<#
.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: uses 49% of 1TB - 512GB free
	✅ Drive D: uses 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 uses $percent% of $(Bytes2String $total) - $(Bytes2String $free) free"
		}
	}
	exit 0 # success
} catch {
	"⚠️ Error in line $($_.InvocationInfo.ScriptLineNumber): $($Error[0])"
	exit 1
}