/*
 * $Id$
 *
 * 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.struts2.components.template;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.util.HashMap;
import java.util.Map;
import java.util.Properties;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import com.opensymphony.xwork2.util.ClassLoaderUtil;

/**
 * Base class for template engines.
 */
public abstract class BaseTemplateEngine implements TemplateEngine {

    private static final Log LOG = LogFactory.getLog(BaseTemplateEngine.class);

    /** The default theme properties file name. Default is 'theme.properties' */
    public static final String DEFAULT_THEME_PROPERTIES_FILE_NAME = "theme.properties";

    final Map<String, Properties> themeProps = new HashMap<String, Properties>();

    public Map getThemeProps(Template template) {
        synchronized (themeProps) {
            Properties props = (Properties) themeProps.get(template.getTheme());
            if (props == null) {
                String propName = template.getDir() + "/" + template.getTheme() + "/"+getThemePropertiesFileName();

                // WW-1292
                // let's try getting it from the filesystem
                File propFile = new File(propName);
                InputStream is = null;
                try {
                    if (propFile.exists()) {
                        is = new FileInputStream(propFile);
                    }
                }
                catch(FileNotFoundException e) {
                    LOG.warn("Unable to find file in filesystem ["+propFile.getAbsolutePath()+"]");
                }

                if (is == null) {
                    // if its not in filesystem. let's try the classpath
                    is = ClassLoaderUtil.getResourceAsStream(propName, getClass());
                }

                props = new Properties();

                if (is != null) {
                    try {
                        props.load(is);
                    } catch (IOException e) {
                        LOG.error("Could not load " + propName, e);
                    } finally {
                        try {
                            is.close();
                        } catch(IOException io) {
                            LOG.warn("Unable to close input stream", io);
                        }
                    }
                }

                themeProps.put(template.getTheme(), props);
            }

            return props;
        }
    }

    protected String getFinalTemplateName(Template template) {
        String t = template.toString();
        if (t.indexOf(".") <= 0) {
            return t + "." + getSuffix();
        }

        return t;
    }

    protected String getThemePropertiesFileName() {
        return DEFAULT_THEME_PROPERTIES_FILE_NAME;
    }

    protected abstract String getSuffix();
}