<?php

declare(strict_types=1);

namespace App\Framework\Process\Services;

use App\Framework\Process\ValueObjects\Alert\Alert;
use App\Framework\Process\ValueObjects\Alert\AlertReport;
use App\Framework\Process\ValueObjects\Alert\AlertSeverity;
use App\Framework\Process\ValueObjects\Alert\AlertThreshold;
use App\Framework\Process\ValueObjects\Health\HealthReport;

/**
 * Alert Service.
 *
 * Verwaltet System-Alerts basierend auf Health Checks und Thresholds.
 */
final readonly class AlertService
{
    /**
     * @param AlertThreshold[] $thresholds
     */
    public function __construct(
        private SystemHealthCheckService $healthCheck,
        private array $thresholds = []
    ) {
    }

    /**
     * Prüft alle Alerts und gibt einen Report zurück.
     */
    public function checkAlerts(): AlertReport
    {
        $healthReport = ($this->healthCheck)();
        $alerts = [];

        // Check health checks for alerts
        foreach ($healthReport->checks as $check) {
            $threshold = $this->findThreshold($check->name);

            if ($threshold === null) {
                // Use default thresholds based on health check status
                if ($check->status->value === 'unhealthy') {
                    $alerts[] = Alert::create(
                        id: $this->generateAlertId($check->name),
                        name: $check->name,
                        severity: AlertSeverity::CRITICAL,
                        message: $check->message,
                        description: "Value: {$check->value} {$check->unit} exceeds critical threshold",
                        metadata: [
                            'value' => $check->value,
                            'unit' => $check->unit,
                            'threshold' => $check->threshold,
                        ]
                    );
                } elseif ($check->status->value === 'degraded') {
                    $alerts[] = Alert::create(
                        id: $this->generateAlertId($check->name),
                        name: $check->name,
                        severity: AlertSeverity::WARNING,
                        message: $check->message,
                        description: "Value: {$check->value} {$check->unit} exceeds warning threshold",
                        metadata: [
                            'value' => $check->value,
                            'unit' => $check->unit,
                            'threshold' => $check->threshold,
                        ]
                    );
                }
            } else {
                // Use configured threshold
                $severity = $threshold->getSeverity($check->value);

                if ($severity !== AlertSeverity::INFO) {
                    $alerts[] = Alert::create(
                        id: $this->generateAlertId($check->name),
                        name: $check->name,
                        severity: $severity,
                        message: $check->message,
                        description: "Value: {$check->value} {$check->unit} exceeds {$severity->value} threshold",
                        metadata: [
                            'value' => $check->value,
                            'unit' => $check->unit,
                            'threshold' => $threshold->criticalThreshold,
                            'warning_threshold' => $threshold->warningThreshold,
                        ]
                    );
                }
            }
        }

        return AlertReport::fromAlerts($alerts);
    }

    /**
     * Findet Threshold für einen Check-Namen.
     */
    private function findThreshold(string $checkName): ?AlertThreshold
    {
        foreach ($this->thresholds as $threshold) {
            if ($threshold->name === $checkName) {
                return $threshold;
            }
        }

        return null;
    }

    /**
     * Generiert eine eindeutige Alert-ID.
     */
    private function generateAlertId(string $checkName): string
    {
        return 'alert_' . md5($checkName . time());
    }

    /**
     * Gibt die Standard-Thresholds zurück.
     *
     * @return AlertThreshold[]
     */
    public static function getDefaultThresholds(): array
    {
        return [
            new AlertThreshold(
                name: 'Memory Usage',
                warningThreshold: 80.0,
                criticalThreshold: 90.0,
                unit: '%',
                description: 'Memory usage percentage'
            ),
            new AlertThreshold(
                name: 'Disk Usage',
                warningThreshold: 80.0,
                criticalThreshold: 90.0,
                unit: '%',
                description: 'Disk usage percentage'
            ),
            new AlertThreshold(
                name: 'System Load',
                warningThreshold: 80.0,
                criticalThreshold: 120.0,
                unit: '%',
                description: 'System load percentage'
            ),
        ];
    }
}