<#
.SYNOPSIS
    Sorts comic and manga files (or whole series folders) into genre or decade folders from a CSV you provide.
.DESCRIPTION
    Looks at every comic file (.cbz, .cbr, .cb7 by default) and every series folder directly inside -Path,
    works out the series name, and looks it up in a CSV with Series, Genre and Year columns. Matching items
    are moved into <Destination>\<Genre> (or <Destination>\<Decade>, like 1990s, with -GroupBy Decade).

    Series names come from the folder or file name, with the usual clutter removed: a trailing (2019),
    [scanlator] tags, and volume or issue numbers like v01, Vol. 3, #012, c045 or a bare 012. If there's no
    exact match, the longest series in the CSV that the name starts with wins, so "Series - Side Story"
    lands with "Series". For -GroupBy Decade, the year comes from the CSV, or from a (1998) in the name.

    Anything it can't place is reported with Status Uncategorized and left alone, unless you name an
    -UncategorizedFolder. When it's done, it counts comic files again and warns if the totals don't match.
    Supports -WhatIf.
.PARAMETER Path
    The folder to sort. Only items directly inside it are moved.
.PARAMETER MapCsv
    CSV with a Series column plus Genre and/or Year. Extra columns are ignored.
.PARAMETER Destination
    Where the genre or decade folders go. Defaults to -Path.
.PARAMETER GroupBy
    Genre (default) or Decade.
.PARAMETER Extension
    Comic file extensions. Default: .cbz, .cbr, .cb7.
.PARAMETER UncategorizedFolder
    Folder name to move unmatched items into. By default they stay where they are.
.EXAMPLE
    .\Move-ComicByGenre.ps1 -Path D:\Manga -MapCsv .\series.csv -WhatIf
.EXAMPLE
    .\Move-ComicByGenre.ps1 -Path D:\Manga -MapCsv .\series.csv | Where-Object Status -eq Uncategorized | Select-Object Name, Series
#>
[CmdletBinding(SupportsShouldProcess)]
param(
    [Parameter(Mandatory)][ValidateScript({ Test-Path -LiteralPath $_ -PathType Container })][string]$Path,
    [Parameter(Mandatory)][ValidateScript({ Test-Path -LiteralPath $_ -PathType Leaf })][string]$MapCsv,
    [string]$Destination,
    [ValidateSet('Genre', 'Decade')][string]$GroupBy = 'Genre',
    [string[]]$Extension = @('.cbz', '.cbr', '.cb7'),
    [ValidatePattern('^[^\\/:*?"<>|]+$')][string]$UncategorizedFolder
)

$Path = (Resolve-Path -LiteralPath $Path).ProviderPath
$Destination = if ($Destination) { $PSCmdlet.GetUnresolvedProviderPathFromPSPath($Destination) } else { $Path }
$Extension = @($Extension | ForEach-Object { if ($_ -like '.*') { $_.ToLower() } else { ".$_".ToLower() } })

function Get-MatchKey([string]$Text) { ($Text.ToLowerInvariant() -replace '&', ' and ' -replace '[^\p{L}\p{N}]+', ' ').Trim() }

function Get-SeriesName([string]$Name) {
    $n = $Name -replace '\[[^\]]*\]', '' -replace '\((19|20)\d{2}\)', '' -replace '\((Digital|Complete|Ongoing|[^)]*Scan[^)]*)\)', '' -replace '_', ' '
    # Volume, issue and chapter numbers at the end: v01, Vol. 3, Volume 03, #012, c045, Chapter 12, or a bare 012.
    $n = $n -replace '(?i)[\s\-]+(v|vol\.?|volume|c|ch\.?|chapter|#|issue)\s*\d+(\.\d+)?(\s*-\s*\d+)?\b.*$', ''
    $n = $n -replace '\s+\d{1,4}(\.\d+)?\s*$', ''
    ($n -replace '\s{2,}', ' ').Trim(' ', '-', '.')
}

function Get-ComicCount([string[]]$Roots) {
    $seen = [System.Collections.Generic.HashSet[string]]::new([StringComparer]::OrdinalIgnoreCase)
    foreach ($r in $Roots | Select-Object -Unique) {
        if (Test-Path -LiteralPath $r) {
            Get-ChildItem -LiteralPath $r -File -Recurse -ErrorAction SilentlyContinue | Where-Object { $Extension -contains $_.Extension.ToLower() } | ForEach-Object { $null = $seen.Add($_.FullName) }
        }
    }
    $seen.Count
}

# Load the map. Keys are normalized so punctuation and case don't matter.
$map = @{}
foreach ($row in Import-Csv -LiteralPath $MapCsv) {
    if (-not $row.Series) { continue }
    $map[(Get-MatchKey $row.Series)] = [pscustomobject]@{ Series = $row.Series.Trim(); Genre = "$($row.Genre)".Trim(); Year = "$($row.Year)".Trim() }
}
if (-not $map.Count) { throw "No rows with a Series column found in $MapCsv." }
$keysByLength = $map.Keys | Sort-Object Length -Descending
Write-Verbose "Loaded $($map.Count) series from $MapCsv"

