<#
  .SYNOPSIS
  Upload files to Azure blob storage.

  .DESCRIPTION
  Wrapper around AzCopy.exe to upload files to Azure blob storage with retry logic.

  .PARAMETER Path
  The folder containing data to upload. (Example: C:\)

  .PARAMETER KeyFile
   Azure storage account access key, encoded as a SecureString object and exported to XML with Export-CliXml. (Example: C:\keyfile.xml)

  .PARAMETER Destination
  The URL of the storage account with container name. (Example: https://mystorageaccount.blob.core.windows.net/mycontainer)

  .PARAMETER AzCopyBinPath
  The full file path to AzCopy.exe. -- https://aka.ms/azcopy

  .PARAMETER BlobType
  The type of blob to upload. Must be either block, page, or append. (Default: block)

  .PARAMETER LoopCount
  The number of times to attempt the upload. (Default: 100)

  .PARAMETER Pattern
  The file pattern of files to upload. (Example: fileprefix*.txt)

  .LINK
  https://aka.ms/azcopy
#>

Param(
  [Parameter(Mandatory=$False,
             HelpMessage='The path to a directory to upload')]
  [Alias('Source')]
  [String]
  $Path = 'C:\Users\Public\Documents\Hyper-V\Virtual hard disks',

  [Parameter(Mandatory=$False,
             HelpMessage='File path to a storage account key SecureString object exported as a Powershell XML')]
  [Alias('Key')]
  [String]
  $KeyFile = 'C:\keyfile.xml',

  [Parameter(Mandatory=$False,
             HelpMessage='The destination URL')]
  [Alias('Dest')]
  [String]
  $Destination = 'https://mystorageaccount.blob.core.windows.net/mycontainer',

  [Parameter(Mandatory=$False,
             HelpMessage='The full file path to AzCopy.exe')]
  [String]
  $AzCopyBinPath = [System.IO.Path]::Combine(${Env:ProgramFiles(x86)}, 'Microsoft SDKs', 'Azure', 'AzCopy', 'AzCopy.exe'),

  [Parameter(Mandatory=$False,
             HelpMessage='The blob type: either block, page, or append (default: block)')]
  [ValidateSet('append', 'block', 'page')] 
  [String]
  $BlobType = 'block',

  [Parameter(Mandatory=$False,
             HelpMessage='The number of times to attempt to upload')]
  [UInt16]
  $LoopCount = 100,

  [Parameter(Mandatory=$False,
             HelpMessage='The pattern of file or files to upload')]
  [Alias('Filter')]
  [String]
  $Pattern = '*.vhdx'
)
$ErrorActionPreference = 'Stop'
Set-StrictMode -Version 2

Set-Variable -Option ReadOnly -Name time_str -Value 'yyyy-MM-dd HH:mm:ss.ffffff'

Function LogError {
  Param([String] $Message)
  Write-Error ("{0} {1}" -f ((Get-Date).ToString($time_str), $Message))
  Return
}

Function Log {
  Param([String] $Message)
  Write-Host ("{0} {1}" -f ((Get-Date).ToString($time_str), $Message))
  Return
}

Function LogTimeSpan {
  Param([String] $Name, [TimeSpan] $TimeSpan)
  $hours = [System.Math]::Floor($TimeSpan.TotalMinutes/60)
  Log ("{0} time: {1:0} hr {2:0} min ({3:0} sec)" -f ($Name.PadRight(5,' '), $hours, $TimeSpan.Minutes, $TimeSpan.TotalSeconds))
  Return
}

Function Summary {
  Param()
  $out = 0
  $sum = 0
  $files = @(Get-Childitem -Path $Path -Filter $Pattern -ErrorAction SilentlyContinue | Where-Object { -not $_.PSIsContainer })
  foreach ($f in $files) { $sum += $f.Length }

  if (1 -gt $out) { $out = $sum / [Math]::Pow(2,40); $unit = 'TiB' }
  if (1 -gt $out) { $out = $sum / [Math]::Pow(2,30); $unit = 'GiB' }
  if (1 -gt $out) { $out = $sum / [Math]::Pow(2,20); $unit = 'MiB' }
  if (1 -gt $out) { $out = $sum / [Math]::Pow(2,10); $unit = 'KiB' }

