using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;

using Amazon.CloudFormation;
using Amazon.CloudFormation.Model;


using ThirdParty.Json.LitJson;
using Amazon.Common.DotNetCli.Tools;
using Amazon.Common.DotNetCli.Tools.Options;
using Amazon.Lambda.Tools.TemplateProcessor;
using Newtonsoft.Json.Linq;

namespace Amazon.Lambda.Tools.Commands
{
    /// <summary>
    /// Deployment command that uses an AWS Serverless CloudFormation template to drive the creation of the resources
    /// for an AWS Serverless application.
    /// </summary>
    public class DeployServerlessCommand : LambdaBaseCommand
    {
        public const string COMMAND_NAME = "deploy-serverless";
        public const string COMMAND_DESCRIPTION = "Command to deploy an AWS Serverless application";
        public const string COMMAND_ARGUMENTS = "<STACK-NAME> The name of the CloudFormation stack used to deploy the AWS Serverless application";

        // CloudFormation statuses for when the stack is in transition all end with IN_PROGRESS
        const string IN_PROGRESS_SUFFIX = "IN_PROGRESS";



        public static readonly IList<CommandOption> DeployServerlessCommandOptions = BuildLineOptions(new List<CommandOption>
        {
            CommonDefinedCommandOptions.ARGUMENT_CONFIGURATION,
            CommonDefinedCommandOptions.ARGUMENT_FRAMEWORK,
            CommonDefinedCommandOptions.ARGUMENT_MSBUILD_PARAMETERS,
            LambdaDefinedCommandOptions.ARGUMENT_PACKAGE,
            LambdaDefinedCommandOptions.ARGUMENT_RESOLVE_S3,
            LambdaDefinedCommandOptions.ARGUMENT_S3_BUCKET,
            LambdaDefinedCommandOptions.ARGUMENT_S3_PREFIX,
            LambdaDefinedCommandOptions.ARGUMENT_CLOUDFORMATION_TEMPLATE,
            LambdaDefinedCommandOptions.ARGUMENT_CLOUDFORMATION_TEMPLATE_PARAMETER,
            LambdaDefinedCommandOptions.ARGUMENT_CLOUDFORMATION_TEMPLATE_SUBSTITUTIONS,
            LambdaDefinedCommandOptions.ARGUMENT_CLOUDFORMATION_ROLE,
            LambdaDefinedCommandOptions.ARGUMENT_STACK_NAME,
            LambdaDefinedCommandOptions.ARGUMENT_CLOUDFORMATION_DISABLE_CAPABILITIES,
            LambdaDefinedCommandOptions.ARGUMENT_FUNCTION_TAGS,
            LambdaDefinedCommandOptions.ARGUMENT_STACK_WAIT,
            LambdaDefinedCommandOptions.ARGUMENT_DISABLE_VERSION_CHECK
        });

        public string Configuration { get; set; }
        public string TargetFramework { get; set; }
        public string Package { get; set; }
        public string MSBuildParameters { get; set; }

        public bool? ResolveS3 { get; set; }
        public string S3Bucket { get; set; }
        public string S3Prefix { get; set; }

        public string CloudFormationTemplate { get; set; }
        public string StackName { get; set; }
        public bool? WaitForStackToComplete { get; set; }
        public string CloudFormationRole { get; set; }
        public Dictionary<string, string> TemplateParameters { get; set; }
        public Dictionary<string, string> TemplateSubstitutions { get; set; }
        public Dictionary<string, string> Tags { get; set; }

        public bool? DisableVersionCheck { get; set; }

        public string[] DisabledCapabilities { get; set; }

        /// <summary>
        /// Parse the CommandOptions into the Properties on the command.
        /// </summary>
        /// <param name="values"></param>
        protected override void ParseCommandArguments(CommandOptions values)
        {
            base.ParseCommandArguments(values);
            if (values.Arguments.Count > 0)
            {
                this.StackName = values.Arguments[0];
            }

