param (
    [Parameter(ParameterSetName="list",Mandatory=$true)] [switch] $list,
    [Parameter(ParameterSetName="create",Mandatory=$true)] [switch] $create,
    [Parameter(ParameterSetName="create",Mandatory=$true)] [string] $volume,
    [Parameter(ParameterSetName="delete",Mandatory=$true)] [switch] $delete,
    [Parameter(ParameterSetName="delete",Mandatory=$true)] [string] $snapshotid
)

$scriptdir = Split-Path $script:MyInvocation.MyCommand.Path
$vshadow = Join-Path $scriptdir "vshadow-2008-r2-x64"

function exiterror($vshadowout)
{
    "fail"
    $vshadowout | Out-String
    exit 1
}

function checkoutput($vshadowout)
{
    foreach ($line in $vshadowout)
    {
        if ($line -imatch ".*ERROR.*")
        {
            exiterror($vshadowout)
        }
    }
}

function listsnaps()
{
    & $vshadow "-q" | Out-String
    if ($LASTEXITCODE -ne 0)
    {
        exiterror($vshadowout)
    }
}

function createsnap([string]$volume)
{
    $vshadowout = @(& $vshadow "-p" $volume)

    checkoutput($vshadowout)
    if ($LASTEXITCODE -ne 0)
    {
        exiterror($vshadowout)
    }
    else
    {
        # Parse vshadow output and print the snapshot id
        foreach ($line in $vshadowout)
        {
            if ($line -match "\* SNAPSHOT ID = ({.*}) \.\.\.")
            {
                $matches[1]
                "success"
                exit 0
            }
        }
    }
}

function deletesnap([string]$snapshotid)
{
    # This will delete all the snapshots
    if ($snapshotid -eq "ALL")
    {
        $vshadowout = @("Y" | & $vshadow "-da")
    }
    else
    {
        $vshadowout = @(& $vshadow "-ds=$snapshotid")
    }

    checkoutput($vshadowout)
    if ($LASTEXITCODE -ne 0)
    {
        exiterror($vshadowout)
    }
    else
    {
        $vshadowout
        "success"
        exit 0
    }
}

switch ($PSCmdlet.ParameterSetName)
{
    "list" { listsnaps }
    "create" { createsnap($volume) }
    "delete" { deletesnap($snapshotid) }
}