package goodjava.webserver.handlers;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.text.ParseException;
import java.util.Date;
import java.util.TimeZone;
import goodjava.webserver.Handler;
import goodjava.webserver.Request;
import goodjava.webserver.Response;
import goodjava.webserver.Status;


public class FileHandler implements Handler {
	final File dir;

	public FileHandler() {
		this(".");
	}

	public FileHandler(String pathname) {
		this(new File(pathname));
	}

	public FileHandler(File dir) {
		if( !dir.isDirectory() )
			throw new RuntimeException("must be a directory");
		this.dir = dir;
	}

	File file(Request request) {
		return new File(dir,request.path);
	}

	public Response handle(Request request) {
		try {
			File file = file(request);
			if( file.isFile() ) {
				Response response = new Response();

				DateFormat fmt = new SimpleDateFormat("EEE, dd MMM yyyy HH:mm:ss z");
				fmt.setTimeZone(TimeZone.getTimeZone("GMT"));
				String lastModified = fmt.format(new Date(file.lastModified()));
				String ifMod = (String)request.headers.get("If-Modified-Since");
				if( ifMod != null ) {
					try {
						Date ifModDate = fmt.parse(ifMod);
						if( ifModDate != null && ifModDate.getTime() >= fmt.parse(lastModified).getTime() ) {
							response.status = Status.NOT_MODIFIED;
							return response;
						}

					} catch(ParseException e) {}
				}
				response.headers.put("Last-Modified",lastModified);

				response.body = new Response.Body( file.length(), new FileInputStream(file) );
				return response;
			}
			return null;
		} catch(IOException e) {
			throw new RuntimeException(e);
		}
	}
}