ConvertTo-HtmlFromMarkdown.ps1

<#
.SYNOPSIS
    Convert a Markdown file to HTML using Pandoc

.PARAMETER File
    The file path of the markdown file

.PARAMETER OutFile
    The resulting html. If this parameter is not specified an HTML file with the same name of the markdown file will be created.

#>
function ConvertTo-HtmlFromMarkdown
{
    param(
        [Parameter(Mandatory=$true, HelpMessage="Path to Markdown file")]
        [ValidateScript({ Test-Path $_ -PathType Leaf})]
        [string]$File,

        [Parameter(HelpMessage="File path to create")]
        #[ValidateScript({ Test-Path $_ -Include "*.html" -PathType Container})]
        [string]$OutFile
    )

    # ensure that the file is an absolute path because pandoc.exe doesn't like powershell relative paths
    $File = (Resolve-Path $File).Path

    # Use pandoc to convert the markdown to Html 
    $pandocArgs =  "`"{0}`" " -f $File
    $pandocArgs += "-f {0} " -f $BloggerSession.PandocMarkdownFormat
    $pandocArgs += "-t {0} " -f $BloggerSession.PandocHtmlFormat

    # add template and toc if template is available
    if (Test-Path $BloggerSession.PandocTemplate) {
        Write-Verbose "Using template"
        $pandocArgs += "--template `"{0}`" --toc " -f $BloggerSession.PandocTemplate
    }
    # add additional command-line arguments
    if ($BloggerSession.PandocAdditionalArgs) {
        Write-Verbose "Using additional args"
        $pandocArgs += "{0} " -f $BloggerSession.PandocAdditionalArgs
    }

    if (!($OutFile))
    {
        $OutFile = Join-Path (Split-Path $File -Parent) ((Split-Path $File -LeafBase) + ".html")
        Write-Verbose "Using OutFile: $OutFile"
    }

    $pandocArgs += "-o `"{0}`" " -f $OutFile

    Write-Verbose ">> pandoc $($pandocArgs)"
    Start-Process pandoc -ArgumentList $pandocArgs -NoNewWindow -Wait

    # Apply additional transforms
    $content = Get-Content $OutFile -Raw
    
    ## TEMP: My blog doesn't support <pre><code> yet, so I'm trimming it out.
    # convert <pre><code> -> <pre>
    $content = $content -replace '<pre(.*)><code>','<pre$1>'
    # convert </code></pre> -> </pre>
    $content = $content -replace '</code></pre>','</pre>'

    Set-Content -Path $OutFile -Value $content

    Remove-Item $OutFile

    return $content
}