/*
 * 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.utils;

import org.onosproject.yangutils.datamodel.CollisionDetector;
import org.onosproject.yangutils.datamodel.ResolvableType;
import org.onosproject.yangutils.datamodel.YangAtomicPath;
import org.onosproject.yangutils.datamodel.YangAugment;
import org.onosproject.yangutils.datamodel.YangBase;
import org.onosproject.yangutils.datamodel.YangEntityToResolveInfoImpl;
import org.onosproject.yangutils.datamodel.YangEnumeration;
import org.onosproject.yangutils.datamodel.YangIdentityRef;
import org.onosproject.yangutils.datamodel.YangIfFeature;
import org.onosproject.yangutils.datamodel.YangImport;
import org.onosproject.yangutils.datamodel.YangLeaf;
import org.onosproject.yangutils.datamodel.YangLeafList;
import org.onosproject.yangutils.datamodel.YangLeafRef;
import org.onosproject.yangutils.datamodel.YangLeavesHolder;
import org.onosproject.yangutils.datamodel.YangModule;
import org.onosproject.yangutils.datamodel.YangNode;
import org.onosproject.yangutils.datamodel.YangReferenceResolver;
import org.onosproject.yangutils.datamodel.YangResolutionInfo;
import org.onosproject.yangutils.datamodel.YangRpc;
import org.onosproject.yangutils.datamodel.YangType;
import org.onosproject.yangutils.datamodel.YangUnion;
import org.onosproject.yangutils.datamodel.YangUses;
import org.onosproject.yangutils.datamodel.exceptions.DataModelException;
import org.onosproject.yangutils.datamodel.utils.builtindatatype.YangDataTypes;

import java.io.FileInputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.Set;

/**
 * Represents utilities for data model tree.
 */
public final class DataModelUtils {

    /**
     * Creates a new data model tree utility.
     */
    private DataModelUtils() {
    }

    /**
     * Detects the colliding identifier name in a given YANG node and its child.
     *
     * @param identifierName name for which collision detection is to be checked
     * @param dataType       type of YANG node asking for detecting collision
     * @param node           instance of calling node
     * @throws DataModelException a violation of data model rules
     */
    public static void detectCollidingChildUtil(String identifierName, YangConstructType dataType, YangNode node)
            throws DataModelException {
        if (dataType == YangConstructType.USES_DATA || dataType == YangConstructType.GROUPING_DATA) {
            detectCollidingForUsesGrouping(identifierName, dataType, node);
        } else {
            if (node instanceof YangLeavesHolder) {
                YangLeavesHolder leavesHolder = (YangLeavesHolder) node;
                detectCollidingLeaf(leavesHolder.getListOfLeaf(), identifierName);
                detectCollidingLeafList(leavesHolder.getListOfLeafList(), identifierName);
            }
            node = node.getChild();
            while (node != null) {
                Parsable parsable = (Parsable) node;
                if (node instanceof CollisionDetector
                        && parsable.getYangConstructType() != YangConstructType.USES_DATA
                        && parsable.getYangConstructType() != YangConstructType.GROUPING_DATA) {
                    ((CollisionDetector) node).detectSelfCollision(identifierName, dataType);
                }
                node = node.getNextSibling();
            }
        }
    }

    /**
     * Detects colliding of uses and grouping only with uses and grouping respectively.
     *
     * @param identifierName name for which collision detection is to be checked
     * @param dataType       type of YANG node asking for detecting collision
     * @param node           node instance of calling node
     * @throws DataModelException a violation of data model rules
     */
    public static void detectCollidingForUsesGrouping(String identifierName, YangConstructType dataType, YangNode node)
            throws DataModelException {

        node = node.getChild();
        while (node != null) {
            Parsable parsable = (Parsable) node;
            if (node instanceof CollisionDetector
                    && parsable.getYangConstructType() == dataType) {
                ((CollisionDetector) node).detectSelfCollision(identifierName, dataType);
            }
            node = node.getNextSibling();
        }
    }

    /**
     * Detects the colliding identifier name in a given leaf node.
     *
     * @param listOfLeaf     List of leaves to detect collision
     * @param identifierName name for which collision detection is to be checked
     * @throws DataModelException a violation of data model rules
     */
    private static void detectCollidingLeaf(List<YangLeaf> listOfLeaf, String identifierName)
            throws DataModelException {

        if (listOfLeaf == null) {
            return;
        }
        for (YangLeaf leaf : listOfLeaf) {
            if (leaf.getName().equals(identifierName)) {
                throw new DataModelException("YANG file error: Duplicate input identifier detected, same as leaf \""
                        + leaf.getName() + "\"");
            }
        }
    }

