using Amazon.Common.DotNetCli.Tools;
using Amazon.Common.DotNetCli.Tools.Options;
using Amazon.ElasticBeanstalk.Model;
using System;
using System.Collections.Generic;
using System.Globalization;
using System.IO;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using ThirdParty.Json.LitJson;

namespace Amazon.ElasticBeanstalk.Tools.Commands
{
    public class DeployEnvironmentCommand : EBBaseCommand
    {
        public const string COMMAND_NAME = "deploy-environment";
        public const string COMMAND_DESCRIPTION = "Deploy the application to an AWS Elastic Beanstalk environment.";

        public static readonly IList<CommandOption> CommandOptions = BuildLineOptions(new List<CommandOption>
        {
            CommonDefinedCommandOptions.ARGUMENT_PROJECT_LOCATION,
            CommonDefinedCommandOptions.ARGUMENT_CONFIGURATION,
            CommonDefinedCommandOptions.ARGUMENT_FRAMEWORK,
            CommonDefinedCommandOptions.ARGUMENT_SELF_CONTAINED,
            CommonDefinedCommandOptions.ARGUMENT_PUBLISH_OPTIONS,

            EBDefinedCommandOptions.ARGUMENT_EB_APPLICATION,
            EBDefinedCommandOptions.ARGUMENT_EB_ENVIRONMENT,
            EBDefinedCommandOptions.ARGUMENT_EB_VERSION_LABEL,
            EBDefinedCommandOptions.ARGUMENT_EB_TAGS,
            EBDefinedCommandOptions.ARGUMENT_APP_PATH,
            EBDefinedCommandOptions.ARGUMENT_IIS_WEBSITE,
            EBDefinedCommandOptions.ARGUMENT_EB_ADDITIONAL_OPTIONS,

            EBDefinedCommandOptions.ARGUMENT_CNAME_PREFIX,
            EBDefinedCommandOptions.ARGUMENT_SOLUTION_STACK,
            EBDefinedCommandOptions.ARGUMENT_ENVIRONMENT_TYPE,
            EBDefinedCommandOptions.ARGUMENT_EC2_KEYPAIR,
            EBDefinedCommandOptions.ARGUMENT_INSTANCE_TYPE,
            EBDefinedCommandOptions.ARGUMENT_HEALTH_CHECK_URL,
            EBDefinedCommandOptions.ARGUMENT_ENABLE_XRAY,
            EBDefinedCommandOptions.ARGUMENT_ENHANCED_HEALTH_TYPE,
            EBDefinedCommandOptions.ARGUMENT_INSTANCE_PROFILE,
            EBDefinedCommandOptions.ARGUMENT_SERVICE_ROLE,
            EBDefinedCommandOptions.ARGUMENT_INPUT_PACKAGE,

            EBDefinedCommandOptions.ARGUMENT_LOADBALANCER_TYPE,
            EBDefinedCommandOptions.ARGUMENT_ENABLE_STICKY_SESSIONS,
            EBDefinedCommandOptions.ARGUMENT_PROXY_SERVER,
            EBDefinedCommandOptions.ARGUMENT_APPLICATION_PORT,

            EBDefinedCommandOptions.ARGUMENT_WAIT_FOR_UPDATE
        });

        const string OPTIONS_NAMESPACE_ENVIRONMENT_PROXY = "aws:elasticbeanstalk:environment:proxy";
        const string OPTIONS_NAMESPACE_APPLICATION_ENVIRONMENT = "aws:elasticbeanstalk:application:environment";

        const string OPTIONS_NAME_PROXY_SERVER = "ProxyServer";
        const string OPTIONS_NAME_APPLICATION_PORT = "PORT";

        public string Package { get; set; }

        public DeployEnvironmentProperties DeployEnvironmentOptions { get; } = new DeployEnvironmentProperties();

        public DeployEnvironmentCommand(IToolLogger logger, string workingDirectory, string[] args)
            : base(logger, workingDirectory, CommandOptions, args)
        {
        }

        /// <summary>
        /// Parse the CommandOptions into the Properties on the command.
        /// </summary>
        /// <param name="values"></param>
        protected override void ParseCommandArguments(CommandOptions values)
        {
            base.ParseCommandArguments(values);

            this.DeployEnvironmentOptions.ParseCommandArguments(values);

