<?php
/**
 * Base class for migrations that add columns.
 *
 * @package HostKhata
 */

namespace HostKhata\Database\Migrations;

defined( 'ABSPATH' ) || exit;

use HostKhata\Database\Schema;
use HostKhata\Database\Tables;
use RuntimeException;
use wpdb;

/**
 * A migration that adds columns to one existing table.
 *
 * The current CREATE TABLE statement in {@see Schema} already contains the new
 * columns. `dbDelta()` compares it with the live table and adds what is
 * missing, so the migration only names the table and the columns it expects.
 * Fresh installs create the columns in migration 1 and this one does nothing.
 *
 * @since 0.1.0
 */
abstract class AddColumnsMigration implements Migration {

	/**
	 * Short key of the table, for example `customers`.
	 *
	 * @since 0.1.0
	 *
	 * @return string
	 */
	abstract protected function table_key(): string;

	/**
	 * Columns that must exist afterwards.
	 *
	 * @since 0.1.0
	 *
	 * @return string[]
	 */
	abstract protected function columns(): array;

	/**
	 * Adds the columns and checks that they exist.
	 *
	 * @since 0.1.0
	 *
	 * @param wpdb $wpdb WordPress database object.
	 * @return void
	 *
	 * @throws RuntimeException When a column could not be added.
	 */
	public function up( wpdb $wpdb ): void {
		require_once ABSPATH . 'wp-admin/includes/upgrade.php';

		$statements = Schema::statements( $wpdb->prefix, $wpdb->get_charset_collate() );

		dbDelta( $statements[ $this->table_key() ] );

		$table = $wpdb->prefix . 'hostkhata_' . $this->table_key();

		foreach ( $this->columns() as $column ) {
			$found = $wpdb->get_var( $wpdb->prepare( "SHOW COLUMNS FROM {$table} LIKE %s", $column ) ); // phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching,WordPress.DB.PreparedSQL.InterpolatedNotPrepared,WordPress.DB.PreparedSQL.NotPrepared,PluginCheck.Security.DirectDB.UnescapedDBParameter -- Table name is built from the prefix and a fixed suffix.

			if ( $column !== $found ) {
				throw new RuntimeException( sprintf( 'Column %s could not be added to %s.', $column, $table ) ); // phpcs:ignore WordPress.Security.EscapeOutput.ExceptionNotEscaped
			}
		}
	}
}