<#
.SYNOPSIS
    Standardized Zabbix Agent 2 Enterprise Deployer (V2 Fleet Reconciliation)
#>
$ErrorActionPreference = "Stop"

# --- 1. Versioned Idempotency Check ---
$markerDir = "C:\ProgramData\Zabbix"
$marker    = "$markerDir\installed_v3.flag"
$service   = Get-Service -Name "Zabbix Agent 2" -ErrorAction SilentlyContinue

if ((Test-Path $marker) -and ($service -and $service.Status -eq "Running")) {
    exit 0
}

if (-not (Test-Path $markerDir)) { 
    New-Item -ItemType Directory -Path $markerDir -Force | Out-Null
}

# --- 2. Complete Network Subnet Resolution ---
$localIPs = (Get-NetIPAddress -AddressFamily IPv4 | Where-Object { $_.IPAddress -notmatch '^(127\.|169\.254\.)' }).IPAddress

# Node 1: 192.168.100.0/24 through 192.168.105.255
if ($localIPs -match '^192\.168\.(10[0-5])\.') {
    $Location     = "Node1"
    $ZabbixServer = "192.168.101.30"
    $ShareSource  = "\\EHI-DC4.efhosting.sbcit.com.au\Zabbix"
}
# Node 2: 192.168.130.0-135.255 AND 192.168.141.0-145.255
elseif ($localIPs -match '^192\.168\.(13[0-5]|14[1-5])\.') {
    $Location     = "Node2"
    $ZabbixServer = "192.168.130.80"
    $ShareSource  = "\\E2HI-DC5.efhosting.sbcit.com.au\Zabbix"
}
# Brisbane: 192.168.3.0/24 AND 192.168.200.0/24
elseif ($localIPs -match '^192\.168\.(3|200)\.') {
    $Location     = "Brisbane"
    $ZabbixServer = "192.168.3.43"
    $ShareSource  = "\\BI-DC1.efhosting.sbcit.com.au\Zabbix"
}
# Fallback Default to Node 1
else {
    $Location     = "Node1"
    $ZabbixServer = "192.168.101.30"
    $ShareSource  = "\\EHI-DC4.efhosting.sbcit.com.au\Zabbix"
}

# --- 3. Dynamic Hardware and Role Detection ---
$osInfo   = Get-CimInstance -ClassName Win32_OperatingSystem
$Hostname = $env:COMPUTERNAME

# Workstations
if ($osInfo.ProductType -eq 1) {
    $Role = "Workstation"
}
# Primary: SQL servers (e.g., EHPS-SS19L, EHTS-SS16A, BI-SS22B)
elseif ($Hostname -match '-ss\d{2}[a-z]?') {
    $Role = "SQL"
}
# Primary: Application servers (e.g., EHTS-APP38, BI-APP02)
elseif ($Hostname -match '-app\d*') {
    $Role = "Application"
}
# Secondary Fallback: Running standalone default MSSQLSERVER instance on non-standard naming
elseif (Get-Service -Name "MSSQLSERVER" -ErrorAction SilentlyContinue | Where-Object { $_.Status -eq "Running" }) {
    $Role = "SQL"
}
# Default: Member servers, DCs, and general workloads
else {
    $Role = "Application"
}

$HardwareType = if ((Get-CimInstance -ClassName Win32_ComputerSystem).Model -match "Virtual|VMware|KVM|Hyper-V") { 
    "VM" 
} else { 
    "Physical" 
}

$MetadataVal = "Windows:$($HardwareType):$($Location):$($Role)"

# --- 4. File Acquisition with Multi-Tier Fallback (SMB -> Git -> CDN) ---
$SourceZip   = "$ShareSource\zabbix_agent2.zip"
$GitZipUrl   = "https://git.mkau.au/DistractADD/zabbix/raw/branch/main/zabbix_agent2.zip"
$CdnZipUrl   = "https://cdn.zabbix.com/zabbix/binaries/stable/7.4/7.4.11/zabbix_agent2-7.4.11-windows-amd64-openssl-static.zip"
$InstallDir  = "C:\Program Files\Zabbix Agent 2"
$TempZip     = "C:\Temp\zabbix_agent2.zip"

if (-not (Test-Path "C:\Temp")) { 
    New-Item -ItemType Directory -Path "C:\Temp" -Force | Out-Null 
}

# Stop running instances safely before replacing files
Get-Service "Zabbix Agent*" -ErrorAction SilentlyContinue | Stop-Service -Force -ErrorAction SilentlyContinue
Get-Process "zabbix_agent*" -ErrorAction SilentlyContinue | Stop-Process -Force -ErrorAction SilentlyContinue

