/*
 * Copyright 2016-2019 Red Hat, Inc. and/or its affiliates
 * and other contributors as indicated by the @author tags.
 *
 * 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.jboss.galleon.xml;

import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
import javax.xml.namespace.QName;
import javax.xml.stream.XMLStreamConstants;
import javax.xml.stream.XMLStreamException;

import org.jboss.galleon.spec.PackageSpec;
import org.jboss.galleon.util.ParsingUtils;
import org.jboss.staxmapper.XMLExtendedStreamReader;


/**
 *
 * @author Alexey Loubyansky
 */
public class PackageXmlParser20 implements PlugableXmlParser<PackageSpec.Builder> {

    public static final String NAMESPACE_2_0 = "urn:jboss:galleon:package:2.0";
    public static final QName ROOT_2_0 = new QName(NAMESPACE_2_0, Element.PACKAGE_SPEC.getLocalName());

    public enum Element implements XmlNameProvider {

        DEPENDENCIES("dependencies"),
        PACKAGE_SPEC("package-spec"),

        // default unknown element
        UNKNOWN(null);

        private static final Map<QName, Element> elements;

        static {
            elements = new HashMap<>(3);
            elements.put(new QName(NAMESPACE_2_0, DEPENDENCIES.name), DEPENDENCIES);
            elements.put(new QName(NAMESPACE_2_0, PACKAGE_SPEC.name), PACKAGE_SPEC);
            elements.put(null, UNKNOWN);
        }

        static Element of(QName qName) {
            QName name;
            if (qName.getNamespaceURI().equals("")) {
                name = new QName(NAMESPACE_2_0, qName.getLocalPart());
            } else {
                name = qName;
            }
            final Element element = elements.get(name);
            return element == null ? UNKNOWN : element;
        }

        private final String name;
        private final String namespace = NAMESPACE_2_0;

        Element(final String name) {
            this.name = name;
        }

        /**
         * Get the local name of this element.
         *
         * @return the local name
         */
        @Override
        public String getLocalName() {
            return name;
        }

        @Override
        public String getNamespace() {
            return namespace;
        }
    }

    enum Attribute implements XmlNameProvider {

        NAME("name"),
        // default unknown attribute
        UNKNOWN(null);

        private static final Map<QName, Attribute> attributes;

        static {
            attributes = new HashMap<>(2);
            attributes.put(new QName(NAME.name), NAME);
            attributes.put(null, UNKNOWN);
        }

        static Attribute of(QName qName) {
            final Attribute attribute = attributes.get(qName);
            return attribute == null ? UNKNOWN : attribute;
        }

        private final String name;

        Attribute(final String name) {
            this.name = name;
        }

        /**
         * Get the local name of this element.
         *
         * @return the local name
         */
        @Override
        public String getLocalName() {
            return name;
        }

        @Override
        public String getNamespace() {
            return null;
        }
    }

    @Override
    public void plugin(XmlParsers parsers) {
        parsers.plugin(ROOT_2_0, this);
    }

    @Override
    public QName getRoot() {
        return ROOT_2_0;
    }

    @Override
    public void readElement(XMLExtendedStreamReader reader, PackageSpec.Builder pkgBuilder) throws XMLStreamException {
        pkgBuilder.setName(parseName(reader, false));
        while (reader.hasNext()) {
            switch (reader.nextTag()) {
                case XMLStreamConstants.END_ELEMENT: {
                    return;
                }
                case XMLStreamConstants.START_ELEMENT: {
                    final Element element = Element.of(reader.getName());
                    switch (element) {
                        case DEPENDENCIES:
                            PackageDepsSpecXmlParser.parsePackageDeps(Element.DEPENDENCIES, reader, pkgBuilder);
                            break;
                        default:
                            throw ParsingUtils.unexpectedContent(reader);
                    }
                    break;
                }
                default: {
                    throw ParsingUtils.unexpectedContent(reader);
                }
            }
        }
        throw ParsingUtils.endOfDocument(reader.getLocation());
    }

    private String parseName(final XMLExtendedStreamReader reader, boolean exclusive) throws XMLStreamException {
        final int count = reader.getAttributeCount();
        String path = null;
        boolean parsedTarget = false;
        for (int i = 0; i < count; i++) {
            final Attribute attribute = Attribute.of(reader.getAttributeName(i));
            switch (attribute) {
                case NAME:
                    path = reader.getAttributeValue(i);
                    parsedTarget = true;
                    break;
                default:
                    throw ParsingUtils.unexpectedContent(reader);
            }
        }
        if (!parsedTarget) {
            throw ParsingUtils.missingAttributes(reader.getLocation(), Collections.singleton(Attribute.NAME));
        }
        if(exclusive) {
            ParsingUtils.parseNoContent(reader);
        }
        return path;
    }
}
