/*
 * Copyright 2010-2015 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 *
 * 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://aws.amazon.com/apache2.0
 *
 * This file 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.amazonaws.auth;

import static org.junit.Assert.assertEquals;

import com.amazonaws.internal.StaticCredentialsProvider;

import org.junit.Test;

public class AWSCredentialsProviderChainTest {

    /**
     * Tests that, by default, the chain remembers which provider was able to
     * provide credentials, and only calls that provider for any additional
     * calls to getCredentials.
     */
    @Test
    public void testReusingLastProvider() throws Exception {
        MockCredentialsProvider provider1 = new MockCredentialsProvider();
        provider1.throwException = true;
        MockCredentialsProvider provider2 = new MockCredentialsProvider();
        AWSCredentialsProviderChain chain = new AWSCredentialsProviderChain(provider1, provider2);

        assertEquals(0, provider1.getCredentialsCallCount);
        assertEquals(0, provider2.getCredentialsCallCount);

        chain.getCredentials();
        assertEquals(1, provider1.getCredentialsCallCount);
        assertEquals(1, provider2.getCredentialsCallCount);

        chain.getCredentials();
        assertEquals(1, provider1.getCredentialsCallCount);
        assertEquals(2, provider2.getCredentialsCallCount);

        chain.getCredentials();
        assertEquals(1, provider1.getCredentialsCallCount);
        assertEquals(3, provider2.getCredentialsCallCount);
    }

    /**
     * Tests that, when provider caching is disabled, the chain will always try
     * all providers in the chain, starting with the first, until it finds a
     * provider that can return credentials.
     */
    @Test
    public void testDisableReusingLastProvider() throws Exception {
        MockCredentialsProvider provider1 = new MockCredentialsProvider();
        provider1.throwException = true;
        MockCredentialsProvider provider2 = new MockCredentialsProvider();
        AWSCredentialsProviderChain chain = new AWSCredentialsProviderChain(provider1, provider2);
        chain.setReuseLastProvider(false);

        assertEquals(0, provider1.getCredentialsCallCount);
        assertEquals(0, provider2.getCredentialsCallCount);

        chain.getCredentials();
        assertEquals(1, provider1.getCredentialsCallCount);
        assertEquals(1, provider2.getCredentialsCallCount);

        chain.getCredentials();
        assertEquals(2, provider1.getCredentialsCallCount);
        assertEquals(2, provider2.getCredentialsCallCount);
    }

    private static final class MockCredentialsProvider extends StaticCredentialsProvider {
        public int getCredentialsCallCount = 0;
        public boolean throwException = false;

        public MockCredentialsProvider() {
            super(new BasicAWSCredentials("accessKey", "secretKey"));
        }

        @Override
        public AWSCredentials getCredentials() {
            getCredentialsCallCount++;

            if (throwException)
                throw new RuntimeException("No credentials");
            else
                return super.getCredentials();
        }
    }
}