# Compatible with Windows PowerShell 2.0. Reuse a verified full Python install.
param([switch]$ProbeOnly)

$ErrorActionPreference = 'Stop'
$kitRoot = Split-Path -Parent (Split-Path -Parent $MyInvocation.MyCommand.Path)
$logDirectory = Join-Path $kitRoot 'logs'
[void][IO.Directory]::CreateDirectory($logDirectory)
$runId = Get-Date -Format 'yyyyMMdd-HHmmss-fff'
$setupLog = Join-Path $logDirectory ('setup-' + $runId + '.log')
$utf8 = New-Object System.Text.UTF8Encoding($true)
[IO.File]::WriteAllText($setupLog, '', $utf8)
$env:PYTHONUTF8 = '1'
$env:PYTHONIOENCODING = 'utf-8'
$env:PYTHONHOME = $null
$env:PYTHONPATH = $null
[Console]::OutputEncoding = New-Object System.Text.UTF8Encoding($false)
$targetBits = 32
if ($env:PROCESSOR_ARCHITECTURE -eq 'AMD64' -or $env:PROCESSOR_ARCHITEW6432 -eq 'AMD64') {
    $targetBits = 64
}

function Write-Log([string]$message) {
    Write-Host $message
    [IO.File]::AppendAllText($setupLog, $message + [Environment]::NewLine, $utf8)
}

function Invoke-Logged([string]$executable, [string[]]$arguments) {
    # PowerShell 2 treats native stderr as ErrorRecord; preserve it in the log
    # without mistaking harmless warnings for a failed process.
    $savedPreference = $ErrorActionPreference
    $ErrorActionPreference = 'Continue'
    try {
        $global:LASTEXITCODE = $null
        & $executable @arguments 2>&1 | ForEach-Object { Write-Log ([string]$_) }
        $code = $global:LASTEXITCODE
    } finally {
        $ErrorActionPreference = $savedPreference
    }
    if ($null -eq $code) { return 1 }
    return $code
}

function Test-Python([string]$candidate) {
    if (-not (Test-Path -LiteralPath $candidate -PathType Leaf)) { return $false }
    Write-Log ('Checking Python: ' + $candidate)
    $probe = 'import sys, struct, venv, ensurepip, ssl, sqlite3; print(sys.version); print(sys.executable); sys.exit(0 if sys.version_info[:3] == (3,8,10) and struct.calcsize(''P'')*8 == ' + $targetBits + ' else 3)'
    $code = Invoke-Logged $candidate @('-I', '-X', 'utf8', '-c', $probe)
    if ($code -ne 0) { Write-Log ('Python rejected; exit code: ' + $code) }
    return ($code -eq 0)
}

function Find-Python {
    $manualFile = Join-Path $kitRoot 'python_path.txt'
    if (Test-Path -LiteralPath $manualFile) {
        $manualPath = [IO.File]::ReadAllText($manualFile).Trim().Trim('"')
        if (Test-Python $manualPath) { return $manualPath }
        throw 'python_path.txt must contain the full path to a working Python 3.8.10 of the required architecture.'
    }
    $candidates = New-Object System.Collections.ArrayList
    [void]$candidates.Add((Join-Path $kitRoot '.python38\python.exe'))
    # Python's official installer registers the full interpreter, even when
    # its files live in an older source kit directory.
    foreach ($registryRoot in @('HKCU:\Software\Python\PythonCore',
                                'HKCU:\Software\WOW6432Node\Python\PythonCore',
                                'HKLM:\Software\Python\PythonCore',
                                'HKLM:\Software\WOW6432Node\Python\PythonCore')) {
        foreach ($tag in @('3.8', '3.8-32')) {
            $keyPath = Join-Path $registryRoot ($tag + '\InstallPath')
            try {
                if (Test-Path -LiteralPath $keyPath) {
                    $key = Get-Item -LiteralPath $keyPath
                    $executable = [string]$key.GetValue('ExecutablePath')
                    $directory = [string]$key.GetValue('')
                    if ($executable) { [void]$candidates.Add($executable) }
                    if ($directory) { [void]$candidates.Add((Join-Path $directory 'python.exe')) }
                }
            } catch {
                Write-Log ('Registry lookup skipped: ' + $keyPath + ' : ' + $_.Exception.Message)
            }
        }
    }
    foreach ($candidate in ($candidates | Select-Object -Unique)) {
        if (Test-Python $candidate) { return $candidate }
    }
    return $null
}