            Tuple<CommandOption, CommandOptionValue> tuple;
            if ((tuple = values.FindCommandOption(EBDefinedCommandOptions.ARGUMENT_INPUT_PACKAGE.Switch)) != null)
                this.Package = tuple.Item2.StringValue;

        }


        protected override async Task<bool> PerformActionAsync()
        {
            string package = this.GetStringValueOrDefault(this.Package, EBDefinedCommandOptions.ARGUMENT_INPUT_PACKAGE, false);
            string application = this.GetStringValueOrDefault(this.DeployEnvironmentOptions.Application, EBDefinedCommandOptions.ARGUMENT_EB_APPLICATION, true);
            string versionLabel = this.GetStringValueOrDefault(this.DeployEnvironmentOptions.VersionLabel, EBDefinedCommandOptions.ARGUMENT_EB_VERSION_LABEL, false) ?? DateTime.Now.Ticks.ToString();
            string environment = this.GetStringValueOrDefault(this.DeployEnvironmentOptions.Environment, EBDefinedCommandOptions.ARGUMENT_EB_ENVIRONMENT, true);

            bool doesApplicationExist = await DoesApplicationExist(application);
            var environmentDescription = doesApplicationExist ? await GetEnvironmentDescription(application, environment) : null;

            bool isWindowsEnvironment;
            List<ConfigurationOptionSetting> existingSettings = null;
            if(environmentDescription != null)
            {
                isWindowsEnvironment = EBUtilities.IsSolutionStackWindows(environmentDescription.SolutionStackName);

                var response = await this.EBClient.DescribeConfigurationSettingsAsync(new DescribeConfigurationSettingsRequest
                {
                    ApplicationName = environmentDescription.ApplicationName,
                    EnvironmentName = environmentDescription.EnvironmentName
                });

                if(response.ConfigurationSettings.Count != 1)
                {
                    throw new ElasticBeanstalkExceptions($"Unknown error to retrieving settings for existing Beanstalk environment.", ElasticBeanstalkExceptions.EBCode.FailedToDescribeEnvironmentSettings);
                }
                existingSettings = response.ConfigurationSettings[0].OptionSettings;
            }
            else
            {
                isWindowsEnvironment = EBUtilities.IsSolutionStackWindows(this.GetSolutionStackOrDefault(this.DeployEnvironmentOptions.SolutionStack, EBDefinedCommandOptions.ARGUMENT_SOLUTION_STACK, true));
            }

            await CreateEBApplicationIfNotExist(application, doesApplicationExist);

            string zipArchivePath = null;

            if (string.IsNullOrEmpty(package))
            {
                this.EnsureInProjectDirectory();

                var projectLocation = Utilities.DetermineProjectLocation(this.WorkingDirectory,
                    this.GetStringValueOrDefault(this.ProjectLocation, CommonDefinedCommandOptions.ARGUMENT_PROJECT_LOCATION, false));

                string configuration = this.GetStringValueOrDefault(this.DeployEnvironmentOptions.Configuration, CommonDefinedCommandOptions.ARGUMENT_CONFIGURATION, false) ?? "Release";
                string targetFramework = this.GetStringValueOrDefault(this.DeployEnvironmentOptions.TargetFramework, CommonDefinedCommandOptions.ARGUMENT_FRAMEWORK, false);

                if (string.IsNullOrEmpty(targetFramework))
                {
                    targetFramework = Utilities.LookupTargetFrameworkFromProjectFile(projectLocation);
                    if (string.IsNullOrEmpty(targetFramework))
                    {
                        targetFramework = this.GetStringValueOrDefault(this.DeployEnvironmentOptions.TargetFramework, CommonDefinedCommandOptions.ARGUMENT_FRAMEWORK, true);
                    }
                }

                var dotnetCli = new DotNetCLIWrapper(this.Logger, projectLocation);

                var publishLocation = Utilities.DeterminePublishLocation(null, projectLocation, configuration, targetFramework);
                this.Logger?.WriteLine("Determine publish location: " + publishLocation);

                var publishOptions = GetPublishOptions(isWindowsEnvironment);

                this.Logger?.WriteLine("Executing publish command");
                if (dotnetCli.Publish(projectLocation, publishLocation, targetFramework, configuration, publishOptions) != 0)
                {
                    throw new ElasticBeanstalkExceptions("Error executing \"dotnet publish\"", ElasticBeanstalkExceptions.CommonErrorCode.DotnetPublishFailed);
                }

