/*
 * 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.datamodel;

import java.io.Serializable;
import java.math.BigInteger;
import java.util.Iterator;
import java.util.ListIterator;

import org.onosproject.yangutils.datamodel.exceptions.DataModelException;
import org.onosproject.yangutils.datamodel.utils.DataModelUtils;
import org.onosproject.yangutils.datamodel.utils.Parsable;
import org.onosproject.yangutils.datamodel.utils.ResolvableStatus;
import org.onosproject.yangutils.datamodel.utils.YangConstructType;
import org.onosproject.yangutils.datamodel.utils.builtindatatype.DataTypeException;
import org.onosproject.yangutils.datamodel.utils.builtindatatype.YangDataTypes;
import org.onosproject.yangutils.datamodel.utils.builtindatatype.YangUint64;

import static org.onosproject.yangutils.datamodel.BuiltInTypeObjectFactory.getDataObjectFromString;
import static org.onosproject.yangutils.datamodel.utils.builtindatatype.YangDataTypeUtils.isOfRangeRestrictedType;
import static org.onosproject.yangutils.datamodel.utils.builtindatatype.YangDataTypes.DERIVED;

/*
 * Reference:RFC 6020.
 * The "type" statement takes as an argument a string that is the name
 *  of a YANG built-in type or a derived type, followed by an optional
 *  block of sub-statements that are used to put further restrictions
 *  on the type.
 *
 *  The restrictions that can be applied depend on the type being restricted.
 *  The type's sub-statements
 *
 * +------------------+---------+-------------+------------------------------------+
 * | substatement     | section | cardinality | mapped data type                   |
 * +------------------+---------+-------------+------------------------------------+
 * | bit              | 9.7.4   | 0..n        | - YangBit used in YangBits         |
 * | enum             | 9.6.4   | 0..n        | - YangEnum used in YangEnumeration |
 * | length           | 9.4.4   | 0..1        | - used for string                  |
 * | path             | 9.9.2   | 0..1        | - path for referred leaf/leaf-list |
 * | pattern          | 9.4.6   | 0..n        | - used for string                  |
 * | range            | 9.2.4   | 0..1        | - used for integer data type       |
 * | require-instance | 9.13.2  | 0..1        | - TODO instance-identifier         |
 * | type             | 7.4     | 0..n        | - TODO union                       |
 * +------------------+---------+-------------+------------------------------------+
 */

/**
 * Represents the data type information.
 *
 * @param <T> YANG data type info
 */
public class YangType<T>
        implements Parsable, Resolvable, Serializable {

    private static final long serialVersionUID = 8062016054L;

    /**
     * YANG node identifier.
     */
    private YangNodeIdentifier nodeIdentifier;

    /**
     * YANG data type.
     */
    private YangDataTypes dataType;

    /**
     * Additional information about data type, example restriction info, named
     * values, etc. The extra information is based on the data type. Based on
     * the data type, the extended info can vary.
     */
    private T dataTypeExtendedInfo;

    /**
     * Status of resolution. If completely resolved enum value is "RESOLVED",
     * if not enum value is "UNRESOLVED", in case reference of grouping/typedef
     * is added to uses/type but it's not resolved value of enum should be
     * "INTRA_FILE_RESOLVED".
     */
    private ResolvableStatus resolvableStatus;

    /**
     * Creates a YANG type object.
     */
    public YangType() {

        nodeIdentifier = new YangNodeIdentifier();
        resolvableStatus = ResolvableStatus.UNRESOLVED;
    }

    /**
     * Returns prefix associated with data type name.
     *
     * @return prefix associated with data type name
     */
    public String getPrefix() {
        return nodeIdentifier.getPrefix();
    }

    /**
     * Sets prefix associated with data type name.
     *
     * @param prefix prefix associated with data type name
     */
    public void setPrefix(String prefix) {
        nodeIdentifier.setPrefix(prefix);
    }

    /**
     * Returns the name of data type.
     *
     * @return the name of data type
     */
    public String getDataTypeName() {
        return nodeIdentifier.getName();
    }

    /**
     * Sets the name of the data type.
     *
     * @param typeName the name to set
     */
    public void setDataTypeName(String typeName) {
        nodeIdentifier.setName(typeName);
    }

