<#
.SYNOPSIS
  Interactive TUI for managing (list/create) Scheduled Tasks on local or remote servers under SYSTEM account.
.DESCRIPTION
  - Menu-driven console interface
  - Always runs as SYSTEM (highest privilege)
  - Supports Once/Daily/Weekly/Monthly triggers
  - Custom actions, settings (start when available, wake to run, retry on failure)
  - Remote targeting via CIM session
.PARAMETER RunTUI
  Launch the text-based UI.
#>
[CmdletBinding()]
Param(
    [switch]$RunTUI
)

function New-UniversalScheduledTask {
    [CmdletBinding()]
    Param(
        [string]$ServerName,
        [string]$TaskName,
        [string]$Description,
        [ValidateSet('Once','Daily','Weekly','Monthly')][string]$Frequency,
        [datetime]$At,
        [string[]]$DaysOfWeek,
        [string[]]$Months,
        [int[]]$DaysOfMonth,
        [string]$Command    = 'powershell.exe',
        [string]$Arguments  = '',
        [switch]$StartWhenAvailable,
        [switch]$WakeToRun,
        [int]$RestartIntervalMinutes = 0,
        [int]$RestartCount = 0
    )
    # Determine target
    $target = if ($ServerName) { $ServerName } else { 'local' }
    if ($ServerName) {
        Write-Host "Creating CIM session to $ServerName..."
        $CimSession = New-CimSession -ComputerName $ServerName
    }
    # Build trigger
    switch ($Frequency) {
        'Once'    { $trigger = New-ScheduledTaskTrigger -Once    -At $At }
        'Daily'   { $trigger = New-ScheduledTaskTrigger -Daily   -At $At.TimeOfDay }
        'Weekly'  { $trigger = New-ScheduledTaskTrigger -Weekly  -DaysOfWeek $DaysOfWeek  -At $At.TimeOfDay }
        'Monthly' { $trigger = New-ScheduledTaskTrigger -Monthly -MonthsOfYear $Months -DaysOfMonth $DaysOfMonth -At $At.TimeOfDay }
    }
    # Action and settings
    $action = New-ScheduledTaskAction -Execute $Command -Argument $Arguments
    $settings = New-ScheduledTaskSettingsSet -StartWhenAvailable:$StartWhenAvailable.IsPresent -WakeToRun:$WakeToRun.IsPresent
    if ($RestartIntervalMinutes -gt 0) {
        $interval = New-TimeSpan -Minutes $RestartIntervalMinutes
        $settings = $settings | Set-ScheduledTaskSettings -RestartOnFailureInterval $interval -RestartCount $RestartCount
    }
    # Register task
    Write-Host "Registering task '$TaskName' on $target"
    Register-ScheduledTask -TaskName $TaskName -Action $action -Trigger $trigger -Settings $settings -Description $Description -User 'NT AUTHORITY\\SYSTEM' -RunLevel Highest${($CimSession) ? ' -CimSession $CimSession' : ''} -Force
    Write-Host "Task '$TaskName' created successfully on $target."
}

function List-ScheduledTasks {
    [CmdletBinding()]
    Param([string]$ServerName)
    # Determine target
    $target = if ($ServerName) { $ServerName } else { 'local' }
    if ($ServerName) {
        Write-Host "Creating CIM session to $ServerName..."
        $CimSession = New-CimSession -ComputerName $ServerName
    }
    Write-Host "Listing tasks on $target"
    Get-ScheduledTask${($CimSession) ? ' -CimSession $CimSession' : ''} | Select-Object TaskName, State, Actions | Format-Table -AutoSize
}

function Show-Menu {
    Write-Host "=== Scheduled Task Manager ===" -ForegroundColor Cyan
    Write-Host "1) List Tasks"
    Write-Host "2) Create Task"
    Write-Host "3) Exit"
    return Read-Host 'Choose [1-3]'
}

function Prompt-TaskParameters {
    $p = @{}
    $p.ServerName  = Read-Host 'Server (blank=local)'
    $p.TaskName    = Read-Host 'Task Name'
    $p.Description = Read-Host 'Description'
    $p.Frequency   = Read-Host 'Frequency (Once,Daily,Weekly,Monthly)'
    $p.At          = [datetime](Read-Host 'Date/time (e.g. 2025-06-27 22:00)')
    if ($p.Frequency -eq 'Weekly') {
        $p.DaysOfWeek = (Read-Host 'DaysOfWeek (Monday,Tuesday)').Split(',')
    }
    if ($p.Frequency -eq 'Monthly') {
        $p.Months      = (Read-Host 'Months (January,June)').Split(',')
        $p.DaysOfMonth = (Read-Host 'DaysOfMonth (1,15)').Split(',') | ForEach-Object {[int]$_}
    }
    $cmd = Read-Host 'Command (default=powershell.exe)'
    if ($cmd) { $p.Command = $cmd }
    $p.Arguments = Read-Host 'Arguments'
    if ((Read-Host 'Start when available? (Y/N)') -eq 'Y') { $p.StartWhenAvailable = $true }
    if ((Read-Host 'Wake to run? (Y/N)')          -eq 'Y') { $p.WakeToRun          = $true }
    $retry = [int](Read-Host 'Retry interval minutes (0=none)')
    if ($retry -gt 0) {
        $p.RestartIntervalMinutes = $retry
        $p.RestartCount           = [int](Read-Host 'Retry count')
    }
    return $p
}

# Entry point
if ($RunTUI) {
    do {
        switch (Show-Menu) {
            '1' {
                $srv = Read-Host 'Server to list (blank=local)'
                List-ScheduledTasks -ServerName $srv
                Write-Host 'Press Enter to continue...'
                Read-Host
            }
            '2' {
                $params = Prompt-TaskParameters
                New-UniversalScheduledTask @params
                Write-Host 'Press Enter to continue...'
                Read-Host
            }
            '3' { break }
            default { Write-Host 'Invalid choice.' -ForegroundColor Red }
        }
    } while ($true)
    return
}

Write-Host 'No action specified. Use -RunTUI to launch the console interface.' -ForegroundColor Yellow