  Log ("uploading {0:0.0} {1} in {2} file(s)" -f ($out, $unit, $files.Count))
  Return
}

Function Main {
  Param()

  if (-not (Test-Path -Path $Path)) {
    LogError ("source dir {0} not found" -f ($Path))
    Return
  }

  if (-not (Test-Path -Path $AzCopyBinPath)) {
    LogError 'AzCopy.exe not found -- https://aka.ms/azcopy'
    Return
  }

  $ts_copy   = New-Object -TypeName System.TimeSpan
  $sleep_sec = 30

  # key file created like so:
  # $sec_str = ConvertTo-SecureString -AsPlainText -Force -String 'REMOVED'
  # Export-CliXml -InputObject $sec_str -Force -Encoding 'UTF8' -Path 'keyfile.xml'
  $sa_key_sec_str = Import-CliXml -Path (Get-Item -Path $KeyFile).FullName
  $sa_key_sec_ptr = [System.Runtime.InteropServices.Marshal]::SecureStringToBSTR($sa_key_sec_str)
  $sa_key         = [System.Runtime.InteropServices.Marshal]::PtrToSTringBSTR($sa_key_sec_ptr)

  $azcopy_args = @('/V', '/Y', '/XO', "/BlobType:$BlobType", "/Source:`"$Path`"", "/Dest:$Destination", "/DestKey:$sa_key", "/Pattern:$Pattern")
  Clear-Variable -Name sa_key
  [System.Runtime.InteropServices.Marshal]::ZeroFreeBSTR($sa_key_sec_ptr)

  Summary
  Log 'start'
  $copy_start = Get-Date

  :AZCOPYLOOP for ($i = 0; $i -lt $LoopCount; $i++) {
    Log ("run {0}" -f ((1+$i)))
    if (0 -lt $i) {
      Log ("sleep {0} sec" -f ($sleep_sec)) # AzCopy 5.2.0 has an automatic sleep built-in
      Start-Sleep -Seconds $sleep_sec
    }

    # wait for any other running instances of AzCopy to stop
    :WAITLOOP while ($True) {
      $procs = @(Get-Process -Name ([System.IO.Path]::GetFileNameWithoutExtension($AzCopyBinPath)) -ErrorAction SilentlyContinue)
      if (0 -eq $procs.Count) { break :WAITLOOP }
      $procs[0].WaitForExit()
    }
    $loop_start = Get-Date

    # "This cmdlet generates a System.Diagnostics.Process object, if you
    # specify the PassThru parameter. Otherwise, this cmdlet does not
    # return any output."
    # <URL:https://docs.microsoft.com/en-us/powershell/module/Microsoft.PowerShell.Management/Start-Process?view=powershell-5.1>
    $proc = Start-Process -FilePath $AzCopyBinPath -ArgumentList $azcopy_args -PassThru
    Log ("pid {0} waiting" -f ($proc.Id))
    $proc.WaitForExit()
    Log ("pid {0} exitcode {1}" -f ($proc.Id, $proc.ExitCode))

    $ts = (Get-Date) - $loop_start
    if (0 -gt $ts.Ticks) {
      LogError '$ts < 0: time travel has been invented'
      Return
    }
    LogTimeSpan -Name 'run' -TimeSpan $ts
    $ts_copy += $ts
    if (0 -eq $proc.ExitCode) { break :AZCOPYLOOP } # AzCopy v5.2.0 exits 0 on success
  }

  $ts_total = (Get-Date) - $copy_start
  if (0 -gt $ts_total.Ticks) {
    LogError '$ts_total < 0: time travel has been invented'
    Return
  }

  Log 'end'
  LogTimeSpan -Name 'copy'  -TimeSpan $ts_copy
  LogTimeSpan -Name 'total' -TimeSpan $ts_total
  Return
}
. Main
Exit