/**
 * (The MIT License)
 *
 * Copyright (c) 2008 - 2011:
 *
 * * {Aaron Patterson}[http://tenderlovemaking.com]
 * * {Mike Dalessio}[http://mike.daless.io]
 * * {Charles Nutter}[http://blog.headius.com]
 * * {Sergio Arbeo}[http://www.serabe.com]
 * * {Patrick Mahoney}[http://polycrystal.org]
 * * {Yoko Harada}[http://yokolet.blogspot.com]
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * 'Software'), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 * 
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
 * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

package nokogiri;

import static nokogiri.internals.NokogiriHelpers.getLocalNameForNamespace;
import static nokogiri.internals.NokogiriHelpers.getNokogiriClass;
import static nokogiri.internals.NokogiriHelpers.getPrefix;
import static nokogiri.internals.NokogiriHelpers.isNamespace;
import static nokogiri.internals.NokogiriHelpers.rubyStringToString;

import java.util.HashMap;
import java.util.Map;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import org.jruby.Ruby;
import org.jruby.RubyArray;
import org.jruby.RubyClass;
import org.jruby.RubyString;
import org.jruby.anno.JRubyClass;
import org.jruby.anno.JRubyMethod;
import org.jruby.runtime.Helpers;
import org.jruby.runtime.ThreadContext;
import org.jruby.runtime.builtin.IRubyObject;
import org.jruby.util.ByteList;
import org.w3c.dom.Attr;
import org.w3c.dom.NamedNodeMap;

/**
 * Class for Nokogiri::XML::DocumentFragment
 * 
 * @author sergio
 * @author Yoko Harada <yokolet@gmail.com>
 */
@JRubyClass(name="Nokogiri::XML::DocumentFragment", parent="Nokogiri::XML::Node")
public class XmlDocumentFragment extends XmlNode {

    private XmlElement fragmentContext;

    public XmlDocumentFragment(Ruby ruby) {
        this(ruby, getNokogiriClass(ruby, "Nokogiri::XML::DocumentFragment"));
    }

    public XmlDocumentFragment(Ruby ruby, RubyClass klazz) {
        super(ruby, klazz);
    }

    @JRubyMethod(name="new", meta = true, required=1, optional=2)
    public static IRubyObject rbNew(ThreadContext context, IRubyObject cls, IRubyObject[] args) {
        if (args.length < 1) {
            throw context.runtime.newArgumentError(args.length, 1);
        }

        if (!(args[0] instanceof XmlDocument)){
            throw context.runtime.newArgumentError("first parameter must be a Nokogiri::XML::Document instance");
        }

        XmlDocument doc = (XmlDocument) args[0];
        
        // make wellformed fragment, ignore invalid namespace, or add appropriate namespace to parse
        if (args.length > 1 && args[1] instanceof RubyString) {
            final RubyString arg1 = (RubyString) args[1];
            if (XmlDocumentFragment.isTag(arg1)) {
                args[1] = RubyString.newString(context.runtime, addNamespaceDeclIfNeeded(doc, rubyStringToString(arg1)));
            }
        }

        XmlDocumentFragment fragment = (XmlDocumentFragment) NokogiriService.XML_DOCUMENT_FRAGMENT_ALLOCATOR.allocate(context.runtime, (RubyClass)cls);
        fragment.setDocument(context, doc);
        fragment.setNode(context.runtime, doc.getDocument().createDocumentFragment());

        //TODO: Get namespace definitions from doc.
        if (args.length == 3 && args[2] != null && args[2] instanceof XmlElement) {
            fragment.fragmentContext = (XmlElement)args[2];
        }
        Helpers.invoke(context, fragment, "initialize", args);
        return fragment;
    }

    private static final ByteList TAG_BEG = ByteList.create("<");
    private static final ByteList TAG_END = ByteList.create(">");

    private static boolean isTag(final RubyString str) {
        return str.getByteList().startsWith(TAG_BEG) && str.getByteList().endsWith(TAG_END);
    }

    private static boolean isNamespaceDefined(String qName, NamedNodeMap nodeMap) {
        if (isNamespace(qName.intern())) return true;
        for (int i=0; i < nodeMap.getLength(); i++) {
            Attr attr = (Attr)nodeMap.item(i);
            if (isNamespace(attr.getNodeName())) {
                String localPart = getLocalNameForNamespace(attr.getNodeName(), null);
                if (getPrefix(qName).equals(localPart)) {
                    return true;
                }
            }
        }
        return false;
    }

    private static final Pattern QNAME_RE = Pattern.compile("[^</:>\\s]+:[^</:>=\\s]+");
    private static final Pattern START_TAG_RE = Pattern.compile("<[^</>]+>");

    private static String addNamespaceDeclIfNeeded(XmlDocument doc, String tags) {
        if (doc.getDocument() == null) return tags;
        if (doc.getDocument().getDocumentElement() == null) return tags;
        Matcher matcher = START_TAG_RE.matcher(tags);
        Map<CharSequence, CharSequence> rewriteTable = null;
        while (matcher.find()) {
            String start_tag = matcher.group();
            Matcher matcher2 = QNAME_RE.matcher(start_tag);
            while (matcher2.find()) {
                String qName = matcher2.group();
                NamedNodeMap nodeMap = doc.getDocument().getDocumentElement().getAttributes();
                if (isNamespaceDefined(qName, nodeMap)) {
                    CharSequence namespaceDecl = getNamespaceDecl(getPrefix(qName), nodeMap);
                    if (namespaceDecl != null) {
                        if (rewriteTable == null) rewriteTable = new HashMap(8, 1);
                        StringBuilder str = new StringBuilder(qName.length() + namespaceDecl.length() + 3);
                        String key = str.append('<').append(qName).append('>').toString();
                        str.setCharAt(key.length() - 1, ' '); // (last) '>' -> ' '
                        rewriteTable.put(key, str.append(namespaceDecl).append('>'));
                    }
                }
            }
        }
        if (rewriteTable != null) {
            for (Map.Entry<CharSequence, CharSequence> e : rewriteTable.entrySet()) {
                tags = tags.replace(e.getKey(), e.getValue());
            }
        }
        
        return tags;
    }
    
    private static CharSequence getNamespaceDecl(final String prefix, NamedNodeMap nodeMap) {
        for (int i=0; i < nodeMap.getLength(); i++) {
            Attr attr = (Attr) nodeMap.item(i);
            if (prefix.equals(attr.getLocalName())) {
                return new StringBuilder().
                    append(attr.getName()).append('=').append('"').append(attr.getValue()).append('"');
            }
        }
        return null;
    }

    public XmlElement getFragmentContext() {
        return fragmentContext;
    }

    @Override
    public void relink_namespace(ThreadContext context) {
        relink_namespace(context, getChildren());
    }
}