# Set up your TrueNAS server details and API Key
$TrueNASSource = "https://truenas3.kwyjibo.info"
$APIKeySource = "1-JLgbBRp1c0xRlAi5237SFeb7LZnLT23k4K8u95ewqgvTDO8jauv5r6s2MIPH7GmW"  # Replace with your actual API key

# Construct the full API URL
$TrueNASSourceUrl = "$TrueNASSource$Endpoint"

# Set up the headers with the API Key for authentication
$headers = @{
    "Authorization" = "Bearer $APIKeySource"
    "Content-Type"  = "application/json"
}

$Endpoint = "/api/v2.0/zfs/snapshot"
$TrueNASSourceUrl = "$TrueNASSource$Endpoint"
$SnapshotSplat = @{
    Uri                  = $TrueNASSourceUrl
    Headers              = $headers
    Method               = "Get"
    SkipCertificateCheck = $true
}
$Snapshots = Invoke-RestMethod @SnapshotSplat


# report on snapshot sizes
$Report =
$Snapshots |
ForEach-Object {
    [PSCustomObject]@{
        Dataset  = $_.dataset

        UsedGB   = [math]::Round(
            [int64]$_.properties.logicalreferenced.rawvalue / 1GB, 2
        )

        Creation = [DateTimeOffset]::FromUnixTimeSeconds(
            [int64]$_.properties.creation.rawvalue
        ).LocalDateTime
    }
} |
Group-Object Dataset | ForEach-Object {
    $snaps = $_.Group | Sort-Object Creation
    $newest = $snaps[-1]

    [PSCustomObject]@{
        Dataset            = $_.Name

        NewestSnapshotDate = $newest.Creation
        NewestSnapshotGB   = $newest.UsedGB

        SmallestSnapshotGB = ($snaps | Measure-Object UsedGB -Minimum).Minimum
        LargestSnapshotGB  = ($snaps | Measure-Object UsedGB -Maximum).Maximum

        SnapshotCount      = $snaps.Count
        SnapshotOverhead   = ($snaps | Measure-Object UsedGB -Maximum).Maximum - $newest.UsedGB
    }
}

$Report | Where-Object { $_.Dataset -NotLike "*boot*" -and $_.Dataset -notlike "*apps*" } | Format-Table -AutoSize

$Report | Where-Object { $_.Dataset -Like "*Delta*" } | Measure-Object -Property SnapshotOverhead -Sum

$DatasetRoots = @($Report | ForEach-Object { $_.Dataset.split('/')[0] } | Where-Object { $_ -notlike "*boot*" -and $_ -notlike "*nvme*" -and $_ -notlike "*Sidewinder*" } | Select-Object -Unique )

$DatasetRoots | ForEach-Object { 
    $_;
    $Report | Where-Object { $_.Dataset -like "*$_*" } 
 }