import static org.onosproject.yangutils.parser.impl.parserutils.ListenerValidation.validateCardinalityMaxOne;
import static org.onosproject.yangutils.parser.impl.parserutils.ListenerValidation.validateMutuallyExclusiveChilds;
import static org.onosproject.yangutils.translator.tojava.YangDataModelFactory.getYangAugmentNode;

/*
 * Reference: RFC6020 and YANG ANTLR Grammar
 *
 * ABNF grammar as per RFC6020
 *  augment-stmt        = augment-keyword sep augment-arg-str optsep
 *                        "{" stmtsep
 *                            ;; these stmts can appear in any order
 *                            [when-stmt stmtsep]
 *                            *(if-feature-stmt stmtsep)
 *                            [status-stmt stmtsep]
 *                            [description-stmt stmtsep]
 *                            [reference-stmt stmtsep]
 *                            1*((data-def-stmt stmtsep) /
 *                               (case-stmt stmtsep))
 *                         "}"
 *
 * ANTLR grammar rule
 * augmentStatement : AUGMENT_KEYWORD augment LEFT_CURLY_BRACE (whenStatement | ifFeatureStatement | statusStatement
 *      | descriptionStatement | referenceStatement | dataDefStatement  | caseStatement)* RIGHT_CURLY_BRACE;
 */

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

    /**
     * Creates a new augment listener.
     */
    private AugmentListener() {
    }

    /**
     * It is called when parser receives an input matching the grammar rule
     * (augment), performs validation and updates the data model tree.
     *
     * @param listener listener's object
     * @param ctx context object of the grammar rule
     */
    public static void processAugmentEntry(TreeWalkListener listener,
            GeneratedYangParser.AugmentStatementContext ctx) {

        // Check for stack to be non empty.
        checkStackIsNotEmpty(listener, MISSING_HOLDER, AUGMENT_DATA, ctx.augment().getText(), ENTRY);

        // Validate augment argument string
        List<YangNodeIdentifier> targetNodes = getValidAbsoluteSchemaNodeId(ctx.augment().getText(),
                AUGMENT_DATA, ctx);

        // Validate sub statement cardinality.
        validateSubStatementsCardinality(ctx);

        // Check for identifier collision
        int line = ctx.getStart().getLine();
        int charPositionInLine = ctx.getStart().getCharPositionInLine();
        detectCollidingChildUtil(listener, line, charPositionInLine, "", AUGMENT_DATA);

        Parsable curData = listener.getParsedDataStack().peek();
        if (curData instanceof YangModule || curData instanceof YangSubModule || curData instanceof YangUses) {
            YangNode curNode = (YangNode) curData;
            YangAugment yangAugment = getYangAugmentNode(JAVA_GENERATION);

            //validateTargetNodePath(targetNodes, curNode, ctx);
            // TODO: handle in linker.

            yangAugment.setTargetNode(targetNodes);
            yangAugment.setName(generateNameForAugmentNode(curData, targetNodes, listener));

            try {
                curNode.addChild(yangAugment);
            } catch (DataModelException e) {
                throw new ParserException(constructExtendedListenerErrorMessage(UNHANDLED_PARSED_DATA,
                        AUGMENT_DATA, ctx.augment().getText(), ENTRY, e.getMessage()));
            }
            listener.getParsedDataStack().push(yangAugment);
        } else {
            throw new ParserException(constructListenerErrorMessage(INVALID_HOLDER, AUGMENT_DATA,
                    ctx.augment().getText(), ENTRY));
        }

    }

    /**
     * It is called when parser exits from grammar rule (augment), 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 processAugmentExit(TreeWalkListener listener,
            GeneratedYangParser.AugmentStatementContext ctx) {

        //Check for stack to be non empty.
        checkStackIsNotEmpty(listener, MISSING_HOLDER, AUGMENT_DATA, ctx.augment().getText(), EXIT);

        if (!(listener.getParsedDataStack().peek() instanceof YangAugment)) {
            throw new ParserException(constructListenerErrorMessage(MISSING_CURRENT_HOLDER, AUGMENT_DATA,
                    ctx.augment().getText(), EXIT));
        }
        listener.getParsedDataStack().pop();
    }

    /**
     * Validates the cardinality of augment sub-statements as per grammar.
     *
     * @param ctx context object of the grammar rule
     */
    private static void validateSubStatementsCardinality(GeneratedYangParser.AugmentStatementContext ctx) {
        validateCardinalityMaxOne(ctx.statusStatement(), STATUS_DATA, AUGMENT_DATA, ctx.augment().getText());
        validateCardinalityMaxOne(ctx.descriptionStatement(), DESCRIPTION_DATA, AUGMENT_DATA, ctx.augment().getText());
        validateCardinalityMaxOne(ctx.referenceStatement(), REFERENCE_DATA, AUGMENT_DATA, ctx.augment().getText());
        validateCardinalityMaxOne(ctx.whenStatement(), WHEN_DATA, AUGMENT_DATA, ctx.augment().getText());
        validateMutuallyExclusiveChilds(ctx.dataDefStatement(), DATA_DEF_DATA, ctx.caseStatement(),
                CASE_DATA, AUGMENT_DATA, ctx.augment().getText());
    }

    /**
     * Validates whether the current target node path is correct or not.
     *
     * @param targetNodes list of target nodes
     * @param curNode current Node
     * @param ctx augment context
     * @param curNode current YANG node
     */
    private static void validateTargetNodePath(List<YangNodeIdentifier> targetNodes, YangNode curNode,
            GeneratedYangParser.AugmentStatementContext ctx) {

        YangNodeIdentifier moduleId = targetNodes.get(0);
        if (moduleId.getPrefix() == null) {
            if (!moduleId.getName().equals(curNode.getName())) {
                throw parserException(ctx);
            } else {
                //validateNodeInTargetPath(curNode, targetNodes, ctx);
                // TODO: handle in linker.
            }
        } else {
            String parentPrefix = getParentsPrefix(curNode);
            if (parentPrefix != null) {
                if (!parentPrefix.equals(moduleId.getPrefix())) {
                    // TODO: handle in linker.
                } else {
                    validateNodeInTargetPath(curNode, targetNodes, ctx);
                }
            } else {
                // TODO: handle in linker.
            }
        }
    }
}