    /**
     * Returns the type of data.
     *
     * @return the data type
     */
    public YangDataTypes getDataType() {
        return dataType;
    }

    /**
     * Sets the type of data.
     *
     * @param dataType data type
     */
    public void setDataType(YangDataTypes dataType) {
        this.dataType = dataType;
    }

    /**
     * Returns the data type meta data.
     *
     * @return the data type meta data
     */
    public T getDataTypeExtendedInfo() {
        return dataTypeExtendedInfo;
    }

    /**
     * Sets the data type meta data.
     *
     * @param dataTypeInfo the meta data to set
     */
    public void setDataTypeExtendedInfo(T dataTypeInfo) {
        this.dataTypeExtendedInfo = dataTypeInfo;
    }

    /**
     * Returns node identifier.
     *
     * @return node identifier
     */
    public YangNodeIdentifier getNodeIdentifier() {
        return nodeIdentifier;
    }

    /**
     * Sets node identifier.
     *
     * @param nodeIdentifier the node identifier
     */
    public void setNodeIdentifier(YangNodeIdentifier nodeIdentifier) {
        this.nodeIdentifier = nodeIdentifier;
    }

    /**
     * Resets the class attributes to its default value.
     */
    public void resetYangType() {
        nodeIdentifier = new YangNodeIdentifier();
        resolvableStatus = ResolvableStatus.UNRESOLVED;
        dataType = null;
        dataTypeExtendedInfo = null;
    }

    /**
     * Returns the type of the parsed data.
     *
     * @return returns TYPE_DATA
     */
    @Override
    public YangConstructType getYangConstructType() {
        return YangConstructType.TYPE_DATA;
    }

    /**
     * Validates the data on entering the corresponding parse tree node.
     *
     * @throws DataModelException a violation of data model rules
     */
    @Override
    public void validateDataOnEntry()
            throws DataModelException {
        // TODO auto-generated method stub, to be implemented by parser
    }

    /**
     * Validates the data on exiting the corresponding parse tree node.
     *
     * @throws DataModelException a violation of data model rules
     */
    @Override
    public void validateDataOnExit()
            throws DataModelException {
        // TODO auto-generated method stub, to be implemented by parser
    }

    @Override
    public ResolvableStatus getResolvableStatus() {
        return resolvableStatus;
    }

    @Override
    public void setResolvableStatus(ResolvableStatus resolvableStatus) {
        this.resolvableStatus = resolvableStatus;
    }

    @Override
    public Object resolve()
            throws DataModelException {
        /*
         * Check whether the data type is derived.
         */
        if (getDataType() != DERIVED) {
            throw new DataModelException("Linker Error: Resolve should only be called for derived data types.");
        }

        // Check if the derived info is present.
        YangDerivedInfo<?> derivedInfo = (YangDerivedInfo<?>) getDataTypeExtendedInfo();
        if (derivedInfo == null) {
            throw new DataModelException("Linker Error: Derived information is missing.");
        }

        // Initiate the resolution
        try {
            setResolvableStatus(derivedInfo.resolve());
        } catch (DataModelException e) {
            throw new DataModelException(e.getMessage());
        }
        return null;
    }

