param(
    [ValidateSet('apk', 'appbundle', 'windows', 'web', 'ios', 'ipa', 'macos', 'linux')]
    [string]$Target = 'apk',
    [string]$FlutterCommand = 'flutter',
    [string[]]$FlutterArguments = @()
)

$ErrorActionPreference = 'Stop'
$projectRoot = Split-Path -Parent $PSScriptRoot
$pubspecPath = Join-Path $projectRoot 'pubspec.yaml'
$lockPath = Join-Path $projectRoot '.release-build.lock'
$buildLock = $null
$originalBytes = $null
$updated = $false
$succeeded = $false

try {
    # Hold an exclusive lock; the OS releases it even if PowerShell is closed.
    $buildLock = [System.IO.File]::Open(
        $lockPath, [System.IO.FileMode]::OpenOrCreate,
        [System.IO.FileAccess]::ReadWrite, [System.IO.FileShare]::None
    )
    foreach ($argument in $FlutterArguments) {
        if ($argument -match '^--(build-name|build-number|debug|profile|config-only)(=|$)') {
            throw "Argument $argument ist im versionierten Release-Build nicht erlaubt."
        }
    }
    $originalBytes = [System.IO.File]::ReadAllBytes($pubspecPath)
    $source = [System.Text.Encoding]::UTF8.GetString($originalBytes)
    $versionMatch = [regex]::Match($source, '(?m)^version:\s*(\d+)\.(\d+)\.(\d+)\+(\d+)[ \t]*\r?$')
    if (-not $versionMatch.Success) {
        throw 'In pubspec.yaml wird eine Version wie 1.0.0+1 erwartet.'
    }
    $patch = [long]::Parse($versionMatch.Groups[3].Value) + 1
    $build = [long]::Parse($versionMatch.Groups[4].Value) + 1
    $nextVersion = '{0}.{1}.{2}+{3}' -f $versionMatch.Groups[1].Value, $versionMatch.Groups[2].Value, $patch, $build
    $replacement = "version: $nextVersion"
    if ($versionMatch.Value.EndsWith("`r")) { $replacement += "`r" }
    $nextSource = $source.Remove($versionMatch.Index, $versionMatch.Length).Insert($versionMatch.Index, $replacement)
    [System.IO.File]::WriteAllText($pubspecPath, $nextSource, [System.Text.UTF8Encoding]::new($false))
    $updated = $true

    Push-Location $projectRoot
    try {
        Write-Host "Release $nextVersion ($Target) wird erstellt ..."
        $global:LASTEXITCODE = 0
        & $FlutterCommand build $Target --release @FlutterArguments
        if ($LASTEXITCODE -ne 0) {
            throw "Flutter-Build fehlgeschlagen (Exitcode $LASTEXITCODE)."
        }
        $succeeded = $true
        Write-Host "Release $nextVersion erfolgreich. Die Version wurde in pubspec.yaml gespeichert."
    } finally {
        Pop-Location
    }
} finally {
    if ($updated -and -not $succeeded) {
        [System.IO.File]::WriteAllBytes($pubspecPath, $originalBytes)
        Write-Host 'Build nicht erfolgreich: Bisherige Version wiederhergestellt.'
    }
    if ($null -ne $buildLock) { $buildLock.Dispose() }
}