<?php
/**
 * CODING CONVENTION:
 * This file follows the coding convention where variable_names and function_names
 * use snake_case (underscore_wherever_possible).
 */

namespace App\Console\Commands;

use Illuminate\Console\Command;
use Illuminate\Support\Facades\DB;
use Log;

/**
 * Session Cleanup Command
 * ========================
 *
 * PURPOSE:
 * This command performs routine cleanup of expired and abandoned sessions from
 * the database to prevent unbounded growth of the sessions table.
 *
 * CLEANUP RULES:
 * 1. Guest sessions (user_id = null, site_id = null) older than 24 hours
 * 2. Any sessions older than 3 years (regardless of user/site association)
 *
 * IMPLEMENTATION:
 * - Uses raw DB::statement() for efficiency
 * - Runs hourly via Laravel scheduler
 * - Tracks deletion counts for monitoring
 *
 * WHY RAW SQL:
 * - More efficient for bulk deletions
 * - Clear audit trail in logs
 * - Avoids ORM overhead for maintenance tasks
 *
 * INDEXING:
 * The sessions table has indexes on:
 * - user_id
 * - site_id
 * - updated_at
 * - (updated_at, user_id) composite
 * These indexes ensure efficient query execution.
 */
class SessionCleanupCommand extends Command
{
    /**
     * The name and signature of the console command.
     *
     * @var string
     */
    protected $signature = 'session:cleanup';

    /**
     * The console command description.
     *
     * @var string
     */
    protected $description = 'Clean up expired and abandoned sessions from the database';

    /**
     * Execute the console command.
     */
    public function handle()
    {
        $start_time = microtime(true);

        // Delete guest sessions older than 24 hours
        // Using MySQL date functions for accuracy and performance
        $guest_count = DB::delete('
            DELETE FROM sessions
            WHERE updated_at < DATE_SUB(NOW(), INTERVAL 24 HOUR)
            AND user_id IS NULL
            AND site_id IS NULL
        ');

        // Delete any sessions older than 3 years
        $old_count = DB::delete('
            DELETE FROM sessions
            WHERE updated_at < DATE_SUB(NOW(), INTERVAL 1 YEAR)
        ');

        $total_deleted = $guest_count + $old_count;
        $execution_time = round(microtime(true) - $start_time, 3);

        // Log results
        if ($total_deleted > 0) {
            $this->info('Session cleanup completed:');
            $this->info("  • Guest sessions (>24h): {$guest_count} deleted");
            $this->info("  • Old sessions (>3y): {$old_count} deleted");
            $this->info("  • Total: {$total_deleted} sessions removed");
            $this->info("  • Execution time: {$execution_time}s");

            // Also log to Laravel log for monitoring
            Log::info("Session cleanup: {$total_deleted} sessions deleted", [
                'guest_sessions' => $guest_count,
                'old_sessions' => $old_count,
                'execution_time' => $execution_time,
            ]);
        } else {
            $this->info("No sessions to clean up (execution time: {$execution_time}s)");
        }

        return 0;
    }
}