<?php

namespace App\Jobs;

use App\Models\HealthCheck;
use App\Notifications\HealthCheckAlert;
use App\Notifications\PerformanceAlert;
use GuzzleHttp\Client;
use GuzzleHttp\Exception\ConnectException;
use GuzzleHttp\Exception\RequestException;
use Illuminate\Bus\Queueable;
use Illuminate\Contracts\Queue\ShouldQueue;
use Illuminate\Foundation\Bus\Dispatchable;
use Illuminate\Queue\InteractsWithQueue;
use Illuminate\Queue\SerializesModels;
use Illuminate\Support\Facades\Log;

class CheckHealthEndpoint implements ShouldQueue
{
    use Dispatchable, InteractsWithQueue, Queueable, SerializesModels;

    /**
     * The number of times the job may be attempted.
     *
     * @var int
     */
    public $tries = 3;

    /**
     * The number of seconds the job can run before timing out.
     *
     * @var int
     */
    public $timeout = 60;

    /**
     * Create a new job instance.
     */
    public function __construct(
        public HealthCheck $healthCheck
    ) {}

    /**
     * Execute the job.
     */
    public function handle(): void
    {
        try {
            $client = new Client([
                'timeout' => 10,
                'connect_timeout' => 5,
                'allow_redirects' => [
                    'max' => 3,
                    'track_redirects' => true,
                ],
                'http_errors' => false,
            ]);

            $url = $this->healthCheck->full_url;
            $startTime = microtime(true);

            Log::info('CheckHealthEndpoint: Starting check', [
                'health_check_id' => $this->healthCheck->id,
                'url' => $url,
            ]);

            $response = $client->get($url, [
                'headers' => [
                    'Accept' => 'application/json',
                    'User-Agent' => 'IsMySiteUp Health Monitor/1.0',
                ],
            ]);

            $endTime = microtime(true);
            $responseTime = (int) round(($endTime - $startTime) * 1000);
            $statusCode = $response->getStatusCode();
            $body = (string) $response->getBody();

            // Try to decode JSON
            $responseData = null;
            $isValidJson = false;

            try {
                $responseData = json_decode($body, true, 512, JSON_THROW_ON_ERROR);
                $isValidJson = true;
            } catch (\JsonException $e) {
                Log::warning('CheckHealthEndpoint: Invalid JSON response', [
                    'health_check_id' => $this->healthCheck->id,
                    'error' => $e->getMessage(),
                    'body_preview' => substr($body, 0, 500),
                ]);
            }

            // Determine if endpoint is healthy
            $isHealthy = $this->determineHealth($statusCode, $isValidJson, $responseData);

            $wasHealthy = $this->healthCheck->is_healthy;

            // Update health check record
            $this->healthCheck->update([
                'last_checked_at' => now(),
                'is_healthy' => $isHealthy,
                'response_data' => $responseData,
                'response_time_ms' => $responseTime,
                'status_code' => $statusCode,
            ]);

            Log::info('CheckHealthEndpoint: Check completed', [
                'health_check_id' => $this->healthCheck->id,
                'is_healthy' => $isHealthy,
                'status_code' => $statusCode,
                'response_time_ms' => $responseTime,
            ]);

            // Send notification if health status changed from healthy to unhealthy
            if ($wasHealthy === true && $isHealthy === false) {
                $this->healthCheck->site->user->notify(new HealthCheckAlert(
                    $this->healthCheck,
                    'unhealthy',
                    $statusCode,
                    $responseTime
                ));

                Log::warning('CheckHealthEndpoint: Unhealthy alert sent', [
                    'health_check_id' => $this->healthCheck->id,
                    'status_code' => $statusCode,
                ]);
            }

            // Optionally send notification when health is restored
            if ($wasHealthy === false && $isHealthy === true) {
                $this->healthCheck->site->user->notify(new HealthCheckAlert(
                    $this->healthCheck,
                    'healthy',
                    $statusCode,
                    $responseTime
                ));

