<#
=============================================================================================
Name:           Get distribution group members report
Version:        3.0
Website:        o365reports.com
For detailed script execution:  https://o365reports.com/2019/05/23/export-office-365-distribution-group-members-csv/
============================================================================================
#>
Param
(
    [Parameter(Mandatory = $false)]
    [string]$GroupNamesFile,
    [switch]$IsEmpty,
    [int]$MinGroupMembersCount,
    [Nullable[boolean]]$ExternalSendersBlocked = $null,
    [string]$UserName,
    [string]$Password
)

Function Get_members
{
 $DisplayName=$_.DisplayName
 Write-Progress -Activity "`n     Processed Group count: $Count "`n"  Getting members of: $DisplayName"
 $Alias=$_.Alias
 $EmailAddress=$_.PrimarySmtpAddress
 $GroupType=$_.GroupType
 $ManagedBy=$_.ManagedBy
 $ExternalSendersAllowed=$_.RequireSenderAuthenticationEnabled
 if(($ExternalSendersBlocked -ne $null) -and ($ExternalSendersBlocked -ne $ExternalSendersAllowed))
 {
  $Print=0
 }
 #Get Distribution Group Authorized Senders
 $AcceptMessagesOnlyFrom=$_.AcceptMessagesOnlyFromSendersOrMembers
 $AuthorizedSenders=""
 if($AcceptMessagesOnlyFrom.Count -gt 0)
 {
  foreach($item in $AcceptMessagesOnlyFrom)
  {
   $AuthorizedSenders=$AuthorizedSenders+$item
   if($AcceptMessagesOnlyFrom.indexof($item) -lt (($AcceptMessagesOnlyFrom.count)-1))
   {
    $AuthorizedSenders=$AuthorizedSenders+","
   }
  }
 }
 elseif($ExternalSendersAllowed -eq "True")
 {
  $AuthorizedSenders="Only Senders in Your Organization"
 }
 else
 {
  $AuthorizedSenders="Senders inside & Outside of Your Organization"
 }

 $Manager=""
 if($_.ManagedBy.Count -gt 0)
 {
  foreach($ManageBy in $ManagedBy)
  {
   $Manager=$Manager+$ManageBy
   if($ManagedBy.indexof($ManageBy) -lt (($ManagedBy.count)-1))
   {
    $Manager=$Manager+","
   }
  }
 }
 $Recipient=""
 $RecipientHash=@{}
 for($KeyIndex = 0; $KeyIndex -lt $RecipientTypeArray.Length; $KeyIndex += 2)
 {
  $key=$RecipientTypeArray[$KeyIndex]
  $Value=$RecipientTypeArray[$KeyIndex+1]
  $RecipientHash.Add($key,$Value)
 }
 $Members=Get-DistributionGroupMember -ResultSize Unlimited -Identity $DisplayName
 $MembersCount=($Members.name).Count

 #GroupSize Filter
 if(([int]$MinGroupMembersCount -ne "") -and ($MembersCount -lt [int]$MinGroupMembersCount))
 {
  $Print=0
 }

 #Check for Empty Group
 elseif($MembersCount -eq 0)
 {
  $Member="No Members"
  $MemberEmail="-"
  $RecipientTypeDetail="-"
  Print_Output
 }

 #Loop through each member in a group
 else
 {
  foreach($Member in $Members)
  {
   if($IsEmpty.IsPresent)
   {
    $Print=0
    break
   }
   $RecipientTypeDetail=$Member.RecipientTypeDetails
   $MemberEmail=$Member.PrimarySMTPAddress
   if($MemberEmail -eq "")
   {
    $MemberEmail="-"
   }
   #Get Counts by RecipientTypeDetail
   foreach($key in [object[]]$Recipienthash.Keys)
   {
    if(($RecipientTypeDetail -eq $key) -eq "true")
    {
     [int]$RecipientHash[$key]+=1
    }
   }
   Print_Output
  }
 }
 
 #Print Summary report
 if($Print -eq 1)
 {
  #Order RecipientTypeDetail based on count
  $Hash=@{}
  $Hash=$RecipientHash.GetEnumerator() | Sort-Object -Property value -Descending |foreach{
   if([int]$($_.Value) -gt 0 )
   {
    if($Recipient -ne "")
    { $Recipient+=";"} 
    $Recipient+=@("$($_.Key) - $($_.Value)")    
   }
   if($Recipient -eq "")
   {$Recipient="-"}
  }
  $Result=@{'DisplayName'=$DisplayName;'PrimarySmtpAddress'=$EmailAddress;'Alias'=$Alias;'GroupType'=$GroupType;'Manager'=$Manager;'GroupMembersCount'=$MembersCount;'MembersCountByType'=$Recipient;'AuthorizedSenders'=$AuthorizedSenders;'ExternalSendersBlocked'=$ExternalSendersAllowed <#;'HiddenFromAddressList'=$_.HiddenFromAddressListsEnabled;
 'Description'=$_.Description;'CreationTime'=$_.WhenCreated;'DirSyncEnabled'=$_.IsDirSynced;'JoinGroupWithoutApproval'=$_.MemberJoinRestriction;'LeaveGroupWithoutApproval'=$_.MemberDepartRestriction #>} #Uncomment to print additional attributes in output
  $Results= New-Object PSObject -Property $Result 
  $Results | Select-Object DisplayName,PrimarySmtpAddress,Alias,GroupType,Manager,GroupMembersCount,AuthorizedSenders,ExternalSendersBlocked,MembersCountByType <#,HiddenFromAddressList,Description,CreationTime,DirSyncEnabled,JoinGroupWithoutApproval,LeaveGroupWithoutApproval #>  | Export-Csv -Path $ExportSummaryCSV -Notype -Append
 }
}

