/*
 * Copyright 2004-2009 the Seasar Foundation and the Others.
 *
 * 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.seasar.mayaa.impl.builder.injection;

import org.seasar.mayaa.builder.injection.InjectionChain;
import org.seasar.mayaa.builder.injection.InjectionResolver;
import org.seasar.mayaa.engine.specification.NodeAttribute;
import org.seasar.mayaa.engine.specification.QName;
import org.seasar.mayaa.engine.specification.SpecificationNode;
import org.seasar.mayaa.impl.CONST_IMPL;
import org.seasar.mayaa.impl.ParameterAwareImpl;
import org.seasar.mayaa.impl.engine.specification.SpecificationUtil;
import org.seasar.mayaa.impl.util.StringUtil;

/**
 * テンプレートのmetaタグからContent-Type, Cache-Control (or Pragma) の値を
 * 読み出す。
 *
 * @author Masataka Kurihara (Gluegent, Inc.)
 */
public class MetaValuesSetter extends ParameterAwareImpl
        implements InjectionResolver, CONST_IMPL {

    private static final long serialVersionUID = 3263443313691061874L;
    protected static final QName QH_CONTENT =
        SpecificationUtil.createQName(URI_HTML, "content");
    protected static final QName QH_HTTP_EQUIV =
        SpecificationUtil.createQName(URI_HTML, "http-equiv");
    protected static final QName QH_META =
        SpecificationUtil.createQName(URI_HTML, "meta");
    protected static final QName QX_CONTENT =
        SpecificationUtil.createQName(URI_XHTML, "content");
    protected static final QName QX_HTTP_EQUIV =
        SpecificationUtil.createQName(URI_XHTML, "http-equiv");
    protected static final QName QX_META =
        SpecificationUtil.createQName(URI_XHTML, "meta");

    protected void addMayaaAttribute(
            SpecificationNode original, QName qName, String value) {
        if (original == null || qName == null || StringUtil.isEmpty(value)) {
            throw new IllegalArgumentException();
        }
        SpecificationNode mayaa = SpecificationUtil.getMayaaNode(original);
        if (mayaa == null) {
            throw new IllegalStateException("mayaaNode not found in current specification");
        }
        mayaa.addAttribute(qName, value);
    }

    protected void setEquiv(SpecificationNode original,
            String equivValue , String contentValue) {
        if (original == null) {
            throw new IllegalArgumentException();
        }
        if (StringUtil.hasValue(contentValue)) {
            if ("Content-Type".equalsIgnoreCase(equivValue)) {
                // TemplateNodeHandlerで強制的にcharsetを付与済み
                addMayaaAttribute(original, QM_CONTENT_TYPE, contentValue);
            } else if ("Pragma".equalsIgnoreCase(equivValue)) {
                if ("no-cache".equalsIgnoreCase(contentValue)) {
                    addMayaaAttribute(original, QM_NO_CACHE, "true");
                }
            } else if ("Cache-Control".equalsIgnoreCase(equivValue)) {
                if ("no-cache".equalsIgnoreCase(contentValue)) {
                    addMayaaAttribute(original, QM_NO_CACHE, "true");
                } else {
                    addMayaaAttribute(original, QM_CACHE_CONTROL, contentValue);
                }
            }
        }
    }

    protected void setContentValue(SpecificationNode original,
            QName httpEquivName, QName contentName) {
        NodeAttribute equiv = original.getAttribute(httpEquivName);
        if (equiv != null) {
            NodeAttribute content = original.getAttribute(contentName);
            if (content != null) {
                setEquiv(original, equiv.getValue(), content.getValue());
            }
        }
    }

    public SpecificationNode getNode(
            SpecificationNode original, InjectionChain chain) {
        if (original == null || chain == null) {
            throw new IllegalArgumentException();
        }
        QName originalName = original.getQName();
        if (QH_META.equals(originalName)) {
            setContentValue(original, QH_HTTP_EQUIV, QH_CONTENT);
        } else if (QX_META.equals(originalName)) {
            setContentValue(original, QX_HTTP_EQUIV, QX_CONTENT);
        }
        return chain.getNode(original);
    }

}
