<#
.SYNOPSIS
    Sorts games into tier folders (Must-Play, Great, Good, Average, Niche) from a CSV of titles and review scores.
.DESCRIPTION
    Reads a CSV with Title and Score columns (a 0-100 score from Metacritic, a review site or your own opinion).
    For each game file in the folder it finds the matching row, working out the tier from the score:
      90 and up: 1 Must-Play, 80-89: 2 Great, 70-79: 3 Good, 60-69: 4 Average, below 60: 5 Niche
    and moves the file into that tier's subfolder, creating the folders it needs.
    A row matches when its Title appears anywhere in the file's title, ignoring case and punctuation, and the longest
    match wins. That lets a short row like "Mario Party" act as a fallback for a whole series, while a full title
    still beats it.
    Files with no match stay where they are (Status Unrated), or go to -UnratedFolder if you name one.
    Existing files are never overwritten. Every file gets an object back. Supports -WhatIf.
.PARAMETER Path
    The folder of games. Only files directly in it are sorted, so running it twice doesn't re-sort the tier folders.
.PARAMETER ScoreCsv
    CSV with Title and Score columns.
.PARAMETER Extension
    File extensions to sort. Default: every file.
.PARAMETER Threshold
    The four cut-off scores, highest first. Default: 90, 80, 70, 60.
.PARAMETER TierName
    The five folder names, best first.
.PARAMETER UnratedFolder
    Folder name for games with no score. Default: leave them where they are.
.EXAMPLE
    .\Move-RomToQualityTier.ps1 -Path D:\Games\gamecube -ScoreCsv .\gamecube-scores.csv -Extension .rvz,.iso -WhatIf
.EXAMPLE
    .\Move-RomToQualityTier.ps1 -Path D:\Games\ps2 -ScoreCsv .\ps2-scores.csv -UnratedFolder '6 Unrated' | Export-Csv sorted.csv -NoTypeInformation
#>
[CmdletBinding(SupportsShouldProcess)]
param(
    [Parameter(Mandatory)]
    [ValidateScript({ Test-Path -LiteralPath $_ -PathType Container })]
    [string]$Path,

    [Parameter(Mandatory)]
    [ValidateScript({ Test-Path -LiteralPath $_ -PathType Leaf })]
    [string]$ScoreCsv,

    [string[]]$Extension,

    [ValidateCount(4, 4)]
    [ValidateRange(0, 100)]
    [int[]]$Threshold = @(90, 80, 70, 60),

    [ValidateCount(5, 5)]
    [ValidateNotNullOrEmpty()]
    [string[]]$TierName = @('1 Must-Play', '2 Great', '3 Good', '4 Average', '5 Niche'),

    [string]$UnratedFolder
)

function Get-MatchKey([string]$Text) { ' ' + ($Text.ToLowerInvariant() -replace '[\u0027\u2019]', '' -replace '&', 'and' -replace '[^a-z0-9]+', ' ').Trim() + ' ' }

for ($i = 1; $i -lt $Threshold.Count; $i++) {
    if ($Threshold[$i] -ge $Threshold[$i - 1]) { throw "Thresholds must go from highest to lowest, like 90,80,70,60." }
}

$scores = foreach ($row in Import-Csv -LiteralPath $ScoreCsv) {
    $score = 0
    if ($row.Title -and [int]::TryParse(($row.Score -as [string]).Trim(), [ref]$score) -and $score -ge 0 -and $score -le 100) {
        [pscustomobject]@{ Title = $row.Title; Key = (Get-MatchKey $row.Title); Score = $score }
    }
    elseif ($row.Title) { Write-Warning "Skipping CSV row '$($row.Title)': score '$($row.Score)' isn't a number from 0 to 100." }
}
Write-Verbose "Loaded $(@($scores).Count) scored titles from $ScoreCsv"

$extFilter = @($Extension | Where-Object { $_ } | ForEach-Object { if ($_ -like '.*') { $_.ToLower() } else { ".$_".ToLower() } })
$files = Get-ChildItem -LiteralPath $Path -File | Where-Object { -not $extFilter -or $extFilter -contains $_.Extension.ToLower() }

foreach ($file in $files) {
    # Strip a leading genre code like (PLAT) and everything from the first bracket, to get the title.
    $title = (($file.BaseName -replace '^\([A-Z]{3,4}\)\s*', '') -replace '\s*[\(\[].*$', '').Trim()
    $key = Get-MatchKey $title
    $match = $scores | Where-Object { $key.Contains($_.Key) } | Sort-Object { $_.Key.Length } -Descending | Select-Object -First 1

    $result = [ordered]@{ Name = $file.Name; MatchedTitle = $null; Score = $null; Tier = $null; Status = 'Unrated' }
    $folder = $null
    if ($match) {
        $result.MatchedTitle = $match.Title
        $result.Score = $match.Score
        $index = @($Threshold | Where-Object { $match.Score -lt $_ }).Count
        $folder = $TierName[$index]
        $result.Tier = $folder
    }
    elseif ($UnratedFolder) { $folder = $UnratedFolder; $result.Tier = $UnratedFolder }

    if (-not $folder) { [pscustomobject]$result; continue }

    $destFolder = Join-Path $Path $folder
    $dest = Join-Path $destFolder $file.Name
    if (Test-Path -LiteralPath $dest) {
        $result.Status = 'SkippedExists'
        Write-Warning "$($file.Name) is already in '$folder'. Left alone."
        [pscustomobject]$result; continue
    }

    $result.Status = 'WhatIf'
    if ($PSCmdlet.ShouldProcess($file.FullName, "Move to $folder")) {
        try {
            if (-not (Test-Path -LiteralPath $destFolder)) { New-Item -ItemType Directory -Path $destFolder -ErrorAction Stop | Out-Null }
            Move-Item -LiteralPath $file.FullName -Destination $dest -ErrorAction Stop
            $result.Status = 'Moved'
        }
        catch {
            $result.Status = "Failed: $($_.Exception.Message)"
            Write-Warning "$($file.Name): $($_.Exception.Message)"
        }
    }
    [pscustomobject]$result
}