            Tuple<CommandOption, CommandOptionValue> tuple;
            if ((tuple = values.FindCommandOption(CommonDefinedCommandOptions.ARGUMENT_CONFIGURATION.Switch)) != null)
                this.Configuration = tuple.Item2.StringValue;
            if ((tuple = values.FindCommandOption(CommonDefinedCommandOptions.ARGUMENT_FRAMEWORK.Switch)) != null)
                this.TargetFramework = tuple.Item2.StringValue;
            if ((tuple = values.FindCommandOption(LambdaDefinedCommandOptions.ARGUMENT_PACKAGE.Switch)) != null)
                this.Package = tuple.Item2.StringValue;
            if ((tuple = values.FindCommandOption(LambdaDefinedCommandOptions.ARGUMENT_RESOLVE_S3.Switch)) != null)
                this.ResolveS3 = tuple.Item2.BoolValue;
            if ((tuple = values.FindCommandOption(LambdaDefinedCommandOptions.ARGUMENT_S3_BUCKET.Switch)) != null)
                this.S3Bucket = tuple.Item2.StringValue;
            if ((tuple = values.FindCommandOption(LambdaDefinedCommandOptions.ARGUMENT_S3_PREFIX.Switch)) != null)
                this.S3Prefix = tuple.Item2.StringValue;
            if ((tuple = values.FindCommandOption(LambdaDefinedCommandOptions.ARGUMENT_STACK_NAME.Switch)) != null)
                this.StackName = tuple.Item2.StringValue;
            if ((tuple = values.FindCommandOption(LambdaDefinedCommandOptions.ARGUMENT_CLOUDFORMATION_TEMPLATE.Switch)) != null)
                this.CloudFormationTemplate = tuple.Item2.StringValue;
            if ((tuple = values.FindCommandOption(LambdaDefinedCommandOptions.ARGUMENT_STACK_WAIT.Switch)) != null)
                this.WaitForStackToComplete = tuple.Item2.BoolValue;
            if ((tuple = values.FindCommandOption(LambdaDefinedCommandOptions.ARGUMENT_CLOUDFORMATION_TEMPLATE_PARAMETER.Switch)) != null)
                this.TemplateParameters = tuple.Item2.KeyValuePairs;
            if ((tuple = values.FindCommandOption(LambdaDefinedCommandOptions.ARGUMENT_CLOUDFORMATION_TEMPLATE_SUBSTITUTIONS.Switch)) != null)
                this.TemplateSubstitutions = tuple.Item2.KeyValuePairs;
            if ((tuple = values.FindCommandOption(LambdaDefinedCommandOptions.ARGUMENT_CLOUDFORMATION_ROLE.Switch)) != null)
                this.CloudFormationRole = tuple.Item2.StringValue;
            if ((tuple = values.FindCommandOption(LambdaDefinedCommandOptions.ARGUMENT_DISABLE_VERSION_CHECK.Switch)) != null)
                this.DisableVersionCheck = tuple.Item2.BoolValue;
            if ((tuple = values.FindCommandOption(LambdaDefinedCommandOptions.ARGUMENT_FUNCTION_TAGS.Switch)) != null)
                this.Tags = tuple.Item2.KeyValuePairs;

            if ((tuple = values.FindCommandOption(CommonDefinedCommandOptions.ARGUMENT_MSBUILD_PARAMETERS.Switch)) != null)
                this.MSBuildParameters = tuple.Item2.StringValue;

            if (!string.IsNullOrEmpty(values.MSBuildParameters))
            {
                if (this.MSBuildParameters == null)
                    this.MSBuildParameters = values.MSBuildParameters;
                else
                    this.MSBuildParameters += " " + values.MSBuildParameters;
            }
        }


        public DeployServerlessCommand(IToolLogger logger, string workingDirectory, string[] args)
            : base(logger, workingDirectory, DeployServerlessCommandOptions, args)
        {
        }

        protected override async Task<bool> PerformActionAsync()
        {
            string projectLocation = this.GetStringValueOrDefault(this.ProjectLocation, CommonDefinedCommandOptions.ARGUMENT_PROJECT_LOCATION, false);
            string stackName = this.GetStringValueOrDefault(this.StackName, LambdaDefinedCommandOptions.ARGUMENT_STACK_NAME, true);
            string s3Prefix = this.GetStringValueOrDefault(this.S3Prefix, LambdaDefinedCommandOptions.ARGUMENT_S3_PREFIX, false);
            string templatePath = this.GetStringValueOrDefault(this.CloudFormationTemplate, LambdaDefinedCommandOptions.ARGUMENT_CLOUDFORMATION_TEMPLATE, true);

            string s3Bucket = await DetermineS3Bucket();

            await Utilities.ValidateBucketRegionAsync(this.S3Client, s3Bucket);

            if (!Path.IsPathRooted(templatePath))
            {
                templatePath = Path.Combine(Utilities.DetermineProjectLocation(this.WorkingDirectory, projectLocation), templatePath);
            }

            if (!File.Exists(templatePath))
                throw new LambdaToolsException($"Template file {templatePath} cannot be found.", LambdaToolsException.LambdaErrorCode.ServerlessTemplateNotFound);

