<#
.SYNOPSIS
  Collects scheduled tasks and basic system information on this Windows host and
  POSTs them to the Homelab Manager API.

.DESCRIPTION
  Intended to run as SYSTEM on a schedule (see install.ps1), but can be run by
  hand for testing:

    $env:API_URL='https://homelab.example.lan'; $env:API_TOKEN='hlm_xxx'
    .\report-tasks.ps1 -DryRun

  Configuration comes from the API_URL / API_TOKEN / API_INSECURE environment
  variables, or else from %ProgramData%\HomelabManager\agent.json (written by
  install.ps1). Works in Windows PowerShell 5.1 and PowerShell 7.

  Set API_INSECURE=true if Homelab Manager uses a self-signed certificate. That
  skips certificate checks for every request this agent makes - only do it on a
  trusted LAN.

  Microsoft's built-in scheduled tasks (the \Microsoft\ folder, several hundred
  of them) are left out; set INCLUDE_MICROSOFT_TASKS=true to report them too.

  NOTE: keep this file plain ASCII. It is downloaded as text and Windows
  PowerShell 5.1 reads a file without a BOM as ANSI, so anything else garbles.
#>
[CmdletBinding()]
param(
  [switch]$DryRun
)

$ErrorActionPreference = 'Stop'

$script:DefaultConfigPath = Join-Path $env:ProgramData 'HomelabManager\agent.json'

# ---- configuration ------------------------------------------------------------

function Get-AgentConfig {
  $config = @{ ApiUrl = $null; ApiToken = $null; Insecure = $false; IncludeMicrosoftTasks = $false }

  $path = if ($env:HLM_CONFIG) { $env:HLM_CONFIG } else { $script:DefaultConfigPath }
  if (Test-Path -LiteralPath $path) {
    $file = Get-Content -LiteralPath $path -Raw | ConvertFrom-Json
    if ($file.apiUrl) { $config.ApiUrl = [string]$file.apiUrl }
    if ($file.apiToken) { $config.ApiToken = [string]$file.apiToken }
    if ($null -ne $file.insecure) { $config.Insecure = [bool]$file.insecure }
    if ($null -ne $file.includeMicrosoftTasks) { $config.IncludeMicrosoftTasks = [bool]$file.includeMicrosoftTasks }
  }

  # Environment variables win over the file, like the Linux agent.
  if ($env:API_URL) { $config.ApiUrl = $env:API_URL }
  if ($env:API_TOKEN) { $config.ApiToken = $env:API_TOKEN }
  if ($env:API_INSECURE) { $config.Insecure = $env:API_INSECURE -match '^(1|true|yes)$' }
  if ($env:INCLUDE_MICROSOFT_TASKS) { $config.IncludeMicrosoftTasks = $env:INCLUDE_MICROSOFT_TASKS -match '^(1|true|yes)$' }

  if ($config.ApiUrl) { $config.ApiUrl = $config.ApiUrl.TrimEnd('/') }
  return $config
}

# ---- describing scheduled tasks -------------------------------------------------

# "PT15M" -> "15 min", "P1D" -> "1 day", "PT1H30M" -> "1 h 30 min". Returns $null for empty/unparseable.
function Convert-IsoDuration([string]$Iso) {
  if (-not $Iso) { return $null }
  $m = [regex]::Match($Iso, '^P(?:(\d+)D)?(?:T(?:(\d+)H)?(?:(\d+)M)?(?:(\d+)S)?)?$')
  if (-not $m.Success) { return $null }
  $parts = @()
  if ($m.Groups[1].Success) { $parts += ('{0} day{1}' -f $m.Groups[1].Value, $(if ($m.Groups[1].Value -eq '1') { '' } else { 's' })) }
  if ($m.Groups[2].Success) { $parts += ('{0} h' -f $m.Groups[2].Value) }
  if ($m.Groups[3].Success) { $parts += ('{0} min' -f $m.Groups[3].Value) }
  if ($m.Groups[4].Success) { $parts += ('{0} s' -f $m.Groups[4].Value) }
  if ($parts.Count -eq 0) { return $null }
  return ($parts -join ' ')
}

# StartBoundary is "2026-01-01T02:00:00" (local time, sometimes with an offset). Returns @{ Date = 'yyyy-MM-dd'; Time = 'HH:mm' }.
function Split-Boundary([string]$Boundary) {
  $m = [regex]::Match([string]$Boundary, '^(\d{4}-\d{2}-\d{2})T(\d{2}:\d{2})')
  if (-not $m.Success) { return @{ Date = $null; Time = $null } }
  return @{ Date = $m.Groups[1].Value; Time = $m.Groups[2].Value }
}