# Category folders this run could create, so a re-run doesn't try to sort them.
$categoryNames = [System.Collections.Generic.HashSet[string]]::new([StringComparer]::OrdinalIgnoreCase)
foreach ($entry in $map.Values) { if ($entry.Genre) { $null = $categoryNames.Add(($entry.Genre -replace '[\\/:*?"<>|]', '-')) } }
if ($UncategorizedFolder) { $null = $categoryNames.Add($UncategorizedFolder) }

$before = Get-ComicCount @($Path, $Destination)
$items = Get-ChildItem -LiteralPath $Path | Where-Object {
    ($_.PSIsContainer -and -not $categoryNames.Contains($_.Name) -and $_.Name -notmatch '^\d{4}s$' -and $_.FullName -ne $Destination) -or
    (-not $_.PSIsContainer -and $Extension -contains $_.Extension.ToLower())
}

foreach ($item in $items) {
    $baseName = if ($item.PSIsContainer) { $item.Name } else { $item.BaseName }
    $series = Get-SeriesName $baseName
    $key = Get-MatchKey $series
    $entry = $map[$key]
    if (-not $entry) {
        $prefix = $keysByLength | Where-Object { $key.StartsWith("$_ ") } | Select-Object -First 1
        if ($prefix) { $entry = $map[$prefix] }
    }

    $category = $null
    if ($entry -and $GroupBy -eq 'Genre' -and $entry.Genre) { $category = $entry.Genre -replace '[\\/:*?"<>|]', '-' }
    elseif ($GroupBy -eq 'Decade') {
        $year = if ($entry -and $entry.Year -match '^\d{4}$') { [int]$entry.Year } elseif ($baseName -match '\(((19|20)\d{2})\)') { [int]$Matches[1] }
        if ($year) { $category = '{0}s' -f ([math]::Floor($year / 10) * 10) }
    }

    $result = [ordered]@{ Name = $item.Name; Type = $(if ($item.PSIsContainer) { 'Folder' } else { 'File' }); Series = $series; MatchedAs = $(if ($entry) { $entry.Series }); Category = $category; Destination = $null; Status = $null }
    if (-not $category) {
        $result.Status = 'Uncategorized'
        if (-not $UncategorizedFolder) { [pscustomobject]$result; continue }
        $category = $UncategorizedFolder
        $result.Category = $category
    }

    $catDir = Join-Path $Destination $category
    $target = Join-Path $catDir $item.Name
    $result.Destination = $target
    $leftBehind = 0
    $fileCount = if ($item.PSIsContainer) { Get-ComicCount $item.FullName } else { 1 }

    try {
        if (-not $PSCmdlet.ShouldProcess($item.FullName, "Move to $catDir")) { if (-not $result.Status) { $result.Status = 'WhatIf' }; [pscustomobject]$result; continue }
        if (-not (Test-Path -LiteralPath $catDir)) { $null = New-Item -ItemType Directory -Path $catDir -ErrorAction Stop }

        if (-not (Test-Path -LiteralPath $target)) {
            Move-Item -LiteralPath $item.FullName -Destination $target -ErrorAction Stop
        }
        elseif ($item.PSIsContainer) {
            # The series folder already exists there (an earlier run, or a split library): merge into it.
            foreach ($child in Get-ChildItem -LiteralPath $item.FullName) {
                $childTarget = Join-Path $target $child.Name
                if (Test-Path -LiteralPath $childTarget) { Write-Warning "$($item.Name): '$($child.Name)' already exists in $target. Left in place."; $leftBehind++; continue }
                Move-Item -LiteralPath $child.FullName -Destination $childTarget -ErrorAction Stop
            }
            if (-not (Get-ChildItem -LiteralPath $item.FullName -Force)) { Remove-Item -LiteralPath $item.FullName -ErrorAction Stop }
        }
        else { throw "A file named '$($item.Name)' already exists in $catDir." }

        if ($leftBehind) { $result.Status = "PartlyMoved: $leftBehind item(s) already existed"; [pscustomobject]$result; continue }
        $moved = if ($item.PSIsContainer) { Get-ComicCount $target } else { [int](Test-Path -LiteralPath $target) }
        $result.Status = if ($moved -ge $fileCount) { if ($result.Status -eq 'Uncategorized') { 'MovedUncategorized' } else { 'Moved' } } else { "Check: $fileCount comic file(s) before, $moved after" }
    }
    catch {
        $result.Status = "Failed: $($_.Exception.Message)"
        Write-Warning "$($item.Name): $($_.Exception.Message)"
    }
    [pscustomobject]$result
}

if (-not $WhatIfPreference) {
    $after = Get-ComicCount @($Path, $Destination)
    if ($after -ne $before) { Write-Warning "Comic file count changed: $before before, $after after. Something went missing or got duplicated; check the Failed rows." }
    else { Write-Verbose "Verified: $after comic file(s) before and after." }
}