#Requires -RunAsAdministrator
Param(
	[Parameter(Mandatory, HelpMessage="Please provide an alias for 127.0.0.1")][string] $LoopbackAlias,
	[string] $Action = "install"
)

New-Variable -Name "sysdir" -Value ([Environment]::SystemDirectory) -Option Constant -Scope Global
New-Variable -Name "hostsFile" -Value "$sysdir\drivers\etc\hosts" -Option Constant -Scope Global

# Adds an alias for 127.0.0.1 to the hosts file
function Add-AliasToHost {
    param (
        [string]$LoopbackAlias
    )
    $aliasLine = "127.0.0.1 $LoopbackAlias"

    foreach ($line in Get-Content $hostsFile) {
        if ($line -eq $aliasLine){
            return
        }
    }

    $content = Get-Content $hostsFile
    $content += "`r`n$aliasLine"

    $content | Set-Content "$hostsFile.tmp" -Encoding ascii
    Move-Item "$hostsFile.tmp" $hostsFile -Force
}

# Removes an alias for 127.0.0.1 from the hosts file
function Remove-AliasFromHost {
    param (
    	[string]$LoopbackAlias
    )
    $aliasLine = "127.0.0.1 $LoopbackAlias"

    $content = Get-Content $hostsFile
    $newContent = $content | Where-Object { $_ -ne $aliasLine }

    $newContent | Set-Content "$hostsFile.tmp" -Encoding ascii
	Move-Item "$hostsFile.tmp" $hostsFile -Force
}

# Sets in the registry the webclient file size limit to the maximum value
function Set-WebDAVFileSizeLimit {
    # Set variables to indicate value and key to set
    $RegistryPath = 'HKLM:\SYSTEM\CurrentControlSet\Services\WebClient\Parameters'
    $Name         = 'FileSizeLimitInBytes'
    $Value        = '0xffffffff'

    # Create the key if it does not exist
    If (-NOT (Test-Path $RegistryPath)) {
        New-Item -Path $RegistryPath -Force | Out-Null
    }

    # Now set the value
    New-ItemProperty -Path $RegistryPath -Name $Name -Value $Value -PropertyType DWORD -Force | Out-Null
}


# Changes the network provider order such that the builtin Windows webclient is always first
function Edit-ProviderOrder {
    $RegistryPath    = 'HKLM:\SYSTEM\CurrentControlSet\Control\NetworkProvider\HwOrder'
    $Name            = 'ProviderOrder'
    $WebClientString = 'webclient'

    $CurrentOrder =  (Get-ItemProperty $RegistryPath $Name).$Name

    $OrderWithoutWebclientArray = $CurrentOrder -split ',' | Where-Object {$_ -ne $WebClientString}
    $WebClientArray = @($WebClientString)

    $UpdatedOrder = ($WebClientArray + $OrderWithoutWebclientArray) -join ","
    New-ItemProperty -Path $RegistryPath -Name $Name -Value $UpdatedOrder -PropertyType String -Force | Out-Null
}

if ($Action -eq "install") {
	Add-AliasToHost $LoopbackAlias
    Write-Output 'Ensured alias exists in hosts file'

	Set-WebDAVFileSizeLimit
    Write-Output 'Set WebDAV file size limit'

    Edit-ProviderOrder
    Write-Output 'Ensured correct provider order'
} elseif ($Action -eq "uninstall") {
    Remove-AliasFromHost $LoopbackAlias
    Write-Output 'Ensured alias removed from hosts file'
} else {
	Write-Error "Invalid action: $Action. Only 'install' or 'uninstall' are valid."
}

exit 0