/*
 * 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.translator.tojava;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.onosproject.yangutils.datamodel.TraversalType;
import org.onosproject.yangutils.datamodel.YangAugment;
import org.onosproject.yangutils.datamodel.YangCase;
import org.onosproject.yangutils.datamodel.YangChoice;
import org.onosproject.yangutils.datamodel.YangInput;
import org.onosproject.yangutils.datamodel.YangLeaf;
import org.onosproject.yangutils.datamodel.YangLeafList;
import org.onosproject.yangutils.datamodel.YangNode;
import org.onosproject.yangutils.datamodel.YangNodeType;
import org.onosproject.yangutils.datamodel.YangOutput;
import org.onosproject.yangutils.datamodel.exceptions.DataModelException;
import org.onosproject.yangutils.translator.exception.InvalidNodeForTranslatorException;
import org.onosproject.yangutils.translator.exception.TranslatorException;
import org.onosproject.yangutils.utils.io.YangPluginConfig;

import static org.onosproject.yangutils.datamodel.TraversalType.CHILD;
import static org.onosproject.yangutils.datamodel.TraversalType.PARENT;
import static org.onosproject.yangutils.datamodel.TraversalType.ROOT;
import static org.onosproject.yangutils.datamodel.TraversalType.SIBILING;
import static org.onosproject.yangutils.datamodel.utils.GeneratedLanguage.JAVA_GENERATION;
import static org.onosproject.yangutils.translator.tojava.YangDataModelFactory.getYangCaseNode;
import static org.onosproject.yangutils.translator.tojava.YangJavaModelUtils.getAugmentClassName;
import static org.onosproject.yangutils.utils.UtilConstants.CASE;
import static org.onosproject.yangutils.utils.io.impl.YangIoUtils.getCapitalCase;
import static org.onosproject.yangutils.utils.io.impl.YangIoUtils.searchAndDeleteTempDir;

/**
 * Representation of java code generator based on application schema.
 */
public final class JavaCodeGeneratorUtil {

    private static final Log log = LogFactory.getLog(JavaCodeGeneratorUtil.class);
    /**
     * Current YANG node.
     */
    private static YangNode curNode;

    /**
     * Root node.
     */
    private static YangNode rootNode;

    private static int calls = 0;

    /**
     * Creates a java code generator utility object.
     */
    private JavaCodeGeneratorUtil() {
    }

    /**
     * Returns current YANG node.
     *
     * @return current YANG node
     */
    public static YangNode getCurNode() {
        return curNode;
    }

    /**
     * Sets current YANG node.
     *
     * @param node current YANG node
     */
    public static void setCurNode(YangNode node) {
        curNode = node;
    }

    /**
     * Generates Java code files corresponding to the YANG schema.
     *
     * @param rootNode   root node of the data model tree
     * @param yangPlugin YANG plugin config
     * @throws TranslatorException when fails to generate java code file the current node
     * @throws IOException         when fails to do IO operations
     */
    public static void generateJavaCode(YangNode rootNode, YangPluginConfig yangPlugin)
            throws TranslatorException, IOException {

        YangNode codeGenNode = rootNode;
        setRootNode(rootNode);
        TraversalType curTraversal = ROOT;

        while (codeGenNode != null) {
            if (codeGenNode instanceof YangAugment) {
                if (((YangAugment) codeGenNode).getAugmentedNode() instanceof YangChoice) {
                    addCaseNodeToChoiceTarget((YangAugment) codeGenNode);
                }
            }
            if (curTraversal != PARENT) {
                if (!(codeGenNode instanceof JavaCodeGenerator)) {
                    throw new TranslatorException("Unsupported node to generate code");
                }
                setCurNode(codeGenNode);
                try {
                    generateCodeEntry(codeGenNode, yangPlugin);
                    codeGenNode.setNameSpaceAndAddToParentSchemaMap();
                } catch (InvalidNodeForTranslatorException e) {
                    if (codeGenNode.getNextSibling() != null) {
                        curTraversal = SIBILING;
                        codeGenNode = codeGenNode.getNextSibling();
                    } else {
                        curTraversal = PARENT;
                        codeGenNode = codeGenNode.getParent();
                    }
                    continue;
                } catch (Exception e) {
                    if (log.isDebugEnabled()) {
                        e.printStackTrace();
                    }
                    close(codeGenNode, yangPlugin);
                    throw new TranslatorException(e.getMessage());
                }

