/*
 * Copyright (C) 2013 David Sowerby
 * 
 * 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 uk.q3c.krail.core.shiro;

import org.apache.shiro.SecurityUtils;
import org.apache.shiro.UnavailableSecurityManagerException;
import org.apache.shiro.mgt.SecurityManager;
import org.apache.shiro.subject.Subject;
import org.apache.shiro.subject.support.SubjectThreadState;
import org.apache.shiro.util.LifecycleUtils;
import org.apache.shiro.util.ThreadState;
import org.junit.AfterClass;

/**
 * Abstract test case enabling Shiro in test environments.
 */
public abstract class AbstractShiroTest {

    private static ThreadState subjectThreadState;

    public AbstractShiroTest() {
    }

    @AfterClass
    public static void tearDownShiro() {
        doClearSubject();
        try {
            SecurityManager securityManager = getSecurityManager();
            LifecycleUtils.destroy(securityManager);
        } catch (UnavailableSecurityManagerException e) {
            // we don't care about this when cleaning up the test environment
            // (for example, maybe the subclass is a unit test and it didn't
            // need a SecurityManager instance because it was using only
            // mock Subject instances)
        }
        setSecurityManager(null);
    }

    protected static KrailSecurityManager getSecurityManager() {
        return (KrailSecurityManager) SecurityUtils.getSecurityManager();
    }

    protected static void setSecurityManager(SecurityManager securityManager) {
        SecurityUtils.setSecurityManager(securityManager);
    }

    private static void doClearSubject() {
        if (subjectThreadState != null) {
            subjectThreadState.clear();
            subjectThreadState = null;
        }
    }

    protected Subject getSubject() {
        return SecurityUtils.getSubject();
    }

    /**
     * Allows subclasses to set the currently executing {@link Subject} instance.
     *
     * @param subject
     *         the Subject instance
     */
    protected void setSubject(Subject subject) {
        clearSubject();
        subjectThreadState = createThreadState(subject);
        subjectThreadState.bind();
    }

    protected ThreadState createThreadState(Subject subject) {
        return new SubjectThreadState(subject);
    }

    /**
     * Clears Shiro's thread state, ensuring the thread remains clean for future test execution.
     */
    protected void clearSubject() {
        doClearSubject();
    }
}