# Usage:	Export-PSCredential [-Credential <PSCredential object>] [-Path <file to export>]
#			Export-PSCredential [-Credential <username>] [-Path <file to export>]
#			If Credential is not specififed, user is prompted by Get-Credential cmdlet.
#			If a username is specified, then Get-Credential will prompt for password.
#			If the Path is not specififed, it will default to "./credentials.enc.xml".
#			Output: FileInfo object referring to saved credentials
#
#			Import-PSCredential [-Path <file to import>]
#
#			If not specififed, Path is "./credentials.enc.xml".
#			Output: PSCredential object

function Export-PSCredential {
	param ( $Credential = (Get-Credential), $Path = "credentials.enc.xml" )

	# Look at the object type of the $Credential parameter to determine how to handle it
	switch ( $Credential.GetType().Name ) {
		# It is a credential, so continue
		PSCredential		{ continue } 
		# It is a string, so use that as the username and prompt for the password
		String				{ $Credential = Get-Credential -credential $Credential }
		# In all other caess, throw an error and exit
		default				{ Throw "You must specify a credential object to export to disk." }
	}
	
	# Create temporary object to be serialized to disk
	$export = New-Object PSObject
	Add-Member -InputObject $export -Name Username -Value $Credential.Username `
		-MemberType NoteProperty 

	# Encrypt SecureString password using Data Protection API
	$EncryptedPassword = $Credential.Password | ConvertFrom-SecureString
	Add-Member -InputObject $export -Name EncryptedPassword -Value $EncryptedPassword `
		-MemberType NoteProperty

	# Export using the Export-Clixml cmdlet
	$export | Export-Clixml $Path
	Write-Host -foregroundcolor Green "Credentials saved to: " -noNewLine

	# Return FileInfo object referring to saved credentials
	Get-Item $Path
}

function Import-PSCredential {
	param ( $Path = "credentials.enc.xml" )

	# Import credential file
	$import = Import-Clixml $Path 
	
	# Test for valid import
	if ( !$import.UserName -or !$import.EncryptedPassword ) {
		Throw "Input is not a valid ExportedPSCredential object, exiting."
	}
	$Username = $import.Username
	
	# Decrypt the password and store as a SecureString object for safekeeping
	$SecurePass = $import.EncryptedPassword | ConvertTo-SecureString
	
	# Build the new credential object
	$Credential = New-Object System.Management.Automation.PSCredential $Username, $SecurePass
	Write-Output $Credential
}