<?php

namespace Doctrine\DBAL\Platforms;

use Doctrine\DBAL\Types\JsonType;

use function sprintf;

/**
 * Provides the behavior, features and SQL dialect of the MariaDB 10.4 (10.4.6 GA) database platform.
 *
 * Extend deprecated MariaDb1027Platform to ensure correct functions used in MySQLSchemaManager which
 * tests for MariaDb1027Platform not MariaDBPlatform.
 *
 * @deprecated This class will be merged with {@see MariaDBPlatform} in 4.0 because support for MariaDB
 *             releases prior to 10.4.3 will be dropped.
 */
class MariaDb1043Platform extends MariaDb1027Platform
{
    /**
     * Use JSON rather than LONGTEXT for json columns. Since it is not a true native type, do not override
     * hasNativeJsonType() so the DC2Type comment will still be set.
     *
     * {@inheritDoc}
     */
    public function getJsonTypeDeclarationSQL(array $column): string
    {
        return 'JSON';
    }

    /**
     * {@inheritDoc}
     *
     * From version 10.4.3, MariaDb aliases JSON to LONGTEXT and adds a constraint CHECK (json_valid). Reverse
     * this process when introspecting tables.
     *
     * @see https://mariadb.com/kb/en/information-schema-check_constraints-table/
     * @see https://mariadb.com/kb/en/json-data-type/
     * @see https://jira.mariadb.org/browse/MDEV-13916
     */
    public function getListTableColumnsSQL($table, $database = null): string
    {
        // @todo 4.0 - call getColumnTypeSQLSnippet() instead
        [$columnTypeSQL, $joinCheckConstraintSQL] = $this->getColumnTypeSQLSnippets('c', $database);

        return sprintf(
            <<<SQL
            SELECT c.COLUMN_NAME AS Field,
                   $columnTypeSQL AS Type,
                   c.IS_NULLABLE AS `Null`,
                   c.COLUMN_KEY AS `Key`,
                   c.COLUMN_DEFAULT AS `Default`,
                   c.EXTRA AS Extra,
                   c.COLUMN_COMMENT AS Comment,
                   c.CHARACTER_SET_NAME AS CharacterSet,
                   c.COLLATION_NAME AS Collation
            FROM information_schema.COLUMNS c
                $joinCheckConstraintSQL
            WHERE c.TABLE_SCHEMA = %s
            AND c.TABLE_NAME = %s
            ORDER BY ORDINAL_POSITION ASC;
            SQL
            ,
            $this->getDatabaseNameSQL($database),
            $this->quoteStringLiteral($table),
        );
    }

    /**
     * Generate SQL snippets to reverse the aliasing of JSON to LONGTEXT.
     *
     * MariaDb aliases columns specified as JSON to LONGTEXT and sets a CHECK constraint to ensure the column
     * is valid json. This function generates the SQL snippets which reverse this aliasing i.e. report a column
     * as JSON where it was originally specified as such instead of LONGTEXT.
     *
     * The CHECK constraints are stored in information_schema.CHECK_CONSTRAINTS so query that table.
     */
    public function getColumnTypeSQLSnippet(string $tableAlias = 'c', ?string $databaseName = null): string
    {
        if ($this->getJsonTypeDeclarationSQL([]) !== 'JSON') {
            return parent::getColumnTypeSQLSnippet($tableAlias, $databaseName);
        }

        $databaseName = $this->getDatabaseNameSQL($databaseName);

        // The check for `CONSTRAINT_SCHEMA = $databaseName` is mandatory here to prevent performance issues
        return <<<SQL
            IF(
                $tableAlias.COLUMN_TYPE = 'longtext'
                AND EXISTS(
                    SELECT * from information_schema.CHECK_CONSTRAINTS 
                    WHERE CONSTRAINT_SCHEMA = $databaseName
                    AND TABLE_NAME = $tableAlias.TABLE_NAME
                    AND CHECK_CLAUSE = CONCAT(
                        'json_valid(`',
                            $tableAlias.COLUMN_NAME,
                        '`)'
                    )
                ),
                'json',
                $tableAlias.COLUMN_TYPE
            )
        SQL;
    }

    /** {@inheritDoc} */
    public function getColumnDeclarationSQL($name, array $column)
    {
        // MariaDb forces column collation to utf8mb4_bin where the column was declared as JSON so ignore
        // collation and character set for json columns as attempting to set them can cause an error.
        if ($this->getJsonTypeDeclarationSQL([]) === 'JSON' && ($column['type'] ?? null) instanceof JsonType) {
            unset($column['collation']);
            unset($column['charset']);
        }

        return parent::getColumnDeclarationSQL($name, $column);
    }
}
