定时任务怎么设置：写清输入、失败通知、重试和停止条件

$ErrorActionPreference = 'Stop'
$base = $PSScriptRoot
$paused = Join-Path $base 'paused.flag'
if (Test-Path -LiteralPath $paused) { exit 2 }
$batch = (Get-Date).AddDays(-1).ToString('yyyy-MM-dd')
$inputFile = Join-Path $base ("input\" + $batch + ".txt")
$outputFile = Join-Path $base ("output\" + $batch + ".txt")
$stateFile = Join-Path $base ("output\" + $batch + ".sha256")
try {
  for ($attempt = 1; $attempt -le 3; $attempt++) {
    if (Test-Path -LiteralPath $inputFile) { break }
    if ($attempt -lt 3) { Start-Sleep -Seconds 10 }
  }
  if (!(Test-Path -LiteralPath $inputFile)) { throw "输入缺失：$batch；已检查3次" }
  $hash = (Get-FileHash -LiteralPath $inputFile -Algorithm SHA256).Hash
  if (Test-Path -LiteralPath $outputFile) {
    if (!(Test-Path -LiteralPath $stateFile)) { throw '输出存在但无状态，人工核对' }
    if ((Get-Content -LiteralPath $stateFile -Raw).Trim() -ne $hash) { throw '同批次输入已变化，人工核对' }
    Add-Content -LiteralPath (Join-Path $base 'run.log') -Value "$batch skipped same-input"
    exit 0
  }
  Copy-Item -LiteralPath $inputFile -Destination $outputFile -ErrorAction Stop
  Set-Content -LiteralPath $stateFile -Value $hash
  Add-Content -LiteralPath (Join-Path $base 'run.log') -Value "$batch completed"
} catch {
  $message = "$batch FAILED: $($_.Exception.Message)"
  Add-Content -LiteralPath (Join-Path $base 'run.log') -Value $message
  Set-Content -LiteralPath $paused -Value $message
  Add-Type -AssemblyName System.Windows.Forms
  [System.Windows.Forms.MessageBox]::Show($message, '教学定时任务需处理') | Out-Null
  exit 1
}

$taskUser = [System.Security.Principal.WindowsIdentity]::GetCurrent().Name
$action = New-ScheduledTaskAction -Execute 'powershell.exe' -Argument '-NoProfile -File "C:\LearningTasks\run.ps1"' -WorkingDirectory 'C:\LearningTasks'
$trigger = New-ScheduledTaskTrigger -Daily -At '09:00'
$principal = New-ScheduledTaskPrincipal -UserId $taskUser -LogonType Interactive
$settings = New-ScheduledTaskSettingsSet -MultipleInstances IgnoreNew -StartWhenAvailable
Register-ScheduledTask -TaskName 'Xiaohe-Lesson-Report' -Action $action -Trigger $trigger -Principal $principal -Settings $settings
Start-ScheduledTask -TaskName 'Xiaohe-Lesson-Report'
Get-ScheduledTaskInfo -TaskName 'Xiaohe-Lesson-Report'

Disable-ScheduledTask -TaskName 'Xiaohe-Lesson-Report'
Get-Content -LiteralPath 'C:\LearningTasks\paused.flag'
# 核对输入、输出和日志后，把 paused.flag 移至留档位置；再运行下一条
Enable-ScheduledTask -TaskName 'Xiaohe-Lesson-Report'
# 结束练习时在任务计划程序删除该同名任务，保留日志与输入