// initializeBookkeepingLocations - initializes all folder locations required for bookkeeping
func initializeBookkeepingLocations(log logger.T, instanceID string) bool {

	//Create folders pending, current, completed, corrupt under the location DefaultLogDirPath/<instanceId>
	log.Info("Initializing bookkeeping folders")
	initStatus := true
	folders := []string{
		appconfig.DefaultLocationOfPending,
		appconfig.DefaultLocationOfCurrent,
		appconfig.DefaultLocationOfCompleted,
		appconfig.DefaultLocationOfCorrupt}

	for _, folder := range folders {

		directoryName := path.Join(appconfig.DefaultDataStorePath,
			instanceID,
			appconfig.DefaultCommandRootDirName,
			appconfig.DefaultLocationOfState,
			folder)

		err := fileutil.MakeDirs(directoryName)
		if err != nil {
			log.Errorf("Encountered error while creating folders for internal state management. %v", err)
			initStatus = false
			break
		}
	}

	return initStatus
}

// MoveCommandState moves the CommandState object
func MoveCommandState(log log.T, commandID, instanceID, srcLocationFolder, dstLocationFolder string) {

	//get a lock for documentID specific lock
	lockDocument(commandID)

	absoluteSource := path.Join(appconfig.DefaultDataStorePath,
		instanceID,
		appconfig.DefaultCommandRootDirName,
		appconfig.DefaultLocationOfState,
		srcLocationFolder)

	absoluteDestination := path.Join(appconfig.DefaultDataStorePath,
		instanceID,
		appconfig.DefaultCommandRootDirName,
		appconfig.DefaultLocationOfState,
		dstLocationFolder)

	if s, err := fileutil.MoveFile(commandID, absoluteSource, absoluteDestination); s && err == nil {
		log.Debugf("moved file %v from %v to %v successfully", commandID, srcLocationFolder, dstLocationFolder)
	} else {
		log.Debugf("moving file %v from %v to %v failed with error %v", commandID, srcLocationFolder, dstLocationFolder, err)
	}

	//release documentID specific lock - before deleting the entry from the map
	unlockDocument(commandID)

	//delete documentID specific lock if document has finished executing. This is to avoid documentLock growing too much in memory.
	//This is done by ensuring that as soon as document finishes executing it is removed from documentLock
	//Its safe to assume that document has finished executing if it is being moved to appconfig.DefaultLocationOfCompleted
	if dstLocationFolder == appconfig.DefaultLocationOfCompleted {
		deleteLock(commandID)
	}
}

// process launches one job in a separate go routine and waits
// for either the job to finish or for a cancel to be requested.
// If cancel is requested, this function waits for some time to allow the
// job to complete. If the job does not complete by the timeout, the go routine
// of the job is abandoned, and this function returns.
func process(log log.T, job Job, cancelFlag *ChanneledCancelFlag, cancelWait time.Duration, clock times.Clock) {
	// Make a buffered channel to avoid blocking on send. This helps
	// in case the job fails to cancel on time and we give up on it.
	// If the job finally ends, it will succeed to send a signal
	// on the channel and then it will terminate. This will allow
	// the garbage collector to collect the go routine's resources
	// and the channel.
	doneChan := make(chan struct{}, 1)

	go runJob(log, func() { job(cancelFlag) }, doneChan)

	done := waitEither(doneChan, cancelFlag.ch)
	if done {
		// task done, set the flag to wake up waiting routines
		cancelFlag.Set(Completed)
		return
	}

	log.Debugf("Execution has been canceled, waiting up to %v to finish", cancelWait)
	done = waitEither(doneChan, clock.After(cancelWait))
	if done {
		// job completed within cancel waiting window
		cancelFlag.Set(Completed)
		return
	}