    /**
     * Detects the colliding identifier name in a given leaf-list node.
     *
     * @param listOfLeafList list of leaf-lists to detect collision
     * @param identifierName name for which collision detection is to be checked
     * @throws DataModelException a violation of data model rules
     */
    private static void detectCollidingLeafList(List<YangLeafList> listOfLeafList, String identifierName)
            throws DataModelException {

        if (listOfLeafList == null) {
            return;
        }
        for (YangLeafList leafList : listOfLeafList) {
            if (leafList.getName().equals(identifierName)) {
                throw new DataModelException("YANG file error: Duplicate input identifier detected, same as leaf " +
                        "list \"" + leafList.getName() + "\"");
            }
        }
    }

    /**
     * Add a resolution information.
     *
     * @param resolutionInfo information about the YANG construct which has to be resolved
     * @throws DataModelException a violation of data model rules
     */
    public static void addResolutionInfo(YangResolutionInfo resolutionInfo)
            throws DataModelException {

        /* get the module node to add maintain the list of nested reference */
        YangNode curNode = resolutionInfo.getEntityToResolveInfo()
                .getHolderOfEntityToResolve();
        while (!(curNode instanceof YangReferenceResolver)) {
            curNode = curNode.getParent();
            if (curNode == null) {
                throw new DataModelException("Internal datamodel error: Datamodel tree is not correct");
            }
        }
        YangReferenceResolver resolutionNode = (YangReferenceResolver) curNode;

        if (resolutionInfo.getEntityToResolveInfo()
                .getEntityToResolve() instanceof YangType) {
            resolutionNode.addToResolutionList(resolutionInfo,
                    ResolvableType.YANG_DERIVED_DATA_TYPE);
        } else if (resolutionInfo.getEntityToResolveInfo()
                .getEntityToResolve() instanceof YangUses) {
            resolutionNode.addToResolutionList(resolutionInfo,
                    ResolvableType.YANG_USES);
        } else if (resolutionInfo.getEntityToResolveInfo()
                .getEntityToResolve() instanceof YangAugment) {
            resolutionNode.addToResolutionList(resolutionInfo,
                    ResolvableType.YANG_AUGMENT);
        } else if (resolutionInfo.getEntityToResolveInfo()
                .getEntityToResolve() instanceof YangIfFeature) {
            resolutionNode.addToResolutionList(resolutionInfo,
                    ResolvableType.YANG_IF_FEATURE);
        } else if (resolutionInfo.getEntityToResolveInfo()
                .getEntityToResolve() instanceof YangLeafRef) {
            resolutionNode.addToResolutionList(resolutionInfo,
                    ResolvableType.YANG_LEAFREF);
        } else if (resolutionInfo.getEntityToResolveInfo().getEntityToResolve() instanceof YangBase) {
            resolutionNode.addToResolutionList(resolutionInfo, ResolvableType.YANG_BASE);
        } else if (resolutionInfo.getEntityToResolveInfo().getEntityToResolve() instanceof YangIdentityRef) {
            resolutionNode.addToResolutionList(resolutionInfo, ResolvableType.YANG_IDENTITYREF);
        }
    }

    /**
     * Resolve linking for a resolution list.
     *
     * @param resolutionList    resolution list for which linking to be done
     * @param dataModelRootNode module/sub-module node
     * @throws DataModelException a violation of data model rules
     */
    public static void resolveLinkingForResolutionList(List<YangResolutionInfo> resolutionList,
                                                       YangReferenceResolver dataModelRootNode)
            throws DataModelException {

        for (YangResolutionInfo resolutionInfo : resolutionList) {
            resolutionInfo.resolveLinkingForResolutionInfo(dataModelRootNode);
        }
    }

    /**
     * Links type/uses referring to typedef/uses of inter YANG file.
     *
     * @param resolutionList    resolution list for which linking to be done
     * @param dataModelRootNode module/sub-module node
     * @throws DataModelException a violation of data model rules
     */
    public static void linkInterFileReferences(List<YangResolutionInfo> resolutionList,
                                               YangReferenceResolver dataModelRootNode)
            throws DataModelException {
        /*
         * Run through the resolution list, find type/uses referring to inter
         * file typedef/grouping, ask for linking.
         */
        for (YangResolutionInfo resolutionInfo : resolutionList) {
            resolutionInfo.linkInterFile(dataModelRootNode);
        }
    }