            // Read in the serverless template and update all the locations for Lambda functions to point to the app bundle that was just uploaded.
            string templateBody = File.ReadAllText(templatePath);

            // Process any template substitutions
            templateBody = LambdaUtilities.ProcessTemplateSubstitions(this.Logger, templateBody, this.GetKeyValuePairOrDefault(this.TemplateSubstitutions, LambdaDefinedCommandOptions.ARGUMENT_CLOUDFORMATION_TEMPLATE_SUBSTITUTIONS, false), Utilities.DetermineProjectLocation(this.WorkingDirectory, projectLocation));
            
            
            var options = new DefaultLocationOption
            {
                Configuration = this.GetStringValueOrDefault(this.Configuration, CommonDefinedCommandOptions.ARGUMENT_CONFIGURATION, false),
                TargetFramework = this.GetStringValueOrDefault(this.TargetFramework, CommonDefinedCommandOptions.ARGUMENT_FRAMEWORK, false),
                MSBuildParameters = this.GetStringValueOrDefault(this.MSBuildParameters, CommonDefinedCommandOptions.ARGUMENT_MSBUILD_PARAMETERS, false),
                DisableVersionCheck = this.GetBoolValueOrDefault(this.DisableVersionCheck, LambdaDefinedCommandOptions.ARGUMENT_DISABLE_VERSION_CHECK, false).GetValueOrDefault(),
                Package = this.GetStringValueOrDefault(this.Package, LambdaDefinedCommandOptions.ARGUMENT_PACKAGE, false)
            };
            
            var templateProcessor = new TemplateProcessorManager(this, s3Bucket, s3Prefix, options);
            templateBody = await templateProcessor.TransformTemplateAsync(templatePath, templateBody, OriginalCommandLineArguments);

            // Upload the template to S3 instead of sending it straight to CloudFormation to avoid the size limitation
            string s3KeyTemplate;
            using (var stream = new MemoryStream(System.Text.Encoding.UTF8.GetBytes(templateBody)))
            {
                s3KeyTemplate = await Utilities.UploadToS3Async(this.Logger, this.S3Client, s3Bucket, s3Prefix, stackName + "-" + Path.GetFileName(templatePath), stream);
            }

            var existingStack = await GetExistingStackAsync(stackName);
            this.Logger.WriteLine("Found existing stack: " + (existingStack != null));
            var changeSetName = "Lambda-Tools-" + DateTime.Now.Ticks;

            List<Tag> tagList = null;
            {
                var tags = this.GetKeyValuePairOrDefault(this.Tags, LambdaDefinedCommandOptions.ARGUMENT_FUNCTION_TAGS, false);
                if(tags != null)
                {
                    tagList = new List<Tag>();
                    foreach(var kvp in tags)
                    {
                        tagList.Add(new Tag { Key = kvp.Key, Value = kvp.Value });
                    }
                }
            }

            // Determine if the stack is in a good state to be updated.
            ChangeSetType changeSetType;
            if (existingStack == null || existingStack.StackStatus == StackStatus.REVIEW_IN_PROGRESS || existingStack.StackStatus == StackStatus.DELETE_COMPLETE)
            {
                changeSetType = ChangeSetType.CREATE;
            }
            // If the status was ROLLBACK_COMPLETE that means the stack failed on initial creation
            // and the resources were cleaned up. It is safe to delete the stack so we can recreate it.
            else if (existingStack.StackStatus == StackStatus.ROLLBACK_COMPLETE)
            {
                await DeleteRollbackCompleteStackAsync(existingStack);
                changeSetType = ChangeSetType.CREATE;
            }
            // If the status was ROLLBACK_IN_PROGRESS that means the initial creation is failing.
            // Wait to see if it goes into ROLLBACK_COMPLETE status meaning everything got cleaned up and then delete it.
            else if (existingStack.StackStatus == StackStatus.ROLLBACK_IN_PROGRESS)
            {
                existingStack = await WaitForNoLongerInProgress(existingStack.StackName);
                if (existingStack != null && existingStack.StackStatus == StackStatus.ROLLBACK_COMPLETE)
                    await DeleteRollbackCompleteStackAsync(existingStack);

