<#
.SYNOPSIS
    Moves each game file into a folder named after its title, so a game's base file, updates and DLC sit together.
.DESCRIPTION
    Works out a folder name from each file name by taking everything before the first " [" (or the delimiter you
    choose), so "Space Blaster [0100ABCD00010000][v0].nsz" and "Space Blaster [0100ABCD00010800][v65536].nsz" both
    go into a "Space Blaster" folder. Files with no delimiter in the name are left where they are.
    Characters that aren't allowed in folder names are replaced with a dash, and trailing dots and spaces are trimmed.
    Only files sitting directly in the folder are moved. Nothing is ever deleted or overwritten.
    Every file gets an object back. Supports -WhatIf.
.PARAMETER Path
    The folder to organize.
.PARAMETER Extension
    File extensions to move. Default: .nsp, .nsz, .xci and .xcz.
.PARAMETER Delimiter
    Where the title ends. Default: " [". Use " (" for No-Intro-style names like "Title (USA).zip".
.PARAMETER AllExtensions
    Move every file regardless of extension.
.EXAMPLE
    .\Move-GameToTitleFolder.ps1 -Path E:\Backups\switch -WhatIf
.EXAMPLE
    .\Move-GameToTitleFolder.ps1 -Path D:\Games\psx -Extension .chd,.m3u -Delimiter ' ('
#>
[CmdletBinding(SupportsShouldProcess)]
param(
    [Parameter(Mandatory)]
    [ValidateScript({ Test-Path -LiteralPath $_ -PathType Container })]
    [string]$Path,

    [string[]]$Extension = @('.nsp', '.nsz', '.xci', '.xcz'),

    [ValidateNotNullOrEmpty()]
    [string]$Delimiter = ' [',

    [switch]$AllExtensions
)

$extFilter = @($Extension | Where-Object { $_ } | ForEach-Object { if ($_ -like '.*') { $_.ToLower() } else { ".$_".ToLower() } })
$badChars = [regex]::Escape(-join [System.IO.Path]::GetInvalidFileNameChars())

$files = Get-ChildItem -LiteralPath $Path -File | Where-Object { $AllExtensions -or $extFilter -contains $_.Extension.ToLower() }

foreach ($file in $files) {
    $result = [ordered]@{ Name = $file.Name; Folder = $null; Status = 'NoDelimiter' }
    $cut = $file.Name.IndexOf($Delimiter)
    if ($cut -le 0) { [pscustomobject]$result; continue }

    $folderName = ($file.Name.Substring(0, $cut) -replace "[$badChars]", '-').Trim().TrimEnd('.', ' ')
    if (-not $folderName) { [pscustomobject]$result; continue }
    $result.Folder = $folderName

    $destFolder = Join-Path $Path $folderName
    $dest = Join-Path $destFolder $file.Name
    if (Test-Path -LiteralPath $dest) {
        $result.Status = 'SkippedExists'
        Write-Warning "$($file.Name) is already in '$folderName'. Left alone."
        [pscustomobject]$result; continue
    }
    if ((Test-Path -LiteralPath $destFolder) -and -not (Test-Path -LiteralPath $destFolder -PathType Container)) {
        $result.Status = 'SkippedNotAFolder'
        Write-Warning "'$folderName' exists as a file, not a folder. $($file.Name) left alone."
        [pscustomobject]$result; continue
    }

    $result.Status = 'WhatIf'
    if ($PSCmdlet.ShouldProcess($file.FullName, "Move into folder '$folderName'")) {
        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
}