    /**
     * Checks if there is any rpc defined in the module or sub-module.
     *
     * @param rootNode root node of the data model
     * @return status of rpc's existence
     */
    public static boolean isRpcChildNodePresent(YangNode rootNode) {
        YangNode childNode = rootNode.getChild();
        while (childNode != null) {
            if (childNode instanceof YangRpc) {
                return true;
            }
            childNode = childNode.getNextSibling();
        }
        return false;
    }

    /**
     * Returns referred node in a given set.
     *
     * @param yangNodeSet YANG node set
     * @param refNodeName name of the node which is referred
     * @return referred node's reference
     */
    public static YangNode findReferredNode(Set<YangNode> yangNodeSet, String refNodeName) {
        /*
         * Run through the YANG files to see which YANG file matches the
         * referred node name.
         */
        for (YangNode yangNode : yangNodeSet) {
            if (yangNode.getName().equals(refNodeName)) {
                return yangNode;
            }
        }
        return null;
    }

    /**
     * Returns the contained data model parent node.
     *
     * @param currentNode current node which parent contained node is required
     * @return parent node in which the current node is an attribute
     */
    public static YangNode getParentNodeInGenCode(YangNode currentNode) {

        /*
         * TODO: recursive parent lookup to support choice/augment/uses. TODO:
         * need to check if this needs to be updated for
         * choice/case/augment/grouping
         */
        return currentNode.getParent();
    }

    /**
     * Returns de-serializes YANG data-model nodes.
     *
     * @param serializableInfoSet YANG file info set
     * @return de-serializes YANG data-model nodes
     * @throws IOException when fails do IO operations
     */
    public static List<YangNode> deSerializeDataModel(List<String> serializableInfoSet) throws IOException {

        List<YangNode> nodes = new ArrayList<>();
        for (String fileInfo : serializableInfoSet) {
            YangNode node = null;
            try {
                FileInputStream fileInputStream = new FileInputStream(fileInfo);
                ObjectInputStream objectInputStream = new ObjectInputStream(fileInputStream);
                node = (YangNode) objectInputStream.readObject();
                nodes.add(node);
                objectInputStream.close();
                fileInputStream.close();
            } catch (IOException | ClassNotFoundException e) {
                throw new IOException(fileInfo + " not found.");
            }
        }
        return nodes;
    }

    /**
     * Clones the list of leaves and list of leaf list in the leaves holder.
     *
     * @param leavesHolder YANG node potentially containing leaves or leaf lists
     * @param yangUses     instance of YANG uses
     * @throws CloneNotSupportedException clone is not supported
     * @throws DataModelException         data model error
     */
    public static void cloneLeaves(YangLeavesHolder leavesHolder, YangUses yangUses)
            throws CloneNotSupportedException, DataModelException {
        List<YangLeaf> currentListOfLeaves = leavesHolder.getListOfLeaf();
        if (currentListOfLeaves != null) {
            List<YangLeaf> clonedLeavesList = new LinkedList<YangLeaf>();
            for (YangLeaf leaf : currentListOfLeaves) {
                YangLeaf clonedLeaf = leaf.clone();
                if (yangUses.getCurrentGroupingDepth() == 0) {
                    YangEntityToResolveInfoImpl resolveInfo =
                            resolveLeafrefUnderGroupingForLeaf(clonedLeaf, leavesHolder, yangUses);
                    if (resolveInfo != null) {
                        yangUses.addEntityToResolve(resolveInfo);
                    }
                }
                clonedLeaf.setContainedIn(leavesHolder);
                clonedLeavesList.add(clonedLeaf);
            }
            leavesHolder.setListOfLeaf(clonedLeavesList);
        }

        List<YangLeafList> currentListOfLeafList = leavesHolder.getListOfLeafList();
        if (currentListOfLeafList != null) {
            List<YangLeafList> clonedListOfLeafList = new LinkedList<YangLeafList>();
            for (YangLeafList leafList : currentListOfLeafList) {
                YangLeafList clonedLeafList = leafList.clone();
                if (yangUses.getCurrentGroupingDepth() == 0) {
                    YangEntityToResolveInfoImpl resolveInfo =
                            resolveLeafrefUnderGroupingForLeafList(clonedLeafList, leavesHolder);
                    if (resolveInfo != null) {
                        yangUses.addEntityToResolve(resolveInfo);
                    }
                }
                clonedLeafList.setContainedIn(leavesHolder);
                clonedListOfLeafList.add(clonedLeafList);
            }
            leavesHolder.setListOfLeafList(clonedListOfLeafList);
        }
    }