# Days of the week as Task Scheduler's bitmask stores them. (A list of pairs, not a dictionary keyed by number: indexing a
# dictionary with an integer reads by position in some PowerShell types, which would silently pick the wrong day.)
$script:DayBits = @(
  @{ Bit = 1; Name = 'Sun' }, @{ Bit = 2; Name = 'Mon' }, @{ Bit = 4; Name = 'Tue' }, @{ Bit = 8; Name = 'Wed' },
  @{ Bit = 16; Name = 'Thu' }, @{ Bit = 32; Name = 'Fri' }, @{ Bit = 64; Name = 'Sat' }
)

# One trigger as a sentence, e.g. "Daily at 02:00, repeating every 15 min".
function Describe-Trigger($Trigger) {
  $kind = [string]$Trigger.CimClass.CimClassName
  $at = (Split-Boundary $Trigger.StartBoundary)
  $time = $at.Time
  $text = switch -Regex ($kind) {
    'DailyTrigger$' {
      $n = [int]$Trigger.DaysInterval
      $when = if ($time) { " at $time" } else { '' }
      if ($n -gt 1) { "Every $n days$when" } else { "Daily$when" }
    }
    'WeeklyTrigger$' {
      $days = @()
      foreach ($d in $script:DayBits) { if ([int]$Trigger.DaysOfWeek -band $d.Bit) { $days += $d.Name } }
      $n = [int]$Trigger.WeeksInterval
      $prefix = if ($n -gt 1) { "Every $n weeks" } else { 'Weekly' }
      $on = if ($days.Count -gt 0) { ' on ' + ($days -join ', ') } else { '' }
      $when = if ($time) { " at $time" } else { '' }
      "$prefix$on$when"
    }
    'MonthlyDOWTrigger$' { $when = if ($time) { " at $time" } else { '' }; "Monthly (by weekday)$when" }
    'MonthlyTrigger$' {
      $dayNumbers = @()
      for ($i = 0; $i -lt 31; $i++) { if ([int64]$Trigger.DaysOfMonth -band ([int64]1 -shl $i)) { $dayNumbers += ($i + 1) } }
      $when = if ($time) { " at $time" } else { '' }
      $on = if ($dayNumbers.Count -gt 0) { ' on day ' + ($dayNumbers -join ', ') } else { '' }
      "Monthly$on$when"
    }
    'TimeTrigger$' { if ($at.Date) { "Once at $($at.Date) $time" } else { 'Once' } }
    'BootTrigger$' { 'At startup' }
    'LogonTrigger$' { 'At logon' }
    'IdleTrigger$' { 'When idle' }
    'EventTrigger$' { 'On an event' }
    'SessionStateChangeTrigger$' { 'On session state change' }
    'RegistrationTrigger$' { 'When the task is created' }
    default { 'Custom trigger' }
  }

  $interval = $null
  if ($Trigger.Repetition -and $Trigger.Repetition.Interval) { $interval = Convert-IsoDuration ([string]$Trigger.Repetition.Interval) }
  if ($interval) { $text = "$text, repeating every $interval" }
  return $text
}

function Describe-Triggers($Triggers) {
  $list = @($Triggers | Where-Object { $_ })
  if ($list.Count -eq 0) { return '(no trigger - run manually)' }
  return (($list | ForEach-Object { Describe-Trigger $_ }) -join '; ')
}

function Describe-Actions($Actions) {
  $parts = @()
  foreach ($a in @($Actions | Where-Object { $_ })) {
    $kind = [string]$a.CimClass.CimClassName
    if ($kind -match 'ExecAction$' -or $a.Execute) {
      $argText = if ($a.Arguments) { ' ' + $a.Arguments } else { '' }
      $parts += ([string]$a.Execute + $argText).Trim()
    } elseif ($a.ClassId) {
      $parts += "COM handler $($a.ClassId)"
    } elseif ($kind) {
      $parts += ($kind -replace '^MSFT_Task', '')
    }
  }
  return ($parts -join ' ; ')
}

# ---- collecting tasks -----------------------------------------------------------

function Get-ReportedTasks([bool]$IncludeMicrosoft) {
  $out = @()
  foreach ($task in @(Get-ScheduledTask)) {
    if (-not $IncludeMicrosoft -and $task.TaskPath -like '\Microsoft\*') { continue }

