/*
 * Copyright 2011-17 Fraunhofer ISE, energy & meteo Systems GmbH and other contributors
 *
 * 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.openmuc.openiec61850;

import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;

/**
 * ObjectReference syntax: LDName/LNName.DOName[.Name[. ...]]
 * 
 */
public final class ObjectReference implements Iterable<String> {

    private final String objectReference;
    private List<String> nodeNames = null;

    // if the ObjectReference contains an array index this variable will save
    // its position in the nodeNames List
    private int arrayIndexPosition = -1;

    public ObjectReference(String objectReference) {
        if (objectReference == null || objectReference.isEmpty()) {
            throw new IllegalArgumentException();
        }
        this.objectReference = objectReference;
    }

    /**
     * @return Returns name part of the reference.
     */
    public String getName() {
        if (nodeNames == null) {
            parseForNameList();
        }
        return nodeNames.get(nodeNames.size() - 1);
    }

    @Override
    public String toString() {
        return objectReference;
    }

    public boolean isLogicalDeviceRef() {
        if (nodeNames == null) {
            parseForNameList();
        }
        return (nodeNames.size() == 1);
    }

    public boolean isLogicalNodeRef() {
        if (nodeNames == null) {
            parseForNameList();
        }
        return (nodeNames.size() == 2);
    }

    public boolean isDataRef() {
        if (nodeNames == null) {
            parseForNameList();
        }
        return (nodeNames.size() > 2);
    }

    int getArrayIndexPosition() {
        if (nodeNames == null) {
            parseForNameList();
        }
        return arrayIndexPosition;
    }

    @Override
    public Iterator<String> iterator() {
        if (nodeNames == null) {
            parseForNameList();
        }
        return nodeNames.iterator();
    }

    public String get(int i) {
        if (nodeNames == null) {
            parseForNameList();
        }
        return nodeNames.get(i);
    }

    public int size() {
        if (nodeNames == null) {
            parseForNameList();
        }
        return nodeNames.size();
    }

    private void parseForNameList() {

        nodeNames = new LinkedList<>();

        int lastDelim = -1;
        int nextDelim = objectReference.indexOf('/');
        if (nextDelim == -1) {
            nodeNames.add(objectReference.substring(lastDelim + 1, objectReference.length()));
            return;
        }

        nodeNames.add(objectReference.substring(lastDelim + 1, nextDelim));

        int dotIndex = -1;
        int openingbracketIndex = -1;
        int closingbracketIndex = -1;
        while (true) {
            lastDelim = nextDelim;
            if (dotIndex == -1) {
                dotIndex = objectReference.indexOf('.', lastDelim + 1);
                if (dotIndex == -1) {
                    dotIndex = objectReference.length();
                }
            }
            if (openingbracketIndex == -1) {
                openingbracketIndex = objectReference.indexOf('(', lastDelim + 1);
                if (openingbracketIndex == -1) {
                    openingbracketIndex = objectReference.length();
                }
            }
            if (closingbracketIndex == -1) {
                closingbracketIndex = objectReference.indexOf(')', lastDelim + 1);
                if (closingbracketIndex == -1) {
                    closingbracketIndex = objectReference.length();
                }
            }

            if (dotIndex == openingbracketIndex && dotIndex == closingbracketIndex) {
                nodeNames.add(objectReference.substring(lastDelim + 1, objectReference.length()));
                return;
            }

            if (dotIndex < openingbracketIndex && dotIndex < closingbracketIndex) {
                nextDelim = dotIndex;
                dotIndex = -1;
            }
            else if (openingbracketIndex < dotIndex && openingbracketIndex < closingbracketIndex) {
                nextDelim = openingbracketIndex;
                openingbracketIndex = -1;
                arrayIndexPosition = nodeNames.size() + 1;
            }
            else if (closingbracketIndex < dotIndex && closingbracketIndex < openingbracketIndex) {
                if (closingbracketIndex == (objectReference.length() - 1)) {
                    nodeNames.add(objectReference.substring(lastDelim + 1, closingbracketIndex));
                    return;
                }
                nextDelim = closingbracketIndex;
                closingbracketIndex = -1;
            }
            nodeNames.add(objectReference.substring(lastDelim + 1, nextDelim));
        }
    }
}
