GetAllPFStatistics.ps1

[CmdletBinding()]
param (
    [Parameter(Mandatory = $false)]
    [int]$MaxRetries = 20,

    [Parameter(Mandatory = $false)]
    [string]$LogFilePath = "$PSScriptRoot\GetAllPFStatistics.log"
)

function WriteHostAndLog($message) {
    Write-Host $message
    Add-Content -Path $LogFilePath -Value $message
}

function WriteLog($message) {
    Add-Content -Path $LogFilePath -Value $message
}

function GetResidentFoldersWithRetry($PFMailboxResult) {
    while ($true) {
        try {
            WriteHostAndLog "$(Get-Date) Getting hierarchy for $($PFMailboxResult.Mailbox.Name)"
            $folders = @(Get-PublicFolder -Mailbox $PFMailboxResult.Mailbox.Name -ResidentFolders -Recurse -ResultSize Unlimited -ErrorAction Stop)
            # Skip the root folder
            if ($folders.Count -gt 1) {
                $folders = $folders[1..$($folders.Count - 1)]
            } else {
                $folders = @()
            }
            WriteHostAndLog "$(Get-Date) Found $($folders.Count) public folders in mailbox $($PFMailboxResult.Mailbox.Name)"
            $PFMailboxResult.Folders = $folders
            return
        } catch {
            WriteHostAndLog "$(Get-Date) Error getting hierarchy: $($_.Exception.Message)"
            $_ | Format-List * -Force | Out-String | ForEach-Object { WriteLog $_ }
            [void]$PFMailboxResult.Errors.Add([PSCustomObject]@{
                    Time   = (Get-Date)
                    Stage  = "Hierarchy"
                    Folder = $null
                    Error  = $_
                })

            if ($errors.Count -ge $MaxRetries) {
                WriteHostAndLog "$(Get-Date) Max retries reached, skipping mailbox $($PFMailboxResult.Mailbox.Name)"
                break
            } else {
                WriteHostAndLog "$(Get-Date) Retrying in 5 seconds..."
                Start-Sleep -Seconds 5
                continue
            }
        }
    }
}

function GetPFMailboxStatisticsWithRetry($PFMailboxResult) {
    WriteHostAndLog "$(Get-Date) Getting statistics for folders in mailbox $($PFMailboxResult.Mailbox.Name)"
    $mailboxRetryCount = 0
    while ($PFMailboxResult.StatisticsProgressIndex -lt $PFMailboxResult.Folders.Count) {
        if ($mailboxRetryCount -ge $MaxRetries) {
            WriteHostAndLog "$(Get-Date) Max retries reached. Moving on to the next mailbox."
            break
        }

        $folder = $PFMailboxResult.Folders[$PFMailboxResult.StatisticsProgressIndex]
        if ($folder.Identity.ToString() -eq "\") {
            $PFMailboxResult.StatisticsProgressIndex++
            continue
        }

        Write-Progress -Id 2 -ParentId 1 -Activity "Getting statistics" -Status "$($folder.Identity)" -PercentComplete ($PFMailboxResult.StatisticsProgressIndex / $PFMailboxResult.Folders.Count * 100)
        $folderRetryCount = 0
        while ($true) {
            try {
                $stats = $folder | Get-PublicFolderStatistics -ErrorAction Stop
                [void]$PFMailboxResult.Statistics.Add($stats)
                $PFMailboxResult.StatisticsProgressIndex++
                break
            } catch {
                WriteHostAndLog "$(Get-Date) Error getting statistics on folder $($folder.Identity): $($_.Exception.Message)"
                if ($_.ToString().Contains("ManagementObjectNotFoundException")) {
                    WriteHostAndLog "$(Get-Date) Folder appears to be deleted. Skipping..."
                    $PFMailboxResult.StatisticsProgressIndex++
                    break
                }

                $_ | Format-List * -Force | Out-String | ForEach-Object { WriteLog $_ }
                $folderRetryCount++
                [void]$PFMailboxResult.Errors.Add([PSCustomObject]@{
                        Time   = (Get-Date)
                        Stage  = "Statistics"
                        Folder = $folder.Identity
                        Error  = $_
                    })

                if ($folderRetryCount -ge $MaxRetries) {
                    $mailboxRetryCount = $folderRetryCount
                    break
                } else {
                    WriteHostAndLog "$(Get-Date) Retrying in 5 seconds..."
                    Start-Sleep -Seconds 5
                }
            }
        }
    }