    $info = $null
    try { $info = Get-ScheduledTaskInfo -TaskName $task.TaskName -TaskPath $task.TaskPath } catch { }

    $entry = [ordered]@{
      schedule_type       = 'windows_task'
      name                = ('{0}{1}' -f $task.TaskPath, $task.TaskName)
      command             = Describe-Actions $task.Actions
      schedule_expression = Describe-Triggers $task.Triggers
      source              = [string]$task.TaskPath
      enabled             = ($task.State -ne 'Disabled')
    }
    # Windows reports "never" as a date in 1999 (or year 1), not as an empty value.
    if ($info -and $info.NextRunTime -and $info.NextRunTime.Year -gt 2000) {
      $entry['next_run_at'] = $info.NextRunTime.ToUniversalTime().ToString("yyyy-MM-dd'T'HH:mm:ss'Z'")
    }
    $meta = [ordered]@{ state = [string]$task.State; run_as = [string]$task.Principal.UserId }
    if ($info -and $info.LastRunTime -and $info.LastRunTime.Year -gt 2000) {
      $meta['last_run_at'] = $info.LastRunTime.ToUniversalTime().ToString("yyyy-MM-dd'T'HH:mm:ss'Z'")
      $meta['last_result'] = [int64]$info.LastTaskResult
    }
    $entry['metadata'] = $meta
    $out += [pscustomobject]$entry
  }
  # No leading comma: callers wrap the call in @(...), and returning an array wrapped in another array would
  # turn every task into one nested item.
  return $out
}

# ---- collecting system info -----------------------------------------------------

function Get-Fqdn {
  $name = [System.Net.Dns]::GetHostName()
  try {
    $cs = Get-CimInstance -ClassName Win32_ComputerSystem
    if ($cs.PartOfDomain -and $cs.Domain -and ($name -notlike '*.*')) { return ("$name.$($cs.Domain)").ToLowerInvariant() }
  } catch { }
  return $name.ToLowerInvariant()
}

function Get-ListeningPorts {
  $names = @{}
  foreach ($p in Get-Process -ErrorAction SilentlyContinue) { $names[[int]$p.Id] = $p.ProcessName }
  $processOf = { param($id) if ($id -eq 0 -or $id -eq 4) { 'System' } elseif ($names.ContainsKey([int]$id)) { $names[[int]$id] } else { '' } }
  $clean = { param($addr) ([string]$addr) -replace '%.*$', '' }   # drop an IPv6 zone id ("fe80::1%12")

  $seen = @{}
  $rows = @()
  foreach ($c in @(Get-NetTCPConnection -State Listen -ErrorAction SilentlyContinue)) {
    $row = [ordered]@{ protocol = 'tcp'; port = [int]$c.LocalPort; address = (& $clean $c.LocalAddress); process = (& $processOf $c.OwningProcess) }
    $key = "tcp|$($row.port)|$($row.address)"
    if (-not $seen.ContainsKey($key)) { $seen[$key] = 1; $rows += [pscustomobject]$row }
  }
  foreach ($u in @(Get-NetUDPEndpoint -ErrorAction SilentlyContinue)) {
    $row = [ordered]@{ protocol = 'udp'; port = [int]$u.LocalPort; address = (& $clean $u.LocalAddress); process = (& $processOf $u.OwningProcess) }
    $key = "udp|$($row.port)|$($row.address)"
    if (-not $seen.ContainsKey($key)) { $seen[$key] = 1; $rows += [pscustomobject]$row }
  }
  return @($rows | Where-Object { $_.port -ge 1 -and $_.port -le 65535 } | Select-Object -First 2000)
}

function Get-SystemInfo {
  $ips = @(Get-NetIPAddress -AddressFamily IPv4 -ErrorAction SilentlyContinue |
      Where-Object { $_.IPAddress -notlike '127.*' -and $_.IPAddress -notlike '169.254.*' -and $_.AddressState -eq 'Preferred' } |
      ForEach-Object { $_.IPAddress } | Select-Object -Unique)

  $cpus = @(Get-CimInstance -ClassName Win32_Processor)
  $os = Get-CimInstance -ClassName Win32_OperatingSystem
  $totalBytes = [int64]$os.TotalVisibleMemorySize * 1024
  $freeBytes = [int64]$os.FreePhysicalMemory * 1024