                if(isWindowsEnvironment)
                {
                    this.Logger?.WriteLine("Configuring application bundle for a Windows deployment");
                    EBUtilities.SetupAWSDeploymentManifest(this.Logger, this, this.DeployEnvironmentOptions, publishLocation);
                }
                else
                {
                    var proxyServer = this.GetStringValueOrDefault(this.DeployEnvironmentOptions.ProxyServer, EBDefinedCommandOptions.ARGUMENT_PROXY_SERVER, false);
                    if(string.IsNullOrEmpty(proxyServer))
                    {
                        proxyServer = existingSettings.FindExistingValue(OPTIONS_NAMESPACE_ENVIRONMENT_PROXY, OPTIONS_NAMESPACE_APPLICATION_ENVIRONMENT);
                    }

                    var applicationPort = this.GetIntValueOrDefault(this.DeployEnvironmentOptions.ApplicationPort, EBDefinedCommandOptions.ARGUMENT_APPLICATION_PORT, false);
                    if(!applicationPort.HasValue)
                    {
                        var strPort = existingSettings.FindExistingValue(OPTIONS_NAMESPACE_APPLICATION_ENVIRONMENT, OPTIONS_NAME_APPLICATION_PORT);
                        int intPort;
                        if(int.TryParse(strPort, NumberStyles.Any, CultureInfo.InvariantCulture, out intPort))
                        {
                            applicationPort = intPort;
                        }
                    }

                    this.Logger?.WriteLine("Configuring application bundle for a Linux deployment");
                    EBUtilities.SetupPackageForLinux(this.Logger, this, this.DeployEnvironmentOptions, publishLocation, proxyServer, applicationPort);
                }

                zipArchivePath = Path.Combine(Directory.GetParent(publishLocation).FullName, new DirectoryInfo(projectLocation).Name + "-" + DateTime.Now.Ticks + ".zip");

                this.Logger?.WriteLine("Zipping up publish folder");
                Utilities.ZipDirectory(this.Logger, publishLocation, zipArchivePath);
                this.Logger?.WriteLine("Zip archive created: " + zipArchivePath);
            }
            else
            {
                if (!File.Exists(package))
                    throw new ElasticBeanstalkExceptions($"Package {package} does not exist", ElasticBeanstalkExceptions.EBCode.InvalidPackage);
                if (!string.Equals(Path.GetExtension(package), ".zip", StringComparison.OrdinalIgnoreCase))
                    throw new ElasticBeanstalkExceptions($"Package {package} must be a zip file", ElasticBeanstalkExceptions.EBCode.InvalidPackage);

                this.Logger?.WriteLine($"Skipping compilation and using precompiled package {package}");
                zipArchivePath = package;
            }

            S3Location s3Loc;
            try
            {
                s3Loc = await this.UploadDeploymentPackageAsync(application, versionLabel, zipArchivePath).ConfigureAwait(false);
            }
            catch (Exception e)
            {
                throw new ElasticBeanstalkExceptions("Error uploading application bundle to S3: " + e.Message, ElasticBeanstalkExceptions.EBCode.FailedToUploadBundle);
            }

            try
            {
                this.Logger?.WriteLine("Creating new application version: " + versionLabel);
                await this.EBClient.CreateApplicationVersionAsync(new CreateApplicationVersionRequest
                {
                    ApplicationName = application,
                    VersionLabel = versionLabel,
                    SourceBundle = s3Loc
                }).ConfigureAwait(false);
            }
            catch(Exception e)
            {
                throw new ElasticBeanstalkExceptions("Error creating Elastic Beanstalk application version: " + e.Message, ElasticBeanstalkExceptions.EBCode.FailedCreateApplicationVersion);
            }

            this.Logger?.WriteLine("Getting latest environment event date before update");
            var startingEventDate = await GetLatestEventDateAsync(application, environment);

            string environmentArn;
            if(environmentDescription != null)
            {                
                environmentArn = await UpdateEnvironment(environmentDescription, versionLabel);
            }
            else
            {
                environmentArn = await CreateEnvironment(application, environment, versionLabel, isWindowsEnvironment);
            }

            bool? waitForUpdate = this.GetBoolValueOrDefault(this.DeployEnvironmentOptions.WaitForUpdate, EBDefinedCommandOptions.ARGUMENT_WAIT_FOR_UPDATE, false);
            if(!waitForUpdate.HasValue || waitForUpdate.Value)
            {
                this.Logger?.WriteLine("Waiting for environment update to complete");
                var success = await this.WaitForDeploymentCompletionAsync(application, environment, startingEventDate);

                if (success)
                    this.Logger?.WriteLine("Update Complete");
                else
                    throw new ElasticBeanstalkExceptions("Environment update failed", ElasticBeanstalkExceptions.EBCode.FailedEnvironmentUpdate);