                changeSetType = ChangeSetType.CREATE;
            }
            // If the status was DELETE_IN_PROGRESS then just wait for delete to complete 
            else if (existingStack.StackStatus == StackStatus.DELETE_IN_PROGRESS)
            {
                await WaitForNoLongerInProgress(existingStack.StackName);
                changeSetType = ChangeSetType.CREATE;
            }
            // The Stack state is in a normal state and ready to be updated.
            else if (existingStack.StackStatus == StackStatus.CREATE_COMPLETE ||
                    existingStack.StackStatus == StackStatus.UPDATE_COMPLETE ||
                    existingStack.StackStatus == StackStatus.UPDATE_ROLLBACK_COMPLETE)
            {
                changeSetType = ChangeSetType.UPDATE;
                if(tagList == null)
                {
                    tagList = existingStack.Tags;
                }
            }
            // All other states means the Stack is in an inconsistent state.
            else
            {
                throw new LambdaToolsException($"The stack's current state of {existingStack.StackStatus} is invalid for updating", LambdaToolsException.LambdaErrorCode.InvalidCloudFormationStackState);
            }

            CreateChangeSetResponse changeSetResponse;
            try
            {
                var definedParameters = LambdaUtilities.GetTemplateDefinedParameters(templateBody);
                var templateParameters = GetTemplateParameters(changeSetType == ChangeSetType.UPDATE ? existingStack : null, definedParameters);
                if (templateParameters != null && templateParameters.Any())
                {
                    var setParameters = templateParameters.Where(x => !x.UsePreviousValue);
                    // ReSharper disable once PossibleMultipleEnumeration
                    if (setParameters.Any())
                    {
                        this.Logger.WriteLine("Template Parameters Applied:");
                        foreach (var parameter in setParameters)
                        {
                            Tuple<string, bool> dp = null;
                            if (definedParameters != null)
                            {
                                dp = definedParameters.FirstOrDefault(x => string.Equals(x.Item1, parameter.ParameterKey));
                            }

                            if (dp != null && dp.Item2)
                            {
                                this.Logger.WriteLine($"\t{parameter.ParameterKey}: ****");
                            }
                            else
                            {
                                this.Logger.WriteLine($"\t{parameter.ParameterKey}: {parameter.ParameterValue}");
                            }
                        }
                    }
                }

                var capabilities = new List<string>();
                var disabledCapabilties = GetStringValuesOrDefault(this.DisabledCapabilities, LambdaDefinedCommandOptions.ARGUMENT_CLOUDFORMATION_DISABLE_CAPABILITIES, false);

                if (disabledCapabilties?.FirstOrDefault(x => string.Equals(x, "CAPABILITY_IAM", StringComparison.OrdinalIgnoreCase)) == null)
                {
                    capabilities.Add("CAPABILITY_IAM");
                }
                if (disabledCapabilties?.FirstOrDefault(x => string.Equals(x, "CAPABILITY_NAMED_IAM", StringComparison.OrdinalIgnoreCase)) == null)
                {
                    capabilities.Add("CAPABILITY_NAMED_IAM");
                }
                if (disabledCapabilties?.FirstOrDefault(x => string.Equals(x, "CAPABILITY_AUTO_EXPAND", StringComparison.OrdinalIgnoreCase)) == null)
                {
                    capabilities.Add("CAPABILITY_AUTO_EXPAND");
                }

                if (tagList == null)
                {
                    tagList = new List<Tag>();
                }

                if(tagList.FirstOrDefault(x => string.Equals(x.Key, LambdaConstants.SERVERLESS_TAG_NAME)) == null)
                {
                    tagList.Add(new Tag { Key = LambdaConstants.SERVERLESS_TAG_NAME, Value = "true" });
                }