	log.Debugf("Job failed to terminate within %v!", cancelWait)
}

// LatestVersion returns latest version for specific package
func (m *Manifest) LatestVersion(log log.T, context *updateutil.InstanceContext, packageName string) (result string, err error) {
	var version = minimumVersion
	var compareResult = 0
	for _, p := range m.Packages {
		if p.Name == packageName {
			for _, f := range p.Files {
				if f.Name == context.FileName(packageName) {
					for _, v := range f.AvailableVersions {
						if compareResult, err = updateutil.VersionCompare(v.Version, version); err != nil {
							return version, err
						}
						if compareResult > 0 {
							version = v.Version
						}
					}
				}
			}
		}
	}
	if version == minimumVersion {
		log.Debugf("Filename: %v", context.FileName(packageName))
		log.Debugf("Package Name: %v", packageName)
		log.Debugf("Manifest: %v", m)
		return version, fmt.Errorf("cannot find the latest version for package %v", packageName)
	}

	return version, nil
}

// validateManifest makes sure all the fields are provided.
func validateManifest(log log.T, parsedManifest *Manifest, context *updateutil.InstanceContext, packageName string) error {
	if len(parsedManifest.URIFormat) == 0 {
		return fmt.Errorf("folder format cannot be null in the Manifest file")
	}
	fileName := context.FileName(packageName)
	foundPackage := false
	foundFile := false
	for _, p := range parsedManifest.Packages {
		if p.Name == packageName {
			log.Infof("found package %v", packageName)
			foundPackage = true
			for _, f := range p.Files {
				if f.Name == fileName {
					foundFile = true
					if len(f.AvailableVersions) == 0 {
						return fmt.Errorf("at least one available version is required for the %v", fileName)
					}

					log.Infof("found file %v", fileName)
					break
				}
			}
		}
	}

	if !foundPackage {
		return fmt.Errorf("cannot find the %v information in the Manifest file", packageName)
	}
	if !foundFile {
		return fmt.Errorf("cannot find the %v information in the Manifest file", fileName)
	}

	return nil
}

// HandleAwsError logs an AWS error.
func HandleAwsError(log log.T, err error, stopPolicy *StopPolicy) {
	if err != nil {
		// notice that we're using 1, so it will actually log the where
		// the error happened, 0 = this function, we don't want that.
		pc, fn, line, _ := runtime.Caller(1)
		log.Debugf("error in %s[%s:%d] %v", runtime.FuncForPC(pc).Name(), fn, line, err)

		// In case this is aws error, update the stop policy as well.
		if aErr, ok := err.(awserr.Error); ok {
			// Generic AWS Error with Code, Message, and original error (if any)
			log.Debugf("AWS error. Code: %v, Message: %v, origerror: %v ", aErr.Code(), aErr.Message(), aErr.OrigErr())

			// special treatment for Timeout exception - as this is expected
			if aErr.Code() == "RequestError" && aErr.OrigErr() != nil && strings.Contains(aErr.OrigErr().Error(), "Client.Timeout") {
				// resetting the error count to 0 - as these exceptions are all expected
				if stopPolicy != nil {
					resetStopPolicy(stopPolicy)
				}
				return
			}
		}

		log.Errorf("error when calling AWS APIs. error details - %v", err)
		if stopPolicy != nil {
			log.Infof("increasing error count by 1")
			stopPolicy.AddErrorCount(1)
		}

	} else {
		// there is no error,
		resetStopPolicy(stopPolicy)
	}
}

// install executes the install script for the specific version of agent
func installAgent(mgr *updateManager, log log.T, version string, context *UpdateContext) (err error) {
	log.Infof("Initiating %v %v installation", context.Current.PackageName, version)

	// find the path for the install script
	installerPath := updateutil.InstallerFilePath(
		context.Current.UpdateRoot,
		context.Current.PackageName,
		version)
	// calculate work directory
	workDir := updateutil.UpdateArtifactFolder(
		context.Current.UpdateRoot,
		context.Current.PackageName,
		version)

