/*
 * Copyright 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;

import java.util.regex.Pattern;

import org.onosproject.yangutils.datamodel.YangRangeRestriction;
import org.onosproject.yangutils.datamodel.YangRangeInterval;
import org.onosproject.yangutils.datamodel.YangStringRestriction;
import org.onosproject.yangutils.datamodel.YangType;
import org.onosproject.yangutils.datamodel.YangDataTypes;
import org.onosproject.yangutils.datamodel.YangDerivedInfo;
import org.onosproject.yangutils.datamodel.exceptions.DataModelException;
import org.onosproject.yangutils.parser.Parsable;
import org.onosproject.yangutils.parser.antlrgencode.GeneratedYangParser;
import org.onosproject.yangutils.parser.exceptions.ParserException;
import org.onosproject.yangutils.parser.impl.TreeWalkListener;
import org.onosproject.yangutils.utils.YangConstructType;
import org.onosproject.yangutils.utils.builtindatatype.DataTypeException;
import org.onosproject.yangutils.utils.builtindatatype.YangBuiltInDataTypeInfo;

import static org.onosproject.yangutils.parser.impl.parserutils.ListenerUtil.removeQuotesAndHandleConcat;
import static org.onosproject.yangutils.utils.YangConstructType.LENGTH_DATA;
import static org.onosproject.yangutils.utils.YangConstructType.TYPE_DATA;
import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorLocation.ENTRY;
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_HOLDER;
import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorType.UNHANDLED_PARSED_DATA;
import static org.onosproject.yangutils.parser.impl.parserutils.ListenerValidation.checkStackIsNotEmpty;
import static org.onosproject.yangutils.utils.builtindatatype.BuiltInTypeObjectFactory.getDataObjectFromString;

/*
 * Reference: RFC6020 and YANG ANTLR Grammar
 *
 * ABNF grammar as per RFC6020
 *  length-stmt         = length-keyword sep length-arg-str optsep
 *                        (";" /
 *                         "{" stmtsep
 *                             ;; these stmts can appear in any order
 *                             [error-message-stmt stmtsep]
 *                             [error-app-tag-stmt stmtsep]
 *                             [description-stmt stmtsep]
 *                             [reference-stmt stmtsep]
 *                          "}")
 *
 *
 * ANTLR grammar rule
 * lengthStatement : LENGTH_KEYWORD length
 *                 (STMTEND | LEFT_CURLY_BRACE commonStatements RIGHT_CURLY_BRACE);
 */

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

    private static final String PIPE = "|";
    private static final String LENGTH_INTERVAL = "..";
    private static final int MAX_RANGE_BOUNDARY = 2;
    private static final int MIN_RANGE_BOUNDARY = 1;

    /**
     * Creates a new length restriction listener.
     */
    private LengthRestrictionListener() {
    }

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

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

        Parsable tmpData = listener.getParsedDataStack().peek();
        if (tmpData.getYangConstructType() == TYPE_DATA) {
            YangType type = (YangType) tmpData;
            setLengthRestriction(type, ctx);
        } else {
            throw new ParserException(constructListenerErrorMessage(INVALID_HOLDER, LENGTH_DATA,
                    ctx.length().getText(), ENTRY));
        }
    }

    /**
     * Sets the length restriction to type.
     *
     * @param type Yang type for which length restriction to be set
     * @param ctx context object of the grammar rule
     */
    private static void setLengthRestriction(YangType type,
                                            GeneratedYangParser.LengthStatementContext ctx) {

        YangStringRestriction stringRestriction;
        YangBuiltInDataTypeInfo<?> startValue;
        YangBuiltInDataTypeInfo<?> endValue;
        YangRangeRestriction lengthRestriction = new YangRangeRestriction<>();

        if (type.getDataType() != YangDataTypes.STRING && type.getDataType() != YangDataTypes.DERIVED) {

            ParserException parserException = new ParserException("YANG file error : " +
                    YangConstructType.getYangConstructType(LENGTH_DATA) + " name " + ctx.length().getText() +
                    " can be used to restrict the built-in type string or types derived from string.");
            parserException.setLine(ctx.getStart().getLine());
            parserException.setCharPosition(ctx.getStart().getCharPositionInLine());
            throw parserException;
        }

        if (type.getDataType() == YangDataTypes.STRING) {
            stringRestriction = (YangStringRestriction) type.getDataTypeExtendedInfo();
        } else {
            stringRestriction = (YangStringRestriction) ((YangDerivedInfo<?>) type
                    .getDataTypeExtendedInfo()).getExtendedInfo();
        }

        if (stringRestriction == null) {
            stringRestriction = new YangStringRestriction();
            if (type.getDataType() == YangDataTypes.STRING) {
                type.setDataTypeExtendedInfo(stringRestriction);
            } else {
                ((YangDerivedInfo<YangStringRestriction>) type.getDataTypeExtendedInfo())
                        .setExtendedInfo(stringRestriction);
            }
        }

        String rangeArgument = removeQuotesAndHandleConcat(ctx.length().getText());
        String[] rangeArguments = rangeArgument.trim().split(Pattern.quote(PIPE));

        for (String rangePart : rangeArguments) {
            String startInterval;
            String endInterval;
            YangRangeInterval rangeInterval = new YangRangeInterval<>();
            String[] rangeBoundary = rangePart.trim().split(Pattern.quote(LENGTH_INTERVAL));

            if (rangeBoundary.length > MAX_RANGE_BOUNDARY) {
                ParserException parserException = new ParserException("YANG file error : " +
                        YangConstructType.getYangConstructType(LENGTH_DATA) + " " + rangeArgument +
                        " is not valid.");
                parserException.setLine(ctx.getStart().getLine());
                parserException.setCharPosition(ctx.getStart().getCharPositionInLine());
                throw parserException;
            }

            if (rangeBoundary.length == MIN_RANGE_BOUNDARY) {
                startInterval = rangeBoundary[0];
                endInterval = rangeBoundary[0];
            } else {
                startInterval = rangeBoundary[0];
                endInterval = rangeBoundary[1];
            }

            try {
                startValue = getDataObjectFromString(startInterval, YangDataTypes.UINT64);
                endValue = getDataObjectFromString(endInterval, YangDataTypes.UINT64);
            } catch (DataTypeException e) {
                ParserException parserException = new ParserException(e.getMessage());
                parserException.setLine(ctx.getStart().getLine());
                parserException.setCharPosition(ctx.getStart().getCharPositionInLine());
                throw parserException;
            }

            rangeInterval.setStartValue(startValue);
            rangeInterval.setEndValue(endValue);

            try {
                lengthRestriction.addRangeRestrictionInterval(rangeInterval);
            } catch (DataModelException e) {
                ParserException parserException = new ParserException(constructExtendedListenerErrorMessage(
                        UNHANDLED_PARSED_DATA, LENGTH_DATA, rangeArgument, ENTRY, e.getMessage()));
                parserException.setLine(ctx.getStart().getLine());
                parserException.setCharPosition(ctx.getStart().getCharPositionInLine());
                throw parserException;
            }
        }

        stringRestriction.setLengthRestriction(lengthRestriction);
    }
}