Elizium.Klassy

0.0.3

Elizium.Klassy.psm1

Set-StrictMode -Version 1.0

function New-ShellOperant {
  [OutputType([Operant])]
  param(
    [Parameter()]
    [string]$BaseFilename,

    [Parameter()]
    [string]$Directory,

    [Parameter()]
    [ValidateSet('UndoRename')]
    [string]$Operant = 'UndoRename',

    [Parameter()]
    [ValidateSet('PoShShell')]
    [string]$Shell = 'PoShShell'
  )
  [string]$filename = "{0}_{1}.ps1" -f $BaseFilename, $(get-CurrentTime);
  [string]$fullPath = Join-Path -Path $Directory -ChildPath $filename;

  [Shell]$shell = if ($Shell -eq 'PoShShell') {
    [PoShShell]::new($fullPath);
  }
  else {
    $null;
  }

  [Operant]$operant = if ($shell) {
    if ($Operant -eq 'UndoRename') {
      [UndoRename]::new($shell);
    }
    else {
      $null;
    }
  }
  else {
    $null;
  }

  return $operant;
}

function get-CurrentTime {
  param(
    [string]$Format = 'dd-MMM-yyyy_HH-mm-ss'
  )
  return Get-Date -Format $Format;
}

# These classes in the same file because of the issues of class reference in modules.
# We can't add a using module statement in files that reference these classes. Class
# references via import module only works with classes defined in other modules. Any
# class defined inside Shelly can't be accessed across different files.
#
class Shell {
  [string]$FullPath;
  [System.Text.StringBuilder] $_builder = [System.Text.StringBuilder]::new()

  Shell([string]$path) {
    $this.FullPath = $path;
  }

  [void] persist() {
    throw [System.Management.Automation.MethodInvocationException]::new(
      'Abstract method not implemented (Shell.persist)');
  }
}

class PoShShell : Shell {
  PoShShell([string]$path): base($path) {
  }

  [void] rename ([string]$from, [string]$to) {
    [string]$toFilename = [System.IO.Path]::GetFileName($to)
    [void]$this._builder.AppendLine($("Rename-Item -LiteralPath '$from' -NewName '$toFilename'"));
  }

  [void] persist([string]$content) {
    Set-Content -LiteralPath $this.FullPath -Value $content;
  }
}

class Operant {

}

class Undo : Operant {
  [Shell]$Shell;
  [System.Collections.ArrayList]$Operations = [System.Collections.ArrayList]::new();

  Undo([Shell]$shell) {
    $this.Shell = $shell;
  }

  [void] alert([PSCustomObject]$operation) {
    # User should pass in a PSCustomObject with Directory, From and To fields
    #
    [void]$this.Operations.Add($operation);
  }

  [void] persist() {
    throw [System.Management.Automation.MethodInvocationException]::new(
      'Abstract method not implemented (Undo.persist)');
  }
}

class UndoRename : Undo {
  UndoRename([Shell]$shell) : base($shell) {

  }

  [string] generate() {
    [string]$result = if ($this.Operations.count -gt 0) {
      $($this.Operations.count - 1)..0 | ForEach-Object {
        [PSCustomObject]$operation = $this.Operations[$_];

        [string]$toPath = Join-Path -Path $operation.Directory -ChildPath $operation.To;
        $this.Shell.rename($toPath, $operation.From);
      }

      $this.Shell._builder.ToString();
    }
    else {
      [string]::Empty;
    }

    return $result;
  }

  [void] finalise() {
    $this.Shell.persist($this.generate());
  }
}
Export-ModuleMember -Function New-ShellOperant