/*
 Licensed to the Apache Software Foundation (ASF) under one or more
 contributor license agreements.  See the NOTICE file distributed with
 this work for additional information regarding copyright ownership.
 The ASF licenses this file to You 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.lenya.cms.editors.tinymce;

import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.UnsupportedEncodingException;
import java.io.Writer;

import javax.servlet.http.HttpServletRequest;
import javax.xml.parsers.ParserConfigurationException;

import org.apache.lenya.cms.cocoon.source.SourceUtil;
import org.apache.lenya.cms.linking.LinkConverter;
import org.apache.lenya.cms.publication.Node;
import org.apache.lenya.cms.publication.ResourceType;
import org.apache.lenya.cms.usecase.DocumentUsecase;
import org.apache.lenya.cms.usecase.UsecaseException;
import org.apache.lenya.cms.usecase.xml.UsecaseErrorHandler;
import org.apache.lenya.cms.workflow.WorkflowUtil;
import org.apache.lenya.cms.workflow.usecases.UsecaseWorkflowHelper;
import org.apache.lenya.xml.DocumentHelper;
import org.apache.lenya.xml.Schema;
import org.apache.lenya.xml.ValidationUtil;
import org.w3c.dom.Document;
import org.xml.sax.SAXException;

/**
 * TinyMce Usecase
 * 
 * since there is no really tinymce-specific code in here, most methods should eventually be moved
 * into DocumentUsecase and shared across all editor usecases.
 */

public class TinyMce extends DocumentUsecase {

    /**
     * @see org.apache.lenya.cms.usecase.AbstractUsecase#getNodesToLock()
     */
    protected Node[] getNodesToLock() throws UsecaseException {
        Node[] objects = { getSourceDocument() };
        return objects;
    }

    /**
     * @see org.apache.lenya.cms.usecase.AbstractUsecase#initParameters()
     */
    protected void initParameters() {
        super.initParameters();

        HttpServletRequest request = getRequest();
        setParameter("host", "http://" + request.getServerName() + ":" + request.getServerPort());
        setParameter("requesturi", request.getRequestURI());
    }

    /**
     * @see org.apache.lenya.cms.usecase.AbstractUsecase#doCheckPreconditions()
     */
    protected void doCheckPreconditions() throws Exception {
        super.doCheckPreconditions();
        UsecaseWorkflowHelper.checkWorkflow(this, getEvent(), getSourceDocument(), getLogger());
    }

    /**
     * @see org.apache.lenya.cms.usecase.AbstractUsecase#doExecute()
     */
    protected void doExecute() throws Exception {
        super.doExecute();

        String content = getXmlString(getEncoding());

        if (getLogger().isDebugEnabled()) {
            getLogger().debug(content);
        }

        saveDocument(getEncoding(), content);
    }

    protected String getEncoding() {
        return getRequest().getCharacterEncoding();
    }

    protected String getXmlString(String encoding) {
        // Get namespaces
        String namespaces = removeRedundantNamespaces(getParameterAsString("tinymce.namespaces"));
        if (getLogger().isDebugEnabled()) {
            getLogger().debug(namespaces);
        }
        // Aggregate content
        String content = "<?xml version=\"1.0\" encoding=\"" + encoding + "\"?>\n"
                + "<html xmlns=\"http://www.w3.org/1999/xhtml\" " + namespaces + ">\n"
                + "  <head><title></title></head>\n" + "  <body>\n"
                + getParameterAsString("tinymce.content") + "  </body>\n" + "</html>\n";
        return content;
    }

    public void advance() throws UsecaseException {
        clearErrorMessages();
        try {
            Document xml = getXml();
            if (xml != null) {
                validate(xml);
            }
            if (!hasErrors()) {
                SourceUtil.writeDOM(xml, getSourceDocument().getOutputStream());
                deleteParameter("content");
            }
        } catch (Exception e) {
            throw new UsecaseException(e);
        }
    }

    protected void doCheckExecutionConditions() throws Exception {
        super.doCheckExecutionConditions();
        if (hasErrors()) {
            return;
        }

        Document xml = getXml();
        if (xml != null) {
            validate(xml);
        }
    }

    protected void validate(Document xml) throws Exception {
        ResourceType resourceType = getSourceDocument().getResourceType();
        Schema schema = resourceType.getSchema();
        ValidationUtil.validate(xml, schema, new UsecaseErrorHandler(this));
    }

    protected Document getXml() throws ParserConfigurationException, IOException {
        String encoding = getEncoding();
        String xmlString = getXmlString(encoding);

        Document xml = null;
        try {
            xml = DocumentHelper.readDocument(xmlString, encoding);
        } catch (SAXException e) {
            addErrorMessage("error-document-form", new String[] { e.getMessage() });
        }
        return xml;
    }

    /**
     * Save the content to the document source. After saving, the XML is validated. If validation
     * errors occur, the usecase transaction is rolled back, so the changes are not persistent. If
     * the validation succeeded, the workflow event is invoked.
     * @param encoding The encoding to use.
     * @param content The content to save.
     * @throws Exception if an error occurs.
     */
    protected void saveDocument(String encoding, String content) throws Exception {
        org.apache.lenya.cms.publication.Document doc = getSourceDocument();
        saveXMLFile(encoding, content, doc);
        LinkConverter converter = new LinkConverter(getLogger());
        converter.convertUrlsToUuids(doc, false);

        WorkflowUtil.invoke(doc, getEvent());
    }

    /**
     * Save the XML file
     * @param encoding The encoding
     * @param content The content
     * @param document The source
     * @throws FileNotFoundException if the file was not found
     * @throws UnsupportedEncodingException if the encoding is not supported
     * @throws IOException if an IO error occurs
     */
    private void saveXMLFile(String encoding, String content,
            org.apache.lenya.cms.publication.Document document) throws FileNotFoundException,
            UnsupportedEncodingException, IOException {
        Writer writer = null;

        try {
            writer = new OutputStreamWriter(document.getOutputStream(), encoding);
            writer.write(content, 0, content.length());
        } catch (FileNotFoundException e) {
            getLogger().error("File not found " + e.toString());
        } catch (UnsupportedEncodingException e) {
            getLogger().error("Encoding not supported " + e.toString());
        } catch (IOException e) {
            getLogger().error("IO error " + e.toString());
        } finally {
            // close all streams
            if (writer != null)
                writer.close();
        }
    }

    /**
     * Remove redundant namespaces
     * @param namespaces The namespaces to remove
     * @return The namespace string without the removed namespaces
     */
    private String removeRedundantNamespaces(String namespaces) {
        String[] namespace = namespaces.split(" ");

        String ns = "";
        for (int i = 0; i < namespace.length; i++) {
            if (ns.indexOf(namespace[i]) < 0) {
                ns = ns + " " + namespace[i];
            } else {
                if (getLogger().isDebugEnabled()) {
                    getLogger().debug("Redundant namespace: " + namespace[i]);
                }
            }
        }
        return ns;
    }

    /**
     * Add namespaces
     * @param namespaces The namespaces to add
     * @param content The content to add them to
     * @return The content with the added namespaces
     */
    /*
     * private String addNamespaces(String namespaces, String content) { int i =
     * content.indexOf(">"); return content.substring(0, i) + " " + namespaces +
     * content.substring(i); }
     */

    protected String getEvent() {
        return "edit";
    }

}