param(
  [string]$Origin = 'https://agentchat.innovacors.com',
  [string]$InstallDir = (Join-Path $env:LOCALAPPDATA 'AgentChat')
)

# Instalador de AgentChat para Windows. Uso: irm https://TU-SERVIDOR/install.ps1 | iex
# El servidor sustituye https://agentchat.innovacors.com por su propia URL, asi que no hace falta pasar parametros.
$previousPreference = $ErrorActionPreference
$ErrorActionPreference = 'Stop'

function Get-AgentChatPrioritizedPath {
  param([string]$InstallDir, [string]$PathValue)
  $normalized = $InstallDir.TrimEnd('\')
  $entries = @($PathValue -split ';' | Where-Object { $_ -and $_.TrimEnd('\') -ne $normalized })
  return (@($InstallDir) + $entries) -join ';'
}

try {
  $server = $null
  if (-not [uri]::TryCreate($Origin, [System.UriKind]::Absolute, [ref]$server)) { throw 'Indica el servidor: -Origin https://dominio' }
  if ($server.UserInfo -or $server.Query -or $server.Fragment -or $server.AbsolutePath -ne '/') { throw 'Origin debe ser solo https://dominio, sin ruta, credenciales ni parámetros.' }
  if ($server.Scheme -ne 'https' -and $server.Host -notin @('localhost', '127.0.0.1')) { throw 'Se requiere HTTPS fuera de localhost.' }
  $base = $server.GetLeftPart([System.UriPartial]::Authority).TrimEnd('/')
  $platform = 'windows-amd64'
  $name = 'agentchat.exe'
  # ngrok (plan gratuito) sirve una página intermedia a agentes tipo navegador, como el de PowerShell; esta cabecera la omite y otros servidores la ignoran.
  $headers = @{ 'ngrok-skip-browser-warning' = '1' }
  $checksum = (Invoke-WebRequest -UseBasicParsing -Headers $headers -Uri "$base/client/download/$platform.sha256").Content.Trim()
  $expected = ($checksum -split '\s+')[0].ToLowerInvariant()
  if ($expected -notmatch '^[a-f0-9]{64}$') { throw 'El servidor devolvió un checksum inválido.' }
  $temp = Join-Path ([System.IO.Path]::GetTempPath()) ("agentchat-" + [guid]::NewGuid().ToString('N') + '.exe')
  try {
    Invoke-WebRequest -UseBasicParsing -Headers $headers -Uri "$base/client/download/$platform" -OutFile $temp
    $sha = [System.Security.Cryptography.SHA256]::Create()
    try { $actual = [System.BitConverter]::ToString($sha.ComputeHash([System.IO.File]::ReadAllBytes($temp))).Replace('-', '').ToLowerInvariant() }
    finally { $sha.Dispose() }
    if ($actual -ne $expected) { throw 'El checksum del cliente no coincide; se canceló la instalación.' }
    New-Item -ItemType Directory -Path $InstallDir -Force | Out-Null
    $target = Join-Path $InstallDir $name
    $backup = $target + '.previous'
    if (Test-Path -LiteralPath $backup) { Remove-Item -LiteralPath $backup -Force }
    if (Test-Path -LiteralPath $target) { Move-Item -LiteralPath $target -Destination $backup }
    try { Move-Item -LiteralPath $temp -Destination $target }
    catch {
      if (Test-Path -LiteralPath $backup) { Move-Item -LiteralPath $backup -Destination $target }
      throw
    }
    Write-Output "AgentChat instalado/actualizado: $target"
    # La carpeta Go debe preceder a npm para que `agentchat` resuelva al binario Go; AGENTCHAT_NO_PATH=1 lo evita.
    if (-not $PSBoundParameters.ContainsKey('InstallDir') -and $env:AGENTCHAT_NO_PATH -ne '1') {
      $userPath = Get-AgentChatPrioritizedPath -InstallDir $InstallDir -PathValue ([Environment]::GetEnvironmentVariable('Path', 'User'))
      [Environment]::SetEnvironmentVariable('Path', $userPath, 'User')
      $env:Path = Get-AgentChatPrioritizedPath -InstallDir $InstallDir -PathValue $env:Path
      try {
        if (-not ('AgentChatEnvironmentBroadcast' -as [type])) {
          Add-Type -TypeDefinition 'using System; using System.Runtime.InteropServices; public static class AgentChatEnvironmentBroadcast { [DllImport("user32.dll", CharSet=CharSet.Auto, SetLastError=true)] public static extern IntPtr SendMessageTimeout(IntPtr hWnd, uint msg, IntPtr wParam, string lParam, uint flags, uint timeout, out IntPtr result); }'
        }
        $broadcastResult = [IntPtr]::Zero
        [void][AgentChatEnvironmentBroadcast]::SendMessageTimeout([IntPtr]0xffff, 0x001A, [IntPtr]::Zero, 'Environment', 0x0002, 2000, [ref]$broadcastResult)
      } catch { }
      $first = Get-Command agentchat -ErrorAction SilentlyContinue | Select-Object -First 1
      if ($first -and $first.Source -ne $target) {
        Write-Output "Aviso: PowerShell aún resuelve otro comando 'agentchat' ($($first.Source)). Abre una terminal nueva; el PATH de Go quedó primero."
      } else {
        Write-Output "Ya puedes escribir: agentchat --version (abre una terminal nueva para usarlo)."
      }
    } else {
      Write-Output "Para usarlo: & '$target' --version"
    }
    Write-Output "Para actualizar, vuelve a ejecutar el instalador."
  } finally {
    if (Test-Path -LiteralPath $temp) { Remove-Item -LiteralPath $temp -Force }
  }
} finally {
  $ErrorActionPreference = $previousPreference
}