Copy-File.psm1

function Copy-File {

    param(

        #Path to the source file
        [Parameter(
            Mandatory = $True,
            Position = 0
        )]
        [String]$SourceFilePath,

        #Path to the destination file
        [Parameter(
            Mandatory = $True,
            Position = 1
        )]
        [String]$DestinationFilePath

    )

    process{

        # Get the file name.
        $SourceFileName = $SourceFilePath.Split("\") | Select-Object -Last 1
        
        # Open the source and destination files.
        $Pref = $ErrorActionPreference
        $ErrorActionPreference = 'Stop'
        $SourceFile = [System.IO.File]::OpenRead($SourceFilePath)
        $DestinationFile = [System.IO.File]::OpenWrite($DestinationFilePath)
        $ErrorActionPreference = $Pref


        # Show a progress bar.
        $Progress = @{
            Activity = "Copying file"
            Status = $SourceFileName
            PercentComplete = 0
        }
        Write-Progress @Progress

        try {

            # Start a timer
            $Stopwatch = [System.Diagnostics.Stopwatch]::StartNew()

            # Create a 4 MiB buffer.
            $Buffer = New-Object -TypeName Byte[] (4194304)

            # Initialize counters to track progress based on the number of bytes written.
            [Long]$CurrentByteCount = 0
            [Long]$TotalBytesRead = 0

            do {
                
                # Read 4 MiB from the source file into the buffer.
                $CurrentByteCount = $SourceFile.Read($Buffer, 0, $Buffer.Length)

                # Write the buffer to the destination file.
                $DestinationFile.Write($Buffer, 0, $CurrentByteCount)

                # Update the counters to track progress
                [Int64]$MillisecondsElapsed = $Stopwatch.ElapsedMilliseconds
                [Int64]$SecondsElapsed = $MillisecondsElapsed/1000
                $TotalBytesRead += $CurrentByteCount
                
                if ( $MillisecondsElapsed -ne 0 ) {
                    [Int64]$BytesPerMillisecond = $TotalBytesRead / $MillisecondsElapsed
                }
                else {
                    [Int64]$BytesPerMillisecond = 0
                }

                #Update the progress bar every MiB
                if ($TotalBytesRead % 1048576 -eq 0) {

                    [Int16]$PercentComplete = $TotalBytesRead / $SourceFile.Length * 100

                    if($PercentComplete -gt 0){

                        [int]$EstimatedSecondsRemaining = $SecondsElapsed / $PercentComplete * 100 - $SecondsElapsed

                    }
                    else {

                        [int]$EstimatedSecondsRemaining = 0

                    }

                    $CopySpeed = '{0:N2}' -f ($BytesPerMillisecond*1000/1048576)
                    $Elapsed = New-TimeSpan -Seconds $SecondsElapsed
                    $Progress = @{
                        Activity = "Copying file"
                        Status = "$PercentComplete% copying '$SourceFileName' @ $CopySpeed MiB/s.  Elapsed: $Elapsed"
                        PercentComplete = $PercentComplete
                        SecondsRemaining = $EstimatedSecondsRemaining
                    }
                    Write-Progress @Progress

                }
            }
            # Loop until the end of the FileStream is reached and 0 bytes are read into the buffer.
            while ($CurrentByteCount -gt 0)

        }
        finally {

            if ( $MillisecondsElapsed -ne 0 ) {

                [Int64]$AverageBytesPerMillisecond = $SourceFile.Length/$MillisecondsElapsed
                Write-Verbose "$SourceFileName ($($SourceFile.Length) B) copied in $($MillisecondsElapsed) Milliseconds at $AverageBytesPerMillisecond B/ms."

            }
            else {

                [Int64]$AverageBytesPerMillisecond = 0

            }

            #Reset the timer.
            $Stopwatch.Reset()

            $AmountCopied = '{0:N2}' -f ($SourceFile.Length/1048576)
            $CopySpeed = '{0:N2}' -f ($AverageBytesPerMillisecond*1000/1048576)
            Write-Host "$SourceFileName ($AmountCopied MiB) copied in $SecondsElapsed seconds at $CopySpeed MiB/s."

            #Close the Source and Destination Files
            $SourceFile.Close()
            $DestinationFile.Close()
        }
        Write-Progress -Activity "Copying file" -Completed

    }
}