param([string]$Action)
$ErrorActionPreference = 'Stop'
$interactiveMenu = [string]::IsNullOrWhiteSpace($Action)
# User-requested delay after an interactive menu action finishes.
$menuCloseDelaySeconds = 5
$launcherExitCode = 0
Set-Location -LiteralPath $PSScriptRoot

function Merge-Settings($Base, $Override) {
    foreach ($property in $Override.PSObject.Properties) {
        $existing = $Base.PSObject.Properties[$property.Name]
        if ($existing -and $property.Value -is [pscustomobject] -and $existing.Value -is [pscustomobject]) {
            Merge-Settings $existing.Value $property.Value
        } else {
            $Base | Add-Member -MemberType NoteProperty -Name $property.Name -Value $property.Value -Force
        }
    }
}
function Resolve-ProjectPath([string]$Path) {
    if ([IO.Path]::IsPathRooted($Path)) { return [IO.Path]::GetFullPath($Path) }
    return [IO.Path]::GetFullPath((Join-Path $PSScriptRoot $Path))
}
function Stop-ProjectServer([string]$Name) {
    $target = Resolve-ProjectPath ($Name + '.exe')
    Get-Process -Name $Name -ErrorAction SilentlyContinue | ForEach-Object {
        if ($_.Path -and [string]::Equals($_.Path, $target, [StringComparison]::OrdinalIgnoreCase)) {
            Stop-Process -Id $_.Id -ErrorAction Stop
            if (-not $_.WaitForExit(5000)) { throw "Server did not stop: $target" }
        }
    }
}
function Start-ProjectServer([string]$Name) {
    $path = Resolve-ProjectPath ($Name + '.exe')
    if (-not (Test-Path -LiteralPath $path -PathType Leaf)) { throw "$Name is not built. Run build first." }
    Stop-ProjectServer $Name
    $process = Start-Process -FilePath $path -WorkingDirectory $PSScriptRoot -WindowStyle Normal -PassThru
    if ($process.WaitForExit(250)) { throw "$Name exited with code $($process.ExitCode). Run .\$Name.exe in a terminal to inspect the startup error." }
    Write-Host "Started $Name (PID $($process.Id)) in its own visible console."
}
function Build-Servers {
    $go = $env:GAC_GO_COMMAND
    if ([string]::IsNullOrWhiteSpace($go)) { $go = $settings.launcher.go_command }
    if ([string]::IsNullOrWhiteSpace($go)) { throw 'Set launcher.go_command or GAC_GO_COMMAND.' }
    $command = Get-Command -Name $go -CommandType Application -ErrorAction Stop
    foreach ($name in @('gameserver', 'sdkserver')) {
        $next = Resolve-ProjectPath ($name + '-go.next.exe')
        & $command.Source build -o $next ('./cmd/' + $name)
        if ($LASTEXITCODE -ne 0) { throw "Build failed: $name. Existing binaries were not replaced." }
    }
    foreach ($name in @('gameserver-go', 'sdkserver-go')) {
        $next = Resolve-ProjectPath ($name + '.next.exe')
        $target = Resolve-ProjectPath ($name + '.exe')
        Stop-ProjectServer $name
        Move-Item -LiteralPath $next -Destination $target -Force
    }
    Write-Host 'Build successful. Binaries are in the project root.'
}
function Start-External([string]$Setting, [string]$EnvironmentName) {
    $path = [Environment]::GetEnvironmentVariable($EnvironmentName)
    if ([string]::IsNullOrWhiteSpace($path)) { $path = $settings.launcher.$Setting }
    if ([string]::IsNullOrWhiteSpace($path)) {
        Write-Host "Servers started. Set launcher.$Setting or $EnvironmentName to launch the external program."