            }
            else
            {
                this.Logger?.WriteLine("Environment update initiated");
            }

            if (environmentDescription != null)
            {
                var tags = ConvertToTagsCollection();
                if (tags != null && tags.Count > 0)
                {
                    var updateTagsRequest = new UpdateTagsForResourceRequest
                    {
                        ResourceArn = environmentArn,
                        TagsToAdd = tags
                    };
                    this.Logger?.WriteLine("Updating Tags on environment");
                    try
                    {
                        await this.EBClient.UpdateTagsForResourceAsync(updateTagsRequest);
                    }
                    catch(Exception e)
                    {
                        throw new ElasticBeanstalkExceptions("Error updating tags for environment: " + e.Message, ElasticBeanstalkExceptions.EBCode.FailedToUpdateTags);
                    }
                }
            }

            return true;
        }

        public string GetPublishOptions(bool isWindowsEnvironment)
        {
            var initialOptions = this.GetStringValueOrDefault(this.DeployEnvironmentOptions.PublishOptions, CommonDefinedCommandOptions.ARGUMENT_PUBLISH_OPTIONS, false);
            var selfContained = this.GetBoolValueOrDefault(this.DeployEnvironmentOptions.SelfContained, CommonDefinedCommandOptions.ARGUMENT_SELF_CONTAINED, false) ?? false;
            return new PublishOptions(initialOptions, isWindowsEnvironment, selfContained).ToCliString();
        }

        private async Task CreateEBApplicationIfNotExist(string application, bool doesApplicationExist)
        {
            if (!doesApplicationExist)
            {
                try
                {
                    this.Logger?.WriteLine("Creating new Elastic Beanstalk Application");
                    await this.EBClient.CreateApplicationAsync(new CreateApplicationRequest
                    {
                        ApplicationName = application
                    });
                }
                catch (Exception e)
                {
                    throw new ElasticBeanstalkExceptions("Error creating Elastic Beanstalk application: " + e.Message, ElasticBeanstalkExceptions.EBCode.FailedCreateApplication);
                }
            }
        }

        private List<Tag> ConvertToTagsCollection()
        {
            var tags = this.GetKeyValuePairOrDefault(this.DeployEnvironmentOptions.Tags, EBDefinedCommandOptions.ARGUMENT_EB_TAGS, false);
            if (tags == null || tags.Count == 0)
                return null;

            var collection = new List<Tag>();
            foreach(var kvp in tags)
            {
                collection.Add(new Tag { Key = kvp.Key, Value = kvp.Value });
            }
            return collection;
        }

        private async Task<string> CreateEnvironment(string application, string environment, string versionLabel, bool isWindowsEnvironment)
        {
            var createRequest = new CreateEnvironmentRequest
            {
                ApplicationName = application,
                EnvironmentName = environment,
                VersionLabel = versionLabel,
                SolutionStackName = this.GetSolutionStackOrDefault(this.DeployEnvironmentOptions.SolutionStack, EBDefinedCommandOptions.ARGUMENT_SOLUTION_STACK, true),
                CNAMEPrefix = this.GetStringValueOrDefault(this.DeployEnvironmentOptions.CNamePrefix, EBDefinedCommandOptions.ARGUMENT_CNAME_PREFIX, false)
            };

            string environmentType, loadBalancerType;
            DetermineEnvironment(out environmentType, out loadBalancerType);

            if (!string.IsNullOrEmpty(environmentType))
            {
                createRequest.OptionSettings.Add(new ConfigurationOptionSetting()
                {
                    Namespace = "aws:elasticbeanstalk:environment",
                    OptionName = "EnvironmentType",
                    Value = environmentType
                });
            }

            var ec2KeyPair = this.GetStringValueOrDefault(this.DeployEnvironmentOptions.EC2KeyPair, EBDefinedCommandOptions.ARGUMENT_EC2_KEYPAIR, false);
            if (!string.IsNullOrEmpty(ec2KeyPair))
            {
                createRequest.OptionSettings.Add(new ConfigurationOptionSetting()
                {
                    Namespace = "aws:autoscaling:launchconfiguration",
                    OptionName = "EC2KeyName",
                    Value = ec2KeyPair
                });
            }

