#Requires -Version 5.1
<#
.SYNOPSIS
    Baut den NexusRMM Agent für Windows (und optional Linux/amd64)
.DESCRIPTION
    Sucht die Go-Binary, baut den Agent für Windows und optional für Linux.
    Erstellt eine Standard-Konfigurationsdatei, wenn noch keine vorhanden ist.
.PARAMETER Linux
    Baut zusätzlich eine Linux-Binary (nexus-agent-linux).
.EXAMPLE
    .\build-agent.ps1
    .\build-agent.ps1 -Linux
#>
param(
    [switch]$Linux
)

$ErrorActionPreference = "Stop"
$AgentDir  = "D:\001_Projekte\IT_Tool\Agent"
$ConfigFile = "$AgentDir\nexus-agent.yaml"

# ---------------------------------------------------------------------------
# Helper
# ---------------------------------------------------------------------------
function Write-Step { param($msg) Write-Host "`n==> $msg" -ForegroundColor Cyan }
function Write-OK   { param($msg) Write-Host "    [OK] $msg"     -ForegroundColor Green }
function Write-Warn { param($msg) Write-Host "    [!]  $msg"     -ForegroundColor Yellow }
function Write-Fail { param($msg) Write-Host "    [FEHLER] $msg" -ForegroundColor Red }

function Format-FileSize {
    param([long]$Bytes)
    if ($Bytes -ge 1MB) { return "{0:N1} MB" -f ($Bytes / 1MB) }
    return "{0:N0} KB" -f ($Bytes / 1KB)
}

# ---------------------------------------------------------------------------
# 1. Go-Binary finden
# ---------------------------------------------------------------------------
Write-Step "Suche Go-Installation..."

# Kandidaten: expliziter Standardpfad zuerst, dann PATH
$goCandidates = @(
    "C:\Program Files\Go\bin\go.exe",
    "C:\Go\bin\go.exe"
)

$goExe = $null

foreach ($candidate in $goCandidates) {
    if (Test-Path $candidate) {
        $goExe = $candidate
        break
    }
}

if ($null -eq $goExe) {
    # Fallback: PATH
    $fromPath = Get-Command "go" -ErrorAction SilentlyContinue
    if ($null -ne $fromPath) {
        $goExe = $fromPath.Source
    }
}

if ($null -eq $goExe) {
    Write-Fail "Go wurde nicht gefunden. Bitte Go installieren (https://go.dev/dl/) oder PATH prüfen."
    exit 1
}

$goVersion = & $goExe version
Write-OK "Go gefunden: $goExe"
Write-OK "Version:     $goVersion"

# ---------------------------------------------------------------------------
# 2. Ins Agent-Verzeichnis wechseln
# ---------------------------------------------------------------------------
if (-not (Test-Path $AgentDir)) {
    Write-Fail "Agent-Verzeichnis nicht gefunden: $AgentDir"
    exit 1
}

Push-Location $AgentDir
try {

    # -----------------------------------------------------------------------
    # 3. Windows-Build
    # -----------------------------------------------------------------------
    Write-Step "Baue Windows-Binary (nexus-agent.exe)..."

    $env:GOOS   = "windows"
    $env:GOARCH = "amd64"
    $env:CGO_ENABLED = "0"

    $winOut = "$AgentDir\nexus-agent.exe"

    & $goExe build -ldflags="-s -w" -o $winOut ./cmd/agent/
    if ($LASTEXITCODE -ne 0) {
        Write-Fail "Windows-Build fehlgeschlagen."
        exit 1
    }

    $winSize = (Get-Item $winOut).Length
    Write-OK "Windows-Binary erstellt:"
    Write-OK "  Pfad:  $winOut"
    Write-OK "  Groesse: $(Format-FileSize $winSize)"

    # -----------------------------------------------------------------------
    # 4. Linux-Build (optional)
    # -----------------------------------------------------------------------
    if ($Linux) {
        Write-Step "Baue Linux-Binary (nexus-agent-linux)..."

        $env:GOOS   = "linux"
        $env:GOARCH = "amd64"
        $env:CGO_ENABLED = "0"

        $linuxOut = "$AgentDir\nexus-agent-linux"

        & $goExe build -ldflags="-s -w" -o $linuxOut ./cmd/agent/
        if ($LASTEXITCODE -ne 0) {
            Write-Fail "Linux-Build fehlgeschlagen."
            exit 1
        }

        $linuxSize = (Get-Item $linuxOut).Length
        Write-OK "Linux-Binary erstellt:"
        Write-OK "  Pfad:    $linuxOut"
        Write-OK "  Groesse: $(Format-FileSize $linuxSize)"
    } else {
        Write-Warn "Linux-Build übersprungen. Mit -Linux Parameter ausführen um Linux-Binary zu bauen."
    }

} finally {
    # Umgebungsvariablen zurücksetzen
    Remove-Item Env:\GOOS        -ErrorAction SilentlyContinue
    Remove-Item Env:\GOARCH      -ErrorAction SilentlyContinue
    Remove-Item Env:\CGO_ENABLED -ErrorAction SilentlyContinue
    Pop-Location
}

# ---------------------------------------------------------------------------
# 5. Konfigurationsdatei erstellen (nur wenn nicht vorhanden)
# ---------------------------------------------------------------------------
Write-Step "Prüfe Konfigurationsdatei..."

if (Test-Path $ConfigFile) {
    Write-OK "Konfiguration bereits vorhanden: $ConfigFile (wird nicht überschrieben)"
} else {
    Write-Warn "Keine Konfigurationsdatei gefunden. Erstelle Standard-Konfiguration..."

    $defaultConfig = @"
# NexusRMM Agent Konfiguration
server_address: localhost:5001
heartbeat_interval: 30
tls_enabled: false
mesh_enabled: false
mesh_central_url: ""
"@

    Set-Content -Path $ConfigFile -Value $defaultConfig -Encoding UTF8
    Write-OK "Konfiguration erstellt: $ConfigFile"
}

# ---------------------------------------------------------------------------
# 6. Zusammenfassung
# ---------------------------------------------------------------------------
Write-Host ""
Write-Host "Build abgeschlossen." -ForegroundColor Green
Write-Host "Agent starten:     .\Agent\nexus-agent.exe" -ForegroundColor Yellow
Write-Host "Konfiguration:     $ConfigFile" -ForegroundColor Yellow