	// Install version
	if err = mgr.util.ExeCommand(
		log,
		installerPath,
		workDir,
		context.Current.UpdateRoot,
		context.Current.StdoutFileName,
		context.Current.StderrFileName,
		false); err != nil {

		return err
	}

	log.Infof("%v %v installed successfully", context.Current.PackageName, version)
	return nil
}

func (svc *sdkService) SendCommand(log log.T,
	documentName string,
	instanceIDs []string,
	parameters map[string][]*string,
	timeoutSeconds *int64,
	outputS3BucketName *string,
	outputS3KeyPrefix *string) (response *ssm.SendCommandOutput, err error) {
	params := ssm.SendCommandInput{
		DocumentName:       aws.String(documentName),
		InstanceIds:        makeAwsStrings(instanceIDs),
		Comment:            aws.String("Comment"),
		OutputS3BucketName: outputS3BucketName,
		OutputS3KeyPrefix:  outputS3KeyPrefix,
		Parameters:         parameters,
		TimeoutSeconds:     timeoutSeconds,
	}

	log.Debug("SendCommand params:", params)
	response, err = svc.sdk.SendCommand(&params)
	if err != nil {
		sdkutil.HandleAwsError(log, err, ssmStopPolicy)
		return
	}
	log.Debug("SendCommand Response", response)
	return
}

// processFingerprint handles flags related to the fingerprint category
func processFingerprint(log logger.T) (exitCode int) {
	if err := fingerprint.SetSimilarityThreshold(similarityThreshold); err != nil {
		log.Errorf("Error setting the SimilarityThreshold. %v", err)
		return 1
	}
	log.Infof("Fingerprint SimilarityTHreshold set to %v", similarityThreshold)
	return 0
}

// clearRegistration clears any existing registration data
func clearRegistration(log logger.T) (exitCode int) {
	err := registration.UpdateServerInfo("", "", "", "")
	if err == nil {
		log.Info("Registration information has been removed from the instance.")
		return 0
	}
	log.Errorf("error clearing the instance registration information. %v\nTry running as sudo/administrator.", err)
	return 1
}

// Run as a single process. Used by Unix systems and when running agent from console.
func run(log logger.T) {
	// run core manager
	cpm, err := start(log, instanceIDPtr, regionPtr)
	if err != nil {
		log.Errorf("error occured when starting amazon-ssm-agent: %v", err)
		return
	}
	blockUntilSignaled(log)
	stop(log, cpm)
}

// RemoveData deletes the fileName from locationFolder under defaultLogDir/instanceID
func RemoveData(log log.T, commandID, instanceID, locationFolder string) {

	absoluteFileName := getCmdStateFileName(commandID, instanceID, locationFolder)

	err := fileutil.DeleteFile(absoluteFileName)
	if err != nil {
		log.Errorf("encountered error %v while deleting file %v", err, absoluteFileName)
	} else {
		log.Debugf("successfully deleted file %v", absoluteFileName)
	}
}

func killProcessOnTimeout(log log.T, command *exec.Cmd, timer *time.Timer) {
	<-timer.C
	log.Debug("Process exceeded timeout. Attempting to kill process!")

	// task has been exceeded the allowed execution timeout, kill process
	if err := command.Process.Kill(); err != nil {
		log.Error(err)
		return
	}

	log.Debug("Done kill process!")
}

func processSendReply(log log.T, messageID string, mdsService service.Service, payloadDoc messageContracts.SendReplyPayload, processorStopPolicy *sdkutil.StopPolicy) {
	payloadB, err := json.Marshal(payloadDoc)
	if err != nil {
		log.Error("could not marshal reply payload!", err)
	}
	payload := string(payloadB)
	log.Info("Sending reply ", jsonutil.Indent(payload))
	err = mdsService.SendReply(log, messageID, payload)
	if err != nil {
		sdkutil.HandleAwsError(log, err, processorStopPolicy)
	}
}

// killProcessOnTimeout waits for a timeout.
// When the timeout is reached, this method kills the underlying
// process of the command. This will unblock the command.Wait() call.
// If the task completed successfully this method returns with no action.
func killProcessOnTimeout(log log.T, command *exec.Cmd, timer *time.Timer) {
	<-timer.C
	log.Debug("Process exceeded timeout. Attempting to stop process.")