                var changeSetRequest = new CreateChangeSetRequest
                {
                    StackName = stackName,
                    Parameters = templateParameters,
                    ChangeSetName = changeSetName,
                    ChangeSetType = changeSetType,
                    Capabilities = capabilities,
                    RoleARN = this.GetStringValueOrDefault(this.CloudFormationRole, LambdaDefinedCommandOptions.ARGUMENT_CLOUDFORMATION_ROLE, false),
                    Tags = tagList
                };

                if(templateBody.Length < LambdaConstants.MAX_TEMPLATE_BODY_IN_REQUEST_SIZE)
                {
                    changeSetRequest.TemplateBody = templateBody;
                }
                else
                {
                    changeSetRequest.TemplateURL = this.S3Client.GetPreSignedURL(new S3.Model.GetPreSignedUrlRequest { BucketName = s3Bucket, Key = s3KeyTemplate, Expires = DateTime.Now.AddHours(1) });
                }

                // Create the change set which performs the transformation on the Serverless resources in the template.
                changeSetResponse = await this.CloudFormationClient.CreateChangeSetAsync(changeSetRequest);


                this.Logger.WriteLine("CloudFormation change set created");
            }
            catch(LambdaToolsException)
            {
                throw;
            }
            catch (Exception e)
            {
                throw new LambdaToolsException($"Error creating CloudFormation change set: {e.Message}", LambdaToolsException.LambdaErrorCode.CloudFormationCreateStack, e);
            }

            // The change set can take a few seconds to be reviewed and be ready to be executed.
            await WaitForChangeSetBeingAvailableAsync(changeSetResponse.Id);

            var executeChangeSetRequest = new ExecuteChangeSetRequest
            {
                StackName = stackName,
                ChangeSetName = changeSetResponse.Id
            };

            // Execute the change set.
            DateTime timeChangeSetExecuted = DateTime.Now;
            try
            {
                await this.CloudFormationClient.ExecuteChangeSetAsync(executeChangeSetRequest);
                if (changeSetType == ChangeSetType.CREATE)
                    this.Logger.WriteLine($"Created CloudFormation stack {stackName}");
                else
                    this.Logger.WriteLine($"Initiated CloudFormation stack update on {stackName}");
            }
            catch (Exception e)
            {
                throw new LambdaToolsException($"Error executing CloudFormation change set: {e.Message}", LambdaToolsException.LambdaErrorCode.CloudFormationCreateChangeSet, e);
            }

            // Wait for the stack to finish unless the user opts out of waiting. The VS Toolkit opts out and
            // instead shows the stack view in the IDE, enabling the user to view progress.
            var shouldWait = GetBoolValueOrDefault(this.WaitForStackToComplete, LambdaDefinedCommandOptions.ARGUMENT_STACK_WAIT, false);
            if (!shouldWait.HasValue || shouldWait.Value)
            {
                var updatedStack = await WaitStackToCompleteAsync(stackName, timeChangeSetExecuted);

                if (updatedStack.StackStatus == StackStatus.CREATE_COMPLETE || updatedStack.StackStatus == StackStatus.UPDATE_COMPLETE)
                {
                    this.Logger.WriteLine($"Stack finished updating with status: {updatedStack.StackStatus}");

                    // Display the output parameters.
                    DisplayOutputs(updatedStack);
                }
                else
                {
                    throw new LambdaToolsException($"Stack update failed with status: {updatedStack.StackStatus} ({updatedStack.StackStatusReason})", LambdaToolsException.LambdaErrorCode.FailedLambdaCreateOrUpdate);
                }
            }

            return true;
        }



        private void DisplayOutputs(Stack stack)
        {
            if (stack.Outputs.Count == 0)
                return;

            const int OUTPUT_NAME_WIDTH = 30;
            const int OUTPUT_VALUE_WIDTH = 50;

            this.Logger.WriteLine("   ");
            this.Logger.WriteLine("Output Name".PadRight(OUTPUT_NAME_WIDTH) + " " + "Value".PadRight(OUTPUT_VALUE_WIDTH));
            this.Logger.WriteLine($"{new string('-', OUTPUT_NAME_WIDTH)} {new string('-', OUTPUT_VALUE_WIDTH)}");
            foreach (var output in stack.Outputs)
            {
                string line = output.OutputKey.PadRight(OUTPUT_NAME_WIDTH) + " " + output.OutputValue?.PadRight(OUTPUT_VALUE_WIDTH);
                this.Logger.WriteLine(line);
            }
        }

        static readonly TimeSpan POLLING_PERIOD = TimeSpan.FromSeconds(3);
        private async Task<Stack> WaitStackToCompleteAsync(string stackName, DateTime mintimeStampForEvents)
        {
            const int TIMESTAMP_WIDTH = 20;
            const int LOGICAL_RESOURCE_WIDTH = 40;
            const int RESOURCE_STATUS = 40;
            string mostRecentEventId = "";