    /**
     * Resolves leafref in leaf, which are under grouping by adding it to the resolution list.
     *
     * @param clonedLeaf       cloned leaf in uses from grouping
     * @param leafParentHolder holder of the leaf from uses
     * @return entity of leafref which has to be resolved
     * @throws DataModelException data model error
     */
    public static YangEntityToResolveInfoImpl resolveLeafrefUnderGroupingForLeaf(YangLeaf clonedLeaf,
                                                                                 YangLeavesHolder leafParentHolder,
                                                                                 YangUses yangUses) throws
            DataModelException {
        if (clonedLeaf.getDataType().getDataTypeExtendedInfo() instanceof YangLeafRef) {
            YangLeafRef leafrefForCloning = (YangLeafRef) clonedLeaf.getDataType().getDataTypeExtendedInfo();
            // Conversion of prefixes in absolute path while cloning them.
            convertThePrefixesDuringChange(leafrefForCloning, yangUses);
            leafrefForCloning.setParentNodeOfLeafref((YangNode) leafParentHolder);
            YangEntityToResolveInfoImpl yangEntityToResolveInfo = new YangEntityToResolveInfoImpl();
            yangEntityToResolveInfo.setEntityToResolve(leafrefForCloning);
            yangEntityToResolveInfo.setHolderOfEntityToResolve((YangNode) leafParentHolder);
            yangEntityToResolveInfo.setLineNumber(leafrefForCloning.getLineNumber());
            yangEntityToResolveInfo.setCharPosition(leafrefForCloning.getCharPosition());
            return yangEntityToResolveInfo;
        }
        return null;
    }

    /**
     * Converts the prefixes in all the nodes of the leafref with respect to the uses node.
     *
     * @param leafrefForCloning leafref that is to be cloned
     * @param yangUses          instance of YANG uses where cloning is done
     * @throws DataModelException data model error
     */
    private static void convertThePrefixesDuringChange(YangLeafRef leafrefForCloning, YangUses yangUses) throws
            DataModelException {
        List<YangAtomicPath> atomicPathList = leafrefForCloning.getAtomicPath();
        if (atomicPathList != null && !atomicPathList.isEmpty()) {
            Iterator<YangAtomicPath> atomicPathIterator = atomicPathList.listIterator();
            while (atomicPathIterator.hasNext()) {
                YangAtomicPath atomicPath = atomicPathIterator.next();
                Map<String, String> prefixesAndItsImportNameNode = leafrefForCloning.getPrefixAndItsImportedModule();
                if (!prefixesAndItsImportNameNode.isEmpty() || prefixesAndItsImportNameNode != null) {
                    String prefixInPath = atomicPath.getNodeIdentifier().getPrefix();
                    String importedNodeName = prefixesAndItsImportNameNode.get(prefixInPath);
                    assignCurrentLeafrefWithNewPrefixes(importedNodeName, atomicPath, yangUses);
                }
            }
        }
    }

    /**
     * Assigns leafref with new prefixes while cloning.
     *
     * @param importedNodeName imported node name from grouping
     * @param atomicPath       atomic path in leafref
     * @param node             instance of YANG uses where cloning is done
     * @throws DataModelException data model error
     */
    private static void assignCurrentLeafrefWithNewPrefixes(String importedNodeName, YangAtomicPath atomicPath,
                                                            YangNode node) throws DataModelException {
        while (!(node instanceof YangReferenceResolver)) {
            node = node.getParent();
            if (node == null) {
                throw new DataModelException("Internal datamodel error: Datamodel tree is not correct");
            }
        }
        if (node instanceof YangModule) {
            List<YangImport> importInUsesList = ((YangModule) node).getImportList();
            if (importInUsesList != null && !importInUsesList.isEmpty()) {
                Iterator<YangImport> importInUsesListIterator = importInUsesList.listIterator();
                while (importInUsesListIterator.hasNext()) {
                    YangImport importInUsesNode = importInUsesListIterator.next();
                    if (importInUsesNode.getModuleName().equals(importedNodeName)) {
                        atomicPath.getNodeIdentifier().setPrefix(importInUsesNode.getPrefixId());
                    }
                }
            }
        }
    }