	// task has been exceeded the allowed execution timeout, kill process
	if err := killProcess(command.Process); err != nil {
		log.Error(err)
		return
	}

	log.Debug("Process stopped successfully")
}

func getPlatformDetail(log log.T, param string) (value string, err error) {
	var contentsBytes []byte
	value = notAvailableMessage

	log.Debugf(gettingPlatformDetailsMessage)
	if contentsBytes, err = exec.Command(platformDetailsCommand, param).Output(); err != nil {
		log.Debugf(errorOccurredMessage, platformDetailsCommand, err)
		return
	}
	value = strings.TrimSpace(string(contentsBytes))
	log.Debugf(commandOutputMessage, value)
	return
}

// LoadUpdateContext loads update context info from local storage, set current update with new update detail
func LoadUpdateContext(log log.T, source string) (context *UpdateContext, err error) {
	log.Debugf("file %v", source)
	if _, err := os.Stat(source); os.IsNotExist(err) {
		log.Debugf("UpdateContext file doesn't exist, creating new one")
		context = &UpdateContext{}
	} else {
		log.Debugf("UpdateContext file exists")
		if context, err = parseContext(log, source); err != nil {
			return context, err
		}
	}
	return context, nil
}

// ReplaceParameters traverses an arbitrarily complex input object (maps/slices/strings/etc.)
// and tries to replace parameters given as {{parameter}} with their values from the parameters map.
//
// Strings like "{{ parameter }}" are replaced directly with the value associated with
// the parameter. That value need not be a string.
//
// Strings like "a {{ parameter1 }} within a string" are replaced with strings where the parameters
// are replaced by a marshaled version of their values. In this case, the resulting object is always a string.
//
// Note: this only works on composite types []interface{} and map[string]interface{} which are what json.Unmarshal
// produces by default. If your object contains []string, for example, the object will be returned as is.
//
// Returns a new object with replaced parameters.
func ReplaceParameters(input interface{}, parameters map[string]interface{}, logger log.T) interface{} {
	switch input := input.(type) {
	case string:
		// handle single parameter case first
		for parameterName, parameterValue := range parameters {
			if isSingleParameterString(input, parameterName) {
				return parameterValue
			}
		}

		// look for multiple parameter strings
		for parameterName, parameterValue := range parameters {
			var parameterValueString string
			var err error
			if parameterValueString, err = convertToString(parameterValue); err != nil {
				logger.Error(err)
			}
			input = ReplaceParameter(input, parameterName, parameterValueString)
		}
		return input

	case []interface{}:
		// for slices, recursively replace parameters on each element of the slice
		out := make([]interface{}, len(input))
		for i, v := range input {
			out[i] = ReplaceParameters(v, parameters, logger)
		}
		return out

	case []map[string]interface{}:
		// this case is not caught by the one above because map cannot be converted to interface{}
		out := make([]map[string]interface{}, len(input))
		for i, v := range input {
			out[i] = ReplaceParameters(v, parameters, logger).(map[string]interface{})
		}
		return out

	case map[string]interface{}:
		// for maps, recursively replace parameters on each value in the map
		out := make(map[string]interface{})
		for k, v := range input {
			out[k] = ReplaceParameters(v, parameters, logger)
		}
		return out

	default:
		// any other type, return as is
		return input
	}
}

// DeleteMessage calls the DeleteMessage MDS API.
func (mds *sdkService) DeleteMessage(log log.T, messageID string) (err error) {
	params := &ssmmds.DeleteMessageInput{
		MessageId: aws.String(messageID), // Required
	}
	log.Debug("Calling DeleteMessage with params", params)
	req, resp := mds.sdk.DeleteMessageRequest(params)
	if err = mds.sendRequest(req); err != nil {
		err = fmt.Errorf("DeleteMessage Error: %v", err)
		log.Debug(err)
	} else {
		log.Debug("DeleteMessage Response", resp)
	}
	return
}

// RebootMachine reboots the machine
func RebootMachine(log log.T) {
	log.Info("Executing reboot request...")
	if RebootInitiated() {
		return
	}

	syncObject.Lock()
	defer syncObject.Unlock()
	if err := reboot(log); err != nil {
		log.Error("error in rebooting the machine", err)
		return
	}
	rebootInitiated = true
}