<#
.SYNOPSIS
  Interactive TUI for listing and creating 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
#>
[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 = 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
    }

    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 \
      -Force

    Write-Host "Task '$TaskName' created successfully on $target."
}

function List-ScheduledTasks {
    Param([string]$ServerName)
    if ($ServerName) { $CimSession = New-CimSession -ComputerName $ServerName }
    Get-ScheduledTask -CimSession $CimSession |
      Select-Object TaskName, State, Actions |
      Format-Table -AutoSize
}

function Show-Menu {
    Clear-Host
    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(',')
        $p.DaysOfMonth  = (Read-Host 'DaysOfMonth (1,15,28...)').Split(',') | % {[int]$_}
    }
    $cmd = Read-Host 'Command (default=powershell.exe)'
    if ($cmd) { $p.Command = $cmd }
    $p.Arguments = Read-Host 'Arguments (e.g. "-File C:\Scripts\MyScript.ps1")'
    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
}

# Main execution
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