<?php

declare(strict_types=1);

namespace DoctrineMigrations;

use Doctrine\DBAL\Schema\Schema;
use Doctrine\Migrations\AbstractMigration;

/**
 * Admin-edited mail bodies used to be plain text in which a single *asterisk* made a word
 * bold. They are Markdown now (App\Email\MailBodyRenderer), where that is italic and bold
 * is written **twice**, so every saved body is rewritten once.
 *
 * Only `body` is touched: `subject` never took markers, and `headline` is plain text under
 * the new renderer, so a marker left in one is meant to stay the character it is.
 */
final class Version20260820000000 extends AbstractMigration
{
    /**
     * A single asterisk pair on one line. The lookarounds keep three things out: an already
     * doubled **bold**, an escaped \* an admin wrote to get a literal asterisk, and a marker
     * with whitespace next to it - "a * b * c" and "5 * 3" are arithmetic, not emphasis.
     * That last rule is CommonMark's own, and slightly stricter than the renderer this
     * replaces: a text that leant on the old, laxer matching loses its bold here rather
     * than turning into something nobody wrote.
     */
    private const SINGLE_EMPHASIS = '/(?<![\\\\*])\*(?!\*)(?!\s)([^*\n]+?)(?<![\s\\\\*])\*(?!\*)/u';
    private const DOUBLE_EMPHASIS = '/(?<![\\\\*])\*\*(?!\*)(?!\s)([^*\n]+?)(?<![\s\\\\*])\*\*(?!\*)/u';

    public function getDescription(): string
    {
        return 'Rewrite *bold* to **bold** in saved email texts, which are Markdown now';
    }

    public function up(Schema $schema): void
    {
        $this->rewriteBodies(self::SINGLE_EMPHASIS, '**$1**');
    }

    public function down(Schema $schema): void
    {
        $this->rewriteBodies(self::DOUBLE_EMPHASIS, '*$1*');
    }

    /**
     * The rewrite happens in PHP, one row at a time: MySQL's REGEXP_REPLACE has no
     * lookbehind, and getting this wrong would quietly mangle wording that goes out to
     * every teamer. Only the read is done here and now - the writes go through addSql, so
     * they are logged and rolled back like any other migration statement.
     */
    private function rewriteBodies(string $pattern, string $replacement): void
    {
        foreach ($this->connection->fetchAllAssociative('SELECT id, body FROM email_text') as $row) {
            $body = preg_replace($pattern, $replacement, (string) $row['body']);

            if (null === $body || $body === $row['body']) {
                continue;
            }

            $this->addSql('UPDATE email_text SET body = ? WHERE id = ?', [$body, $row['id']]);
        }
    }
}