<?php

namespace Modules\Core\Command;

use Illuminate\Console\Command;
use Lunar\Models\ProductVariant;

/**
 * One-off backfill for variants the Shopify import left with a blank SKU —
 * not an importer bug, the source CSV rows genuinely had no `Variant SKU`
 * value (see Modules\MigrateImport\Shopify\ShopifyExportImporter) — so
 * this synthesizes one instead of re-running the import. Format is
 * "SKU-P{product_id}-V{variant_id}": deterministic and guaranteed unique
 * without a uniqueness check, since product_id/variant_id already are.
 * Only variants with a null `sku` are touched.
 */
class BackfillMissingSkusCommand extends Command
{
    protected $signature = 'boboko:catalog:backfill-skus {--dry-run : List what would change without writing}';

    protected $description = 'Generate a SKU for every product variant that is missing one';

    public function handle(): void
    {
        $dryRun = (bool) $this->option('dry-run');

        $query = ProductVariant::query()->whereNull('sku');
        $total = $query->count();

        if ($total === 0) {
            $this->info('No variants are missing a SKU.');

            return;
        }

        $this->info(($dryRun ? '[dry-run] ' : '') . "Backfilling SKUs for {$total} variant(s)...");

        $bar = $this->output->createProgressBar($total);
        $bar->start();

        $query->chunkById(500, function ($variants) use ($dryRun, $bar) {
            foreach ($variants as $variant) {
                $sku = "SKU-P{$variant->product_id}-V{$variant->id}";

                if ($dryRun) {
                    $this->newLine();
                    $this->line("Variant {$variant->id}: sku => {$sku}");
                } else {
                    $variant->update(['sku' => $sku]);
                }

                $bar->advance();
            }
        });

        $bar->finish();
        $this->newLine();
        $this->info($dryRun ? 'Dry run complete — no changes were written.' : 'Done.');
    }
}