<?php

namespace App\Console\Commands;

use Illuminate\Console\Command;
use Illuminate\Support\Facades\DB;
use Illuminate\Support\Str;

final class NormalizeArtworkSlugsCommand extends Command
{
    protected $signature = 'artworks:normalize-slugs
                            {--dry-run : Show the slug changes without writing them}
                            {--chunk=500 : Number of artworks to process per chunk}
                            {--only-mismatched : Only update rows whose current slug differs from the normalized title slug}';

    protected $description = 'Normalize existing artwork slugs from artwork titles without enforcing uniqueness.';

    public function handle(): int
    {
        $dryRun = (bool) $this->option('dry-run');
        $chunkSize = max(1, (int) $this->option('chunk'));
        $onlyMismatched = (bool) $this->option('only-mismatched');

        if (! $dryRun) {
            $this->ensureSlugIsNotUnique();
        }

        $processed = 0;
        $updated = 0;

        DB::table('artworks')
            ->select(['id', 'title', 'slug'])
            ->orderBy('id')
            ->chunkById($chunkSize, function ($artworks) use ($dryRun, $onlyMismatched, &$processed, &$updated): void {
                foreach ($artworks as $artwork) {
                    $processed++;

                    $normalizedSlug = Str::limit(Str::slug((string) ($artwork->title ?? '')) ?: 'artwork', 160, '');
                    $currentSlug = (string) ($artwork->slug ?? '');

                    if ($onlyMismatched && $currentSlug === $normalizedSlug) {
                        continue;
                    }

                    if ($currentSlug === $normalizedSlug) {
                        continue;
                    }

                    if ($dryRun) {
                        $this->line(sprintf('#%d  %s  =>  %s', $artwork->id, $currentSlug !== '' ? $currentSlug : '[empty]', $normalizedSlug));
                        $updated++;
                        continue;
                    }

                    DB::table('artworks')
                        ->where('id', $artwork->id)
                        ->update(['slug' => $normalizedSlug]);

                    $updated++;
                }
            });

        if ($dryRun) {
            $this->info(sprintf('Dry run complete. Checked %d artworks, %d would be updated.', $processed, $updated));
            return self::SUCCESS;
        }

        $this->info(sprintf('Normalization complete. Checked %d artworks, updated %d.', $processed, $updated));

        return self::SUCCESS;
    }

    private function ensureSlugIsNotUnique(): void
    {
        $driver = DB::getDriverName();

        if ($driver === 'mysql') {
            $indexes = collect(DB::select("SHOW INDEX FROM artworks WHERE Column_name = 'slug'"));

            $indexes
                ->filter(fn ($index) => (int) ($index->Non_unique ?? 1) === 0)
                ->pluck('Key_name')
                ->filter()
                ->unique()
                ->each(function ($indexName): void {
                    $this->warn(sprintf('Dropping unique slug index %s before normalization.', $indexName));
                    DB::statement(sprintf('ALTER TABLE artworks DROP INDEX `%s`', str_replace('`', '``', (string) $indexName)));
                });

            $hasNonUniqueSlugIndex = $indexes->contains(fn ($index) => (string) ($index->Key_name ?? '') === 'artworks_slug_index' || (int) ($index->Non_unique ?? 0) === 1);

            if (! $hasNonUniqueSlugIndex) {
                DB::statement('CREATE INDEX artworks_slug_index ON artworks (slug)');
            }

            return;
        }

        if ($driver === 'sqlite') {
            $indexes = collect(DB::select("PRAGMA index_list('artworks')"));

            $indexes
                ->filter(function ($index): bool {
                    if ((int) ($index->unique ?? 0) !== 1) {
                        return false;
                    }

                    $columns = collect(DB::select(sprintf("PRAGMA index_info('%s')", str_replace("'", "''", (string) $index->name))))
                        ->pluck('name')
                        ->map(fn ($name) => (string) $name);

                    return $columns->contains('slug');
                })
                ->pluck('name')
                ->each(fn ($indexName) => DB::statement(sprintf('DROP INDEX IF EXISTS "%s"', str_replace('"', '""', (string) $indexName))));

            DB::statement('CREATE INDEX IF NOT EXISTS artworks_slug_index ON artworks (slug)');
        }
    }
}