/*
 * Copyright 2010-2013 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.
 * A copy of the License is located at
 *
 *  http://aws.amazon.com/apache2.0
 *
 * or in the "license" file accompanying this file. 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.
 */

import java.util.ArrayList;
import java.util.List;

import com.amazonaws.AmazonServiceException;
import com.amazonaws.auth.AWSCredentials;
import com.amazonaws.auth.PropertiesCredentials;
import com.amazonaws.regions.Region;
import com.amazonaws.regions.Regions;
import com.amazonaws.services.ec2.AmazonEC2;
import com.amazonaws.services.ec2.AmazonEC2Client;
import com.amazonaws.services.ec2.model.CancelSpotInstanceRequestsRequest;
import com.amazonaws.services.ec2.model.DescribeSpotInstanceRequestsRequest;
import com.amazonaws.services.ec2.model.DescribeSpotInstanceRequestsResult;
import com.amazonaws.services.ec2.model.LaunchSpecification;
import com.amazonaws.services.ec2.model.RequestSpotInstancesRequest;
import com.amazonaws.services.ec2.model.RequestSpotInstancesResult;
import com.amazonaws.services.ec2.model.SpotInstanceRequest;
import com.amazonaws.services.ec2.model.TerminateInstancesRequest;

public class Requests {
    private AmazonEC2      ec2;
    private ArrayList<String> instanceIds;
    private ArrayList<String> spotInstanceRequestIds;

    /**
     * Public constructor.
     * @throws Exception
     */
    public Requests () throws Exception {
        init();
    }

    /**
     * The only information needed to create a client are security credentials
     * consisting of the AWS Access Key ID and Secret Access Key. All other
     * configuration, such as the service endpoints, are performed
     * automatically. Client parameters, such as proxies, can be specified in an
     * optional ClientConfiguration object when constructing a client.
     *
     * @see com.amazonaws.auth.BasicAWSCredentials
     * @see com.amazonaws.auth.PropertiesCredentials
     * @see com.amazonaws.ClientConfiguration
     */
    private void init() throws Exception {
        AWSCredentials credentials = new PropertiesCredentials(
                InlineGettingStartedCodeSampleApp.class.getResourceAsStream("AwsCredentials.properties"));

        ec2 = new AmazonEC2Client(credentials);
		Region usWest2 = Region.getRegion(Regions.US_WEST_2);
		ec2.setRegion(usWest2);
    }

    /**
     * The submit method will create 1 x one-time t1.micro request with a maximum bid
     * price of $0.03 using the Amazon Linux AMI.
     *
     * Note the AMI id may change after the release of this code sample, and it is important
     * to use the latest. You can find the latest version by logging into the AWS Management
     * console, and attempting to perform a launch. You will be presented with AMI options,
     * one of which will be Amazon Linux. Simply use that AMI id.
     */
    public void submitRequests() {
    	//==========================================================================//
    	//================= Submit a Spot Instance Request =====================//
    	//==========================================================================//

    	// Initializes a Spot Instance Request
    	RequestSpotInstancesRequest requestRequest = new RequestSpotInstancesRequest();

    	// Request 1 x t1.micro instance with a bid price of $0.03.
    	requestRequest.setSpotPrice("0.03");
    	requestRequest.setInstanceCount(Integer.valueOf(1));

    	// Setup the specifications of the launch. This includes the instance type (e.g. t1.micro)
    	// and the latest Amazon Linux AMI id available. Note, you should always use the latest
    	// Amazon Linux AMI id or another of your choosing.
    	LaunchSpecification launchSpecification = new LaunchSpecification();
    	launchSpecification.setImageId("ami-8c1fece5");
    	launchSpecification.setInstanceType("t1.micro");

    	// Add the security group to the request.
    	ArrayList<String> securityGroups = new ArrayList<String>();
    	securityGroups.add("GettingStartedGroup");
    	launchSpecification.setSecurityGroups(securityGroups);

    	// Add the launch specifications to the request.
    	requestRequest.setLaunchSpecification(launchSpecification);

    	// Call the RequestSpotInstance API.
    	RequestSpotInstancesResult requestResult = ec2.requestSpotInstances(requestRequest);
    	List<SpotInstanceRequest> requestResponses = requestResult.getSpotInstanceRequests();

    	// Setup an arraylist to collect all of the request ids we want to watch hit the running
    	// state.
    	spotInstanceRequestIds = new ArrayList<String>();

