#>


function Reset-CSPassword
{
    [CmdletBinding()]
    Param
    (

        [Parameter(Mandatory=$true,
                   ValueFromPipelineByPropertyName=$true,
                   Position=0)]
        $UserPrincipalName

)

# This defines the domain based on domain stored in the $UserPrincipalName variable.

$Domain = $UserPrincipalName -split '@'

<# This uses the domain stored in the first position of the array stored in $Domain to retrieve the default password policy for the domain.
   This information is then used to call a .NET class and method which will generate a random password which meets the domain's complexity
   requirements.
#>

$PasswordPolicy = Get-ADDefaultDomainPasswordPolicy -Identity $Domain[1]

# A password which contains at least two alphanumeric characters and exceeds the minimum password length by half is generated.

$RandomPassword = [System.Web.Security.Membership]::GeneratePassword($PasswordPolicy.MinPasswordLength*1.5,2)
$NewPassword = ConvertTo-SecureString -String $RandomPassword -AsPlainText -Force

# The current forest is found by calling a .NET class and method.

$ForestInfo = [System.DirectoryServices.ActiveDirectory.Forest]::GetCurrentForest()

# The first Global Catalog found is stored in the 'Name' property of the variable below.

$GlobalCatalog = $ForestInfo.FindGlobalCatalog()

# This is where the function searches for the user on the nearest GC by using the UPN provided. The GC port is appended in the 'Server' parameter.

$User = Get-ADUser -Filter { UserPrincipalName -Like $UserPrincipalName } -Properties UserPrincipalName,Mail -Server $($GlobalCatalog.Name + ":3268")

# The password is changed here.

Invoke-Command -ScriptBlock { $User | Set-ADAccountPassword -NewPassword $NewPassword }

# The e-mail is sent to the user with their username and password.

Send-MailMessage -From admin@somedomain.com -To $User.Mail -Subject "Your password has been reset in $($Domain[1])" -Body "
Per your request, your password has been reset. You may use the following credentials to login:

Username: $UserPrincipalName
Password: $RandomPassword

Please do not reply to this e-mail." -SmtpServer $SmtpServer

}