<?php

declare(strict_types=1);

namespace App\Console\Commands;

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

class ExportLegacyNewsCommentsSqlCommand extends Command
{
    protected $signature = 'news:comments-export-legacy-sql
                            {--path=database/sql/news_article_comments_legacy_import.sql : Output SQL file path}
                            {--skip-empty : Skip comments with empty or whitespace-only content}
                            {--table= : Override legacy source table name (defaults to auto-detect news_comment/news_comments)}';

    protected $description = 'Generate a production-safe SQL file for legacy news comments import';

    public function handle(): int
    {
        try {
            DB::connection('legacy')->getPdo();
        } catch (\Throwable $exception) {
            $this->error('Cannot connect to legacy database: ' . $exception->getMessage());

            return self::FAILURE;
        }

        $legacyTable = $this->resolveLegacyTable();
        if ($legacyTable === null) {
            $this->error('Legacy table `news_comment` or `news_comments` was not found.');

            return self::FAILURE;
        }

        $outputPath = $this->resolveOutputPath((string) $this->option('path'));
        $skipEmpty = (bool) $this->option('skip-empty');

        $directory = dirname($outputPath);
        if (! is_dir($directory)) {
            mkdir($directory, 0777, true);
        }

        $handle = fopen($outputPath, 'wb');
        if ($handle === false) {
            $this->error('Unable to write SQL file: ' . $outputPath);

            return self::FAILURE;
        }

        $written = 0;
        $skippedEmpty = 0;
        $legacyNewsIds = [];

        fwrite($handle, "-- Legacy news comments import generated at " . now()->toDateTimeString() . PHP_EOL);
        fwrite($handle, "START TRANSACTION;" . PHP_EOL . PHP_EOL);

        DB::connection('legacy')
            ->table($legacyTable)
            ->orderBy('comment_id')
            ->chunk(500, function ($rows) use ($handle, $skipEmpty, &$written, &$skippedEmpty, &$legacyNewsIds): void {
                foreach ($rows as $row) {
                    $legacyId = (int) ($row->comment_id ?? 0);
                    $legacyNewsId = (int) ($row->news_id ?? 0);
                    $legacyUserId = (int) ($row->user_id ?? 0);
                    $body = trim((string) ($row->message ?? ''));

                    if ($legacyId < 1 || $legacyNewsId < 1) {
                        continue;
                    }

                    if ($body === '') {
                        if ($skipEmpty) {
                            $skippedEmpty++;
                            continue;
                        }

                        $body = '[no content]';
                    }

                    $legacyNewsIds[$legacyNewsId] = $legacyNewsId;

                    $authorName = trim((string) ($row->author ?? ''));
                    $timestamp = $this->normalizeTimestamp($row->posted ?? null);
                    $renderedBody = nl2br(e($body));
                    $userExpression = $legacyUserId > 0
                        ? "CASE WHEN EXISTS (SELECT 1 FROM users WHERE users.id = {$legacyUserId} AND users.deleted_at IS NULL) THEN {$legacyUserId} ELSE NULL END"
                        : 'NULL';

                    $statement = "INSERT IGNORE INTO news_article_comments (legacy_id, legacy_user_id, article_id, user_id, parent_id, author_name, body, rendered_body, status, legacy_posted_at, created_at, updated_at, deleted_at)\n"
                        . "SELECT {$legacyId}, " . ($legacyUserId > 0 ? (string) $legacyUserId : 'NULL') . ", news_articles.id, {$userExpression}, NULL, " . $this->quote($authorName !== '' ? $authorName : null) . ", " . $this->quote($body) . ", " . $this->quote($renderedBody) . ", 'visible', " . $this->quote($timestamp) . ", " . $this->quote($timestamp) . ", " . $this->quote($timestamp) . ", NULL\n"
                        . "FROM news_articles\n"
                        . "WHERE news_articles.legacy_news_id = {$legacyNewsId}\n"
                        . "LIMIT 1;\n\n";

                    fwrite($handle, $statement);
                    $written++;
                }
            });

        if ($legacyNewsIds !== []) {
            foreach (array_chunk(array_values($legacyNewsIds), 250) as $chunk) {
                fwrite($handle, 'UPDATE news_articles SET comments_enabled = 1 WHERE legacy_news_id IN (' . implode(', ', array_map('intval', $chunk)) . ');' . PHP_EOL);
            }

            fwrite($handle, PHP_EOL);
        }

        fwrite($handle, 'COMMIT;' . PHP_EOL);
        fclose($handle);

        $this->info('SQL export written to ' . $outputPath);
        $this->table(
            ['Result', 'Count'],
            [
                ['Statements written', $written],
                ['Skipped - empty body', $skippedEmpty],
                ['Articles enabled for comments', count($legacyNewsIds)],
            ]
        );

        return self::SUCCESS;
    }

    private function resolveLegacyTable(): ?string
    {
        $configured = trim((string) $this->option('table'));
        if ($configured !== '') {
            return DB::connection('legacy')->getSchemaBuilder()->hasTable($configured) ? $configured : null;
        }

        foreach (['news_comment', 'news_comments'] as $candidate) {
            if (DB::connection('legacy')->getSchemaBuilder()->hasTable($candidate)) {
                return $candidate;
            }
        }

        return null;
    }

    private function resolveOutputPath(string $path): string
    {
        $trimmed = trim($path);

        if ($trimmed === '') {
            return base_path('database/sql/news_article_comments_legacy_import.sql');
        }

        if (preg_match('/^[A-Za-z]:\\\\|^\\\\\\\\|^\//', $trimmed) === 1) {
            return $trimmed;
        }

        return base_path(str_replace(['/', '\\\\'], DIRECTORY_SEPARATOR, $trimmed));
    }

    private function normalizeTimestamp(mixed $value): string
    {
        $raw = trim((string) ($value ?? ''));

        if ($raw === '' || str_starts_with($raw, '0000-00-00')) {
            return now()->toDateTimeString();
        }

        try {
            return Carbon::parse($raw)->toDateTimeString();
        } catch (\Throwable) {
            return now()->toDateTimeString();
        }
    }

    private function quote(?string $value): string
    {
        if ($value === null) {
            return 'NULL';
        }

        $escaped = str_replace(
            ["\\", "\0", "\n", "\r", "\x1a", "'"],
            ["\\\\", "\\0", "\\n", "\\r", "\\Z", "\\'"],
            $value,
        );

        return "'{$escaped}'";
    }
}