            var instanceType = this.GetStringValueOrDefault(this.DeployEnvironmentOptions.InstanceType, EBDefinedCommandOptions.ARGUMENT_INSTANCE_TYPE, false);
            if (string.IsNullOrEmpty(instanceType))
            {
                instanceType = isWindowsEnvironment ? EBConstants.DEFAULT_WINDOWS_INSTANCE_TYPE : EBConstants.DEFAULT_LINUX_INSTANCE_TYPE;
            }
                

            createRequest.OptionSettings.Add(new ConfigurationOptionSetting()
            {
                Namespace = "aws:autoscaling:launchconfiguration",
                OptionName = "InstanceType",
                Value = instanceType
            });

            var instanceProfile = this.GetInstanceProfileOrDefault(this.DeployEnvironmentOptions.InstanceProfile, EBDefinedCommandOptions.ARGUMENT_INSTANCE_PROFILE, true, string.Format("eb_{0}_{1}", application, environment));
            if (!string.IsNullOrEmpty(instanceProfile))
            {
                int pos = instanceProfile.LastIndexOf('/');
                if (pos != -1)
                {
                    instanceProfile = instanceProfile.Substring(pos + 1);
                }

                createRequest.OptionSettings.Add(new ConfigurationOptionSetting()
                {
                    Namespace = "aws:autoscaling:launchconfiguration",
                    OptionName = "IamInstanceProfile",
                    Value = instanceProfile
                });
            }

            var serviceRole = this.GetServiceRoleOrCreateIt(this.DeployEnvironmentOptions.ServiceRole, EBDefinedCommandOptions.ARGUMENT_SERVICE_ROLE, 
                "aws-elasticbeanstalk-service-role", Constants.ELASTICBEANSTALK_ASSUME_ROLE_POLICY, null, "AWSElasticBeanstalkManagedUpdatesCustomerRolePolicy", "AWSElasticBeanstalkEnhancedHealth");
            if (!string.IsNullOrEmpty(serviceRole))
            {
                int pos = serviceRole.LastIndexOf('/');
                if(pos != -1)
                {
                    serviceRole = serviceRole.Substring(pos + 1);
                }

                createRequest.OptionSettings.Add(new ConfigurationOptionSetting()
                {
                    Namespace = "aws:elasticbeanstalk:environment",
                    OptionName = "ServiceRole",
                    Value = serviceRole 
                });
            }

            if (!string.IsNullOrWhiteSpace(loadBalancerType))
            {
                if (!EBConstants.ValidLoadBalancerType.Contains(loadBalancerType))
                    throw new ElasticBeanstalkExceptions($"The loadbalancer type {loadBalancerType} is invalid. Valid values are: {string.Join(", ", EBConstants.ValidLoadBalancerType)}", ElasticBeanstalkExceptions.EBCode.InvalidLoadBalancerType);

                createRequest.OptionSettings.Add(new ConfigurationOptionSetting()
                {
                    Namespace = "aws:elasticbeanstalk:environment",
                    OptionName = "LoadBalancerType",
                    Value = loadBalancerType
                });
            }
           

            AddAdditionalOptions(createRequest.OptionSettings, true, isWindowsEnvironment);

            var tags = ConvertToTagsCollection();
            if (tags != null && tags.Count > 0)
                createRequest.Tags = tags;

            try
            {
                var createResponse = await this.EBClient.CreateEnvironmentAsync(createRequest);
                return createResponse.EnvironmentArn;
            }
            catch (Exception e)
            {
                throw new ElasticBeanstalkExceptions("Error creating environment: " + e.Message, ElasticBeanstalkExceptions.EBCode.FailedToCreateEnvironment);
            }
        }

        private void AddAdditionalOptions(IList<ConfigurationOptionSetting> settings, bool createEnvironmentMode, bool isWindowsEnvironment)
        {
            var additionalOptions = this.GetKeyValuePairOrDefault(this.DeployEnvironmentOptions.AdditionalOptions, EBDefinedCommandOptions.ARGUMENT_EB_ADDITIONAL_OPTIONS, false);
            if (additionalOptions != null && additionalOptions.Count > 0)
            {
                foreach (var kvp in additionalOptions)
                {
                    var tokens = kvp.Key.Split(',');
                    if (tokens.Length != 2)
                    {
                        throw new ToolsException("Additional option \"" + kvp.Key + "=" + kvp.Value + "\" in incorrect format. Format should be <option-namespace>,<option-name>=<option-value>.", ToolsException.CommonErrorCode.DefaultsParseFail);
                    }