                Log::info('CheckHealthEndpoint: Healthy alert sent', [
                    'health_check_id' => $this->healthCheck->id,
                ]);
            }

            // Check performance threshold and send alert if exceeded
            if ($this->healthCheck->performance_threshold && $responseTime > $this->healthCheck->performance_threshold) {
                $this->healthCheck->site->user->notify(new PerformanceAlert(
                    resourceType: 'Health Check',
                    resourceName: $this->healthCheck->endpoint,
                    responseTime: $responseTime,
                    threshold: $this->healthCheck->performance_threshold,
                    url: $this->healthCheck->full_url,
                    resourceId: $this->healthCheck->site_id
                ));

                Log::warning('CheckHealthEndpoint: Performance threshold exceeded', [
                    'health_check_id' => $this->healthCheck->id,
                    'response_time_ms' => $responseTime,
                    'threshold_ms' => $this->healthCheck->performance_threshold,
                ]);
            }

        } catch (ConnectException $e) {
            // Connection timeout or DNS failure
            Log::error('CheckHealthEndpoint: Connection failed', [
                'health_check_id' => $this->healthCheck->id,
                'error' => $e->getMessage(),
            ]);

            $this->healthCheck->update([
                'last_checked_at' => now(),
                'is_healthy' => false,
                'response_data' => ['error' => 'Connection failed: ' . $e->getMessage()],
                'response_time_ms' => null,
                'status_code' => null,
            ]);

        } catch (RequestException $e) {
            // HTTP error occurred
            $statusCode = $e->getResponse() ? $e->getResponse()->getStatusCode() : null;

            Log::error('CheckHealthEndpoint: Request failed', [
                'health_check_id' => $this->healthCheck->id,
                'status_code' => $statusCode,
                'error' => $e->getMessage(),
            ]);

            $this->healthCheck->update([
                'last_checked_at' => now(),
                'is_healthy' => false,
                'response_data' => ['error' => 'Request failed: ' . $e->getMessage()],
                'response_time_ms' => null,
                'status_code' => $statusCode,
            ]);

        } catch (\Exception $e) {
            // Any other exception
            Log::error('CheckHealthEndpoint: Unexpected error', [
                'health_check_id' => $this->healthCheck->id,
                'error' => $e->getMessage(),
                'trace' => $e->getTraceAsString(),
            ]);

            $this->healthCheck->update([
                'last_checked_at' => now(),
                'is_healthy' => false,
                'response_data' => ['error' => 'Unexpected error: ' . $e->getMessage()],
                'response_time_ms' => null,
                'status_code' => null,
            ]);

            throw $e;
        }
    }

    /**
     * Determine if the endpoint is healthy based on response.
     */
    protected function determineHealth(int $statusCode, bool $isValidJson, ?array $responseData): bool
    {
        // Check if status code is successful (2xx)
        if ($statusCode < 200 || $statusCode >= 300) {
            return false;
        }

        // Check if response is valid JSON
        if (!$isValidJson) {
            return false;
        }

        // Validate expected JSON keys if configured
        if (!empty($this->healthCheck->expected_json_keys)) {
            if (!$this->healthCheck->validateResponseKeys($responseData ?? [])) {
                Log::warning('CheckHealthEndpoint: Missing expected JSON keys', [
                    'health_check_id' => $this->healthCheck->id,
                    'expected_keys' => $this->healthCheck->expected_json_keys,
                    'response_keys' => array_keys($responseData ?? []),
                ]);
                return false;
            }
        }

        return true;
    }

    /**
     * Handle a job failure.
     */
    public function failed(\Throwable $exception): void
    {
        Log::error('CheckHealthEndpoint: Job failed after all retries', [
            'health_check_id' => $this->healthCheck->id,
            'exception' => $exception->getMessage(),
        ]);
    }
}