# UseMyPhone — wireless touchpad helper
#
# A web page cannot move your mouse pointer. This small script can, so it is
# the piece that turns your phone into a real trackpad for this computer.
#
# What it does:  connects to your own UseMyPhone session with the code shown
#                on your screen, waits for you to approve it there, and then
#                moves the pointer / clicks / scrolls / types exactly what
#                your phone sends.
# What it never does: read your screen, read your files, send anything out,
#                or run in the background. Close the window and it is gone.
#
# It needs no install and no administrator rights. Read it before you run it —
# it is short on purpose.

param(
  [string]$Code = '',
  [string]$Server = 'https://usemyphone.com'
)

$ErrorActionPreference = 'Stop'
[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12

Write-Host ''
Write-Host '  UseMyPhone — wireless touchpad' -ForegroundColor Green
Write-Host '  Your phone becomes a trackpad for this computer.'
Write-Host ''

if (-not $Code) {
  $Code = Read-Host '  Enter the 6-digit code shown on your screen'
}
$Code = ($Code -replace '[^0-9]', '')
if ($Code.Length -ne 6) { Write-Host '  That is not a 6-digit code.' -ForegroundColor Red; exit 1 }

# ── Windows input ─────────────────────────────────────────────────────────
# mouse_event and keybd_event are the small, stable corner of user32 for this:
# relative movement, buttons, wheel, and layout-aware typing, with none of the
# struct marshalling SendInput needs.
Add-Type -Namespace UMP -Name Input -MemberDefinition @'
[DllImport("user32.dll")]
public static extern void mouse_event(uint dwFlags, int dx, int dy, int dwData, System.IntPtr dwExtraInfo);
[DllImport("user32.dll")]
public static extern void keybd_event(byte bVk, byte bScan, uint dwFlags, System.IntPtr dwExtraInfo);
[DllImport("user32.dll")]
public static extern short VkKeyScanW(char ch);
'@

$MOUSEEVENTF_MOVE       = 0x0001
$MOUSEEVENTF_LEFTDOWN   = 0x0002
$MOUSEEVENTF_LEFTUP     = 0x0004
$MOUSEEVENTF_RIGHTDOWN  = 0x0008
$MOUSEEVENTF_RIGHTUP    = 0x0010
$MOUSEEVENTF_MIDDLEDOWN = 0x0020
$MOUSEEVENTF_MIDDLEUP   = 0x0040
$MOUSEEVENTF_WHEEL      = 0x0800
$KEYEVENTF_KEYUP        = 0x0002

# Named keys the phone's keyboard row can send. Anything else arrives as text.
$VK = @{
  'enter' = 0x0D; 'back' = 0x08; 'tab' = 0x09; 'esc' = 0x1B; 'space' = 0x20;
  'up' = 0x26; 'down' = 0x28; 'left' = 0x25; 'right' = 0x27;
  'home' = 0x24; 'end' = 0x23; 'pgup' = 0x21; 'pgdn' = 0x22;
  'del' = 0x2E; 'win' = 0x5B; 'f5' = 0x74; 'f11' = 0x7A
}

function Send-Key([int]$vk, [bool]$shift) {
  if ($shift) { [UMP.Input]::keybd_event(0x10, 0, 0, [IntPtr]::Zero) }
  [UMP.Input]::keybd_event([byte]$vk, 0, 0, [IntPtr]::Zero)
  [UMP.Input]::keybd_event([byte]$vk, 0, $KEYEVENTF_KEYUP, [IntPtr]::Zero)
  if ($shift) { [UMP.Input]::keybd_event(0x10, 0, $KEYEVENTF_KEYUP, [IntPtr]::Zero) }
}

function Send-Text([string]$text) {
  foreach ($ch in $text.ToCharArray()) {
    $scan = [UMP.Input]::VkKeyScanW($ch)
    if ($scan -eq -1) { continue }          # not on this keyboard layout
    Send-Key ($scan -band 0xFF) ((($scan -shr 8) -band 1) -eq 1)
  }
}