                    settings.Add(new ConfigurationOptionSetting
                    {
                        Namespace = tokens[0],
                        OptionName = tokens[1],
                        Value = kvp.Value
                    });
                }
            }

            var enableXRay = this.GetBoolValueOrDefault(this.DeployEnvironmentOptions.EnableXRay, EBDefinedCommandOptions.ARGUMENT_ENABLE_XRAY, false);
            if(enableXRay.HasValue)
            {
                settings.Add(new ConfigurationOptionSetting()
                {
                    Namespace = "aws:elasticbeanstalk:xray",
                    OptionName = "XRayEnabled",
                    Value = enableXRay.Value.ToString(CultureInfo.InvariantCulture).ToLowerInvariant()
                });

                this.Logger?.WriteLine($"Enable AWS X-Ray: {enableXRay.Value}");
            }

            var enhancedHealthType = this.GetStringValueOrDefault(this.DeployEnvironmentOptions.EnhancedHealthType, EBDefinedCommandOptions.ARGUMENT_ENHANCED_HEALTH_TYPE, false);
            if(!string.IsNullOrWhiteSpace(enhancedHealthType))
            {
                if (!EBConstants.ValidEnhanceHealthType.Contains(enhancedHealthType))
                    throw new ElasticBeanstalkExceptions($"The enhanced value type {enhancedHealthType} is invalid. Valid values are: {string.Join(", ", EBConstants.ValidEnhanceHealthType)}", ElasticBeanstalkExceptions.EBCode.InvalidEnhancedHealthType);

                settings.Add(new ConfigurationOptionSetting()
                {
                    Namespace = "aws:elasticbeanstalk:healthreporting:system",
                    OptionName = "SystemType",
                    Value = enhancedHealthType
                });
            }

            string environmentType, loadBalancerType;
            DetermineEnvironment(out environmentType, out loadBalancerType);
            var healthCheckURL = this.GetStringValueOrDefault(this.DeployEnvironmentOptions.HealthCheckUrl, EBDefinedCommandOptions.ARGUMENT_HEALTH_CHECK_URL, false);

            // If creating a new load balanced environment then a heath check url must be set.
            if (createEnvironmentMode && string.IsNullOrEmpty(healthCheckURL) && EBUtilities.IsLoadBalancedEnvironmentType(environmentType))
            {
                healthCheckURL = "/";
            }

            if (!string.IsNullOrEmpty(healthCheckURL))
            {
                settings.Add(new ConfigurationOptionSetting()
                {
                    Namespace = "aws:elasticbeanstalk:application",
                    OptionName = "Application Healthcheck URL",
                    Value = healthCheckURL
                });

                if (EBUtilities.IsLoadBalancedEnvironmentType(environmentType) && string.Equals(loadBalancerType, EBConstants.LOADBALANCER_TYPE_APPLICATION))
                {
                    settings.Add(new ConfigurationOptionSetting()
                    {
                        Namespace = "aws:elasticbeanstalk:environment:process:default",
                        OptionName = "HealthCheckPath",
                        Value = healthCheckURL
                    });
                }
            }

            if(!isWindowsEnvironment)
            {
                var proxyServer = this.GetStringValueOrDefault(this.DeployEnvironmentOptions.ProxyServer, EBDefinedCommandOptions.ARGUMENT_PROXY_SERVER, false);
                if (!string.IsNullOrEmpty(proxyServer))
                {
                    if (!EBConstants.ValidProxyServer.Contains(proxyServer))
                        throw new ElasticBeanstalkExceptions($"The proxy server {proxyServer} is invalid. Valid values are: {string.Join(", ", EBConstants.ValidProxyServer)}", ElasticBeanstalkExceptions.EBCode.InvalidProxyServer);

                    Logger?.WriteLine($"Configuring reverse proxy to {proxyServer}");
                    settings.Add(new ConfigurationOptionSetting()
                    {
                        Namespace = OPTIONS_NAMESPACE_ENVIRONMENT_PROXY,
                        OptionName = OPTIONS_NAME_PROXY_SERVER,
                        Value = proxyServer
                    });

