param(
    [Parameter(Mandatory=$false)][int]$CUSTOMER_ID=1,
    [Parameter(Mandatory=$false)][string]$INTEGRATOR_ID,
    [Parameter(Mandatory=$false)][string]$AGENT_FILENAME="AteraAgentSetup.msi",
    [Parameter(Mandatory=$false)][switch]$FORCE
)

# Make sure $INTEGRATOR_ID exists, otherwise exit this script as an agent cannot be downloaded
#If ( ($INTEGRATOR_ID -eq $null) -or ($INTEGRATOR_ID -eq '') ) { Exit }

# Source the Tools.ps1 script
Function SourceTools
{ . $([Scriptblock]::Create((New-Object Net.WebClient).DownloadString('https://dev.emberkom.com/emberkom/management-scripts/raw/branch/master/Tools.ps1'))) }
. SourceTools

Function Get-UninstallCodes ([string]$DisplayName) {
    'HKLM:SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall', 'HKLM:SOFTWARE\WOW6432Node\Microsoft\Windows\CurrentVersion\Uninstall' | ForEach-Object {
        Get-ChildItem -Path $_ -ErrorAction SilentlyContinue | ForEach-Object {
            If ( $(Get-ItemProperty -Path $_.PSPath -Name 'DisplayName' -ErrorAction SilentlyContinue) -and ($(Get-ItemPropertyValue -Path $_.PSPath -Name 'DisplayName' -ErrorAction SilentlyContinue) -eq $DisplayName) ) {
                $str = (Get-ItemPropertyValue -Path $_.PSPath -Name 'UninstallString')
                $code = $str.Substring(($str.Length - 37),36)
                LogMsg "    - ${code}"
                $UninstallCodes.Add($code) | Out-Null
            }
        }
    }
}

Function Get-ProductKeys ([string]$ProductName) {
    Get-ChildItem -Path 'HKCR:Installer\Products' | ForEach-Object {
        If ( $(Get-ItemProperty -Path $_.PSPath -Name 'ProductName' -ErrorAction SilentlyContinue) -and ($(Get-ItemPropertyValue -Path $_.PSPath -Name 'ProductName' -ErrorAction SilentlyContinue) -eq $ProductName) ) {
            $prod = $_.PSPath.Substring($_.PSPath.Length - 32)
            LogMsg "    - ${prod}"
            $ProductKeys.Add($prod) | Out-Null
        }
    }
}

Function Get-ServiceStatus ([string]$Name) { (Get-Service -Name $Name -ErrorAction SilentlyContinue).Status }

Function Stop-RunningService ([string]$Name) {
    If ( $(Get-ServiceStatus -Name $Name) -eq "Running" ) { LogMsg "  Stopping : ${Name} service" ; Stop-Service -Name $Name -Force }
}

Function Remove-StoppedService ([string]$Name) {
    $s = (Get-ServiceStatus -Name $Name)
    If ( $s ) {
        If ( $s -eq "Stopped" ) {
            LogMsg "  Deleting : ${Name} service"
            Start-Process "sc.exe" -ArgumentList "delete ${Name}" -Wait
        }
    } Else { LogMsg "  Not Found: ${Name} service" }
}

Function Stop-RunningProcess ([string]$Name) {
    $p = (Get-Process -Name $_ -ErrorAction SilentlyContinue)
    If ( $p ) { LogMsg "  Stopping : ${Name}.exe" ; $p | Stop-Process -Force }
    Else { LogMsg "  Not Found: ${Name}.exe is not running"}
}

Function Remove-Path ([string]$Path) {
    If ( Test-Path $Path ) {
        LogMsg "  Deleting : ${Path}"
        Remove-Item $Path -Recurse -Force
    } Else { LogMsg "  Not Found: ${Path}" }
}

Function Get-AllExeFiles ([string]$Path) {
    If ( Test-Path $Path ) {
        Get-ChildItem -Path $Path -Filter *.exe -Recurse | ForEach-Object { $ExeFiles.Add($_.BaseName) | Out-Null }
    }
}

# Build the path for $AGENT_INSTALLER
$AGENT_INSTALLER = '{0}{1}' -f (GetTempPath), $AGENT_FILENAME

# Make sure we need to install the agent
If ( (Test-Path "${Env:ProgramFiles}\ATERA Networks\AteraAgent\AteraAgent.exe") -or (Test-Path "${Env:ProgramFiles(x86)}\ATERA Networks\AteraAgent\AteraAgent.exe") )
{ $INSTALL = $false ; $PreviousInstall = $true ; LogMsg "Atera agent is already installed on this endpoint" } Else { $INSTALL = $true ; $PreviousInstall = $false }

