package ora.jwsnut.chapter6.contextbookservice;

import java.security.Principal;
import java.util.Date;
import javax.naming.InitialContext;
import javax.naming.NamingException;
import javax.servlet.ServletContext;
import javax.servlet.http.HttpSession;
import javax.xml.rpc.ServiceException;
import javax.xml.rpc.holders.StringHolder;
import javax.xml.rpc.server.ServletEndpointContext;
import javax.xml.rpc.server.ServiceLifecycle;

/**
 * Implementation class for the context-handling book web service.
 */
public class ContextBookServiceServant implements ContextBookQuery, ServiceLifecycle {
    
    // Name of the HttpSession attribute holding the upper-case flag
    private static final String UPPER_CASE = "UpperCaseBookTitles";
    
    // ServletEndpointContext object
    private ServletEndpointContext endpointContext;
    
    // Name of an authorized user.
    private String userName;
    
    // Records whether book names should be sorted
    private boolean sorted;
    
    /* -- Implementation of the ServiceLifeCycle interface -- */
    public void init(Object context) throws ServiceException {
        endpointContext = (ServletEndpointContext)context;
        
        // Get the authorized user name from the init parameters
        ServletContext servletContext = endpointContext.getServletContext();
        userName = servletContext.getInitParameter("UserName");
        
        // Get alphabetic sorting flag from JNDI
        try {
            InitialContext namingCtx = new InitialContext();
            Object value = namingCtx.lookup("java:comp/env/sorted");
            sorted = value instanceof Boolean ? ((Boolean)value).booleanValue() : false; 
            ContextBookServiceServantData.setSorted(sorted);
        } catch (NamingException ex) {
            servletContext.log("Exception while accessing naming context", ex);
        }
    }

    /** 
     * Called when the service instance is no longer required.
     */
    public void destroy() {
        // Nothing to do 
    }
    
    /* -- Implementation of the ContextBookQuery interface -- */

    /**
     * Sets whether book titles returned by the
     * getBookTitle() method should be in upper case.
     * @param cond <code>true</code> if all book titles should
     * be in upper case, <code>false</code> for title case.
     */
    public void setUpperCase(boolean cond) {
        HttpSession session = endpointContext.getHttpSession();
        if (session != null) {
            session.setAttribute(UPPER_CASE, cond ? Boolean.TRUE : Boolean.FALSE);            
        }
    }
    
    /**
     * Returns whether book titles are being forced to
     * upper case.
     * @return <code>true</code> if book titles are forced to
     * upper case, <code>false</code> if not.
     */
    public boolean isUpperCase() {
        HttpSession session = endpointContext.getHttpSession();
        if (session != null) {
            Boolean upperCase = (Boolean)session.getAttribute(UPPER_CASE); 
            return upperCase == null ? false : upperCase.booleanValue();
        }      
        
        // No session - upper case mode not allowed
        return false;
    }
    
    /**
     * Gets the number of books known to the service
     * @return the number of books known to the service.
     */
    public int getBookCount() {
        String[] titles = ContextBookServiceServantData.getBookTitles();
        return titles == null || !checkAccess() ? 0 : titles.length;
    }

    /**
     * Gets the title of a given book.
     * @param index the index of the book whose title is required
     * @return the title of the given book, or <code>null</code> if
     * the index is not valid.
     */
    public String getBookTitle(int index) {
        String[] bookTitles = ContextBookServiceServantData.getBookTitles();        
        if (bookTitles == null || index < 0 || index >= bookTitles.length || !checkAccess()) {
            return null;
        }
        return isUpperCase() ? bookTitles[index].toUpperCase() : bookTitles[index];
    }
    
    /**
     * Gets the author for a books with a given title
     * @param title the titles of the book
     * @param author an output parameter that will be set to the author of the given book
     * @throws ContextBookServiceException if the book title is unknown
     */
    public void getBookAuthor(String title, StringHolder author) throws ContextBookServiceException {
        String authorName = ContextBookServiceServantData.getBookAuthor(title);
        if (authorName == null || !checkAccess()) {
            throw new ContextBookServiceException("Unknown author: " + title);
        }
        author.value = authorName;
    }  
    
    /**
     * Makes a log entry.
     * @param value the value to be logged.
     */
    public void log(String value) {
        if (checkAccess()) {
            endpointContext.getServletContext().log(new Date() + ": " + value);
        }
    }
    
    /**
     * Check whether the calling user is authenticated.
     */
    private boolean checkAccess() {
        boolean allowed = true;
        if (userName != null) {
            // Authentication is configured.
            Principal principal = endpointContext.getUserPrincipal();
            allowed = principal != null && userName.equals(principal.getName());
        }
        return allowed;            
    }
}