function New-WebTierMachineConfigAppSettings {
<#
.SYNOPSIS
    Upserts Web Tier Machine Config App Settings.
#>

    [CmdletBinding()]
    Param()

    $logLead  = (Get-LogLeadName);

    [XML]$machineConfig = Read-MachineConfig
    [System.Xml.XmlElement]$configRoot = $machineConfig.configuration
    $machineConfigIsDirty = $false

    $appSettingsNode = $configRoot.SelectSingleNode("//appSettings")

    if ($null -eq $appSettingsNode) {
        Write-Verbose "$logLead : Creating appSettings Node"
        $appSettingsNode = $machineConfig.CreateElement("appSettings")
        $configRoot.AppendChild($appSettingsNode) | Out-Null
    }


    # Add App Settings
    foreach ($setting in $webTierAppSettings) {
        # Some settings are derived values which depend on other settings being instrumented.
        # We will change the value to REPLACEME here if the dependent values are not properly set so that they're skipped
        if ($setting.Name -eq "ReportServerUrl" -and ($webTierAppSettings | Where-Object {$_.Name -eq "ReportServer"}).Value -eq "REPLACEME") {
            $setting.Value = "REPLACEME"
        }
        elseif ($setting.Name -eq "ReportServerPath" -and $setting.Value -eq "/" -and [String]::IsNullOrEmpty([Environment]::GetEnvironmentVariable("POD", "Machine"))) {
            $setting.Value = "REPLACEME"
        }

        $appSetting = $appSettingsNode.SelectSingleNode(("//add[@key='{0}']" -f $setting.Name))

        if ($null -eq $appSetting) {
            Write-Output ("$logLead : Adding {0} node with value {1}" -f $setting.Name, $setting.Value)
            $appSettingElement = $machineConfig.CreateElement("add")
            $appSettingElement.SetAttribute("key", $setting.Name)

            if ($setting.Value -eq "REPLACEME") {
                Write-Warning ("$logLead : Value read as REPLACEME.  Node {0} will be added with an empty value" -f $setting.Name)
                $appSettingElement.SetAttribute("value", "")
            }
            else {
                $appSettingElement.SetAttribute("value", $setting.Value)
            }

            $appSettingsNode.AppendChild($appSettingElement) | Out-Null
            $machineConfigIsDirty = $true
        }
        elseif ($appSetting.Attributes["value"].Value -ne $setting.Value) {
            if ($setting.Value -ne "REPLACEME" -and $setting.Name -ne "ReportServerPath") {
                Write-Output ("$logLead : Update setting {0} value from {1} to {2}" -f $setting.Name, $appSetting.Attributes["value"].Value, $setting.Value)
                $appSetting.SetAttribute("value", $setting.Value)
                $machineConfigIsDirty = $true
            }
            elseif ($setting.Value -ne "REPLACEME" -and $setting.Name -eq "ReportServerPath") {
                Write-Warning ("$logLead : The ReportServerPath setting exists but does not follow convention.  Please confirm the value is correct.  Value in machine.config: {0}.  Value in script: {1}" -f $appSetting.Attributes["value"].Value, $setting.Value)
            }
            else {
                Write-Warning ("$logLead : Value read as REPLACEME.  Node {0} will not be updated" -f $setting.Name)
            }
        }
        else {
            Write-Verbose ("$logLead : AppSetting {0} already exists with correct value" -f $setting.Name)
        }
    }

    if ($machineConfigIsDirty) {
        Write-Output ("$logLead : Saving Modified machine.config")
        $machineConfig.Save($machineConfigPath)
    }
    else {
        Write-Output ("$logLead : No changes required to the machine.config")
    }
}

Set-Alias -name Create-WebTierMachineConfigAppSettings -value New-WebTierMachineConfigAppSettings;