try {
    Write-Log ('Setup log: ' + $setupLog)
    Write-Log ('Package: ' + $kitRoot)
    Write-Log ('Windows: ' + [Environment]::OSVersion.VersionString)
    Write-Log ('PowerShell: ' + $PSVersionTable.PSVersion.ToString())
    Write-Log ('Required Python: 3.8.10, ' + $targetBits + '-bit')
    $python = Find-Python
    if ($ProbeOnly) {
        if ($python) { Write-Log ('FOUND reusable Python: ' + $python) }
        else { Write-Log 'No working matching Python was found. No installation was attempted.' }
        Write-Log 'DIAGNOSTIC COMPLETE. No dependencies or system settings were changed.'
        exit 0
    }
    if (-not $python) {
        $installerName = 'python-3.8.10.exe'
        if ($targetBits -eq 64) { $installerName = 'python-3.8.10-amd64.exe' }
        $installer = Join-Path $kitRoot ('installers\' + $installerName)
        if (-not (Test-Path -LiteralPath $installer)) { throw ('Installer missing: ' + $installer) }
        $installerLog = Join-Path $logDirectory ('python-installer-' + $runId + '.log')
        $targetDirectory = Join-Path $kitRoot '.python38'
        Write-Log ('No reusable Python found. Starting installer: ' + $installer)
        Write-Log ('Installer log: ' + $installerLog)
        $installerArgs = @('/passive', '/log', ('"' + $installerLog + '"'),
            'InstallAllUsers=0', ('TargetDir="' + $targetDirectory + '"'),
            'Include_launcher=0', 'InstallLauncherAllUsers=0', 'PrependPath=0',
            'Include_doc=0', 'Include_test=0', 'Include_tcltk=0', 'Shortcuts=0', 'AssociateFiles=0')
        $process = Start-Process -FilePath $installer -ArgumentList $installerArgs -Wait -PassThru -WindowStyle Hidden
        $installerCode = $process.ExitCode
        Write-Log ('Python installer exit code: ' + $installerCode)
        if ($installerCode -eq 3010 -or $installerCode -eq 1641) {
            Write-Log 'Windows requested a restart. Restart the computer and run 01_install_env.cmd again.'
            exit $installerCode
        }
        if ($installerCode -ne 0) {
            throw ('Python installer failed with exit code ' + $installerCode + '. See ' + $installerLog)
        }
        # Maintenance mode may leave Python in its original registered folder.
        $python = Find-Python
        if (-not $python) {
            throw 'Installer returned success but no matching Python was found. Keep logs; do not uninstall the old working environment.'
        }
    }
    Write-Log ('Using existing Python: ' + $python)
    Write-Log 'Keep this Python directory while using the build environment.'
    $buildScript = Join-Path $kitRoot 'win7\build.py'
    $code = Invoke-Logged $python @('-I', '-X', 'utf8', $buildScript, 'setup')
    Write-Log ('Environment setup exit code: ' + $code)
    if ($code -ne 0) { exit $code }
    Write-Log 'SETUP COMPLETE. Run 02_build_exe.cmd next.'
    exit 0
} catch {
    Write-Log ('FAILED: ' + $_.Exception.Message)
    Write-Log ('Details: ' + $_.ScriptStackTrace)
    Write-Log ('Keep the logs folder. Setup log: ' + $setupLog)
    exit 1
}