            }
            if (curTraversal != PARENT && codeGenNode.getChild() != null) {
                curTraversal = CHILD;
                codeGenNode = codeGenNode.getChild();
            } else if (codeGenNode.getNextSibling() != null) {
                try {
                    generateCodeExit(codeGenNode, yangPlugin);
                } catch (Exception e) {
                    if (log.isDebugEnabled()) {
                        e.printStackTrace();
                    }
                    close(codeGenNode, yangPlugin);
                    throw new TranslatorException(e.getMessage());
                }
                curTraversal = SIBILING;
                codeGenNode = codeGenNode.getNextSibling();
            } else {
                try {
                    generateCodeExit(codeGenNode, yangPlugin);
                } catch (Exception e) {
                    if (log.isDebugEnabled()) {
                        e.printStackTrace();
                    }
                    close(codeGenNode, yangPlugin);
                    throw new TranslatorException(e.getMessage());
                }
                curTraversal = PARENT;
                codeGenNode = codeGenNode.getParent();
            }
        }
    }

    /**
     * Generates the current nodes code snippet.
     *
     * @param codeGenNode current data model node for which the code needs to be generated
     * @param yangPlugin  YANG plugin config
     * @throws TranslatorException when fails to generate java code file the current node
     * @throws IOException         when fails to do IO operations
     */
    private static void generateCodeEntry(YangNode codeGenNode, YangPluginConfig yangPlugin)
            throws TranslatorException, IOException {

        if (codeGenNode instanceof JavaCodeGenerator) {
            ((JavaCodeGenerator) codeGenNode).generateCodeEntry(yangPlugin);
        } else {
            close(codeGenNode, yangPlugin);
            throw new TranslatorException(
                    "Generated data model node cannot be translated to target language code");
        }
    }

    /**
     * Generates the current nodes code target code from the snippet.
     *
     * @param codeGenNode  current data model node for which the code needs to be generated
     * @param pluginConfig plugin configurations
     * @throws TranslatorException when fails to generate java code file the current node
     * @throws IOException         when fails to do IO operations
     */
    private static void generateCodeExit(YangNode codeGenNode, YangPluginConfig pluginConfig)
            throws TranslatorException, IOException {

        if (codeGenNode instanceof JavaCodeGenerator) {
            ((JavaCodeGenerator) codeGenNode).generateCodeExit();
        } else {
            close(codeGenNode, pluginConfig);
            throw new TranslatorException(
                    "Generated data model node cannot be translated to target language code");
        }
    }

    /**
     * Free other YANG nodes of data-model tree when error occurs while file generation of current node.
     */
    private static void freeRestResources() {

        YangNode freedNode = getCurNode();
        if (getCurNode() != null) {
            YangNode tempNode = freedNode;
            TraversalType curTraversal = ROOT;

            while (freedNode != tempNode.getParent()) {

                if (curTraversal != PARENT && freedNode.getChild() != null) {
                    curTraversal = CHILD;
                    freedNode = freedNode.getChild();
                } else if (freedNode.getNextSibling() != null) {
                    curTraversal = SIBILING;
                    if (freedNode != tempNode) {
                        free(freedNode);
                    }
                    freedNode = freedNode.getNextSibling();
                } else {
                    curTraversal = PARENT;
                    if (freedNode != tempNode) {
                        free(freedNode);
                    }
                    freedNode = freedNode.getParent();
                }
            }
        }
    }

    /**
     * Free the current node.
     *
     * @param node YANG node
     */
    private static void free(YangNode node) {

        YangNode parent = node.getParent();
        parent.setChild(null);

        if (node.getNextSibling() != null) {
            parent.setChild(node.getNextSibling());
        } else if (node.getPreviousSibling() != null) {
            parent.setChild(node.getPreviousSibling());
        }
        node = null;
    }

    /**
     * Delete Java code files corresponding to the YANG schema.
     *
     * @param rootNode         root node of data-model tree
     * @param yangPluginConfig plugin configurations
     * @throws IOException when fails to delete java code file the current node
     */
    public static void translatorErrorHandler(YangNode rootNode, YangPluginConfig yangPluginConfig)
            throws IOException {

        if (rootNode != null) {
            //Free other resources where translator has failed.
            freeRestResources();

