package org.ngbw.web.actions;

import java.io.ByteArrayInputStream;
import java.io.InputStream;

import org.apache.log4j.Logger;

import org.apache.struts2.interceptor.validation.SkipValidation;

import org.ngbw.sdk.database.Task;


/**
 * Struts action class to handle file download based on current task, and
 * request parameter "inputPath".
 * 
 * <p>
 * To Do: this doesn't need to inherit from ManageTasks it just needs to be able
 * to get the current task and the workbench session from the SESSION.
 * 
 * <p>
 * And be careful, if a StreamResult attribute is found in the base class but
 * not here, it may be called w/o the needed context and cause problems. That's 
 * what happened when Paul added getContentLength to DataManager and why I had 
 * to add it here (or I could have made this not inherit from ManageTasks which 
 * is derived from DataManager).
 * 
 */
@SuppressWarnings("serial")
public class DownloadAction extends ManageTasks
{
    private static final Logger logger = Logger.getLogger(DownloadAction.class.getName());

    private String contentType;
    private String inputPath;

    InputStream is;


    public String getInputPath ()
    {
        return inputPath;
    }


    public void setInputPath ( String inputPath )
    {
        this.inputPath = inputPath;
    }


    @Override
    public InputStream getInputStream ()
    {
        return is;
    }


    @SkipValidation
    private InputStream 
    getTheData ( String inputPath ) throws Exception
    {
        Task task = null;

        String[] taskId = (String[]) getParameters().get(ID);

        if (taskId != null && taskId.length > 0)
        {
            setCurrentTask(getSelectedTask(Long.parseLong(taskId[0])));
        }

        if ((task = getCurrentTask()) == null)
        {
            throw new Exception("No task selected.");
        }
        
        return getWorkbenchSession().getFileFromWorkingDirectory(task, inputPath);
    }


    @Override
    public long getDataLength ()
    {
        try
        {
            return is.available();
        }
        catch ( Exception e )
        {
            logger.error(constructMessage(e, "Error retrieving size of data, returning zero."));
            return 0;
        }
    }


    @Override
    public String download ()
    {
        logger.debug("BEGIN: download()::String");
        
        try
        {
            // Filter out user input file path and file name.
            // It is dangerous to allow users to specify file paths and file names.
            if (null != inputPath && !inputPath.trim().isEmpty())
            {
                if (inputPath.contains("*") ||
                    inputPath.contains("$") ||
                    inputPath.contains("{") ||
                    inputPath.contains("}") || 
                    inputPath.trim().startsWith(".") ||
                    inputPath.trim().startsWith("/") ||
                    inputPath.trim().startsWith("~")) 
                {
                    throw new Exception("Invalid filename: " + inputPath.trim());
                }
                
                if (inputPath.trim().endsWith(".") ||
                    inputPath.trim().endsWith("/")) 
                {
                    throw new Exception("Invalid filename: " + inputPath.trim());
                }
            }
            
            is = getTheData(inputPath);
        }
        catch ( Throwable t )
        {
            // An error is expected here if the user tries to download the file 
            // as it's being deleted or after it's been deleted.   
            logger.debug(t.getMessage(), t);
            is = new ByteArrayInputStream(new byte[0]);
        }

        contentType = "application/x-unknown";
        
        logger.debug("END: download()::String");
        
        return SUCCESS;
    }

    
    public String getContentDisposition ()
    {
        return String.format("filename=\"%s\"", inputPath);
    }


    @Override
    public String getContentType ()
    {
        return contentType;
    }

}