<#
.SYNOPSIS
	Checks the drive space
.DESCRIPTION
	This PowerShell script queries the free space of all drives and prints it.
.PARAMETER minLevel
	Specifies the minimum warning level (10GB by default)
.EXAMPLE
	PS> ./check-drives.ps1
	✅ Drive C: at 49% of 1TB - 512GB free
	✅ Drive D: at 84% of 4TB - 641GB free
.LINK
	https://github.com/fleschutz/PowerShell
.NOTES
	Author: Markus Fleschutz | License: CC0
#>

param([int64]$minLevel = 10) # 10 GB minimum

function Bytes2String { param([int64]$number)
        if ($number -lt 1KB) { return "$number bytes" }
        if ($number -lt 1MB) { return '{0:N0}KB' -f ($number / 1KB) }
        if ($number -lt 1GB) { return '{0:N0}MB' -f ($number / 1MB) }
        if ($number -lt 1TB) { return '{0:N0}GB' -f ($number / 1GB) }
        if ($number -lt 1PB) { return '{0:N0}TB' -f ($number / 1TB) }
        return '{0:N0}GB' -f ($number / 1PB)
}

try {
	Write-Progress "Querying drives..."
	$drives = Get-PSDrive -PSProvider FileSystem
	$minLevel *= 1GB
	Write-Progress -completed " "
	foreach($drive in $drives) {
		$details = (Get-PSDrive $drive.Name)
		if ($IsLinux) { $name = $drive.Name } else { $name = $drive.Name + ":" }
		[int64]$free = $details.Free
 		[int64]$used = $details.Used
		[int64]$total = ($used + $free)

		if ($total -eq 0) {
			Write-Host "✅ Drive $name is empty"
		} elseif ($free -eq 0) {
			Write-Host "⚠️ Drive $name with $(Bytes2String $total) is full"
		} elseif ($free -lt $minLevel) {
			Write-Host "⚠️ Drive $name with $(Bytes2String $total) is nearly full, $(Bytes2String $free) free"
		} else {
			[int64]$percent = ($used * 100) / $total
			Write-Host "✅ Drive $name at $percent% of $(Bytes2String $total) - $(Bytes2String $free) free"
		}
	}
	exit 0 # success
} catch {
	"⚠️ Error in line $($_.InvocationInfo.ScriptLineNumber): $($Error[0])"
	exit 1
}