<#
.SYNOPSIS
  Export complete inventory of distribution groups with members and settings

.DESCRIPTION
  Documents all distribution groups including members, owners, email addresses,
  and key settings. Useful for migration planning, documentation, or backup.

.PARAMETER OutputFolder
  Destination folder for reports. Default: .\DistributionGroups-<date>

.PARAMETER IncludeMembers
  Include detailed member lists (default: $true, can be slow)

.PARAMETER GroupFilter
  Optional filter for specific groups (default: all)

.NOTES
  ⚠️  AI-GENERATED SCRIPT - UNTESTED
  This script was generated by Claude AI and has not been tested in production.
  Review and test thoroughly in a non-production environment before use.

  - Run in Exchange Management Shell with appropriate RBAC permissions
  - Large environments may take significant time
  - Includes both Distribution Groups and Mail-Enabled Security Groups

.EXAMPLE
  .\Export-DistributionGroups.ps1

.EXAMPLE
  .\Export-DistributionGroups.ps1 -GroupFilter "Sales*" -OutputFolder "D:\Reports\Groups"
#>

[CmdletBinding()]
param(
    [string]$OutputFolder = (Join-Path -Path (Get-Location) -ChildPath ("DistributionGroups-" + (Get-Date -Format "yyyyMMdd-HHmm"))),
    [bool]$IncludeMembers = $true,
    [string]$GroupFilter = "*"
)

function NowTag { (Get-Date).ToString("yyyy-MM-dd HH:mm:ss") }

Write-Host "[$(NowTag)] ⚠️  AI-GENERATED SCRIPT - UNTESTED" -ForegroundColor Yellow
Write-Host "[$(NowTag)] Starting distribution group export..." -ForegroundColor Green

# Create output folder
New-Item -ItemType Directory -Path $OutputFolder -Force | Out-Null

# Get distribution groups
Write-Host "[$(NowTag)] Retrieving distribution groups..."
$groups = Get-DistributionGroup -Filter "Name -like '$GroupFilter'" -ResultSize Unlimited -ErrorAction SilentlyContinue

$groupCount = ($groups | Measure-Object).Count
Write-Host "[$(NowTag)] Found $groupCount distribution groups"

if ($groupCount -eq 0) {
    Write-Host "[$(NowTag)] No groups found matching filter: $GroupFilter" -ForegroundColor Yellow
    exit
}

# Collect group details
$groupDetails = @()
$groupMembers = @()

$current = 0
foreach ($group in $groups) {
    $current++
    $pct = [int](($current / $groupCount) * 100)
    Write-Progress -Activity "Processing Distribution Groups" -Status "Processing $($group.Name) ($current/$groupCount)" -PercentComplete $pct

    # Get managed by
    $managedByList = @()
    if ($group.ManagedBy) {
        foreach ($mgr in $group.ManagedBy) {
            try {
                $mgrObj = Get-Recipient $mgr -ErrorAction SilentlyContinue
                if ($mgrObj) {
                    $managedByList += $mgrObj.PrimarySmtpAddress
                }
            } catch {}
        }
    }

    # Get email addresses
    $emailAddresses = ($group.EmailAddresses | Where-Object { $_ -like "smtp:*" }) -join "; "

    # Get member count
    $memberCount = 0
    try {
        $members = Get-DistributionGroupMember -Identity $group.Identity -ResultSize Unlimited -ErrorAction SilentlyContinue
        $memberCount = ($members | Measure-Object).Count

        # Collect member details if requested
        if ($IncludeMembers -and $members) {
            foreach ($member in $members) {
                $groupMembers += [PSCustomObject]@{
                    GroupName          = $group.Name
                    GroupPrimarySmtp   = $group.PrimarySmtpAddress
                    MemberName         = $member.Name
                    MemberPrimarySmtp  = $member.PrimarySmtpAddress
                    MemberType         = $member.RecipientType
                }
            }
        }
    } catch {
        Write-Host "[$(NowTag)] WARNING: Could not get members for $($group.Name)" -ForegroundColor Yellow
    }

    $groupDetails += [PSCustomObject]@{
        Name                        = $group.Name
        DisplayName                 = $group.DisplayName
        Alias                       = $group.Alias
        PrimarySmtpAddress          = $group.PrimarySmtpAddress
        EmailAddresses              = $emailAddresses
        RecipientTypeDetails        = $group.RecipientTypeDetails
        MemberCount                 = $memberCount
        ManagedBy                   = ($managedByList -join "; ")
        RequireSenderAuthentication = $group.RequireSenderAuthenticationEnabled
        HiddenFromAddressLists      = $group.HiddenFromAddressListsEnabled
        ModerationEnabled           = $group.ModerationEnabled
        SendModerationNotifications = $group.SendModerationNotifications
        AcceptMessagesOnlyFrom      = (($group.AcceptMessagesOnlyFrom | ForEach-Object { $_.ToString() }) -join "; ")
        RejectMessagesFrom          = (($group.RejectMessagesFrom | ForEach-Object { $_.ToString() }) -join "; ")
        BypassModerationFromSenders = (($group.BypassModerationFromSendersOrMembers | ForEach-Object { $_.ToString() }) -join "; ")
        WhenCreated                 = $group.WhenCreated
        WhenChanged                 = $group.WhenChanged
        OrganizationalUnit          = $group.OrganizationalUnit
    }
}

Write-Progress -Activity "Processing Distribution Groups" -Completed

# Export results
Write-Host "[$(NowTag)] Exporting results..."

$groupsFile = Join-Path $OutputFolder "DistributionGroups.csv"
$groupDetails | Sort-Object Name | Export-Csv -NoTypeInformation -Encoding UTF8 -Path $groupsFile
Write-Host "[$(NowTag)] Groups exported: $groupsFile" -ForegroundColor Green

if ($IncludeMembers -and $groupMembers.Count -gt 0) {
    $membersFile = Join-Path $OutputFolder "DistributionGroup-Members.csv"
    $groupMembers | Sort-Object GroupName, MemberName | Export-Csv -NoTypeInformation -Encoding UTF8 -Path $membersFile
    Write-Host "[$(NowTag)] Members exported: $membersFile" -ForegroundColor Green
}

# Summary
Write-Host "`nSUMMARY:" -ForegroundColor Cyan
Write-Host "  Total Groups: $groupCount"
Write-Host "  Total Members: $($groupMembers.Count)"
Write-Host "  Hidden from Address Lists: $(($groupDetails | Where-Object HiddenFromAddressLists).Count)"
Write-Host "  Moderation Enabled: $(($groupDetails | Where-Object ModerationEnabled).Count)"
Write-Host "  Security Groups: $(($groupDetails | Where-Object { $_.RecipientTypeDetails -like '*Security*' }).Count)"

# Top 10 largest groups
$top10 = $groupDetails | Sort-Object MemberCount -Descending | Select-Object -First 10
if ($top10) {
    Write-Host "`nTop 10 Largest Groups:" -ForegroundColor Cyan
    $top10 | ForEach-Object {
        Write-Host "  $($_.Name): $($_.MemberCount) members"
    }
}

Write-Host "`n[$(NowTag)] Export complete! Output folder: $OutputFolder"