# One pad event → one Windows action.
function Invoke-PadEvent($e) {
  switch ($e.t) {
    'm' { [UMP.Input]::mouse_event($MOUSEEVENTF_MOVE, [int]$e.x, [int]$e.y, 0, [IntPtr]::Zero) }
    'w' { [UMP.Input]::mouse_event($MOUSEEVENTF_WHEEL, 0, 0, [int]$e.d, [IntPtr]::Zero) }
    'l' { [UMP.Input]::mouse_event($MOUSEEVENTF_LEFTDOWN, 0, 0, 0, [IntPtr]::Zero)
          [UMP.Input]::mouse_event($MOUSEEVENTF_LEFTUP, 0, 0, 0, [IntPtr]::Zero) }
    'r' { [UMP.Input]::mouse_event($MOUSEEVENTF_RIGHTDOWN, 0, 0, 0, [IntPtr]::Zero)
          [UMP.Input]::mouse_event($MOUSEEVENTF_RIGHTUP, 0, 0, 0, [IntPtr]::Zero) }
    'i' { [UMP.Input]::mouse_event($MOUSEEVENTF_MIDDLEDOWN, 0, 0, 0, [IntPtr]::Zero)
          [UMP.Input]::mouse_event($MOUSEEVENTF_MIDDLEUP, 0, 0, 0, [IntPtr]::Zero) }
    'dd' { [UMP.Input]::mouse_event($MOUSEEVENTF_LEFTDOWN, 0, 0, 0, [IntPtr]::Zero) }   # drag start
    'du' { [UMP.Input]::mouse_event($MOUSEEVENTF_LEFTUP, 0, 0, 0, [IntPtr]::Zero) }     # drag end
    'k' { if ($VK.ContainsKey([string]$e.k)) { Send-Key $VK[[string]$e.k] $false } }
    'x' { Send-Text ([string]$e.s) }
  }
}

# ── connect ───────────────────────────────────────────────────────────────
$wsUrl = ($Server -replace '^http', 'ws') + '/ws'
Write-Host "  Connecting to $Server …"

$ws = New-Object System.Net.WebSockets.ClientWebSocket
# The server admits only clients from its own pages, so identify as one.
$ws.Options.SetRequestHeader('Origin', $Server)
$cts = New-Object System.Threading.CancellationTokenSource
try {
  $ws.ConnectAsync([Uri]$wsUrl, $cts.Token).Wait()
} catch {
  Write-Host "  Could not reach $Server — check your internet connection." -ForegroundColor Red
  exit 1
}

function Send-Json($obj) {
  $json = $obj | ConvertTo-Json -Compress
  $bytes = [Text.Encoding]::UTF8.GetBytes($json)
  $seg = New-Object System.ArraySegment[byte] -ArgumentList @(,$bytes)
  $ws.SendAsync($seg, [System.Net.WebSockets.WebSocketMessageType]::Text, $true, $cts.Token).Wait()
}

Send-Json @{ t = 'helper'; code = $Code; name = $env:COMPUTERNAME }

$buffer = New-Object byte[] 16384
$seg = New-Object System.ArraySegment[byte] -ArgumentList @(,$buffer)
$approved = $false
$events = 0

Write-Host '  Waiting for you to approve this helper on your screen…' -ForegroundColor Yellow

while ($ws.State -eq 'Open') {
  $task = $ws.ReceiveAsync($seg, $cts.Token)
  try { $task.Wait() } catch { break }
  $result = $task.Result
  if ($result.MessageType -eq [System.Net.WebSockets.WebSocketMessageType]::Close) { break }
  $text = [Text.Encoding]::UTF8.GetString($buffer, 0, $result.Count)

  try { $msg = $text | ConvertFrom-Json } catch { continue }

  switch ($msg.t) {
    'helper-wait' { }
    'helper-no' {
      Write-Host "  Refused: $($msg.reason)" -ForegroundColor Red
      $ws.Dispose(); exit 1
    }
    'helper-ok' {
      $approved = $true
      Write-Host ''
      Write-Host '  Connected. Your phone is now a trackpad.' -ForegroundColor Green
      Write-Host '  Close this window at any time to stop it instantly.'
      Write-Host ''
    }
    'pad' {
      if (-not $approved) { continue }
      foreach ($e in $msg.a) { Invoke-PadEvent $e }
      $events += $msg.a.Count
      if ($events % 200 -lt $msg.a.Count) { Write-Host "`r  active · $events movements" -NoNewline }
    }
    'expired' { Write-Host '  That session has ended.' -ForegroundColor Yellow; break }
  }
}

Write-Host ''
Write-Host '  Touchpad stopped. Nothing is left running.' -ForegroundColor Yellow
try { $ws.Dispose() } catch { }