            // Write header for the status table.
            this.Logger.WriteLine("   ");
            this.Logger.WriteLine(
                "Timestamp".PadRight(TIMESTAMP_WIDTH) + " " +
                "Logical Resource Id".PadRight(LOGICAL_RESOURCE_WIDTH) + " " +
                "Status".PadRight(RESOURCE_STATUS) + " ");
            this.Logger.WriteLine(
                new string('-', TIMESTAMP_WIDTH) + " " +
                new string('-', LOGICAL_RESOURCE_WIDTH) + " " +
                new string('-', RESOURCE_STATUS) + " ");

            Stack stack;
            do
            {
                Thread.Sleep(POLLING_PERIOD);
                stack = await GetExistingStackAsync(stackName);

                var events = await GetLatestEventsAsync(stackName, mintimeStampForEvents, mostRecentEventId);
                if (events.Count > 0)
                    mostRecentEventId = events[0].EventId;

                for (int i = events.Count - 1; i >= 0; i--)
                {
                    string line =
                        events[i].Timestamp.ToString("g").PadRight(TIMESTAMP_WIDTH) + " " +
                        events[i].LogicalResourceId.PadRight(LOGICAL_RESOURCE_WIDTH) + " " +
                        events[i].ResourceStatus.ToString().PadRight(RESOURCE_STATUS);

                    // To save screen space only show error messages.
                    if (!events[i].ResourceStatus.ToString().EndsWith(IN_PROGRESS_SUFFIX) && !string.IsNullOrEmpty(events[i].ResourceStatusReason))
                        line += " " + events[i].ResourceStatusReason;



                    this.Logger.WriteLine(line);
                }

            } while (stack.StackStatus.ToString().EndsWith(IN_PROGRESS_SUFFIX));

            return stack;
        }

        private async Task<List<StackEvent>> GetLatestEventsAsync(string stackName, DateTime mintimeStampForEvents, string mostRecentEventId)
        {
            bool noNewEvents = false;
            List<StackEvent> events = new List<StackEvent>();
            DescribeStackEventsResponse response = null;
            do
            {
                var request = new DescribeStackEventsRequest() { StackName = stackName };
                if (response != null)
                    request.NextToken = response.NextToken;

                try
                {
                    response = await this.CloudFormationClient.DescribeStackEventsAsync(request);
                }
                catch (Exception e)
                {
                    throw new LambdaToolsException($"Error getting events for stack: {e.Message}", LambdaToolsException.LambdaErrorCode.CloudFormationDescribeStackEvents, e);
                }
                foreach (var evnt in response.StackEvents)
                {
                    if (string.Equals(evnt.EventId, mostRecentEventId) || evnt.Timestamp < mintimeStampForEvents)
                    {
                        noNewEvents = true;
                        break;
                    }

                    events.Add(evnt);
                }

            } while (!noNewEvents && !string.IsNullOrEmpty(response.NextToken));

            return events;
        }

        private async Task DeleteRollbackCompleteStackAsync(Stack stack)
        {
            try
            {
                if (stack.StackStatus == StackStatus.ROLLBACK_COMPLETE)
                    await this.CloudFormationClient.DeleteStackAsync(new DeleteStackRequest { StackName = stack.StackName });

                await WaitForNoLongerInProgress(stack.StackName);
            }
            catch (Exception e)
            {
                throw new LambdaToolsException($"Error removing previous failed stack creation {stack.StackName}: {e.Message}", LambdaToolsException.LambdaErrorCode.CloudFormationDeleteStack, e);
            }
        }

        private async Task<Stack> WaitForNoLongerInProgress(string stackName)
        {
            try
            {
                long start = DateTime.Now.Ticks;
                Stack currentStack = null;
                do
                {
                    if (currentStack != null)
                        this.Logger.WriteLine($"... Waiting for stack's state to change from {currentStack.StackStatus}: {TimeSpan.FromTicks(DateTime.Now.Ticks - start).TotalSeconds.ToString("0").PadLeft(3)} secs");
                    Thread.Sleep(POLLING_PERIOD);
                    currentStack = await GetExistingStackAsync(stackName);

