[CmdletBinding()]
param(
    [string]$PythonPath,
    [string]$FfmpegPath,
    [string]$NodePath,
    [switch]$RefreshDependencies,
    [switch]$SkipRegistration,
    [switch]$HelperOnly
)
$ErrorActionPreference = 'Stop'
$taskProjectRoot = $PSScriptRoot
$taskRuntime = Join-Path $taskProjectRoot '.runtime'
New-Item -ItemType Directory -Path $taskRuntime -Force | Out-Null
$taskSavedConfig = $null
if (Test-Path -LiteralPath (Join-Path $taskRuntime 'config.json')) {
    try { $taskSavedConfig = Get-Content -LiteralPath (Join-Path $taskRuntime 'config.json') -Raw | ConvertFrom-Json } catch {}
}

function Install-PrivatePython {
    $taskPythonRoot = Join-Path $taskRuntime 'python'
    $taskPythonInstaller = Join-Path $taskRuntime 'python-setup.exe'
    [Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12
    Write-Host 'Installing Python from python.org...'
    Invoke-WebRequest -UseBasicParsing -Uri 'https://www.python.org/ftp/python/3.14.8/python-3.14.8-amd64.exe' -OutFile $taskPythonInstaller
    $taskSignature = Get-AuthenticodeSignature -LiteralPath $taskPythonInstaller
    if ($taskSignature.Status -ne 'Valid') { throw 'Python installer signature verification failed.' }
    $taskArguments = @('/quiet','InstallAllUsers=0',"TargetDir=`"$taskPythonRoot`"",'PrependPath=0','Include_launcher=0','Include_test=0','Include_doc=0','Shortcuts=0','AssociateFiles=0')
    $taskInstalled = Start-Process -FilePath $taskPythonInstaller -ArgumentList $taskArguments -WindowStyle Hidden -Wait -PassThru
    if ($taskInstalled.ExitCode -notin @(0,3010)) { throw 'Python installation failed.' }
    return (Join-Path $taskPythonRoot 'python.exe')
}

function Find-Tool([string]$ExplicitPath, [string]$Name) {
    if ($ExplicitPath) {
        if (-not (Test-Path -LiteralPath $ExplicitPath -PathType Leaf)) { throw "File not found: $ExplicitPath" }
        return (Resolve-Path -LiteralPath $ExplicitPath).Path
    }
    $taskCommand = Get-Command $Name -ErrorAction SilentlyContinue | Select-Object -First 1
    if ($taskCommand) { return $taskCommand.Source }
    return $null
}

if (-not $PythonPath) {
    $taskExistingPython = Join-Path $env:USERPROFILE '.agent-reach-venv\Scripts\python.exe'
    $taskProjectPython = Join-Path $taskRuntime 'venv\Scripts\python.exe'
    if ($taskSavedConfig.python -and (Test-Path -LiteralPath $taskSavedConfig.python)) { $PythonPath = $taskSavedConfig.python }
    elseif (Test-Path -LiteralPath $taskExistingPython) { $PythonPath = $taskExistingPython }
    elseif (Test-Path -LiteralPath $taskProjectPython) { $PythonPath = $taskProjectPython }
    else {
        $taskSystemPython = Find-Tool '' 'python.exe'
        if (-not $taskSystemPython -or $taskSystemPython -like '*\WindowsApps\*') { $taskSystemPython = Install-PrivatePython }
        & $taskSystemPython -c 'import sys; assert sys.version_info >= (3,10)'
        if ($LASTEXITCODE -ne 0) { $taskSystemPython = Install-PrivatePython }
        & $taskSystemPython -m venv (Join-Path $taskRuntime 'venv')
        if ($LASTEXITCODE -ne 0) { throw 'Python virtual environment creation failed.' }
        $PythonPath = $taskProjectPython
    }
}
$PythonPath = Find-Tool $PythonPath 'python.exe'
& $PythonPath -c 'import sys; assert sys.version_info >= (3,10), "Python 3.10+ required"'
if ($LASTEXITCODE -ne 0) { throw 'Unsupported Python version.' }
& $PythonPath -c 'import yt_dlp, yt_dlp_ejs'
if ($LASTEXITCODE -ne 0 -or $RefreshDependencies) {
    & $PythonPath -m pip install --disable-pip-version-check --upgrade -r (Join-Path $taskProjectRoot 'requirements.txt')
    if ($LASTEXITCODE -ne 0) { throw 'Installing yt-dlp failed.' }
}
if (-not $FfmpegPath -and $taskSavedConfig.ffmpeg -and (Test-Path -LiteralPath $taskSavedConfig.ffmpeg)) { $FfmpegPath = $taskSavedConfig.ffmpeg }
$taskFfmpeg = Find-Tool $FfmpegPath 'ffmpeg.exe'
$taskFfprobe = if ($taskFfmpeg) { Join-Path (Split-Path -Parent $taskFfmpeg) 'ffprobe.exe' } else { $null }
if (-not $taskFfprobe -or -not (Test-Path -LiteralPath $taskFfprobe)) { $taskFfprobe = Find-Tool '' 'ffprobe.exe' }
if (-not $NodePath) {
    if ($taskSavedConfig.node -and (Test-Path -LiteralPath $taskSavedConfig.node)) { $NodePath = $taskSavedConfig.node }
    $taskPortableNode = Join-Path $env:USERPROFILE '.agent-reach\tools\node-v24.21.0-win-x64\node.exe'
    if (-not $NodePath -and (Test-Path -LiteralPath $taskPortableNode)) { $NodePath = $taskPortableNode }
}
$taskNode = Find-Tool $NodePath 'node.exe'