    /**
     * Validates the input data value against the permissible value for the
     * type as per the YANG file.
     *
     * @param value input data value
     * @throws DataModelException a violation of data model rules
     */
    public void isValidValue(String value) throws DataModelException {
        switch (getDataType()) {
            case INT8:
            case INT16:
            case INT32:
            case INT64:
            case UINT8:
            case UINT16:
            case UINT32:
            case UINT64: {
                if (getDataTypeExtendedInfo() == null) {
                    getDataObjectFromString(value, getDataType());
                } else {
                    if (!((YangRangeRestriction) getDataTypeExtendedInfo()).isValidValueString(value)) {
                        throw new DataTypeException("YANG file error : Input value \"" + value + "\" is not a valid " +
                                                            getDataType());
                    }
                }
                break;
            }
            case DECIMAL64: {
                // Fraction-Digits and range needs to get it from yang
                YangDecimal64<YangRangeRestriction> decimal64 =
                        (YangDecimal64<YangRangeRestriction>) getDataTypeExtendedInfo();
                validateDecimal64(value, decimal64.getFractionDigit(),
                                        decimal64.getRangeRestrictedExtendedInfo());
                break;
            }
            case STRING: {
                if (getDataTypeExtendedInfo() == null) {
                    break;
                } else if (!(((YangStringRestriction) getDataTypeExtendedInfo()).isValidStringOnLengthRestriction(value)
                        && ((YangStringRestriction) getDataTypeExtendedInfo())
                        .isValidStringOnPatternRestriction(value))) {
                    throw new DataTypeException("YANG file error : Input value \"" + value + "\" is not a valid " +
                                                        getDataType());
                }
                break;
            }
            case BOOLEAN:
                if (!(value.equals(DataModelUtils.TRUE) || value.equals(DataModelUtils.FALSE))) {
                    throw new DataTypeException("YANG file error : Input value \"" + value + "\" is not a valid " +
                                                        getDataType());
                }
                break;
            case ENUMERATION: {
                Iterator<YangEnum> iterator = ((YangEnumeration) getDataTypeExtendedInfo()).getEnumSet().iterator();
                boolean isValidated = false;
                while (iterator.hasNext()) {
                    YangEnum enumTemp = iterator.next();
                    if (enumTemp.getNamedValue().equals(value)) {
                        isValidated = true;
                        break;
                    }
                }

                if (!isValidated) {
                    throw new DataTypeException("YANG file error : Input value \"" + value + "\" is not a valid " +
                                                        getDataType());
                }
                break;
            }
            case BITS: {
                YangBits bits = (YangBits) getDataTypeExtendedInfo();
                if (bits.fromString(value) == null) {
                    throw new DataTypeException("YANG file error : Input value \"" + value + "\" is not a valid " +
                                                        getDataType());
                }
                break;
            }
            case BINARY: {
                if (!isValidBinary(value, (YangRangeRestriction) getDataTypeExtendedInfo())) {
                    throw new DataTypeException("YANG file error : Input value \"" + value + "\" is not a valid " +
                                                        getDataType());
                }
                break;
            }
            case LEAFREF: {
                YangLeafRef<?> leafRef = (YangLeafRef<?>) getDataTypeExtendedInfo();
                leafRef.validateDataOnExit();
                break;
            }
            case IDENTITYREF: {
                // TODO TBD
                break;
            }
            case EMPTY: {
                if (value.length() > 0) {
                    throw new DataTypeException("YANG file error : Input value \"" + value
                                                        + "\" is not allowed for a data type " + getDataType());
                }
                break;
            }
            case UNION: {
                ListIterator<YangType<?>> listIterator = ((YangUnion) getDataTypeExtendedInfo()).getTypeList()
                                                                                                .listIterator();
                boolean isValidated = false;
                while (listIterator.hasNext()) {
                    YangType<?> type = (YangType<?>) listIterator.next();
                    try {
                        type.isValidValue(value);
                        // If it is not thrown exception then validation is success
                        isValidated = true;
                        break;
                    } catch (Exception e) {
                    }
                }

