import java.io.File;
import org.jboss.netty.buffer.ChannelBuffer;
import org.jboss.netty.buffer.ChannelBuffers;
import org.jboss.netty.channel.*;

class JServerHandler extends SimpleChannelUpstreamHandler {

    @Override
    public void channelConnected(ChannelHandlerContext ctx, ChannelStateEvent event) {

    }

    @Override
    public void messageReceived(ChannelHandlerContext ctx, MessageEvent event) {
        // New Client Connected
        if(ctx.getAttachment() == null|| (ctx.getAttachment() instanceof User) != true) {
            ChannelBuffer buffer = (ChannelBuffer) event.getMessage();
            String[] loginInfo = getLogin(buffer);
            User u = getAuthentication(loginInfo);
            if(u == null) {
                // Was Not Found in Database
                ChannelBuffer denial = ChannelBuffers.buffer(8);
                byte[] denied = "false".getBytes();
                denial.writeBytes(denied);
                event.getChannel().write(denial);
            } else {
                // Was Found in Database
                ctx.setAttachment(u);
                byte[] username = u.getUsername().getBytes();
                byte[] password = u.getPassword().getBytes();
                int flag = u.getFlag();
                ChannelBuffer acceptance = ChannelBuffers.buffer(8);
                acceptance.writeBytes(username);
                acceptance.writeBytes(password);
                acceptance.writeInt(flag);
                event.getChannel().write(acceptance);
            }
        } else {
            String command = parseCommand((ChannelBuffer)event.getMessage());

        }
    }



    /**
     * Will return an Array with Login Information, extracted from a {@code ChannelBuffer}.
     * @param buffer The Buffer to read for information.
     * @return An Array with Username (index 0) and Password (index 1).
     */
    public String[] getLogin(ChannelBuffer buffer) {
        String[] loginInfo = new String[2];
        byte[] bytes = new byte[buffer.readableBytes()];
        for(int i = 0; i < buffer.readableBytes(); i++) {
            bytes[i] = buffer.readByte();
        }
        String s = new String(bytes);
        StringBuilder username = new StringBuilder();
        int specialchar = 0;
        for(int i = 0; i < s.length(); i++) {
            if(s.charAt(i) != '@') {
                username.append(s.charAt(i));
            } else {
                specialchar = i;
                break;
            }
        }
        String password = s.substring(specialchar, s.length());
        loginInfo[0] = username.toString();
        loginInfo[1] = password;
        return loginInfo;
    }

    /**
     * Will create and return a User Object if the information matches an entry
     * in the database and null if nothing matches.
     * @param loginInfo The array with login information. First index MUST ALWAYS
     * be the username, and the second index MUST ALWAYS be the password.
     * @return Will return a {@code User} Object if successful or null if not.
     */
    public User getAuthentication(String[] loginInfo) {
        if(loginInfo != null) {
            return new User(loginInfo[0],loginInfo[1],0);
        }

        return null;
    }

    /**
     * Will Parse out the command gotten from a {@code ChannelBuffer}.
     * @param buffer The Buffer to read for information.
     * @return Will return a string with the command.
     */
    public String parseCommand(ChannelBuffer buffer) {
        byte[] bytes = new byte[buffer.readableBytes()];
        for(int i = 0; i < buffer.readableBytes(); i++) {
            bytes[i] = buffer.readByte();
        }
        String s = new String(bytes);

        return s;
    }

    /**
     * Will fetch Map Cycle files from the specified Server.
     * @param u User who requests Map Cycle Files.
     * @param server Which Server to Fetch from.
     * @return Returns an Array with one or two Map Cycle Files.
     */
    public File[] fetchMapCycleFiles(User u, String server) {
        /*
         * Check through the database for files, check permissions etc.
         * If the user does not have the permission to fetch the map cycle
         * files, null should be returned.
         */
        File[] files = new File[2];

        return null;
    }
}