        return
    }
    $path = Resolve-ProjectPath $path
    if (-not (Test-Path -LiteralPath $path -PathType Leaf)) { throw "Configured program does not exist: $path" }
    $directory = Split-Path -Parent $path
    if ([IO.Path]::GetExtension($path) -in @('.bat', '.cmd')) {
        Start-Process -FilePath 'cmd.exe' -ArgumentList ('/d /c ""' + $path + '""') -WorkingDirectory $directory -WindowStyle Hidden
    } else {
        Start-Process -FilePath $path -WorkingDirectory $directory
    }
}
try {
    $configPath = $env:GAC_CONFIG
    if ([string]::IsNullOrWhiteSpace($configPath)) { $configPath = 'server.json' }
    $configPath = Resolve-ProjectPath $configPath
    $env:GAC_CONFIG = $configPath
    $settings = Get-Content -LiteralPath $configPath -Raw | ConvertFrom-Json
    $localPath = [IO.Path]::ChangeExtension($configPath, 'local.json')
    if (Test-Path -LiteralPath $localPath) {
        Merge-Settings $settings (Get-Content -LiteralPath $localPath -Raw | ConvertFrom-Json)
    }
    $variables = @{
        client_version='GAC_CLIENT_VERSION'; game_host='GAC_GAME_HOST'; game_port='GAC_GAME_PORT';
        sdk_host='GAC_SDK_HOST'; sdk_port='GAC_SDK_PORT'; public_game_host='GAC_PUBLIC_GAME_HOST';
        public_sdk_url='GAC_PUBLIC_SDK_URL'
    }
    foreach ($key in $variables.Keys) {
        $value = [Environment]::GetEnvironmentVariable($variables[$key])
        if ($null -ne $value) { $settings | Add-Member -MemberType NoteProperty -Name $key -Value $value -Force }
    }
    foreach ($key in @('game_port','sdk_port')) {
        $port = 0
        if (-not [int]::TryParse([string]$settings.$key, [ref]$port) -or $port -lt 1 -or $port -gt [uint16]::MaxValue) {
            throw "$key must be a port between 1 and $([uint16]::MaxValue)."
        }
    }
    foreach ($key in @('client_version','game_host','sdk_host','public_game_host','public_sdk_url')) {
        if ([string]::IsNullOrWhiteSpace($settings.$key)) { throw "Missing setting: $key" }
    }
    foreach ($key in @('game_host','sdk_host','public_game_host')) {
        if ([string]$settings.$key -match '[/\\\s]') { throw "Invalid host: $key" }
    }
    $uri = $null
    if (-not [Uri]::TryCreate($settings.public_sdk_url, [UriKind]::Absolute, [ref]$uri) -or $uri.Scheme -notin @('http','https') -or $uri.Query -or $uri.Fragment -or $uri.UserInfo) {
        throw 'public_sdk_url must be an HTTP(S) base URL.'
    }
    if ($Action -eq 'check') { Write-Host 'Configuration valid.'; exit 0 }
    if ([string]::IsNullOrWhiteSpace($Action)) {
        Write-Host "GaC hkrpg GO | Client $($settings.client_version)"
        Write-Host "Game UDP $($settings.game_host):$($settings.game_port) | SDK HTTP $($settings.sdk_host):$($settings.sdk_port)"
        Write-Host '[1] Build, start servers and game (default)'
        Write-Host '[2] Start servers | [3] SDK only | [4] Game server only'
        Write-Host '[5] Start servers and proxy | [6] Build only | [7] Exit | [8] Stop servers'
        $Action = Read-Host 'Select'
        if ([string]::IsNullOrWhiteSpace($Action)) { $Action = '1' }
    }
    switch ($Action.Trim().ToLowerInvariant()) {
        { $_ -in @('1','game') } { Build-Servers; Start-ProjectServer 'sdkserver-go'; Start-ProjectServer 'gameserver-go'; Start-External 'client_path' 'GAC_CLIENT_PATH'; break }
        { $_ -in @('2','servers') } { Start-ProjectServer 'sdkserver-go'; Start-ProjectServer 'gameserver-go'; break }
        { $_ -in @('3','sdk') } { Start-ProjectServer 'sdkserver-go'; break }
        { $_ -in @('4','gs') } { Start-ProjectServer 'gameserver-go'; break }
        { $_ -in @('5','proxy') } { Start-ProjectServer 'sdkserver-go'; Start-ProjectServer 'gameserver-go'; Start-External 'proxy_path' 'GAC_PROXY_PATH'; break }
        { $_ -in @('6','build') } { Build-Servers; break }
        '7' { break }
        { $_ -in @('8','stop') } { Stop-ProjectServer 'sdkserver-go'; Stop-ProjectServer 'gameserver-go'; break }
        default { throw "Unknown action: $Action" }
    }
} catch {
    Write-Host "[ERROR] $($_.Exception.Message)" -ForegroundColor Red
    $launcherExitCode = 1
}
if ($interactiveMenu) {
    Write-Host "Launcher closes in $menuCloseDelaySeconds seconds. Server windows stay open."
    Start-Sleep -Seconds $menuCloseDelaySeconds
}
exit $launcherExitCode