<?php

namespace WP_Statistics\Service\Database\Migrations\Schema;

use Exception;
use WP_Statistics\Abstracts\BaseMigrationOperation;
use WP_Statistics\Service\Database\DatabaseFactory;

/**
 * Manages migrations related to database schema.
 */
class SchemaMigration extends BaseMigrationOperation
{
    /**
     * The name of the migration operation.
     *
     * @var string
     */
    protected $name = 'schema';

    /**
     * The list of migration steps for this operation.
     *
     * This array maps version numbers to their corresponding migration methods.
     * Each version key represents a database schema migration that needs to be applied
     * for that specific version. The associated value is an array of method names
     * that should be executed for the migration step.
     *
     * Example:
     * 'x.x.x' => [
     *     'FirstMethodName',
     *     'SecondMethodName',
     * ],
     *
     * The method names specified should exist within this class, as this class
     * is specifically designed for handling schema migrations. Each method is
     * responsible for tasks such as altering table structures, adding or removing
     * columns, changing column types, or other schema-level changes to the database.
     *
     * Note: This class is not intended for data migrations such as transferring
     * data between tables, modifying data values, or other operations on the
     * contents of the database. Those operations should be handled by a dedicated
     * data migration class.
     *
     * @var array
     */
    protected $migrationSteps = [
        '14.12.6' => [
            'addFirstAndLastPageToVisitors',
        ],
        '14.15' => [
            'dropVisitTable',
            'addUserIdToEvents'
        ],
        '14.16' => [
            'dropOnlineTable'
        ]
    ];

    /**
     * Adds 4 new columns to the 'visitors' table: 'first_page', 'first_view', 'last_page', and 'last_view'.
     *
     * @return void
     */
    public function addFirstAndLastPageToVisitors()
    {
        $this->ensureConnection();

        try {
            DatabaseFactory::table('update')
                ->setName('visitor')
                ->setArgs([
                    'add' => [
                        'first_page' => 'bigint(20) UNSIGNED DEFAULT NULL',
                        'first_view' => 'datetime DEFAULT NULL',
                        'last_page'  => 'bigint(20) UNSIGNED DEFAULT NULL',
                        'last_view'  => 'datetime DEFAULT NULL'
                    ]
                ])
                ->execute();
        } catch (Exception $e) {
            $this->setErrorStatus($e->getMessage());
        }
    }

    public function dropVisitTable()
    {
        try {
            DatabaseFactory::table('drop')
                ->setName('visit')
                ->execute();
        } catch (Exception $e) {
            $this->setErrorStatus($e->getMessage());
        }
    }

    /**
     * Drop the 'user_online' table.
     *
     * @return void
     */
    public function dropOnlineTable()
    {
        try {
            DatabaseFactory::table('drop')
                ->setName('useronline')
                ->execute();
        } catch (Exception $e) {
            $this->setErrorStatus($e->getMessage());
        }
    }

    /**
     * Adds `user_id` column to the 'events' table.
     *
     * @return void
     */
    public function addUserIdToEvents()
    {
        $this->ensureConnection();

        try {
            DatabaseFactory::table('update')
                ->setName('events')
                ->setArgs([
                    'add' => [
                        'user_id' => 'bigint(20) UNSIGNED DEFAULT NULL',
                    ]
                ])
                ->execute();
        } catch (Exception $e) {
            $this->setErrorStatus($e->getMessage());
        }
    }
}