#Print Detailed Output
Function Print_Output
{
 if($Print -eq 1)
 {
  $Result=@{'DisplayName'=$DisplayName;'PrimarySmtpAddress'=$EmailAddress;'Alias'=$Alias;'Members'=$Member;'MemberEmail'=$MemberEmail;'MemberType'=$RecipientTypeDetail} 
  $Results= New-Object PSObject -Property $Result 
  $Results | Select-Object DisplayName,PrimarySmtpAddress,Alias,Members,MemberEmail,MemberType | Export-Csv -Path $ExportCSV -Notype -Append
 }
}


Function main()
{
 #Clean up session 
 Get-PSSession | Remove-PSSession

  #Check for EXO v2 module inatallation
 $Module = Get-Module ExchangeOnlineManagement -ListAvailable
 if($Module.count -eq 0) 
 { 
  Write-Host Exchange Online PowerShell V2 module is not available  -ForegroundColor yellow  
  $Confirm= Read-Host Are you sure you want to install module? [Y] Yes [N] No 
  if($Confirm -match "[yY]") 
  { 
   Write-host "Installing Exchange Online PowerShell module"
   Install-Module ExchangeOnlineManagement -Repository PSGallery -AllowClobber -Force
   Import-Module ExchangeOnlineManagement
  } 
  else 
  { 
   Write-Host EXO V2 module is required to connect Exchange Online.Please install module using Install-Module ExchangeOnlineManagement cmdlet. 
   Exit
  }
 } 
 Write-Host Connecting to Exchange Online...
 #Storing credential in script for scheduling purpose/ Passing credential as parameter - Authentication using non-MFA account
 if(($UserName -ne "") -and ($Password -ne ""))
 {
  $SecuredPassword = ConvertTo-SecureString -AsPlainText $Password -Force
  $Credential  = New-Object System.Management.Automation.PSCredential $UserName,$SecuredPassword
  Connect-ExchangeOnline -Credential $Credential
 }
 else
 {
  Connect-ExchangeOnline
 }
 
 #Set output file 
 $ExportCSV=".\DistributionGroup-DetailedMembersReport_$((Get-Date -format yyyy-MMM-dd-ddd` hh-mm` tt).ToString()).csv" #Detailed report
 $ExportSummaryCSV=".\DistributionGroup-SummaryReport_$((Get-Date -format yyyy-MMM-dd-ddd` hh-mm` tt).ToString()).csv" #Summary report

 #Get a list of RecipientTypeDetail
 $RecipientTypeArray=Get-Content -Path .\RecipientTypeDetails.txt -ErrorAction Stop
 $Result=""  
 $Results=@()

 #Check for input file
 if([string]$GroupNamesFile -ne "") 
 { 
  #We have an input file, read it into memory 
  $DG=@()
  $DG=Import-Csv -Header "DisplayName" $GroupNamesFile
  foreach($item in $DG)
  {
   Get-DistributionGroup -Identity $item.displayname | Foreach{
   $Print=1
   Get_Members}
   $Count++
  }
 }
 else
 {
  #Get all distribution group
  Get-DistributionGroup -ResultSize Unlimited | Foreach{
  $Print=1
  Get_Members
  $Count++}
 }
 #Open output file after execution 
 Write-Host `nScript executed successfully
 if((Test-Path -Path $ExportCSV) -eq "True")
 {
  Write-Host Detailed report available in: $ExportCSV
  Write-host Summary report available in: $ExportSummaryCSV
  Write-Host `nCheck out """AdminDroid Office 365 Reporting tool""" to get access to 1500+ Office 365 reports.`n -ForegroundColor Green
  $Prompt = New-Object -ComObject wscript.shell  
  $UserInput = $Prompt.popup("Do you want to open output file?",`  
  0,"Open Output File",4)  
  If ($UserInput -eq 6)  
  {  
   Invoke-Item "$ExportCSV"  
   Invoke-Item "$ExportSummaryCSV"
  } 
 }
 Else
 {
  Write-Host No DistributionGroup found
 }
 #Disconnect Exchange Online session
Disconnect-ExchangeOnline -Confirm:$false -InformationAction Ignore -ErrorAction SilentlyContinue
 
}
 . main