function Test-Value {
    param (
        [Parameter(Mandatory)]
        [AllowEmptyString()]
        [string]$Value
    )
    if ([string]::IsNullOrEmpty($Value)) {
        $Value = 'Not set'
    }
    return $Value
}

function Get-InputValue {
    param (
        [Parameter(Mandatory)]
        [AllowEmptyString()]
        [string]$Value,
        [Parameter(Mandatory)]
        [bool]$DefaultValue
    )
    if ([string]::IsNullOrEmpty($Value)) { return $DefaultValue }
    $Value = $Value.Trim(' ', "'", '"').ToLower()
    switch ($Value) {
        'yes' { return $true }
        'no' { return $false }
        Default { return $DefaultValue }
    }
}

$Host.UI.WriteLine("The script is running with the following parameters: Show update dialog - ${Show update dialog}, Force application close - ${Force application close}.")

$displayLevel = Get-InputValue -Value ${Show update dialog} -DefaultValue $true
$forceAppShutdown = Get-InputValue -Value ${Force application close} -DefaultValue $false

$displayLevel = 'displaylevel=' + ([string]$displayLevel).ToLower()
$forceAppShutdown = 'forceappshutdown=' + ([string]$forceAppShutdown).ToLower()

$c2rRegPath = Get-ItemProperty -Path "HKLM:\SOFTWARE\Microsoft\Office\ClickToRun\Configuration" -ErrorAction SilentlyContinue

if ($null -eq $c2rRegPath) {
    $Host.UI.WriteLine("Microsoft Office is installed using Windows Installer, not as a Click-To-Run application. Please use Action1 Deploy Update policy to install the latest updates.")
    return
}

if ([string]::IsNullOrEmpty($c2rRegPath.ClientFolder)) {
    $Host.UI.WriteLine("The Click-To-Run directory is not specified in the registry.")
    return
}

if (-not(Test-Path -Path $c2rRegPath.ClientFolder -PathType Container)) {
    $Host.UI.WriteLine("The Click-To-Run directory does not exist.")
    return
}

$updateChannelsObject = @(
    [PSCustomObject]@{ 'Name' = 'Current Channel'; 'Policy Name' = 'Current'; 'GUID' = '492350f6-3a01-4f97-b9c0-c7c6ddf67d60' },
    [PSCustomObject]@{ 'Name' = 'Current Channel (Preview)'; 'Policy Name' = 'FirstReleaseCurrent'; 'GUID' = '64256afe-f5d9-4f86-8936-8840a6a4f5be' },
    [PSCustomObject]@{ 'Name' = 'Monthly Enterprise Channel'; 'Policy Name' = 'MonthlyEnterprise'; 'GUID' = '55336b82-a18d-4dd6-b5f6-9e5095c314a6' },
    [PSCustomObject]@{ 'Name' = 'Semi-Annual Enterprise Channel'; 'Policy Name' = 'Deferred'; 'GUID' = '7ffbc6bf-bc32-4f92-8982-f9dd17fd3114' },
    [PSCustomObject]@{ 'Name' = 'Semi-Annual Enterprise Channel (Preview)'; 'Policy Name' = 'FirstReleaseDeferred'; 'GUID' = 'b8f9b850-328d-4355-9145-c59439a0c4cf' },
    [PSCustomObject]@{ 'Name' = 'Beta Channel'; 'Policy Name' = 'InsiderFast'; 'GUID' = '5440fd1f-7ecb-4221-8110-145efaa6372f' }
)

$cloudUCRegPath = 'HKLM:\SOFTWARE\Policies\Microsoft\cloud\office\16.0\Common\officeupdate'
$policyUCRegPath = 'HKLM:\SOFTWARE\Policies\Microsoft\office\16.0\Common\officeupdate'
$odtUCRegPath = 'HKLM:\SOFTWARE\Microsoft\office\ClickToRun\Configuration'
$unmanagedUCRegPath = 'HKLM:\SOFTWARE\Microsoft\office\ClickToRun\Configuration'

$cloudUC = Get-ItemProperty -Path $cloudUCRegPath -ErrorAction SilentlyContinue
$policyUC = Get-ItemProperty -Path $policyUCRegPath -ErrorAction SilentlyContinue
$odtUC = Get-ItemProperty -Path $odtUCRegPath -ErrorAction SilentlyContinue
$unmanagedUC = Get-ItemProperty -Path $unmanagedUCRegPath -ErrorAction SilentlyContinue

$1Priority = Test-Value -Value $cloudUC.UpdatePath
$2PriorityRaw = Test-Value -Value $cloudUC.UpdateBranch
$3Priority = Test-Value -Value $policyUC.UpdatePath
$4PriorityRaw = Test-Value -Value $policyUC.UpdateBranch
$5Priority = Test-Value -Value $odtUC.UpdateUrl
$6Priority = Test-Value -Value $odtUC.UpdatePath
$7Priority = Test-Value -Value $unmanagedUC.UnmanagedUpdateURL
$8PriorityRaw = Test-Value -Value $unmanagedUC.CDNBaseUrl
if ($8PriorityRaw.Contains('http://') -or $8PriorityRaw.Contains('https://')) {
    $8PriorityRaw = $8PriorityRaw -split '/' | Select-Object -Last 1
}

$2Priority = ($updateChannelsObject | Where-Object { $_.'Policy Name' -eq $2PriorityRaw } | Select-Object Name).Name
if ([string]::IsNullOrEmpty($2Priority)) { $2Priority = $2PriorityRaw }
$4Priority = ($updateChannelsObject | Where-Object { $_.'Policy Name' -eq $4PriorityRaw } | Select-Object Name).Name
if ([string]::IsNullOrEmpty($4Priority)) { $4Priority = $4PriorityRaw }
$8Priority = ($updateChannelsObject | Where-Object { $_.GUID -eq $8PriorityRaw } | Select-Object Name).Name
if ([string]::IsNullOrEmpty($8Priority)) { $8Priority = $8PriorityRaw }

$array = @($1Priority, $2Priority, $3Priority, $4Priority, $5Priority, $6Priority, $7Priority, $8Priority)

$priorityString = ''
foreach ($item in $array) {
    if ($item -ne 'Not set') {
        $priorityString += $item
    }
}

$Host.UI.WriteLine("The Click-To-Run update channel priority: $priorityString.")

$c2rExecutable = 'OfficeC2RClient.exe'
$c2rFullPath = Join-Path -Path $c2rRegPath.ClientFolder -ChildPath $c2rExecutable -ErrorAction SilentlyContinue

if (-not(Test-Path -Path $c2rFullPath -PathType Leaf)) {
    $Host.UI.WriteLine("The Click-To-Run executable file does not exist.")
    return
}

$argumentList = '/update user', $forceAppShutdown, $displayLevel -join ' '

$c2rProc = Start-Process $c2rFullPath -ArgumentList $argumentList -Wait -PassThru -ErrorAction SilentlyContinue

if ($c2rProc.ExitCode -eq 0) {
    $Host.UI.WriteLine("The update process of Microsoft Office is initialized.")
}
else {
    $Host.UI.WriteLine("The update process returned an error $($c2rProc.ExitCode).")
}