                } while (currentStack != null && currentStack.StackStatus.ToString().EndsWith(IN_PROGRESS_SUFFIX));

                return currentStack;
            }
            catch (Exception e)
            {
                throw new LambdaToolsException($"Error waiting for stack state change: {e.Message}", LambdaToolsException.LambdaErrorCode.WaitingForStackError, e);
            }
        }

        private async Task WaitForChangeSetBeingAvailableAsync(string changeSetId)
        {
            try
            {
                var request = new DescribeChangeSetRequest
                {
                    ChangeSetName = changeSetId
                };

                this.Logger.WriteLine("... Waiting for change set to be reviewed");
                DescribeChangeSetResponse response;
                do
                {
                    Thread.Sleep(POLLING_PERIOD);
                    response = await this.CloudFormationClient.DescribeChangeSetAsync(request);
                } while (response.Status == ChangeSetStatus.CREATE_IN_PROGRESS || response.Status == ChangeSetStatus.CREATE_PENDING);

                if (response.Status == ChangeSetStatus.FAILED)
                {
                    throw new LambdaToolsException($"Failed to create CloudFormation change set: {response.StatusReason}", LambdaToolsException.LambdaErrorCode.FailedToCreateChangeSet);
                }
            }
            catch (Exception e)
            {
                throw new LambdaToolsException($"Error getting status of change set: {e.Message}", LambdaToolsException.LambdaErrorCode.CloudFormationDescribeChangeSet, e);
            }
        }

        public async Task<Stack> GetExistingStackAsync(string stackName)
        {
            try
            {
                var response = await this.CloudFormationClient.DescribeStacksAsync(new DescribeStacksRequest { StackName = stackName });
                if (response.Stacks.Count != 1)
                    return null;

                return response.Stacks[0];
            }
            catch (AmazonCloudFormationException)
            {
                return null;
            }
        }


        private List<Parameter> GetTemplateParameters(Stack stack, List<Tuple<string, bool>> definedParameters)
        {
            var parameters = new List<Parameter>();

            var map = GetKeyValuePairOrDefault(this.TemplateParameters, LambdaDefinedCommandOptions.ARGUMENT_CLOUDFORMATION_TEMPLATE_PARAMETER, false);
            if (map != null)
            {
                foreach (var kvp in map)
                {
                    Tuple<string, bool> dp = null;
                    if(definedParameters != null)
                    {
                        dp = definedParameters.FirstOrDefault(x => string.Equals(x.Item1, kvp.Key));
                    }

                    if (dp == null)
                    {
                        this.Logger.WriteLine($"Skipping passed in template parameter {kvp.Key} because the template does not define that parameter");
                    }
                    else
                    {
                        parameters.Add(new Parameter { ParameterKey = kvp.Key, ParameterValue = kvp.Value ?? "" });
                    }
                }
            }

            if (stack != null)
            {
                foreach (var existingParameter in stack.Parameters)
                {
                    if ((definedParameters == null || definedParameters.FirstOrDefault(x => string.Equals(x.Item1, existingParameter.ParameterKey)) != null) && 
                        !parameters.Any(x => string.Equals(x.ParameterKey, existingParameter.ParameterKey)))
                    {
                        parameters.Add(new Parameter { ParameterKey = existingParameter.ParameterKey, UsePreviousValue = true });
                    }
                }
            }

            return parameters;
        }

        private async Task<string> DetermineS3Bucket()
        {
            string s3Bucket = this.GetStringValueOrDefault(this.S3Bucket, LambdaDefinedCommandOptions.ARGUMENT_S3_BUCKET, false);
            bool? resolveS3 = this.GetBoolValueOrDefault(this.ResolveS3, LambdaDefinedCommandOptions.ARGUMENT_RESOLVE_S3, false);

            if (string.IsNullOrEmpty(s3Bucket))
            {
                if (resolveS3 == true)
                {
                    s3Bucket = await LambdaUtilities.ResolveDefaultS3Bucket(this.Logger, this.S3Client, this.STSClient);
                }
                else
                {
                    // Since a bucket wasn't explicitly passed in nor was resolve s3 passed in then ask the user for the S3 bucket.
                    s3Bucket = this.GetStringValueOrDefault(this.S3Bucket, LambdaDefinedCommandOptions.ARGUMENT_S3_BUCKET, true);
                }

