<#
.SYNOPSIS
    - Invoke-WebRequest https://www.microsoft.com/en-us/download/confirmation.aspx?id=41653
    - looks for 'Click Here' (manual download link)
    - loads download into xml variable
    - outputs lists of Azure DC subnets in various formats

.Version 0.5

.DESCRIPTION
   This is based on the script found here: https://gallery.technet.microsoft.com/scriptcenter/Powershell-script-to-6cc03244 modified to output in a couple of useful formats

.SYNTAX
    Get-AzureSubnets -Format <Default|Raw|Fortinet> -Interface <String to use for Fortigate associated-interface>

.NOTES
    File Name    : Get-AzureSubnets.ps1
    Author       : sam.firth@codeblue.co.nz
#>

param ([string]$Format = "Default", [string]$Interface = "all", $OutFile = "" )

#Grab the XML from MS
$AzureIPRangesPage=Invoke-WebRequest -Uri https://www.microsoft.com/en-us/download/confirmation.aspx?id=41653 -Method Get -UseBasicParsing
[XML]$AzureIPRanges=Invoke-RestMethod -uri ($AzureIPRangesPage.Links |Where {$_.outerhtml -like "*Click here*"}).href[0]

#This is the original output from drew's script, this script will give identical output if no arguments are given
Function Default{
    Foreach ($iprange in $Azureipranges.AzurePublicIpAddresses.region)
        {
        Write-Host $iprange.name -ForegroundColor Yellow
        Foreach ($ipsubnet in $iprange.iprange.subnet)
            {
            Write-Host $ipsubnet
            }
        Write-Host "---------------------" -ForegroundColor White
        }
}

#Raw list of subnets, one per line
Function Raw{
    Foreach ($iprange in $Azureipranges.AzurePublicIpAddresses.region)
        {
        Foreach ($ipsubnet in $iprange.iprange.subnet)
            {
            Write-Output $ipsubnet
            }
        }
}

#Output formatted for Fortigate firewalls
Function Fortinet{
    $group = [System.Collections.ArrayList]@()
    Foreach ($iprange in $Azureipranges.AzurePublicIpAddresses.region)
        {
        $count=1
        Write-Output "config firewall address"
        Foreach ($ipsubnet in $iprange.iprange.subnet)
            {
            $name="azure-" + $iprange.name + "-" +  "{0:000}" -f $count
            Write-Output "edit $name"
            Write-Output "set associated-interface ""$Interface"""
            Write-Output "set subnet $ipsubnet"
            Write-Output "next"
            $count ++
            $group += "`"$name`""
            }
        Write-Output "end"
        }

    # Fortigate only accepts 300 Members in a single statement
    $groupnum = 1
    while ($group.Length -gt 1)
        {
        Write-Output "config firewall addrgrp"
        Write-Output "edit ""Azure IPs $groupnum"""
        Write-Output "set member $($group[0..299])"
        Write-Output "next"
        Write-Output "end"
        $edgecase = $group[-1]
        $group = $group[300..($group.Length-1)]
        $groupnum ++
        }

        #This is here in case $group contained exactly 301 items on the last run
        if ($edgecase -ne $group)
            {
            Write-Output "config firewall addrgrp"
            Write-Output "edit ""Azure IPs"""
            Write-Output "set member $group"
            Write-Output "next"
            Write-Output "end"
            }
}

#arg processing
if ($Format -eq "Default") { Default }
elseif ($Format -eq "Fortinet")
    {
    if ($OutFile -ne "" )
        { Fortinet|Out-File -Encoding utf8 $OutFile }
    else { Fortinet }
    }
elseif ($Format -eq "Raw") { Raw }