packages/ztd-query-mysql/src/Sql/Upsert/AssignmentReader.php

1<?php
2
3declare(strict_types=1);
4
5namespace ZtdQuery\Platform\MySql\Sql\Upsert;
6
7use ZtdQuery\Platform\MySql\Sql\MySqlLexerProfile;
8use ZtdQuery\Sql\SqlToken;
9use ZtdQuery\Sql\SqlTokenKind;
10use ZtdQuery\Sql\SqlTokenStream;
11
12/**
13 * Assignment Reader.
14 *
15 * @visibility ZtdQuery\Platform\MySql
16 */
17final class AssignmentReader
18{
19    /**
20     * @return array{column: string, value: string}|null
21     */
22    public function assignment(string $assignment): ?array
23    {
24        $tokens = SqlTokenStream::tokenize($assignment, MySqlLexerProfile::create())->significantTokens();
25        foreach ($tokens as $index => $token) {
26            if ($token->kind !== SqlTokenKind::Symbol || $token->text !== '=' || !$token->isTopLevel()) {
27                continue;
28            }
29            $column = $this->lastIdentifier(array_slice($tokens, 0, $index));
30            $value = trim(substr($assignment, $token->endOffset()));
31            if ($column === null || $value === '') {
32                return null;
33            }
34
35            return ['column' => $column, 'value' => $value];
36        }
37
38        return null;
39    }
40
41    /**
42     * @param list<SqlToken> $tokens
43     */
44    public function lastIdentifier(array $tokens): ?string
45    {
46        $token = array_pop($tokens);
47        return $token !== null
48            ? SqlTokenStream::tokenize($token->text, MySqlLexerProfile::create())->identifierAt()['name'] ?? null
49            : null;
50    }
51}
52