  # Unlike the Linux agent's load average, this is the processor's actual current load.
  $load = ($cpus | Where-Object { $null -ne $_.LoadPercentage } | Measure-Object -Property LoadPercentage -Average).Average
  $cores = ($cpus | Measure-Object -Property NumberOfLogicalProcessors -Sum).Sum

  $disks = @()
  foreach ($d in @(Get-CimInstance -ClassName Win32_LogicalDisk -Filter 'DriveType=3')) {
    if (-not $d.Size) { continue }   # an unformatted or unavailable volume
    $disks += [pscustomobject][ordered]@{ mount = [string]$d.DeviceID; size_bytes = [int64]$d.Size; used_bytes = [int64]($d.Size - $d.FreeSpace) }
  }

  return [ordered]@{
    ip_addresses    = @($ips)
    cpu             = [ordered]@{ model = [string]($cpus[0].Name).Trim(); cores = [int]$cores; load_percent = $(if ($null -ne $load) { [math]::Round([double]$load, 1) } else { $null }) }
    memory          = [ordered]@{ total_bytes = $totalBytes; used_bytes = ($totalBytes - $freeBytes) }
    disks           = @($disks)
    listening_ports = @(Get-ListeningPorts)
  }
}

# ---- sending --------------------------------------------------------------------

function Send-Report($Config, [string]$Json) {
  $body = [System.Text.Encoding]::UTF8.GetBytes($Json)
  $params = @{
    Uri         = "$($Config.ApiUrl)/api/agent/report"
    Method      = 'Post'
    Headers     = @{ Authorization = "Bearer $($Config.ApiToken)" }
    Body        = $body
    ContentType = 'application/json; charset=utf-8'
    TimeoutSec  = 60
  }
  if ($PSVersionTable.PSVersion.Major -ge 6) {
    if ($Config.Insecure) { $params['SkipCertificateCheck'] = $true }
  } else {
    # Windows PowerShell 5.1: modern TLS is off by default, and there is no per-request switch for self-signed certificates.
    [Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12
    if ($Config.Insecure) { [Net.ServicePointManager]::ServerCertificateValidationCallback = { $true } }
    $params['UseBasicParsing'] = $true
  }
  return Invoke-RestMethod @params
}

# ---- main -----------------------------------------------------------------------

# A plain one-line message on stderr: Write-Error would bury it in a stack trace on every manual run.
function Stop-Agent([string]$Message) {
  [Console]::Error.WriteLine($Message)
  exit 1
}

function Invoke-Agent {
  $config = Get-AgentConfig
  if (-not $config.ApiUrl -or -not $config.ApiToken) {
    Stop-Agent "API_URL and API_TOKEN must be set (environment variables, or $script:DefaultConfigPath)."
  }

  $tasks = @()
  try {
    $tasks = @(Get-ReportedTasks $config.IncludeMicrosoftTasks)
  } catch {
    # Still worth reporting the hardware and ports if tasks can't be read.
    Write-Warning "Collecting scheduled tasks failed: $($_.Exception.Message)"
  }

  # Hardware and network facts are best-effort, like the Linux agent: a quirk on one host must not cost the whole report.
  $system = $null
  try {
    $system = Get-SystemInfo
  } catch {
    Write-Warning "Collecting hardware/network info failed - reporting tasks without it. ($($_.Exception.Message))"
  }

  $payload = [ordered]@{
    hostname    = Get-Fqdn
    os_type     = 'windows'
    reported_at = (Get-Date).ToUniversalTime().ToString("yyyy-MM-dd'T'HH:mm:ss'Z'")
    system      = $system
    tasks       = @($tasks)
  }
  $json = ConvertTo-Json -InputObject $payload -Depth 8 -Compress

  if ($DryRun) {
    ConvertTo-Json -InputObject $payload -Depth 8
    return
  }

  try {
    $null = Send-Report $config $json
  } catch {
    $detail = ''
    try {
      if ($_.Exception.Response) {
        $reader = New-Object System.IO.StreamReader($_.Exception.Response.GetResponseStream())
        $detail = ' ' + $reader.ReadToEnd()
      }
    } catch { }
    Stop-Agent "Report failed: $($_.Exception.Message)$detail"
  }
  Write-Output "Reported $(@($tasks).Count) task(s) successfully."
}

# Dot-sourcing (for tests) defines the functions without running anything.
if ($MyInvocation.InvocationName -ne '.') { Invoke-Agent }