If ( $FORCE ) { $INSTALL = $true }

If ( $INSTALL ) {

    # Uninstall if $FORCE is true
    If ( $PreviousInstall ) {
        LogMsg "Getting information from existing installation"
        $ACCOUNT_ID = (Get-ItemPropertyValue -Path 'HKLM:SOFTWARE\ATERA Networks\AlphaAgent' -Name 'AccountId' -ErrorAction SilentlyContinue)
        $AGENT_ID = (Get-ItemPropertyValue -Path 'HKLM:SOFTWARE\ATERA Networks\AlphaAgent' -Name 'AgentId' -ErrorAction SilentlyContinue)
        $CUSTOMER_ID = (Get-ItemPropertyValue -Path 'HKLM:SOFTWARE\ATERA Networks\AlphaAgent' -Name 'CompanyId' -ErrorAction SilentlyContinue)
        $INTEGRATOR_ID = (Get-ItemPropertyValue -Path 'HKLM:SOFTWARE\ATERA Networks\AlphaAgent' -Name 'IntegratorLogin' -ErrorAction SilentlyContinue)
        LogMsg "AccountID   : ${ACCOUNT_ID}"
        LogMsg "AgentID     : ${AGENT_ID}"
        LogMsg "CustomerID  : ${CUSTOMER_ID}"
        LogMsg "IntegratorID: ${INTEGRATOR_ID}"
        
        LogMsg "Uninstalling Atera agent"

        LogMsg "  Mounting HKEY_CLASSES_ROOT registry hive"
        New-PSDrive -Name HKCR -PSProvider Registry -Root HKEY_CLASSES_ROOT | Out-Null

        LogMsg "  Getting MSI package codes from the uninstall key"
        $UninstallCodes = New-Object System.Collections.ArrayList
        'AteraAgent' | ForEach-Object { Get-UninstallCodes -DisplayName $_ }

        LogMsg "  Getting product keys from the list of installed products"
        $ProductKeys = New-Object System.Collections.ArrayList
        'AteraAgent' | ForEach-Object { Get-ProductKeys -ProductName $_ }

        LogMsg "  Directories that we may need to delete"
        $Directories = @("${Env:ProgramFiles}\ATERA Networks")
        $Directories | ForEach-Object { LogMsg "    - ${_}" }

        LogMsg "  Processes that we may need to terminate"
        $ExeFiles = New-Object System.Collections.ArrayList
        $Directories | ForEach-Object { Get-AllExeFiles -Path $_ }
        $ExeFiles.Add('reg')  | Out-Null
        $ExeFiles | ForEach-Object { LogMsg "    - ${_}.exe" }

        LogMsg "  Windows services that we may need to stop and/or delete"
        $ServiceList = @('AteraAgent')
        $ServiceList | ForEach-Object { LogMsg "    - ${_}" }

        LogMsg "  Windows Registry keys we may need to delete"
        $RegistryKeys = @('HKLM:SOFTWARE\ATERA Networks')
        $RegistryKeys | ForEach-Object { LogMsg "    - ${_}" }

        # Uninstall each MSI package code in $UninstallCodes
        $UninstallCodes | ForEach-Object { LogMsg "  Uninstall: ${_}" ; Start-Process "msiexec.exe" -ArgumentList "/X{${_}} /qn" -Wait }

        # Stop services if they're still running
        $ServiceList | ForEach-Object { Stop-RunningService -Name $_ }

        # Terminate all relevant processes that may still be running
        $ExeFiles | ForEach-Object { Stop-RunningProcess $_ }

        # Delete services if they're still present
        $ServiceList | ForEach-Object { Remove-StoppedService -Name $_ }

        # Delete products from MSI installer registry
        $ProductKeys | ForEach-Object { Remove-Path -Path "HKCR:Installer\Products\${_}" }

        LogMsg "  Unmount HKEY_CLASSES_ROOT registry hive"
        Remove-PSDrive -Name HKCR

        # Delete registry keys
        $RegistryKeys | ForEach-Object { Remove-Path -Path $_ }

        # Delete remaining directories
        $Directories | ForEach-Object { Remove-Path -Path $_ }

        LogMsg "Finished uninstalling Atera Agent"
    }

    # Replace the '@' with '%40' - not sure why this is necessary, but it is
    $INTEGRATOR_ID = $INTEGRATOR_ID.Replace('@','%40')

    # Download agent installer
    Download-File -URL "https://app.atera.com/GetAgent/Msi/?customerId=${CUSTOMER_ID}&integratorLogin=${INTEGRATOR_ID}" -File "${AGENT_INSTALLER}"

    # Install the agent
    LogMsg "Installing Atera agent"
    Try { Start-Process "msiexec.exe" -ArgumentList "/i ""${AGENT_INSTALLER}"" /qn /norestart" -Wait }
    Catch { LogErr $_.Exception.Message }

    # Delete the agent installer
    LogMsg "Deleting ""${AGENT_INSTALLER}"""
    Try { Remove-Item $AGENT_INSTALLER -Force }
    Catch { LogErr $_.Exception.Message }

    If ( $PreviousInstall -and $ACCOUNT_ID -and $AGENT_ID -and $CUSTOMER_ID) {
        LogMsg "Restoring agent information from previous install"
        LogMsg "  - Stopping AteraAgent service"
        Stop-Service -Name 'AteraAgent' -Force
        LogMsg "  - Restoring AgentID and AccountID from previous install"
        Set-ItemProperty -Path 'HKLM:SOFTWARE\ATERA Networks\AlphaAgent' -Name 'AccountId' -Value $ACCOUNT_ID
        Set-ItemProperty -Path 'HKLM:SOFTWARE\ATERA Networks\AlphaAgent' -Name 'AgentId' -Value $AGENT_ID
        LogMsg "  - Starting AteraAgent service"
        Start-Service -Name 'AteraAgent'
    }

}

# Delete this script
Remove-Item $MyInvocation.MyCommand.Path -Force