                }

                var applicationPort = this.GetIntValueOrDefault(this.DeployEnvironmentOptions.ApplicationPort, EBDefinedCommandOptions.ARGUMENT_APPLICATION_PORT, false);
                if (applicationPort.HasValue)
                {
                    Logger?.WriteLine($"Application port to {applicationPort}");
                    settings.Add(new ConfigurationOptionSetting()
                    {
                        Namespace = OPTIONS_NAMESPACE_APPLICATION_ENVIRONMENT,
                        OptionName = OPTIONS_NAME_APPLICATION_PORT,
                        Value = applicationPort.Value.ToString(CultureInfo.InvariantCulture)
                    });
                }
            }

            var enableStickySessions = this.GetBoolValueOrDefault(this.DeployEnvironmentOptions.EnableStickySessions, EBDefinedCommandOptions.ARGUMENT_ENABLE_STICKY_SESSIONS, false);
            if (enableStickySessions.HasValue)
            {
                if(enableStickySessions.Value)
                {
                    Logger?.WriteLine($"Enabling sticky sessions");
                }

                settings.Add(new ConfigurationOptionSetting()
                {
                    Namespace = "aws:elasticbeanstalk:environment:process:default",
                    OptionName = "StickinessEnabled",
                    Value = enableStickySessions.Value.ToString(CultureInfo.InvariantCulture).ToLowerInvariant()
                });
            }
        }

        private async Task<string> UpdateEnvironment(EnvironmentDescription environmentDescription, string versionLabel)
        {
            this.Logger?.WriteLine("Updating environment {0} to new application version", environmentDescription.EnvironmentName);
            var updateRequest = new UpdateEnvironmentRequest
            {
                ApplicationName = environmentDescription.ApplicationName,
                EnvironmentName = environmentDescription.EnvironmentName,
                VersionLabel = versionLabel
            };

            AddAdditionalOptions(updateRequest.OptionSettings, false, EBUtilities.IsSolutionStackWindows(environmentDescription.SolutionStackName));

            try
            {
                var updateEnvironmentResponse = await this.EBClient.UpdateEnvironmentAsync(updateRequest);
                return updateEnvironmentResponse.EnvironmentArn;
            }
            catch(Exception e)
            {
                throw new ElasticBeanstalkExceptions("Error updating environment: " + e.Message, ElasticBeanstalkExceptions.EBCode.FailedToUpdateEnvironment);
            }
        }

        private void DetermineEnvironment(out string environmentType, out string loadBalancerType)
        {
            environmentType = this.GetStringValueOrDefault(this.DeployEnvironmentOptions.EnvironmentType, EBDefinedCommandOptions.ARGUMENT_ENVIRONMENT_TYPE, false);
            loadBalancerType = this.GetStringValueOrDefault(this.DeployEnvironmentOptions.LoadBalancerType, EBDefinedCommandOptions.ARGUMENT_LOADBALANCER_TYPE, false);

            if (string.IsNullOrWhiteSpace(environmentType))
            {
                environmentType = string.IsNullOrWhiteSpace(loadBalancerType) ? EBConstants.ENVIRONMENT_TYPE_SINGLEINSTANCE : EBConstants.ENVIRONMENT_TYPE_LOADBALANCED;
            }

            if (string.IsNullOrWhiteSpace(loadBalancerType) && EBUtilities.IsLoadBalancedEnvironmentType(environmentType))
            {
                loadBalancerType = EBConstants.LOADBALANCER_TYPE_APPLICATION;
            }
        }

        private async Task<bool> DoesApplicationExist(string applicationName)
        {
            var request = new DescribeApplicationsRequest();
            request.ApplicationNames.Add(applicationName);
            var response = await this.EBClient.DescribeApplicationsAsync(request);
            return response.Applications.Count == 1;
        }

        private async Task<EnvironmentDescription> GetEnvironmentDescription(string applicationName, string environmentName)
        {
            var request = new DescribeEnvironmentsRequest { ApplicationName = applicationName };
            request.EnvironmentNames.Add(environmentName);
            var response = await this.EBClient.DescribeEnvironmentsAsync(request);
            if (response.Environments.Where(x => x.Status != EnvironmentStatus.Terminated && x.Status != EnvironmentStatus.Terminating).Count() != 1)
                return null;

            var environment = response.Environments[0];
            if (environment.Status == EnvironmentStatus.Terminated || environment.Status == EnvironmentStatus.Terminating)
                return null;

