/*
 * Copyright 2014 astamuse company,Ltd.
 * 
 * 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 com.astamuse.asta4d.web;

import java.io.File;
import java.io.FileInputStream;
import java.io.InputStream;

import javax.servlet.ServletConfig;

import org.apache.commons.io.FilenameUtils;

import com.astamuse.asta4d.web.initialization.Initializer;
import com.astamuse.asta4d.web.initialization.SimplePropertyFileInitializer;
import com.astamuse.asta4d.web.util.SystemPropertyUtil;
import com.astamuse.asta4d.web.util.SystemPropertyUtil.PropertyScope;

public class WebApplicatoinConfigurationInitializer {

    public void initConfigurationFromFile(ServletConfig sc, WebApplicationConfiguration conf) throws Exception {
        String[] fileNames = retrievePossibleConfigurationFileNames();
        InputStream input = null;
        String fileType = null;

        // find file from classpath
        ClassLoader clsLoder = WebApplicatoinConfigurationInitializer.class.getClassLoader();
        for (String name : fileNames) {
            input = clsLoder.getResourceAsStream(name);
            if (input != null) {
                fileType = FilenameUtils.getExtension(name);
                break;
            }
        }

        // find from file system
        // I can do goto by while loop :)
        while (input == null) {

            // find key
            String fileKey = retrieveConfigurationFileNameKey();
            if (fileKey == null) {
                break;
            }

            // get path
            String filePath = retrieveConfigurationFileName(sc, fileKey);
            if (filePath == null) {
                break;
            }

            // load file
            File f = new File(filePath);
            input = new FileInputStream(f);
            fileType = FilenameUtils.getExtension(filePath);
            break;
        }

        if (input != null) {
            try {
                Initializer initializer = retrieveInitializer(fileType);
                initializer.initliaze(input, conf);
            } finally {
                input.close();
            }
        }
    }

    protected Initializer retrieveInitializer(String fileType) {
        // at present, we only support properties file, but we will try to support .js or .groovy as well in future.
        switch (fileType) {
        case "properties":
            return new SimplePropertyFileInitializer();
        default:
            throw new UnsupportedOperationException("File type of " + fileType +
                    " does not be supported for initialize asta4d Configuration.");
        }
    }

    protected String[] retrievePossibleConfigurationFileNames() {
        // return new String[] {
        // "asta4d.conf.properties, ast4d.conf.js, asta4d.conf.groovy" };
        return new String[] { "asta4d.conf.properties" };
    }

    protected String retrieveConfigurationFileNameKey() {
        return "asta4d.conf";
    }

    protected String retrieveConfigurationFileName(ServletConfig sc, String key) {
        return SystemPropertyUtil.retrievePropertyValue(sc, key, PropertyScope.ServletConfig, PropertyScope.JNDI,
                PropertyScope.SystemProperty);
    }
}