package zall.manager;

import zall.bean.Folder;
import zall.bean.Media;
import zall.bean.User;
import zall.util.ServletUtil;
import zutil.Hasher;
import zutil.db.DBConnection;
import zutil.log.LogUtil;

import javax.servlet.http.*;
import java.sql.SQLException;
import java.sql.Timestamp;
import java.util.logging.Logger;


/**
 *
 */
public class AuthenticationManager {
    private static final Logger logger = LogUtil.getLogger();

    public static final String SESSION_KEY_USER      = "zall_user";
    public static final String SESSION_KEY_AUTH_HASH = "zall_ueser_session_hash";
    public static final long   SESSION_TIMEOUT       = 3*24*60*60*1000; // 2 day

    public static final String COOKIE_KEY_USER_HASH  = "zall_auth";
    public static final int    COOKIE_TIMEOUT        = 10*24*60*60; // 10 days

    /**
     * Authenticate a username and password and return the associated Uaer object
     */
    public static User authenticate(DBConnection db, String email, String password, HttpServletRequest request, HttpServletResponse response) throws SQLException {
        User user = User.load(db, email);

        // Valid email?
        if( user != null ){
            if (user.getPassword().equals(Hasher.MD5(password))) {
                setUserAuthenticated(db, user, User.AuthType.USER_INPUT, request, response);
                return user;
            } else {
                logger.info("Incorrect password for username: " + user);
            }
        } else {
            logger.info("Incorrect username provided: " + user);
        }
        return null;
    }

    /**
     * Uses a cookie to authenticate a user,
     *
     * @return a user object or null authentications fails
     */
    public static User authenticate(DBConnection db, HttpServletRequest request, HttpServletResponse response) throws SQLException{
        String cookieHash = ServletUtil.getCookieValue(request.getCookies(), SESSION_KEY_AUTH_HASH);
        if (cookieHash != null) {
            User user = User.loadByCookieHash(db, cookieHash);

            if (user != null) {
                if (request.getRemoteAddr().equals(user.getIpHost()) &&
                        user.getLoginDate().getTime() + SESSION_TIMEOUT > System.currentTimeMillis()) {
                    setUserAuthenticated(db, user, User.AuthType.COOKIE, request, response);
                    return user;
                } else {
                    logger.info("Cookie hash has expired or have incorrect ipHost: " + cookieHash);
                }
            } else {
                logger.info("Cookie hash not associated with any user: " + cookieHash);
            }
        }
        return null;
    }

    private static void setUserAuthenticated(DBConnection db, User user, User.AuthType authType, HttpServletRequest request, HttpServletResponse response) throws SQLException {
        user.setLoginDate(new Timestamp(System.currentTimeMillis()));
        user.setAuthBy(authType);
        user.setIpHost(request.getRemoteAddr());
        user.setCookieHash(Double.toHexString(Math.random()));
        user.save(db);

        setUserSession(user, request.getSession());
        if(authType != User.AuthType.COOKIE){
            Cookie c = new Cookie(COOKIE_KEY_USER_HASH, user.getCookieHash());
            c.setMaxAge(COOKIE_TIMEOUT);
            response.addCookie(c);
        }

        logger.info("User(" + user.getEmail() + ") authenticated by " + user.getAuthBy());
    }

    /**
     * @return the User associated with the provided session.
     */
    public static User getUserSession(HttpSession session) {
        return (User) session.getAttribute(SESSION_KEY_USER);
    }
    public static void setUserSession(User user, HttpSession session) {
        session.setAttribute(SESSION_KEY_USER, user);
    }
    public static void rmUserSession(HttpSession session) {
        session.removeAttribute(SESSION_KEY_USER);
    }

    /**
     * @return true if the user has a isValid authentication session
     */
    public static boolean isValid(User user, HttpServletRequest request) {
        if(user == null)
            return false;
        if(!user.isEnabled())
            return false;
        if(user.getCookieHash() == null || user.getCookieHash().isEmpty() )
            return false;

        switch(user.getAuthBy()){
            case USER_INPUT:
                if (!user.isEmailVerified()) return false;
            case COOKIE:
                String sessionHash = ServletUtil.getCookieValue(request.getCookies(), SESSION_KEY_AUTH_HASH);
                return user.getCookieHash().equals(sessionHash) &&
                        user.getIpHost().equals(request.getRemoteAddr());
        }
        return false;
    }

    /**
     * @return true if the specified user can edit the media
     */
    public static boolean canEdit(User user, Media target) {
        return target != null && (user.isSuperUser() || target.getUser().equals(user));
    }
    /**
     * @return true if the specified user can edit the media
     */
    public static boolean canEdit(User user, Folder target) {
        return target != null && (user.isSuperUser() || user.equals( target.getUser() ));
    }
    /**
     * @return true if the specified user can edit the profile of the other user
     */
    public static boolean canEdit(User user, User target){
        return user.equals( target ) || user.isSuperUser();
    }


    /**
     * Reset the user authentication. In plain word: logout user.
     */
    public static void reset(DBConnection db, User user) throws SQLException {
        user.setCookieHash(null);
        user.save(db);
    }

}