param(
    [Parameter(Mandatory = $true)]
    [string]$Root
)

$ErrorActionPreference = "Stop"
$Root = $Root.Trim().Trim('"').TrimEnd("\")
$Root = (Resolve-Path -LiteralPath $Root).Path
$Venv = Join-Path $Root ".venv"
$Python = Join-Path $Venv "Scripts\python.exe"
$Pip = Join-Path $Venv "Scripts\pip.exe"
$Frontend = Join-Path $Root "frontend"
$Runtime = Join-Path $Root ".runtime"

function Write-Step($Message) {
    Write-Host ""
    Write-Host $Message -ForegroundColor Cyan
}

function Test-Port([int]$Port) {
    $client = [Net.Sockets.TcpClient]::new()
    try {
        $client.Connect("127.0.0.1", $Port)
        return $true
    }
    catch {
        return $false
    }
    finally {
        $client.Close()
    }
}

function Find-FreePort([int]$StartPort) {
    $port = $StartPort
    while (Test-Port $port) { $port++ }
    return $port
}

function Get-LivePid([string]$PidFile) {
    if (!(Test-Path $PidFile)) { return $null }
    $raw = (Get-Content $PidFile -ErrorAction SilentlyContinue | Select-Object -First 1)
    if (!$raw) { return $null }
    $process = Get-Process -Id ([int]$raw) -ErrorAction SilentlyContinue
    if ($process) { return [int]$raw }
    Remove-Item $PidFile -Force -ErrorAction SilentlyContinue
    return $null
}

function Stop-Tree([int]$Id) {
    Get-CimInstance Win32_Process | Where-Object { $_.ParentProcessId -eq $Id } | ForEach-Object { Stop-Tree $_.ProcessId }
    Stop-Process -Id $Id -Force -ErrorAction SilentlyContinue
}

function Invoke-Checked([scriptblock]$Command, [string]$ErrorMessage) {
    & $Command
    if ($LASTEXITCODE -ne 0) { throw $ErrorMessage }
}

Write-Host ""
Write-Host "============================================"
Write-Host "  Knowledge Station - Plataforma completa"
Write-Host "============================================"

New-Item -ItemType Directory -Force -Path $Runtime | Out-Null

$legacyPid = Join-Path $Runtime "server.pid"
if (Test-Path $legacyPid) {
    $legacyRaw = Get-Content $legacyPid -ErrorAction SilentlyContinue | Select-Object -First 1
    if ($legacyRaw) { Stop-Tree ([int]$legacyRaw) }
    Remove-Item $legacyPid -Force -ErrorAction SilentlyContinue
}

if (!(Test-Path $Python)) {
    Write-Step "Preparando Python por primera vez..."
    & py -m venv $Venv 2>$null
    if ($LASTEXITCODE -ne 0) {
        & python -m venv $Venv
    }
    if (!(Test-Path $Python)) {
        throw "No se pudo preparar Python. Instala Python 3.12 o superior."
    }
}

$EnvFile = Join-Path $Root ".env"
$EnvExample = Join-Path $Root ".env.example"
if (!(Test-Path $EnvFile)) {
    Write-Step "Creando configuracion local .env..."
    Copy-Item $EnvExample $EnvFile
    Write-Host "Agrega tus API keys en .env para audio, video u OCR." -ForegroundColor Yellow
}

Write-Step "Verificando dependencias de Python..."
Invoke-Checked { & $Python -m pip install --upgrade pip --disable-pip-version-check | Out-Null } "No se pudo actualizar pip."
Invoke-Checked { & $Pip install -r (Join-Path $Root "requirements.txt") } "No se pudieron instalar dependencias de Python."

Write-Step "Verificando Node.js..."
$node = Get-Command node -ErrorAction SilentlyContinue
$npm = Get-Command npm.cmd -ErrorAction SilentlyContinue
if (!$npm) { $npm = Get-Command npm -ErrorAction SilentlyContinue }
if (!$node -or !$npm) {
    throw "Node.js LTS no esta instalado o npm no esta disponible. Instala Node.js desde https://nodejs.org/."
}

if (!(Test-Path (Join-Path $Frontend "node_modules"))) {
    Write-Step "Instalando dependencias del frontend. Esto puede tardar unos minutos..."
    Invoke-Checked { & $npm.Source install --prefix $Frontend } "No se pudieron instalar dependencias del frontend."
}
else {
    Write-Host "Dependencias del frontend encontradas."
}

$BackendPidFile = Join-Path $Runtime "backend.pid"
$FrontendPidFile = Join-Path $Runtime "frontend.pid"
$BackendPortFile = Join-Path $Runtime "backend.port"
$FrontendPortFile = Join-Path $Runtime "frontend.port"

Write-Step "Iniciando backend..."
$backendPid = Get-LivePid $BackendPidFile
if ($backendPid) {
    $backendPort = Get-Content $BackendPortFile -ErrorAction SilentlyContinue | Select-Object -First 1
    if (!$backendPort) { $backendPort = 8000 }
    Write-Host "Backend ya estaba activo en puerto $backendPort."
}
else {
    $backendPort = Find-FreePort 8000
    $backend = Start-Process -FilePath $Python -ArgumentList @("-m", "uvicorn", "backend.app.main:app", "--host", "127.0.0.1", "--port", [string]$backendPort, "--reload") -WorkingDirectory $Root -PassThru
    Set-Content $BackendPidFile $backend.Id
    Set-Content $BackendPortFile $backendPort
    Write-Host "Backend iniciado en puerto $backendPort."
}

$ApiUrl = "http://127.0.0.1:$backendPort"
Set-Content (Join-Path $Frontend ".env.local") "NEXT_PUBLIC_API_URL=$ApiUrl"

Write-Step "Iniciando frontend..."
$frontendPid = Get-LivePid $FrontendPidFile
if ($frontendPid) {
    $frontendPort = Get-Content $FrontendPortFile -ErrorAction SilentlyContinue | Select-Object -First 1
    if (!$frontendPort) { $frontendPort = 3000 }
    Write-Host "Frontend ya estaba activo en puerto $frontendPort."
}
else {
    $frontendPort = Find-FreePort 3000
    $nextDir = Join-Path $Frontend ".next"
    if (Test-Path $nextDir) {
        Get-ChildItem $nextDir -Recurse -Force -ErrorAction SilentlyContinue | ForEach-Object {
            try { $_.Attributes = "Normal" } catch {}
        }
        Remove-Item $nextDir -Recurse -Force -ErrorAction SilentlyContinue
    }
    $frontend = Start-Process -FilePath $npm.Source -ArgumentList @("run", "dev", "--", "-p", [string]$frontendPort) -WorkingDirectory $Frontend -PassThru
    Set-Content $FrontendPidFile $frontend.Id
    Set-Content $FrontendPortFile $frontendPort
    Write-Host "Frontend iniciado en puerto $frontendPort."
}

$AppUrl = "http://127.0.0.1:$frontendPort"
Set-Content (Join-Path $Runtime "last.url") $AppUrl

Start-Sleep -Seconds 4
Write-Host ""
Write-Host "Plataforma abierta:" -ForegroundColor Green
Write-Host "Frontend: $AppUrl"
Write-Host "API:      $ApiUrl"
Write-Host ""
Start-Process $AppUrl