package sample.contact;

import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.security.access.expression.PermissionEvaluator;
import org.springframework.security.acls.Permission;
import org.springframework.security.acls.domain.BasePermission;
import org.springframework.security.acls.expression.AclPermissionEvaluator;
import org.springframework.security.core.Authentication;
import org.springframework.security.core.context.SecurityContextHolder;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.servlet.ModelAndView;

/**
 * Controller which handles simple, single request use cases such as index pages and contact deletion.
 *
 * @author Luke Taylor
 * @version $Id$
 * @since 3.0
 */
@Controller
public class IndexController {
    private final static Permission[] HAS_DELETE = new Permission[] {BasePermission.DELETE, BasePermission.ADMINISTRATION};
    private final static Permission[] HAS_ADMIN = new Permission[] {BasePermission.ADMINISTRATION};

    //~ Instance fields ================================================================================================

    @Autowired
    private ContactManager contactManager;
    @Autowired
    private PermissionEvaluator permissionEvaluator;

    //~ Methods ========================================================================================================

    /**
     * The public index page, used for unauthenticated users.
     */
    @RequestMapping(value="/hello.htm", method=RequestMethod.GET)
    public ModelAndView displayPublicIndex() {
        Contact rnd = contactManager.getRandomContact();

        return new ModelAndView("hello", "contact", rnd);
    }

    /**
     * The index page for an authenticated user.
     * <p>
     * This controller displays a list of all the contacts for which the current user has read or admin permissions.
     * It makes a call to {@link ContactManager#getAll()} which automatically filters the returned list using Spring
     * Security's ACL mechanism (see the expression annotations on this interface for the details).
     * <p>
     * In addition to rendering the list of contacts, the view will also include a "Del" or "Admin" link beside the
     * contact, depending on whether the user has the corresponding permissions (admin permission is assumed to imply
     * delete here). This information is stored in the model using the injected {@link PermissionEvaluator} instance.
     * The implementation should be an instance of {@link AclPermissionEvaluator} or one which is compatible with Spring
     * Security's ACL module.
     */
    @RequestMapping(value="/secure/index.htm", method=RequestMethod.GET)
    public ModelAndView displayUserContacts() {
        List<Contact> myContactsList = contactManager.getAll();
        Map<Contact, Boolean> hasDelete = new HashMap<Contact, Boolean>(myContactsList.size());
        Map<Contact, Boolean> hasAdmin = new HashMap<Contact, Boolean>(myContactsList.size());

        Authentication user = SecurityContextHolder.getContext().getAuthentication();

        for (Contact contact : myContactsList) {
            hasDelete.put(contact, Boolean.valueOf(permissionEvaluator.hasPermission(user, contact, HAS_DELETE)));
            hasAdmin.put(contact, Boolean.valueOf(permissionEvaluator.hasPermission(user, contact, HAS_ADMIN)));
        }

        Map<String, Object> model = new HashMap<String, Object>();
        model.put("contacts", myContactsList);
        model.put("hasDeletePermission", hasDelete);
        model.put("hasAdminPermission", hasAdmin);

        return new ModelAndView("index", "model", model);
    }
}