[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12
$acquired = $false

# Attempt 1: Local DC SMB Share
try {
    if (Test-Path $SourceZip -ErrorAction Stop) {
        Copy-Item -Path $SourceZip -Destination $TempZip -Force -ErrorAction Stop
        if ((Test-Path $TempZip) -and ((Get-Item $TempZip).Length -gt 1000000)) {
            $acquired = $true
        }
    }
}
catch {}

# Attempt 2: Internal Git Server
if (-not $acquired) {
    try {
        Invoke-WebRequest -Uri $GitZipUrl -OutFile $TempZip -UseBasicParsing -TimeoutSec 30 -ErrorAction Stop
        if ((Test-Path $TempZip) -and ((Get-Item $TempZip).Length -gt 1000000)) {
            $acquired = $true
        }
    }
    catch {}
}

# Attempt 3: Official Zabbix CDN Fallback
if (-not $acquired) {
    try {
        Invoke-WebRequest -Uri $CdnZipUrl -OutFile $TempZip -UseBasicParsing -TimeoutSec 60 -ErrorAction Stop
        if ((Test-Path $TempZip) -and ((Get-Item $TempZip).Length -gt 1000000)) {
            $acquired = $true
        }
    }
    catch {
        throw "Critical: Failed to acquire Zabbix Agent archive via SMB, internal Git, or external CDN."
    }
}

if (Test-Path $InstallDir) { 
    Remove-Item $InstallDir -Recurse -Force -ErrorAction SilentlyContinue 
}
New-Item -Path $InstallDir -ItemType Directory -Force | Out-Null

Expand-Archive -Path $TempZip -DestinationPath $InstallDir -Force

$BinDir = Get-ChildItem -Path $InstallDir -Recurse | Where-Object { $_.Name -eq "zabbix_agent2.exe" } | Select-Object -ExpandProperty DirectoryName
if ($BinDir -ne $InstallDir) {
    Copy-Item -Path "$BinDir\*" -Destination $InstallDir -Recurse -Force
}

# --- 5. Generate Standardized Configuration ---
$ConfigContent = @"
LogType=file
LogFile=$InstallDir\zabbix_agent2.log
Server=$ZabbixServer
ServerActive=$ZabbixServer
Hostname=$Hostname
HostMetadata=$MetadataVal
AllowKey=system.run[*]
Timeout=30
ControlSocket=\\.\pipe\agent.sock
"@
Set-Content -Path "$InstallDir\zabbix_agent2.conf" -Value $ConfigContent

# --- 6. Service Registration & Startup ---
$ExePath  = "$InstallDir\zabbix_agent2.exe"
$ConfPath = "$InstallDir\zabbix_agent2.conf"

$existingService = Get-Service -Name "Zabbix Agent 2" -ErrorAction SilentlyContinue

if (-not $existingService) {
    Remove-Item -Path "HKLM:\SYSTEM\CurrentControlSet\Services\EventLog\Application\Zabbix Agent 2" -Recurse -Force -ErrorAction SilentlyContinue
    & $ExePath --config "$ConfPath" --install
    Start-Sleep -Seconds 2
    Start-Service "Zabbix Agent 2"
}
else {
    # Force a restart so any newly written config or metadata loads into RAM immediately
    Restart-Service "Zabbix Agent 2" -Force
}

Set-Service -Name "Zabbix Agent 2" -StartupType Automatic

Start-Service "Zabbix Agent 2" -ErrorAction SilentlyContinue
Set-Service -Name "Zabbix Agent 2" -StartupType Automatic

# --- 7. Firewall Configuration ---
if (-not (Get-NetFirewallRule -DisplayName "Zabbix Agent Inbound" -ErrorAction SilentlyContinue)) {
    New-NetFirewallRule -DisplayName "Zabbix Agent Inbound" -Direction Inbound -LocalPort 10050 -Protocol TCP -Action Allow -Profile Any | Out-Null
}
if (-not (Get-NetFirewallRule -DisplayName "Zabbix Agent Outbound" -ErrorAction SilentlyContinue)) {
    New-NetFirewallRule -DisplayName "Zabbix Agent Outbound" -Direction Outbound -RemotePort 10051 -Protocol TCP -Action Allow -Profile Any | Out-Null
}

# --- 8. Finalize V2 State ---
New-Item -ItemType File -Path $marker -Force | Out-Null
Remove-Item -Path $TempZip -Force -ErrorAction SilentlyContinue