# Copyright 2012 Aaron Jensen
# 
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
# 
#     http://www.apache.org/licenses/LICENSE-2.0
# 
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

function Get-IPAddress
{
    <#
    .SYNOPSIS
    Gets the IP addresses in use on the local computer.

    .DESCRIPTION
    The .NET API for getting all the IP addresses in use on the current computer's network intefaces is pretty cumbersome.  If all you care about is getting the IP addresses in use on the current computer, and you don't care where/how they're used, use this function.

    If you *do* care about network interfaces, then you'll have to do it yourself using the [System.Net.NetworkInformation.NetworkInterface](http://msdn.microsoft.com/en-us/library/System.Net.NetworkInformation.NetworkInterface.aspx) class's [GetAllNetworkInterfaces](http://msdn.microsoft.com/en-us/library/system.net.networkinformation.networkinterface.getallnetworkinterfaces.aspx) static method, e.g.

        [Net.NetworkInformation.NetworkInterface]::GetNetworkInterfaces()

    .LINK
    http://stackoverflow.com/questions/1069103/how-to-get-my-own-ip-address-in-c

    .OUTPUTS
    System.Net.IPAddress.

    .EXAMPLE
    Get-IPAddress

    Returns all the IP addresses in use on the local computer, IPv4 *and* IPv6.

    .EXAMPLE
    Get-IPAddress -V4

    Returns just the IPv4 addresses in use on the local computer.

    .EXAMPLE
    Get-IPADdress -V6

    Retruns just the IPv6 addresses in use on the local computer.
    #>
    [CmdletBinding(DefaultParameterSetName='NonFiltered')]
    param(
        [Parameter(ParameterSetName='Filtered')]
        [Switch]
        # Return just IPv4 addresses.
        $V4,

        [Parameter(ParameterSetName='Filtered')]
        [Switch]
        # Return just IPv6 addresses.
        $V6
    )

    [Net.NetworkInformation.NetworkInterface]::GetAllNetworkInterfaces() | 
        Where-Object { $_.OperationalStatus -eq 'Up' -and $_.NetworkInterfaceType -ne 'Loopback' } | 
        ForEach-Object { $_.GetIPProperties() } | 
        Select-Object -ExpandProperty UnicastAddresses  | 
        Select-Object -ExpandProperty Address |
        Where-Object {
            if( $PSCmdlet.ParameterSetName -eq 'NonFiltered' )
            {
                return ($_.AddressFamily -eq 'InterNetwork' -or $_.AddressFamily -eq 'InterNetworkV6')
            }

            if( $V4 -and $_.AddressFamily -eq 'InterNetwork' )
            {
                return $true
            }

            if( $V6 -and $_.AddressFamily -eq 'InterNetworkV6' )
            {
                return $true
            }

            return $false
        }
}