    Write-Progress -Id 2 -ParentId 1 -Activity "Getting statistics" -Completed
}

function GetAndSaveResults($PassName, $ExistingResults) {
    for ($i = 0; $i -lt $ExistingResults.Count; $i++) {
        $pfMailboxResult = $ExistingResults[$i]
        if ($null -ne $pfMailboxResult.Folders) {
            continue
        }

        Write-Progress -Id 1 -Activity "Getting hierarchy" -Status "Mailbox: $($pfMailboxResult.Mailbox.Name)" -PercentComplete ($i / $ExistingResults.Count * 100)
        $newResult = GetResidentFoldersWithRetry -PFMailboxResult $pfMailboxResult
        if ($null -ne $newResult.Folders) {
            $pfMailboxResult.Folders = $newResult.Folders
        }
    }

    Write-Progress -Id 1 -Activity "Getting hierarchy" -Completed

    for ($i = 0; $i -lt $ExistingResults.Count; $i++) {
        $pfMailboxResult = $ExistingResults[$i]
        if ($null -eq $pfMailboxResult.Folders -or $pfMailboxResult.StatisticsProgressIndex -ge $pfMailboxResult.Folders.Count) {
            continue
        }

        Write-Progress -Id 1 -Activity "Getting statistics" -Status "Mailbox: $($pfMailboxResult.Mailbox.Name)" -PercentComplete ($i / $ExistingResults.Count * 100)
        # This is null if we had to skip it due to too many retries on the hierarchy
        if ($null -ne $pfMailboxResult.Folders) {
            GetPFMailboxStatisticsWithRetry -pfMailboxResult $pfMailboxResult
        }
    }

    Write-Progress -Id 1 -Activity "Getting statistics" -Completed

    WriteHostAndLog "$(Get-Date) Results after $PassName pass:"

    $pfMailboxResults | ForEach-Object {
        [PSCustomObject]@{
            Mailbox         = $($_.Mailbox.Name)
            ErrorCount      = $($_.Errors.Count)
            HierarchyCount  = $(if ($null -ne $_.Folders) { $_.Folders.Count } else { $null })
            StatisticsCount = $($_.Statistics.Count)
        }
    } | Format-Table -AutoSize | Out-String | ForEach-Object { WriteHostAndLog $_ }

    WriteHostAndLog "$(Get-Date) Writing $PassName pass results to CSV..."

    $pfMailboxResults.Statistics | Select-Object @{Name = "FolderPath"; Expression = { $_.FolderPath -join "\" } }, ItemCount, @{Name = "TotalItemSizeMB"; Expression = { [math]::Round(($_.TotalItemSize.ToString().Split("(")[1].Split(" ")[0].Replace(",", "") / 1MB), 2) } } | Export-Csv $PSScriptRoot\$($PassName)PassResults.csv -NoTypeInformation -Encoding utf8
}

WriteHostAndLog "$(Get-Date) Getting public folder mailboxes..."

$pfMailboxes = Get-Mailbox -PublicFolder

WriteHostAndLog "$(Get-Date) Found $($pfMailboxes.Count) public folder mailboxes."

$pfMailboxResults = [System.Collections.ArrayList]::new()

foreach ($mailbox in $pfMailboxes) {
    [void]$pfMailboxResults.Add([PSCustomObject]@{
            Mailbox                 = $mailbox
            Folders                 = $null
            Statistics              = [System.Collections.ArrayList]::new()
            StatisticsProgressIndex = 0
            Errors                  = [System.Collections.ArrayList]::new()
        })
}

GetAndSaveResults "First" $pfMailboxResults

$skippedHiearchy = $pfMailboxResults | Where-Object { $null -eq $_.Folders }
$skippedStatistics = $pfMailboxResults | Where-Object { $_.Statistics.Count -lt $_.Folders.Count }

if ($skippedHiearchy.Count -eq 0 -and $skippedStatistics.Count -eq 0) {
    WriteHostAndLog "$(Get-Date) No skipped items. Done."
    return
}

WriteHostAndLog "$(Get-Date) Skipped mailboxes due to too many retries on hierarchy: $($skippedHiearchy.Count)"
WriteHostAndLog "$(Get-Date) Skipped mailboxes due to too many retries on statistics: $($skippedStatistics.Count)"
WriteHostAndLog "$(Get-Date) Retrying skipped items..."

GetAndSaveResults "Second" $pfMailboxResults