    	// Add all of the request ids to the hashset, so we can determine when they hit the
    	// active state.
    	for (SpotInstanceRequest requestResponse : requestResponses) {
    		System.out.println("Created Spot Request: "+requestResponse.getSpotInstanceRequestId());
    		spotInstanceRequestIds.add(requestResponse.getSpotInstanceRequestId());
    	}

    }

    /**
     * The areOpen method will determine if any of the requests that were started are still
     * in the open state. If all of them have transitioned to either active, cancelled, or
     * closed, then this will return false.
     * @return
     */
    public boolean areAnyOpen() {
    	//==========================================================================//
    	//============== Describe Spot Instance Requests to determine =============//
    	//==========================================================================//

    	// Create the describeRequest with tall of the request id to monitor (e.g. that we started).
    	DescribeSpotInstanceRequestsRequest describeRequest = new DescribeSpotInstanceRequestsRequest();
    	describeRequest.setSpotInstanceRequestIds(spotInstanceRequestIds);

		System.out.println("Checking to determine if Spot Bids have reached the active state...");

		// Initialize variables.
		instanceIds = new ArrayList<String>();

		try
		{
        	// Retrieve all of the requests we want to monitor.
			DescribeSpotInstanceRequestsResult describeResult = ec2.describeSpotInstanceRequests(describeRequest);
			List<SpotInstanceRequest> describeResponses = describeResult.getSpotInstanceRequests();

        	// Look through each request and determine if they are all in the active state.
        	for (SpotInstanceRequest describeResponse : describeResponses) {
        		System.out.println(" " +describeResponse.getSpotInstanceRequestId() +
        						   " is in the "+describeResponse.getState() + " state.");

        		// If the state is open, it hasn't changed since we attempted to request it.
        		// There is the potential for it to transition almost immediately to closed or
        		// cancelled so we compare against open instead of active.
        		if (describeResponse.getState().equals("open")) {
        			return true;
        		}

        		// Add the instance id to the list we will eventually terminate.
        		instanceIds.add(describeResponse.getInstanceId());
        	}
		} catch (AmazonServiceException e) {
			// Print out the error.
			System.out.println("Error when calling describeSpotInstances");
            System.out.println("Caught Exception: " + e.getMessage());
            System.out.println("Reponse Status Code: " + e.getStatusCode());
            System.out.println("Error Code: " + e.getErrorCode());
            System.out.println("Request ID: " + e.getRequestId());

            // If we have an exception, ensure we don't break out of the loop.
			// This prevents the scenario where there was blip on the wire.
			return true;
        }

		return false;
    }

    /**
     * The cleanup method will cancel and active requests and terminate any running instances
     * that were created using this object.
     */
    public void cleanup () {
    	//==========================================================================//
    	//================= Cancel/Terminate Your Spot Request =====================//
    	//==========================================================================//
    	try {
        	// Cancel requests.
        	System.out.println("Cancelling requests.");
        	CancelSpotInstanceRequestsRequest cancelRequest = new CancelSpotInstanceRequestsRequest(spotInstanceRequestIds);
        	ec2.cancelSpotInstanceRequests(cancelRequest);
    	} catch (AmazonServiceException e) {
    		// Write out any exceptions that may have occurred.
            System.out.println("Error cancelling instances");
		    System.out.println("Caught Exception: " + e.getMessage());
            System.out.println("Reponse Status Code: " + e.getStatusCode());
            System.out.println("Error Code: " + e.getErrorCode());
            System.out.println("Request ID: " + e.getRequestId());
        }

    	try {
        	// Terminate instances.
        	System.out.println("Terminate instances");
        	TerminateInstancesRequest terminateRequest = new TerminateInstancesRequest(instanceIds);
        	ec2.terminateInstances(terminateRequest);
    	} catch (AmazonServiceException e) {
    		// Write out any exceptions that may have occurred.
            System.out.println("Error terminating instances");
    		System.out.println("Caught Exception: " + e.getMessage());
            System.out.println("Reponse Status Code: " + e.getStatusCode());
            System.out.println("Error Code: " + e.getErrorCode());
            System.out.println("Request ID: " + e.getRequestId());
        }

    	// Delete all requests and instances that we have terminated.
    	instanceIds.clear();
    	spotInstanceRequestIds.clear();
    }

}