$taskUtf8 = [System.Text.UTF8Encoding]::new($false)
$taskConfig = @{ python=$PythonPath; ffmpeg=$taskFfmpeg; ffprobe=$taskFfprobe; node=$taskNode }
[System.IO.File]::WriteAllText((Join-Path $taskRuntime 'config.json'), ($taskConfig | ConvertTo-Json), $taskUtf8)
Push-Location -LiteralPath $taskProjectRoot
try {
    if (-not $taskFfmpeg -or -not $taskFfprobe) {
        & $PythonPath -m host.dependencies ffmpeg
        if ($LASTEXITCODE -ne 0) { throw 'Installing FFmpeg failed.' }
    }
    $taskNodeGood = $false
    if ($taskNode) {
        $taskNodeVersion = & $taskNode --version
        $taskNodeGood = $taskNodeVersion -match '^v(\d+)\.' -and [int]$Matches[1] -ge 22
    }
    if (-not $taskNodeGood) {
        & $PythonPath -m host.dependencies node
        if ($LASTEXITCODE -ne 0) { throw 'Installing Node.js failed.' }
    }
} finally { Pop-Location }
$taskLauncherPath = Join-Path $taskRuntime 'launch-host.cmd'
$taskMainPath = Join-Path $taskProjectRoot 'host\main.py'
$taskLauncher = "@echo off`r`nchcp 65001 >nul`r`nset PYTHONIOENCODING=utf-8`r`nset PYTHONUTF8=1`r`n`"$PythonPath`" -u `"$taskMainPath`" %*`r`n"
[System.IO.File]::WriteAllText($taskLauncherPath, $taskLauncher, $taskUtf8)
$taskExtensionId = 'ndnoeiaecgmjnjneekaeapeecmmjheli'
$taskHostName = 'com.youtubedl.native'
$taskNativeManifestPath = Join-Path $taskRuntime 'native-host.json'
$taskNativeManifest = @{ name=$taskHostName; description='YouTubeDL download and NVIDIA NVENC helper'; path=$taskLauncherPath; type='stdio'; allowed_origins=@("chrome-extension://$taskExtensionId/") }
[System.IO.File]::WriteAllText($taskNativeManifestPath, ($taskNativeManifest | ConvertTo-Json), $taskUtf8)
if (-not $SkipRegistration) {
    foreach ($taskBrowser in @('Google\Chrome','Microsoft\Edge','Chromium')) {
        $taskRegistryPath = "HKCU:\Software\$taskBrowser\NativeMessagingHosts\$taskHostName"
        New-Item -Path $taskRegistryPath -Force | Out-Null
        Set-Item -Path $taskRegistryPath -Value $taskNativeManifestPath
    }
}
Write-Host $(if ($SkipRegistration) { 'Native helper files prepared.' } else { 'Native helper registered for Edge and Chrome (current user).' })
Write-Host "Extension ID: $taskExtensionId"
if ($HelperOnly) {
    Write-Host 'Return to YouTubeDL settings and press Start.'
} else {
    Write-Host "Extension folder: $(Join-Path $taskProjectRoot 'extension')"
    Write-Host 'Open edge://extensions or chrome://extensions, enable Developer mode, and load the extension folder.'
    Write-Host 'Then refresh the YouTube page. The Download and Settings buttons are next to Subscribe.'
}