# This is meant to be used with build.ps1, and is not a standalone script.

function check-FileForChanges
{
	param(
		[Parameter(Mandatory=$true)]
		[string]$path_file
	)

	if (-not (Test-Path $path_file -PathType Leaf)) {
		Write-Error "The provided path is not a valid file: $path_file"
	return $false
	}
	$file_name = Split-Path $path_file -Leaf
	$path_csv  = Join-Path $path_build ($file_name + "_file_hash.csv")

	$csv_file_hash = $null
	if (Test-Path $path_csv) {
		$csv_file_hash = Import-Csv $path_csv | Select-Object -ExpandProperty value
	}

	$current_hash_info = Get-FileHash -Path $path_file -Algorithm MD5
	$current_file_hash = $current_hash_info.Hash

	# Save the current hash to the CSV
	[PSCustomObject]@{
		name  = $path_file
 		value = $current_file_hash
	} | Export-Csv $path_csv -NoTypeInformation

	if ($csv_file_hash -and $csv_file_hash -eq $current_file_hash) {
 		return $false
	} else {
 		return $true
	}
}

# Check to see if the module has changed files since the last build
function check-ModuleForChanges
{
	param( [string]$path_module, [array]$excludes )

	$module_name = split-path $path_module -leaf
	$path_csv    = Join-Path $path_build ("module_" + $module_name + "_hashes.csv")

	$csv_file_hashes = $null
	if ( test-path $path_csv ) {
		$csv_file_hashes = @{}
		import-csv $path_csv | foreach-object {
			$csv_file_hashes[ $_.name ] = $_.value
		}
	}

	$file_hashes = @{}
	get-childitem -path $path_module -file -Exclude $excludes -Recurse | foreach-object {
		$id                 = $_.fullname
		$hash_info          = get-filehash -path $id -Algorithm MD5
		$file_hashes[ $id ] = $hash_info.Hash
	}

	$file_hashes.GetEnumerator() | foreach-object { [PSCustomObject]$_ } |
		export-csv $path_csv -NoTypeInformation

	if ( -not $csv_file_hashes )                         { return $true }
	if ( $csv_file_hashes.Count -ne $file_hashes.Count ) { return $true }

	foreach ( $key in $csv_file_hashes.Keys ) {
		if ( $csv_file_hashes[ $key ] -ne $file_hashes[ $key ] ) {
			return $true
		}
	}
	return $false
}

function mark-ModuleDirty {
	param( [string]$path_module )

	$module_name = split-path $path_module -leaf
	$path_csv    = Join-Path $path_build  ("module_" + $module_name + "_hashes.csv")

	remove-item -Force -Path $path_csv
}