    /**
     * Resolves leafref in leaf-list, which are under grouping by adding it to the resolution list.
     *
     * @param clonedLeafList       cloned leaf-list in uses from grouping
     * @param leafListParentHolder holder of the leaf-list from uses
     * @return entity of leafref which has to be resolved
     * @throws DataModelException data model error
     */
    public static YangEntityToResolveInfoImpl resolveLeafrefUnderGroupingForLeafList(YangLeafList clonedLeafList,
                                                                                     YangLeavesHolder
                                                                                             leafListParentHolder)
            throws DataModelException {
        if (clonedLeafList.getDataType().getDataTypeExtendedInfo() instanceof YangLeafRef) {
            YangLeafRef leafrefForCloning = (YangLeafRef) clonedLeafList.getDataType().getDataTypeExtendedInfo();
            leafrefForCloning.setParentNodeOfLeafref((YangNode) leafListParentHolder);
            YangEntityToResolveInfoImpl yangEntityToResolveInfo = new YangEntityToResolveInfoImpl();
            yangEntityToResolveInfo.setEntityToResolve(leafrefForCloning);
            yangEntityToResolveInfo.setHolderOfEntityToResolve((YangNode) leafListParentHolder);
            yangEntityToResolveInfo.setLineNumber(leafrefForCloning.getLineNumber());
            yangEntityToResolveInfo.setCharPosition(leafrefForCloning.getCharPosition());
            return yangEntityToResolveInfo;
        }
        return null;
    }

    /**
     * Clones the union or enum leaves. If there is any cloned leaves whose type is union/enum then the corresponding
     * type info needs to be updated to the cloned new type node.
     *
     * @param leavesHolder cloned leaves holder, for whom the leaves reference needs to be updated
     * @throws DataModelException when fails to do data model operations
     */
    public static void updateClonedLeavesUnionEnumRef(YangLeavesHolder leavesHolder) throws DataModelException {
        List<YangLeaf> currentListOfLeaves = leavesHolder.getListOfLeaf();
        if (currentListOfLeaves != null) {
            for (YangLeaf leaf : currentListOfLeaves) {
                if (leaf.getDataType().getDataType() == YangDataTypes.ENUMERATION
                        || leaf.getDataType().getDataType() == YangDataTypes.UNION) {
                    try {
                        updateClonedTypeRef(leaf.getDataType(), leavesHolder);
                    } catch (DataModelException e) {
                        throw e;
                    }
                }
            }

        }

        List<YangLeafList> currentListOfLeafList = leavesHolder.getListOfLeafList();
        if (currentListOfLeafList != null) {
            for (YangLeafList leafList : currentListOfLeafList) {
                if (leafList.getDataType().getDataType() == YangDataTypes.ENUMERATION
                        || leafList.getDataType().getDataType() == YangDataTypes.UNION) {
                    try {
                        updateClonedTypeRef(leafList.getDataType(), leavesHolder);
                    } catch (DataModelException e) {
                        throw e;
                    }
                }
            }
        }
    }

    /**
     * Updates the types extended info pointer to point to the cloned type node.
     *
     * @param dataType     data type, whose extended info needs to be pointed to the cloned type
     * @param leavesHolder the leaves holder having the cloned type
     */
    private static void updateClonedTypeRef(YangType dataType, YangLeavesHolder leavesHolder)
            throws DataModelException {
        if (!(leavesHolder instanceof YangNode)) {
            throw new DataModelException("Data model error: cloned leaves holder is not a node");
        }
        YangNode potentialTypeNode = ((YangNode) leavesHolder).getChild();
        while (potentialTypeNode != null) {
            String dataTypeName = null;
            if (dataType.getDataType() == YangDataTypes.ENUMERATION) {
                YangEnumeration enumNode = (YangEnumeration) dataType.getDataTypeExtendedInfo();
                dataTypeName = enumNode.getName();
            } else if (dataType.getDataType() == YangDataTypes.UNION) {
                YangUnion unionNode = (YangUnion) dataType.getDataTypeExtendedInfo();
                dataTypeName = unionNode.getName();
            }
            if (potentialTypeNode.getName().contentEquals(dataTypeName)) {
                dataType.setDataTypeExtendedInfo((Object) potentialTypeNode);
                return;
            }
            potentialTypeNode = potentialTypeNode.getNextSibling();
        }

        throw new DataModelException("Data model error: cloned leaves type is not found");
    }
}