package com.onaro.sanscreen.client.help;

import java.io.IOException;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLClassLoader;
import java.util.Properties;

import javax.help.HelpBroker;
import javax.help.HelpSet;
import javax.help.HelpSetException;

import org.apache.commons.lang3.StringUtils;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;

/**
 * This class provides a HelpSet and HelpContextProvider based on classloader and path to a help module's files.
 * 
 * @author rnoel
 *
 */
public class HelpModule implements IHelpModule {
    private static Logger logger = LogManager.getLogger(HelpModule.class);

    // Name of the help set file.
    private static final String HELP_SET_FILE_NAME = "JavaHelp.hs"; //$NON-NLS-1$
    
    private final HelpSet helpSet;
    private HelpBroker helpBroker;
    private final HelpContextProvider helpContextProvider;
    
    /**
     * Constructor.
     * 
     * @param loader the class loader we'll use to find the help resources
     * @param path the path to the root of the help directory containing the HelpSet.
     */
    public HelpModule(ClassLoader loader, String helpPath) throws HelpSetException {
        ClassLoader helpSetLoader;
        String path = helpPath;
        
        boolean isHelpPathEmpty = StringUtils.isEmpty(helpPath);

        // If the helpPath does not end with a "/" then treat it as a jar entry and create
        // a classloader for it.
        if(!isHelpPathEmpty && helpPath.charAt(helpPath.length() - 1) != '/') {
            try {
                String urlStr = HelpManager.SERVER_BASE_URL_STR + HelpManager.SANSCREEN_HELP_ROOT_PATH + "/" + helpPath; //$NON-NLS-1$
                URL url = new URL(urlStr);
                
                helpSetLoader = new URLClassLoader(new URL[] { url } );
                // Since we are loading from a jar file we don't want the path
                path = null;
            }
            catch(MalformedURLException mue) {
                logger.warn("Warning; exception creating a classloader helpPath '" + helpPath + "': " + mue.toString()); //$NON-NLS-1$ //$NON-NLS-2$
                // Try the loader that loads from the directory.  Not likely to work but we will handle not finding
                // the helpset when we try loading it.
                helpSetLoader = loader;
            }
        }
        else {
            // Just use our passed in loader
            helpSetLoader = loader;
        }
        helpSet = getHelpSet(helpSetLoader, path);
        helpBroker = helpSet.createHelpBroker();
        helpContextProvider = new HelpContextProvider(helpSetLoader, path);
      
        helpSet.setHomeID(HelpManager.SANSCREEN_ROOT_CONTEXT);
      
        logger.debug("Found help module: " + (isHelpPathEmpty ? "MASTER" : helpPath)); //$NON-NLS-1$ //$NON-NLS-2$
    }
    
    /**
     * Get the help set, given a path and classloader.
     * 
     * @param loader the class loader we'll use to find the help resources
     * @param helpSetPath the path to the HelpSet file resource
     * @return the HelpSet we found.
     */
    private HelpSet getHelpSet(ClassLoader loader, String helpPath) throws HelpSetException {
        try {
            // If helpPath is null then we want the master hs or we are loading from a jar so don't prepend "/".
            String path = (StringUtils.isEmpty(helpPath) ? StringUtils.EMPTY : helpPath + "/"); //$NON-NLS-1$
            URL url = HelpSet.findHelpSet(loader, path + HELP_SET_FILE_NAME);

            return (new HelpSet(loader, url));
        } catch (HelpSetException e) {
            String error = "Help Set '" + helpPath + "' not found!"; //$NON-NLS-1$ //$NON-NLS-2$

            logger.error(error);
            throw e;
        }
    }

    public HelpSet getHelpSet() {
        return helpSet;
    }

    public HelpBroker getHelpBroker() {
        return helpBroker;
    }
    
    public HelpContextProvider getHelpContextProvider() {
        return helpContextProvider;
    }
    
    // TEMP TEST CODE.  DO NOT RELEASE!!!
    public static void main (String[] args) {
        ClassLoader loader;

        try {
            String urlStr = HelpManager.SERVER_BASE_URL_STR + HelpManager.SANSCREEN_HELP_ROOT_PATH + "/" + "SANscreen/client/si/JavaHelp.zip"; //$NON-NLS-1$ //$NON-NLS-2$
            URL url = new URL(urlStr);
            
            loader = new URLClassLoader(new URL[] { url } );
            String propsFilePath = "contexts.properties"; //$NON-NLS-1$
            InputStream inStream = loader.getResourceAsStream(propsFilePath);
            
            if(inStream == null) {
               System.out.println("Context mapping file '" + propsFilePath + "' not found."); //$NON-NLS-1$ //$NON-NLS-2$
               return;
            }
            try {
                Properties props = new Properties();
                
                props.load(inStream);
                System.out.println(props);
            }
            catch(IOException ioe) {
                ioe.printStackTrace();
            }
            finally {
                try { inStream.close(); } catch(IOException ioe) {}
            }
        }
        catch(MalformedURLException mue) {
            mue.printStackTrace();
        }
    }
}