#Requires -Version 5.1
#Requires -RunAsAdministrator
<#
.SYNOPSIS
    Registers Windows Scheduled Tasks for CI system maintenance.

.DESCRIPTION
    Creates or updates two tasks under the \CI\ task folder:

      CI-CleanupOrphans   — Runs Cleanup-OrphanedBuildVMs.ps1 every 6 hours
                            and at host startup. Destroys stale build VMs
                            (those older than -MaxAgeHours, default 4) that
                            were not cleaned up after a crash or timeout.

      CI-RetentionPolicy  — Runs Invoke-RetentionPolicy.ps1 daily at 3:00 AM
                            and at host startup (with a 15-min random delay).
                            Purges old artifact and log directories per the
                            configured retention window.

    Both tasks run as SYSTEM with highest privilege. Idempotent: safe to re-run
    after updating the scripts — existing tasks are overwritten (-Force).

.PARAMETER ScriptRoot
    Directory containing the CI scripts. Default: N:\Code\Workspace\Local-CI-CD-System\scripts

.PARAMETER MaxAgeHours
    Passed to Cleanup-OrphanedBuildVMs.ps1. VMs older than this are treated as
    orphaned. Must exceed the longest expected build duration. Default: 4

.EXAMPLE
    # Register (or update) tasks — run from an elevated PowerShell session
    .\Register-CIScheduledTasks.ps1

    # Preview what would be registered
    .\Register-CIScheduledTasks.ps1 -WhatIf
#>
[CmdletBinding(SupportsShouldProcess)]
param(
    [string] $ScriptRoot  = 'N:\Code\Workspace\Local-CI-CD-System\scripts',

    [ValidateRange(1, 168)]
    [int] $MaxAgeHours = 4
)

Set-StrictMode -Version Latest
$ErrorActionPreference = 'Stop'

$psExe     = "$env:SystemRoot\System32\WindowsPowerShell\v1.0\powershell.exe"
$taskPath  = '\CI\'
$principal = New-ScheduledTaskPrincipal -UserId 'SYSTEM' -RunLevel Highest

# Ensure task folder exists (Register-ScheduledTask creates it, but be explicit)
$schedulerService = New-Object -ComObject 'Schedule.Service'
$schedulerService.Connect()
$rootFolder = $schedulerService.GetFolder('\')
try { $rootFolder.GetFolder('CI') | Out-Null }
catch { $rootFolder.CreateFolder('CI') | Out-Null }
[System.Runtime.InteropServices.Marshal]::ReleaseComObject($schedulerService) | Out-Null

# ── Task 1: CI-CleanupOrphans ─────────────────────────────────────────────────
$cleanupScript = Join-Path $ScriptRoot 'Cleanup-OrphanedBuildVMs.ps1'
if (-not (Test-Path $cleanupScript -PathType Leaf)) {
    Write-Warning "Script not found — skipping CI-CleanupOrphans: $cleanupScript"
} else {
    $cleanupAction = New-ScheduledTaskAction `
        -Execute  $psExe `
        -Argument "-NoProfile -NonInteractive -ExecutionPolicy Bypass -File `"$cleanupScript`" -MaxAgeHours $MaxAgeHours"

    # Repeat every 6 hours indefinitely (Once trigger + RepetitionInterval)
    $repeat6h = New-ScheduledTaskTrigger -Once -At '00:00' `
        -RepetitionInterval (New-TimeSpan -Hours 6)
    $atStartup = New-ScheduledTaskTrigger -AtStartup

    $cleanupSettings = New-ScheduledTaskSettingsSet `
        -ExecutionTimeLimit (New-TimeSpan -Hours 1) `
        -MultipleInstances  IgnoreNew `
        -StartWhenAvailable

    if ($PSCmdlet.ShouldProcess('CI-CleanupOrphans', 'Register/update scheduled task')) {
        Register-ScheduledTask `
            -TaskName   'CI-CleanupOrphans' `
            -TaskPath   $taskPath `
            -Action     $cleanupAction `
            -Trigger    @($repeat6h, $atStartup) `
            -Principal  $principal `
            -Settings   $cleanupSettings `
            -Description "Destroys orphaned CI build VMs older than ${MaxAgeHours}h (Local CI/CD System)" `
            -Force | Out-Null
        Write-Host "[Register] CI-CleanupOrphans registered (every 6h + at startup, -MaxAgeHours $MaxAgeHours)." -ForegroundColor Green
    }
}

# ── Task 2: CI-RetentionPolicy ────────────────────────────────────────────────
$retentionScript = Join-Path $ScriptRoot 'Invoke-RetentionPolicy.ps1'
if (-not (Test-Path $retentionScript -PathType Leaf)) {
    Write-Warning "Script not found — skipping CI-RetentionPolicy: $retentionScript"
} else {
    $retentionAction = New-ScheduledTaskAction `
        -Execute  $psExe `
        -Argument "-NoProfile -NonInteractive -ExecutionPolicy Bypass -File `"$retentionScript`""

    $daily3am  = New-ScheduledTaskTrigger -Daily -At '03:00' `
        -RandomDelay (New-TimeSpan -Minutes 30)
    $atStartup2 = New-ScheduledTaskTrigger -AtStartup `
        -RandomDelay (New-TimeSpan -Minutes 15)

    $retentionSettings = New-ScheduledTaskSettingsSet `
        -ExecutionTimeLimit (New-TimeSpan -Hours 1) `
        -MultipleInstances  IgnoreNew `
        -StartWhenAvailable

    if ($PSCmdlet.ShouldProcess('CI-RetentionPolicy', 'Register/update scheduled task')) {
        Register-ScheduledTask `
            -TaskName   'CI-RetentionPolicy' `
            -TaskPath   $taskPath `
            -Action     $retentionAction `
            -Trigger    @($daily3am, $atStartup2) `
            -Principal  $principal `
            -Settings   $retentionSettings `
            -Description 'Purges old CI artifacts, logs, and stale IP leases (Local CI/CD System)' `
            -Force | Out-Null
        Write-Host "[Register] CI-RetentionPolicy registered (daily 03:00 + at startup)." -ForegroundColor Green
    }
}

Write-Host "`n[Register] Done. Verify with: Get-ScheduledTask -TaskPath '\CI\' | Format-Table TaskName, State" -ForegroundColor Cyan