            // Start removing all open files.
            YangNode tempNode = rootNode;
            setCurNode(tempNode.getChild());
            TraversalType curTraversal = ROOT;

            while (tempNode != null) {

                if (curTraversal != PARENT) {
                    close(tempNode, yangPluginConfig);
                }
                if (curTraversal != PARENT && tempNode.getChild() != null) {
                    curTraversal = CHILD;
                    tempNode = tempNode.getChild();
                } else if (tempNode.getNextSibling() != null) {
                    curTraversal = SIBILING;
                    tempNode = tempNode.getNextSibling();
                } else {
                    curTraversal = PARENT;
                    tempNode = tempNode.getParent();
                }
            }

            freeRestResources();
        }
    }

    /**
     * Closes all the current open file handles of node and delete all generated files.
     *
     * @param node       current YANG node
     * @param yangPlugin plugin configurations
     * @throws IOException when fails to do IO operations
     */
    private static void close(YangNode node, YangPluginConfig yangPlugin)
            throws IOException {
        if (node instanceof JavaCodeGenerator && ((TempJavaCodeFragmentFilesContainer) node)
                .getTempJavaCodeFragmentFiles() != null) {
            ((TempJavaCodeFragmentFilesContainer) node).getTempJavaCodeFragmentFiles().freeTemporaryResources(true);
        } else {

            if (getRootNode() != null) {
                JavaFileInfoTranslator javaFileInfo = ((JavaFileInfoContainer) getRootNode()).getJavaFileInfo();
                if (javaFileInfo != null) {
                    searchAndDeleteTempDir(javaFileInfo.getBaseCodeGenPath() +
                            javaFileInfo.getPackageFilePath());
                } else {
                    searchAndDeleteTempDir(yangPlugin.getCodeGenDir());
                }
            }
        }
    }

    /**
     * Returns root node.
     *
     * @return root node
     */
    private static YangNode getRootNode() {
        return rootNode;
    }

    /**
     * Sets root node.
     *
     * @param rootNode root node
     */
    private static void setRootNode(YangNode rootNode) {
        JavaCodeGeneratorUtil.rootNode = rootNode;
    }

    /**
     * Searches child node in data model tree.
     *
     * @param parentNode parent node
     * @param nodeType   node type
     * @param nodeName   node name
     * @return child node
     */
    public static YangNode searchYangNode(YangNode parentNode, YangNodeType nodeType, String nodeName) {
        YangNode child = parentNode.getChild();
        TraversalType curTraversal = ROOT;
        if (child == null) {
            throw new IllegalArgumentException("Given parent node does not contain any child nodes");
        }

        while (child != null) {
            if (curTraversal != PARENT) {
                if (child instanceof YangInput || child instanceof YangOutput) {
                    if (child.getNodeType().equals(nodeType)) {
                        return child;
                    }
                } else if (child.getName().equals(nodeName) && child.getNodeType().equals(nodeType)) {
                    return child;
                }
            }
            if (curTraversal != PARENT && child.getChild() != null) {
                curTraversal = CHILD;
                child = child.getChild();
            } else if (child.getNextSibling() != null) {
                curTraversal = SIBILING;
                child = child.getNextSibling();
            } else {
                curTraversal = PARENT;
                child = child.getParent();
            }
        }
        return null;
    }

    /**
     * Adds a case node in augment when augmenting a choice node.
     *
     * @param augment augment node
     */
    private static void addCaseNodeToChoiceTarget(YangAugment augment) {
        calls++;
        if (calls == 1) {
            YangCase javaCase = getYangCaseNode(JAVA_GENERATION);

            YangPluginConfig pluginConfig = new YangPluginConfig();
            javaCase.setName(getAugmentClassName(augment, pluginConfig) + getCapitalCase(CASE));

            if (augment.getListOfLeaf() != null) {
                for (YangLeaf leaf : augment.getListOfLeaf()) {
                    javaCase.addLeaf(leaf);
                }
                augment.getListOfLeaf().clear();
            }
            if (augment.getListOfLeafList() != null) {
                for (YangLeafList leafList : augment.getListOfLeafList()) {
                    javaCase.addLeafList(leafList);
                }
                augment.getListOfLeafList().clear();
            }
            YangNode child = augment.getChild();
            List<YangNode> childNodes = new ArrayList<>();
            while (child != null) {
                child.setParent(javaCase);
                childNodes.add(child);
                child = child.getNextSibling();
            }
            augment.setChild(null);
            try {
                augment.addChild(javaCase);
                for (YangNode node : childNodes) {
                    node.setNextSibling(null);
                    node.setPreviousSibling(null);
                    javaCase.addChild(node);
                }
            } catch (DataModelException e) {
                throw new TranslatorException("Failed to add child nodes to case node of augment " + augment.getName());
            }
        }
    }
}