/**
 * Copyright (c) 2011-2013, dafei 李飞 (myaniu AT gmail DOT com)
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.jfinal.ext.plugin.shiro;

import org.apache.shiro.SecurityUtils;
import org.apache.shiro.subject.Subject;

/**
 * ShiroMethod. (SPI, Singleton, ThreadSafe)
 *
 * @author dafei (myaniu AT gmail DOT com)
 */
public class ShiroMethod {

	private static final String NAMES_DELIMETER = ",";

	/**
	 * 禁止初始化
	 */
	private ShiroMethod() {}

	/**
	 * 获取 Subject
	 *
	 * @return Subject
	 */
	protected static Subject getSubject() {
		return SecurityUtils.getSubject();
	}

	/**
	 * 验证当前用户是否属于该角色？,使用时与lacksRole 搭配使用
	 *
	 * @param roleName
	 *            角色名
	 * @return 属于该角色：true，否则false
	 */
	public static boolean hasRole(String roleName) {
		return getSubject() != null && roleName != null
				&& roleName.length() > 0 && getSubject().hasRole(roleName);
	}

	/**
	 * 与hasRole标签逻辑相反，当用户不属于该角色时验证通过。
	 *
	 * @param roleName
	 *            角色名
	 * @return 不属于该角色：true，否则false
	 */
	public static boolean lacksRole(String roleName) {
		return !hasRole(roleName);
	}

	/**
	 * 验证当前用户是否属于以下任意一个角色。
	 *
	 * @param roleNames
	 *            角色列表
	 * @return 属于:true,否则false
	 */
	public static boolean hasAnyRoles(String roleNames) {
		boolean hasAnyRole = false;
		Subject subject = getSubject();
		if (subject != null && roleNames != null && roleNames.length() > 0) {
			// Iterate through roles and check to see if the user has one of the
			// roles
			for (String role : roleNames.split(NAMES_DELIMETER)) {
				if (subject.hasRole(role.trim())) {
					hasAnyRole = true;
					break;
				}
			}
		}
		return hasAnyRole;
	}

	/**
	 * 验证当前用户是否属于以下所有角色。
	 *
	 * @param roleNames
	 *            角色列表
	 * @return 属于:true,否则false
	 */
	public static boolean hasAllRoles(String roleNames) {
		boolean hasAllRole = true;
		Subject subject = getSubject();
		if (subject != null && roleNames != null && roleNames.length() > 0) {
			// Iterate through roles and check to see if the user has one of the
			// roles
			for (String role : roleNames.split(NAMES_DELIMETER)) {
				if (!subject.hasRole(role.trim())) {
					hasAllRole = false;
					break;
				}
			}
		}
		return hasAllRole;
	}

	/**
	 * 验证当前用户是否拥有指定权限,使用时与lacksPermission 搭配使用
	 *
	 * @param permission
	 *            权限名
	 * @return 拥有权限：true，否则false
	 */
	public static boolean hasPermission(String permission) {
		return getSubject() != null && permission != null
				&& permission.length() > 0
				&& getSubject().isPermitted(permission);
	}

	/**
	 * 与hasPermission标签逻辑相反，当前用户没有制定权限时，验证通过。
	 *
	 * @param permission
	 *            权限名
	 * @return 拥有权限：true，否则false
	 */
	public static boolean lacksPermission(String permission) {
		return !hasPermission(permission);
	}

	/**
	 * 已认证通过的用户。不包含已记住的用户，这是与user标签的区别所在。与notAuthenticated搭配使用
	 *
	 * @return 通过身份验证：true，否则false
	 */
	public static boolean authenticated() {
		return getSubject() != null && getSubject().isAuthenticated();
	}

	/**
	 * 未认证通过用户，与authenticated标签相对应。与guest标签的区别是，该标签包含已记住用户。。
	 *
	 * @return 没有通过身份验证：true，否则false
	 */
	public static boolean notAuthenticated() {
		return !authenticated();
	}

	/**
	 * 认证通过或已记住的用户。与guset搭配使用。
	 *
	 * @return 用户：true，否则 false
	 */
	public static boolean user() {
		return getSubject() != null && getSubject().getPrincipal() != null;
	}

	/**
	 * 验证当前用户是否为“访客”，即未认证（包含未记住）的用户。用user搭配使用
	 *
	 * @return 访客：true，否则false
	 */
	public static boolean guest() {
		return !user();
	}

	/**
	 * 输出当前用户信息，通常为登录帐号信息。
	 * @return 当前用户信息
	 */
	public String principal(){
		if (getSubject() != null) {
            // Get the principal to print out
            Object principal = getSubject().getPrincipal();
            return principal.toString();
        }
		return "Guest";
	}
}