/*   Copyright 2004 The Apache Software Foundation
 *
 *   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.apache.xmlbeans.impl.values;

import org.apache.xmlbeans.SchemaType;
import org.apache.xmlbeans.XmlAnySimpleType;
import org.apache.xmlbeans.XmlErrorCodes;
import org.apache.xmlbeans.XmlObject;
import org.apache.xmlbeans.impl.common.PrefixResolver;
import org.apache.xmlbeans.impl.common.QNameHelper;
import org.apache.xmlbeans.impl.common.ValidationContext;
import org.apache.xmlbeans.impl.common.XMLChar;
import org.apache.xmlbeans.impl.schema.BuiltinSchemaTypeSystem;

import javax.xml.namespace.QName;

public class JavaQNameHolder extends XmlObjectBase {
    public JavaQNameHolder() {
    }

    public SchemaType schemaType() {
        return BuiltinSchemaTypeSystem.ST_QNAME;
    }

    private QName _value;

    protected int get_wscanon_rule() {
        return SchemaType.WS_PRESERVE;
    }

    // an ergonomic prefixer so that you can say stringValue() on a free-floating QName.
    private static final NamespaceManager PRETTY_PREFIXER = new PrettyNamespaceManager();

    private static class PrettyNamespaceManager implements NamespaceManager {
        public String find_prefix_for_nsuri(String nsuri, String suggested_prefix) {
            return QNameHelper.suggestPrefix(nsuri);
        }

        public String getNamespaceForPrefix(String prefix) {
            throw new RuntimeException("Should not be called");
        }
    }

    // SIMPLE VALUE ACCESSORS BELOW -------------------------------------------
    public String compute_text(NamespaceManager nsm) {
        if (nsm == null) {
            // we used to: throw new IllegalStateException("Cannot create QName prefix outside of a document");
            // but it's not nice to throw on stringValue()
            nsm = PRETTY_PREFIXER;
        }

// TODO - what I really need to do here is that if there is no
// namespace for this qname, then instead of finding the prefix for the
// uri, I should make a call to set the default namespace for the
// immediate context for this qname to be "".

        String namespace = _value.getNamespaceURI();
        String localPart = _value.getLocalPart();

        if (namespace == null || namespace.length() == 0) {
            return localPart;
        }

        String prefix = nsm.find_prefix_for_nsuri(namespace, null);

        assert prefix != null;

        return "".equals(prefix) ? localPart : prefix + ":" + localPart;
    }

    public static QName validateLexical(
        String v, ValidationContext context, PrefixResolver resolver) {
        QName name;

        try {
            name = parse(v, resolver);
        } catch (XmlValueOutOfRangeException e) {
            context.invalid(e.getMessage());
            name = null;
        }

        return name;
    }

    private static QName parse(String v, PrefixResolver resolver) {
        String prefix, localname;
        int start;
        int end;
        for (end = v.length(); end > 0; end -= 1) {
            if (!XMLChar.isSpace(v.charAt(end - 1))) {
                break;
            }
        }
        for (start = 0; start < end; start += 1) {
            if (!XMLChar.isSpace(v.charAt(start))) {
                break;
            }
        }

        int firstcolon = v.indexOf(':', start);
        if (firstcolon >= 0) {
            prefix = v.substring(start, firstcolon);
            localname = v.substring(firstcolon + 1, end);
        } else {
            prefix = "";
            localname = v.substring(start, end);
        }

        if (prefix.length() > 0 && !XMLChar.isValidNCName(prefix)) {
            throw new XmlValueOutOfRangeException(XmlErrorCodes.QNAME, new Object[]{"Prefix not a valid NCName in '" + v + "'"});
        }

        if (!XMLChar.isValidNCName(localname)) {
            throw new XmlValueOutOfRangeException(XmlErrorCodes.QNAME, new Object[]{"Localname not a valid NCName in '" + v + "'"});
        }

        String uri =
            resolver == null ? null : resolver.getNamespaceForPrefix(prefix);

        if (uri == null) {
            if (prefix.length() > 0) {
                throw new XmlValueOutOfRangeException(XmlErrorCodes.QNAME, new Object[]{"Can't resolve prefix '" + prefix + "'"});
            }

            uri = "";
        }

        if (prefix != null && prefix.length() > 0) {
            return new QName(uri, localname, prefix);
        } else {
            return new QName(uri, localname);
        }
    }

    protected void set_text(String s) {
        PrefixResolver resolver = NamespaceContext.getCurrent();

        if (resolver == null && has_store()) {
            resolver = get_store();
        }

        _value = parse(s, resolver);
    }

    // BUGBUG - having prefix here may not work
    protected void set_QName(QName name) {
        assert name != null;

        // Sync force of creation of namesapce mapping ..

        if (has_store()) {
            get_store().find_prefix_for_nsuri(name.getNamespaceURI(), null);
        }

        _value = name;
    }

    protected void set_xmlanysimple(XmlAnySimpleType value) {
        _value = parse(value.getStringValue(), NamespaceContext.getCurrent());
    }

    protected void set_nil() {
        _value = null;
    }

    // setters, getters (setter already handled via set_text)

    public QName getQNameValue() {
        check_dated();
        return _value;
    }

    // comparators
    protected boolean equal_to(XmlObject obj) {
        return _value.equals(((XmlObjectBase) obj).getQNameValue());
    }

    protected int value_hash_code() {
        return _value.hashCode();
    }
}