                if (!isValidated) {
                    throw new DataTypeException("YANG file error : Input value \"" + value + "\" is not a valid " +
                                                        getDataType());
                }
                break;
            }
            case INSTANCE_IDENTIFIER: {
                // TODO TBD
                break;
            }
            case DERIVED: {
                YangDataTypes dataType = ((YangDerivedInfo) getDataTypeExtendedInfo()).getEffectiveBuiltInType();
                if (isOfRangeRestrictedType(dataType)) {
                    if (((YangDerivedInfo) getDataTypeExtendedInfo()).getResolvedExtendedInfo() == null) {
                        getDataObjectFromString(value,
                                                ((YangDerivedInfo) getDataTypeExtendedInfo())
                                                        .getEffectiveBuiltInType());
                    } else {
                        if (!((YangRangeRestriction) ((YangDerivedInfo) getDataTypeExtendedInfo())
                                .getResolvedExtendedInfo()).isValidValueString(value)) {
                            throw new DataTypeException("YANG file error : Input value \"" + value
                                                                + "\" is not a valid " + dataType);
                        }
                    }
                } else if (dataType == YangDataTypes.STRING) {
                    if (((YangDerivedInfo) getDataTypeExtendedInfo()).getResolvedExtendedInfo() != null) {
                        YangStringRestriction stringRestriction =
                                ((YangStringRestriction) ((YangDerivedInfo) getDataTypeExtendedInfo())
                                        .getResolvedExtendedInfo());
                        if (!(stringRestriction.isValidStringOnLengthRestriction(value) &&
                                stringRestriction.isValidStringOnPatternRestriction(value))) {
                            throw new DataTypeException("YANG file error : Input value \"" + value
                                                                + "\" is not a valid " + dataType);
                        }
                    }
                } else if (dataType == YangDataTypes.BITS) {
                    YangBits bits = (YangBits) getDataTypeExtendedInfo();
                    if (bits.fromString(value) == null) {
                        throw new DataTypeException("YANG file error : Input value \"" + value + "\" is not a valid " +
                                                            dataType);
                    }
                } else if (dataType == YangDataTypes.BINARY) {
                    if (!isValidBinary(value, (YangRangeRestriction) ((YangDerivedInfo)
                            getDataTypeExtendedInfo()).getResolvedExtendedInfo())) {
                        throw new DataTypeException("YANG file error : Input value \"" + value + "\" is not a valid " +
                                                            dataType);
                    }
                } else if (dataType == YangDataTypes.DECIMAL64) {
                    YangDerivedInfo derivedInfo = (YangDerivedInfo) getDataTypeExtendedInfo();
                    YangTypeDef typedef = (YangTypeDef) derivedInfo.getReferredTypeDef();
                    YangType<YangDecimal64> decimal64Type =
                            (YangType<YangDecimal64>) typedef.getTypeList().iterator().next();
                    YangDecimal64<YangRangeRestriction> decimal64 = decimal64Type.getDataTypeExtendedInfo();
                    // Fraction-Digits and range needs to get it from yang
                    validateDecimal64(value, decimal64.getFractionDigit(),
                                            decimal64.getRangeRestrictedExtendedInfo());
                }
                break;
            }
            default: {
                throw new DataTypeException("YANG file error : Input value \"" + value + "\" received for " +
                                                    "unsupported data type " + getDataType());
            }
        }
    }


    /**
     * Checks whether specific string is valid decimal64 value.
     *
     * @param value decimal64 value
     */
    private  void validateDecimal64(String value, int fractionDigit, YangRangeRestriction rangeRestriction)
            throws DataModelException {
        YangDecimal64<YangRangeRestriction> decimal64 = YangDecimal64.fromString(value);
        decimal64.setFractionDigit(fractionDigit);
        decimal64.setRangeRestrictedExtendedInfo(rangeRestriction);
        decimal64.validateDecimal64();
    }

    /**
     * Checks whether specific string is valid binary.
     *
     * @param value binary value
     * @return true if validation success otherwise false
     */
    private boolean isValidBinary(String value, YangRangeRestriction lengthRestriction) {
        YangBinary binary = new YangBinary(value);

        // After decoding binary, its length should not be zero
        if (binary.getBinaryData().length == 0) {
            return false;
        }

        if (lengthRestriction == null || lengthRestriction.getAscendingRangeIntervals() == null
                || lengthRestriction.getAscendingRangeIntervals().isEmpty()) {
            // Length restriction is optional
            return true;
        }

        ListIterator<YangRangeInterval<YangUint64>> rangeListIterator = lengthRestriction.getAscendingRangeIntervals()
                .listIterator();
        boolean isMatched = false;
        while (rangeListIterator.hasNext()) {
            YangRangeInterval rangeInterval = rangeListIterator.next();
            BigInteger startValue = ((YangUint64) rangeInterval.getStartValue()).getValue();
            BigInteger endValue = ((YangUint64) rangeInterval.getEndValue()).getValue();
            // convert (encode) back and check length
            if ((binary.toString().length() >= startValue.intValue()) &&
                    (binary.toString().length() <= endValue.intValue())) {
                isMatched = true;
                break;
            }
        }

        return isMatched;
    }
}