#requires -version 3.0

Function Get-VMMemoryReport {
<#
.Synopsis
Get a VM memory report
.Description
This command gets memory settings for a given Hyper-V virtual machine. All
memory values are in MB. The command requires the Hyper-V module.
.Parameter Name
The name of the virtual machine or a Hyper-V virtual machine object.
This parameter has an alias of "VM"
.Parameter Computername
The name of the Hyper-V server to query. The default is the local host.
.Example
PS C:\> Get-VM chi-win8 | Get-VMMemoryReport
Name     : CHI-Win8
Dynamic  : True
Assigned : 873
Demand   : 724
Startup  : 768
Minimum  : 512
Maximum  : 1048576
Buffer   : 20
Priority : 50

Get a memory report for a single virtual machine.
.Example
PS C:\> Get-VM | where {$_.state -eq 'running'} | Get-VMMemoryReport | format-table -autosize
Get a memory report for all running virtual machines formatted as a table.
.Example
PS C:\> get-content d:\MyVMs.txt | get-vmmemoryreport | Export-CSV c:\work\VMMemReport.csv -notypeinformation
Get virtual machine names from the text file MyVMs.txt and pipe them to Get-VMMemoryReport.
The results are then exported to a CSV file.
.Example
PS C:\> get-vm | get-vmmemoryreport | Sort Maximum | convertto-html -title "VM Memory Report" -css c:\scripts\blue.css -PreContent "<H2>Hyper-V Memory Report</H2>" -PostContent "<br>An assigned value of 0 means the virtual machine is not running." | out-file c:\work\vmmemreport.htm
Get a memory report for all virtual machines, sorted on the maximum memory
property. This command then creates an HTML report.
.Link
Get-VM
Get-VMMemory
.Inputs
Strings
.Outputs
Custom object
#>

[cmdletbinding()]
Param(
[Parameter(Position=0,Mandatory=$True,HelpMessage="Enter a VM",
ValueFromPipeline=$True)]
[alias("VM")]
[object]$Name,
[ValidateNotNullorEmpty()]
[string]$Computername=$env:COMPUTERNAME
)

Process {
    if ($Name -is [String]) {
        Try {
            $Name = Get-VM -name $Name -ComputerName $computername -ErrorAction Stop
        }
        Catch {
            Write-Warning "Failed to find VM $vm on $computername"
            Return
        }
    } #if
    elseif ($name -isnot [Microsoft.HyperV.PowerShell.VirtualMachine]) {
        Write-Warning "You did not pass a string or a VM object"
        Return
    }

    #get memory values
    $memorysettings = Get-VMMemory -VMName $Name.name -ComputerName $Computername

    #all values are in MB
    $hash=[ordered]@{
        Name = $Name.Name
        Dynamic = $Name.DynamicMemoryEnabled
        Assigned = $Name.MemoryAssigned/1MB
        Demand = $Name.MemoryDemand/1MB
        Startup = $Name.MemoryStartup/1MB
        Minimum = $Name.MemoryMinimum/1MB
        Maximum = $Name.MemoryMaximum/1MB
        Buffer =  $memorysettings.buffer
        Priority = $memorysettings.priority
    }
    
    #write the new object to the pipeline
    New-Object -TypeName PSObject -Property $hash
    
} #process
} #end Get-VMMemoryReport