param(
    [parameter(mandatory=$true)]
    [string]$seriesId,
    [switch]$completeSeries,
    [string]$seriesName,
    [string]$outputFolder=(Resolve-Path .),
    [int]$startChapter=1,
    [int]$endChapter=$startChapter
    
)

### Init ###
$baseUrl = "https://www.mangareader.net"

$usedVarsDownloadChapter = @("chapterNr",
    "outputPath",
    "chapterUrl",
    "chapterBaseHtml",
    "chapterPattern",
    "chapterPages",
    "chapterPage")

$usedVarsForeachChapterPage = @("pageUrl",
    "pageFormat",
    "pageHtml")

$usedVarsCurrentChapter = @("chapterFormat",
    "chapterPath",
    "ebookName")

### Functions ###
Function DownloadChapter($chapterNr,$outputPath){
    $chapterUrl = "${seriesUrl}/${chapterNr}"

    $chapterBaseHtml = Invoke-WebRequest -UseBasicParsing -Uri $chapterUrl

    # Download first image, continue afterwards
    Invoke-WebRequest -UseBasicParsing -Uri $chapterBaseHtml.Images.src -OutFile (Join-Path -Path $outputPath -ChildPath "01.jpg") #"${outputPath}\01.jpg"

    # evaluate regex
    $chapterPattern = '(?<=<option value=\"\/' + [Regex]::Escape("${seriesId}") + '\/' + [Regex]::Escape("${chapterNr}") + '\/)\d+(?=\">\d+<\/option>)'

    $chapterPages = $chapterBaseHtml.Content | Select-String -Pattern $chapterPattern -AllMatches | ForEach-Object {$_.Matches} | ForEach-Object {$_.Value}

    foreach($chapterPage in $chapterPages) {
        $pageUrl = "${chapterUrl}/${chapterPage}"

        # Download every page and save in target file
        $pageFormat = ('{0:d2}' -f [int]$chapterPage)
        $pageHtml = Invoke-WebRequest -UseBasicParsing -Uri $pageUrl
        Invoke-WebRequest -UseBasicParsing -Uri $pageHtml.Images.src -OutFile (Join-Path -Path $outputPath -ChildPath "${pageFormat}.jpg") #"${outputPath}\${pageFormat}.jpg"

        Remove-Variable $usedVarsForeachChapterPage
    }

    Remove-Variable $usedVarsDownloadChapter
}

### Main ###
$currentChapter = $startChapter
$seriesUrl = "${baseUrl}/${seriesId}"
$basePath = (Resolve-Path $outputFolder)
$seriesPath = (Join-Path -Path $basePath -ChildPath $seriesId)

If (!(Test-Path $seriesPath)) {
    New-Item -Path $seriesPath -ItemType Directory
}

if ($completeSeries) {
    $seriesHtml = Invoke-WebRequest -UseBasicParsing -Uri $seriesUrl
    $seriesHtmlCut1 = $seriesHtml.Content.Substring($seriesHtml.Content.IndexOf("<table id=`"listing`">"))
    $seriesHtmlCut2 = $seriesHtmlCut1.Substring(0, ($seriesHtmlCut1.IndexOf("</table>")-1))
    $seriesPattern = '(?<=<a href=\"\/' + [Regex]::Escape("${seriesId}") +'\/)\d+(?=\">)'
    $seriesListing = $seriesHtmlCut2 | Select-String -Pattern $seriesPattern -AllMatches | % {$_.Matches} | % {$_.Value}
    $endChapter = $seriesListing.Count
}

While ($currentChapter -le $endChapter) {
    [string]$chapterFormat = ('{0:d3}' -f [int]$currentChapter)
    [string]$chapterPath = (Join-Path -Path $seriesPath -ChildPath $chapterFormat)

    If (!(Test-Path $chapterPath)) {
        New-Item -ItemType Directory -Path $chapterPath
    }

    DownloadChapter -chapterNr $currentChapter -outputPath $chapterPath

    if ($seriesName) {
        $ebookName = "${seriesName} - Chapter ${chapterFormat}"
    }
    else {
        $ebookName = "${chapterFormat}"
    }

    # Dependency on ImageMagick 'convert.exe' being in $PATH
    convert "${chapterPath}\*.jpg" "${seriesPath}\${ebookName}.pdf"

    Remove-Item -Path "${chapterPath}" -Recurse

    Remove-Variable $usedVarsCurrentChapter
    $currentChapter++
}