param(
    [string]$LibraryRoot = "\\VaultOfData\AKAMedia\음악\처리됨\SUNO",
    [switch]$Apply
)

$ErrorActionPreference = "Stop"

function ConvertTo-SafeName {
    param([string]$Value)

    $name = if ($Value) { $Value } else { "suno-track" }
    $name = $name -replace '[\\/:*?"<>|]+', ' '
    $name = $name -replace '\s+', ' '
    $name = $name.Trim()
    if (-not $name) { $name = "suno-track" }
    if ($name.Length -gt 120) { $name = $name.Substring(0, 120).Trim() }
    return $name
}

function Get-ShortId {
    param([string]$Id)

    if (-not $Id) { return "unknown-id" }
    if ($Id.Length -le 12) { return $Id }
    return $Id.Substring(0, 12)
}

function Get-NextTrackNumber {
    param([string]$Folder)

    if (-not (Test-Path -LiteralPath $Folder)) { return 1 }
    $numbers = Get-ChildItem -LiteralPath $Folder -File -ErrorAction SilentlyContinue |
        Where-Object { $_.Extension -in ".flac", ".mp3", ".m4a" } |
        ForEach-Object {
            if ($_.BaseName -match '^(\d{2})\s') { [int]$Matches[1] }
        }
    if (-not $numbers) { return 1 }
    return (($numbers | Measure-Object -Maximum).Maximum + 1)
}

if (-not (Test-Path -LiteralPath $LibraryRoot)) {
    throw "SUNO library root not found: $LibraryRoot"
}

$candidateDirs = Get-ChildItem -LiteralPath $LibraryRoot -Directory -ErrorAction SilentlyContinue |
    Where-Object { $_.Name -match '^(?<title>.+)\s\[[0-9a-fA-F-]{8,}\]$' }

foreach ($dir in $candidateDirs) {
    $metadata = Get-ChildItem -LiteralPath $dir.FullName -File -Filter "*.json" -ErrorAction SilentlyContinue |
        ForEach-Object {
            try {
                $json = Get-Content -LiteralPath $_.FullName -Raw | ConvertFrom-Json
                if ($json.id) {
                    [pscustomobject]@{ File = $_; Json = $json }
                }
            } catch {}
        } |
        Select-Object -First 1

    if (-not $metadata) {
        Write-Host "SKIP no metadata id: $($dir.FullName)"
        continue
    }

    $id = "$($metadata.Json.id)"
    $title = ConvertTo-SafeName "$($metadata.Json.title)"
    if (-not $title -and $dir.Name -match '^(?<title>.+)\s\[[0-9a-fA-F-]{8,}\]$') {
        $title = ConvertTo-SafeName $Matches.title
    }
    $shortId = Get-ShortId $id
    $targetDir = Join-Path $LibraryRoot $title
    $trackNo = Get-NextTrackNumber $targetDir
    $audio = Get-ChildItem -LiteralPath $dir.FullName -File -ErrorAction SilentlyContinue |
        Where-Object { $_.Extension -in ".flac", ".mp3", ".m4a" } |
        Select-Object -First 1
    $cover = Get-ChildItem -LiteralPath $dir.FullName -File -Filter "cover.*" -ErrorAction SilentlyContinue | Select-Object -First 1

    Write-Host ""
    Write-Host "FROM: $($dir.FullName)"
    Write-Host "TO:   $targetDir"
    Write-Host "ID:   $id"

    if (-not $Apply) {
        Write-Host "DRY: would move audio/metadata/cover"
        continue
    }

    New-Item -ItemType Directory -Force -Path $targetDir | Out-Null

    if ($audio) {
        $newAudio = Join-Path $targetDir ("{0:D2} {1}{2}" -f $trackNo, $title, $audio.Extension)
        Move-Item -LiteralPath $audio.FullName -Destination $newAudio -Force
        Write-Host "audio -> $newAudio"
    }

    $newMetadata = Join-Path $targetDir ("metadata.{0}.json" -f $shortId)
    Move-Item -LiteralPath $metadata.File.FullName -Destination $newMetadata -Force
    Write-Host "metadata -> $newMetadata"

    if ($cover) {
        $coverTarget = Join-Path $targetDir "cover.jpg"
        if (-not (Test-Path -LiteralPath $coverTarget)) {
            Move-Item -LiteralPath $cover.FullName -Destination $coverTarget -Force
            Write-Host "cover -> $coverTarget"
        }
    }

    $remaining = Get-ChildItem -LiteralPath $dir.FullName -Force -ErrorAction SilentlyContinue
    if (-not $remaining) {
        Remove-Item -LiteralPath $dir.FullName -Force
        Write-Host "removed empty old folder"
    } else {
        Write-Host "old folder kept; remaining files exist"
    }
}