            }

            return s3Bucket;
        }


        protected override void SaveConfigFile(JsonData data)
        {
            data.SetIfNotNull(CommonDefinedCommandOptions.ARGUMENT_CONFIGURATION.ConfigFileKey, this.GetStringValueOrDefault(this.Configuration, CommonDefinedCommandOptions.ARGUMENT_CONFIGURATION, false));
            data.SetIfNotNull(CommonDefinedCommandOptions.ARGUMENT_FRAMEWORK.ConfigFileKey, this.GetStringValueOrDefault(this.TargetFramework, CommonDefinedCommandOptions.ARGUMENT_FRAMEWORK, false));
            data.SetIfNotNull(CommonDefinedCommandOptions.ARGUMENT_MSBUILD_PARAMETERS.ConfigFileKey, this.GetStringValueOrDefault(this.MSBuildParameters, CommonDefinedCommandOptions.ARGUMENT_MSBUILD_PARAMETERS, false));
            data.SetIfNotNull(LambdaDefinedCommandOptions.ARGUMENT_RESOLVE_S3.ConfigFileKey, this.GetBoolValueOrDefault(this.ResolveS3, LambdaDefinedCommandOptions.ARGUMENT_RESOLVE_S3, false));
            data.SetIfNotNull(LambdaDefinedCommandOptions.ARGUMENT_S3_BUCKET.ConfigFileKey, this.GetStringValueOrDefault(this.S3Bucket, LambdaDefinedCommandOptions.ARGUMENT_S3_BUCKET, false));
            data.SetIfNotNull(LambdaDefinedCommandOptions.ARGUMENT_S3_PREFIX.ConfigFileKey, this.GetStringValueOrDefault(this.S3Prefix, LambdaDefinedCommandOptions.ARGUMENT_S3_PREFIX, false));

            var template = this.GetStringValueOrDefault(this.CloudFormationTemplate, LambdaDefinedCommandOptions.ARGUMENT_CLOUDFORMATION_TEMPLATE, false);
            if(Path.IsPathRooted(template))
            {
                string projectLocation = this.GetStringValueOrDefault(this.ProjectLocation, CommonDefinedCommandOptions.ARGUMENT_PROJECT_LOCATION, false);
                var projectRoot = Utilities.DetermineProjectLocation(this.WorkingDirectory, projectLocation);
                if(template.StartsWith(projectRoot))
                {
                    template = template.Substring(projectRoot.Length + 1);
                }
            }
            data.SetIfNotNull(LambdaDefinedCommandOptions.ARGUMENT_CLOUDFORMATION_TEMPLATE.ConfigFileKey, template);

            data.SetIfNotNull(LambdaDefinedCommandOptions.ARGUMENT_CLOUDFORMATION_TEMPLATE_PARAMETER.ConfigFileKey, LambdaToolsDefaults.FormatKeyValue(this.GetKeyValuePairOrDefault(this.TemplateParameters, LambdaDefinedCommandOptions.ARGUMENT_CLOUDFORMATION_TEMPLATE_PARAMETER, false)));
            data.SetIfNotNull(LambdaDefinedCommandOptions.ARGUMENT_STACK_NAME.ConfigFileKey, this.GetStringValueOrDefault(this.StackName, LambdaDefinedCommandOptions.ARGUMENT_STACK_NAME, false));
            data.SetIfNotNull(LambdaDefinedCommandOptions.ARGUMENT_CLOUDFORMATION_DISABLE_CAPABILITIES.ConfigFileKey, LambdaToolsDefaults.FormatCommaDelimitedList(this.GetStringValuesOrDefault(this.DisabledCapabilities, LambdaDefinedCommandOptions.ARGUMENT_CLOUDFORMATION_DISABLE_CAPABILITIES, false)));

        }

    }
}