#Requires -Version 5.1
<#
    JbTecWiz Support Centre -- generated fix script

    Fault : 169.254.x.x address -- "Unidentified network, no internet"
    Fix   : Confirm the DHCP client is actually running and asking
    Source: https://jbtecwiz.com/support/win-net-apipa

    Run as     : Elevated PowerShell
    Expect     : 10 minutes
    Risk       : low
    Reversible : yes

    WHEN THIS IS THE RIGHT FIX
    Start here. It is two commands and it rules out the cheapest cause.

    HOW TO UNDO IT
    Nothing changed that matters. If the adapter was deliberately static,
    put the address back with New-NetIPAddress.

    This script walks the fix one step at a time and asks before each
    one. Steps with no command are things you do yourself -- it prints
    those and waits. Run with -DryRun to print without executing.

    --------------------------------------------------------------------
    NO WARRANTY - USE AT YOUR OWN RISK

    This script is provided by JbTecWiz as-is and with no warranty of any
    kind, express or implied. You run it entirely at your own risk.

    JbTecWiz accepts no liability for any loss or damage arising from its
    use, including but not limited to data loss, downtime, or configuration
    changes that turn out to be wrong for your system.

    You are responsible for reading this script before running it, for
    satisfying yourself that it suits the machine in front of you, and for
    having a working backup first. Some steps cannot be undone.
    --------------------------------------------------------------------
#>

[CmdletBinding()]
param(
    # Print every step and command without running anything.
    [switch]$DryRun,
    # Do not ask before each step. Read the script first if you use this.
    [switch]$Unattended
)

$ErrorActionPreference = 'Stop'
$script:Failed = 0

function Write-Rule { param([string]$Text)
    Write-Host ''
    Write-Host ('-' * 70) -ForegroundColor DarkGray
    if ($Text) { Write-Host $Text -ForegroundColor Cyan }
}

function Show-Prose { param([string]$Text, [string]$Colour = "Gray")
    if (-not $Text) { return }
    $words = $Text -split "\s+"; $line = "  "
    foreach ($w in $words) {
        if (($line.Length + $w.Length) -gt 74) { Write-Host $line -ForegroundColor $Colour; $line = "  " }
        $line += "$w "
    }
    if ($line.Trim()) { Write-Host $line -ForegroundColor $Colour }
}

function Invoke-Step {
    param(
        [int]$Number, [string]$Do, [string]$Why,
        [scriptblock]$Command, [switch]$Manual, [string]$Shell = "powershell"
    )
    Write-Rule "  Step $Number of 4"
    Show-Prose $Do "White"
    if ($Why) { Write-Host ""; Show-Prose $Why "DarkGray" }

    if ($Manual) {
        Write-Host ''
        Write-Host '  -> Do this yourself, then press Enter to carry on.' -ForegroundColor Yellow
        if (-not $Unattended -and -not $DryRun) { [void](Read-Host) }
        return
    }

    Write-Host ''
    foreach ($l in ($Command.ToString().Trim() -split "`n")) {
        Write-Host ("    " + $l.Trim()) -ForegroundColor Green
    }
    Write-Host ''

    if ($DryRun) { Write-Host "  (dry run -- not executed)" -ForegroundColor DarkGray; return }
    if (-not $Unattended) {
        $a = Read-Host "  Run this step? [Y]es / [S]kip / [Q]uit"
        if ($a -match "^[Qq]") { Write-Host "  Stopped at your request."; exit 0 }
        if ($a -match "^[Ss]") { Write-Host "  Skipped." -ForegroundColor DarkGray; return }
    }
    try { & $Command }
    catch {
        $script:Failed++
        Write-Host ("  Step $Number failed: " + $_.Exception.Message) -ForegroundColor Red
        Show-Prose "The rest of the fix may depend on this. Read the write-up before carrying on." "Red"
        if (-not $Unattended) {
            $c = Read-Host "  Carry on anyway? [y/N]"
            if ($c -notmatch "^[Yy]") { exit 1 }
        }
    }
}

Write-Rule
Write-Host '  169.254.x.x address -- "Unidentified network, no internet"' -ForegroundColor White
Write-Host '  Confirm the DHCP client is actually running and asking' -ForegroundColor Cyan
Write-Host ''
Write-Host '  Risk: low   Reversible   10 minutes'
Write-Host ''
Show-Prose 'No warranty. Use at your own risk - JbTecWiz accepts no liability. Read it before you run it, and have a backup.' 'DarkYellow'
Write-Rule

if (-not $Unattended -and -not $DryRun) {
    $go = Read-Host '  Ready? [y/N]'
    if ($go -notmatch "^[Yy]") { Write-Host "  Nothing was changed."; exit 0 }
}

Invoke-Step -Number 1 -Do 'Check the service and the adapter''s own DHCP setting -- these are two separate things and either one alone will do it.' -Command {
    Get-Service Dhcp | Format-List Name,Status,StartType
    Get-NetIPInterface -AddressFamily IPv4 | Format-Table InterfaceAlias,Dhcp,ConnectionState
}

Invoke-Step -Number 2 -Do 'If the service is stopped, start it and set it back to automatic.' -Command {
    Set-Service Dhcp -StartupType Automatic
    Start-Service Dhcp
}

Invoke-Step -Number 3 -Do 'If the interface shows Dhcp Disabled but should be automatic, turn it back on.' -Why 'A static address left behind by an old fix is a common cause, and the DNS servers have to be reset with it or the machine keeps pointing at a server that no longer exists.' -Command {
    Set-NetIPInterface -InterfaceAlias 'Ethernet' -Dhcp Enabled
    Set-DnsClientServerAddress -InterfaceAlias 'Ethernet' -ResetServerAddresses
}

Invoke-Step -Number 4 -Do 'Force a fresh request and watch what comes back.' -Command {
    cmd.exe /c 'ipconfig /release & ipconfig /renew & ipconfig /all'
}

Write-Rule "  Confirm it worked"
Show-Prose 'ipconfig shows an address in the site''s range with a default gateway, and the gateway answers.' 'White'
Write-Host ''
if (-not $DryRun) {
    Test-NetConnection -InformationLevel Detailed (Get-NetIPConfiguration).IPv4DefaultGateway.NextHop
}

Write-Rule
if ($script:Failed -gt 0) {
    Write-Host ("  Finished with " + $script:Failed + " failed step(s).") -ForegroundColor Yellow
    Show-Prose 'Read the full write-up at https://jbtecwiz.com/support/win-net-apipa' 'Yellow'
} else {
    Write-Host '  Finished.' -ForegroundColor Green
}
Write-Host ''
Show-Prose 'To undo: Nothing changed that matters. If the adapter was deliberately static, put the address back with New-NetIPAddress.' 'DarkGray'
Write-Rule