            
            return environment;
        }

        private async Task<bool> WaitForDeploymentCompletionAsync(string applicationName, string environmentName, DateTime startingEventDate)
        {
            var requestEnvironment = new DescribeEnvironmentsRequest
            {
                ApplicationName = applicationName,
                EnvironmentNames = new List<string> { environmentName }
            };

            var requestEvents = new DescribeEventsRequest
            {
                ApplicationName = applicationName,
                EnvironmentName = environmentName,
                StartTimeUtc = startingEventDate
            };

            var success = true;
            var lastPrintedEventDate = startingEventDate;
            EnvironmentDescription environment = new EnvironmentDescription();
            do
            {
                Thread.Sleep(5000);

                var responseEnvironments = await this.EBClient.DescribeEnvironmentsAsync(requestEnvironment);
                if (responseEnvironments.Environments.Count == 0)
                    throw new ElasticBeanstalkExceptions("Failed to find environment when waiting for deployment completion", ElasticBeanstalkExceptions.EBCode.FailedToFindEnvironment );

                environment = responseEnvironments.Environments[0];

                requestEvents.StartTimeUtc = lastPrintedEventDate;
                var responseEvents = await this.EBClient.DescribeEventsAsync(requestEvents);
                if(responseEvents.Events.Count > 0)
                {
                    for(int i = responseEvents.Events.Count - 1; i >= 0; i--)
                    {
                        var evnt = responseEvents.Events[i];
                        if (evnt.EventDate <= lastPrintedEventDate)
                            continue;

                        this.Logger?.WriteLine(evnt.EventDate.ToLocalTime() + "    " + evnt.Severity + "    " + evnt.Message);
                        if(evnt.Message.StartsWith("Failed to deploy application", StringComparison.OrdinalIgnoreCase) ||
                           evnt.Message.StartsWith("Failed to launch environment", StringComparison.OrdinalIgnoreCase) ||
                           evnt.Message.StartsWith("Error occurred during build: Command hooks failed", StringComparison.OrdinalIgnoreCase))
                        {
                            success = false;
                        }
                    }

                    lastPrintedEventDate = responseEvents.Events[0].EventDate;
                }

            } while (environment.Status == EnvironmentStatus.Launching || environment.Status == EnvironmentStatus.Updating);

            if(success)
            {
                this.Logger?.WriteLine("Environment update complete: http://{0}/", environment.EndpointURL);
            }

            return success;
        }

        private async Task<DateTime> GetLatestEventDateAsync(string application, string environment)
        {
            var request = new DescribeEventsRequest
            {
                ApplicationName = application,
                EnvironmentName = environment
            };

            var response = await this.EBClient.DescribeEventsAsync(request);
            if (response.Events.Count == 0)
                return DateTime.Now;

            return response.Events[0].EventDate;
        }

        private async Task<S3Location> UploadDeploymentPackageAsync(string application, string versionLabel, string deploymentPackage)
        {
            var bucketName = (await this.EBClient.CreateStorageLocationAsync()).S3Bucket;

            // can't use deploymentPackage directly as vs2008/vs2010 pass different names (vs08 already has version in it),
            // so synthesize one
            string key = string.Format("{0}/AWSDeploymentArchive_{0}_{1}{2}",
                                        application.Replace(' ', '-'),
                                        versionLabel.Replace(' ', '-'),
                                        Path.GetExtension(deploymentPackage));

            var fileInfo = new FileInfo(deploymentPackage);

            if (!(await Utilities.EnsureBucketExistsAsync(this.Logger, this.S3Client, bucketName)))
                throw new ElasticBeanstalkExceptions("Detected error in deployment bucket preparation; abandoning deployment", ElasticBeanstalkExceptions.EBCode.EnsureBucketExistsError );

            this.Logger?.WriteLine("... Uploading from file path {0}, size {1} bytes to Amazon S3", deploymentPackage, fileInfo.Length);

            using (var stream = File.OpenRead(deploymentPackage))
            {
                await Utilities.UploadToS3Async(this.Logger, this.S3Client, bucketName, key, stream);
            }

            return new S3Location() { S3Bucket = bucketName, S3Key = key };
        }


        protected override void SaveConfigFile(JsonData data)
        {
            this.DeployEnvironmentOptions.PersistSettings(this, data);
        }
    }
}