<?php

namespace App\Module\OpenAPI\Services;

use App\Module\OpenAPI\Models\OpenApiApp;
use App\Module\OpenAPI\Models\OpenApiWebhook;
use Illuminate\Support\Facades\Http;
use Illuminate\Support\Facades\Log;
use Illuminate\Support\Facades\Queue;

/**
 * Webhook回调服务
 * 
 * 提供Webhook回调管理和发送功能
 */
class WebhookService
{
    /**
     * 创建Webhook配置
     *
     * @param OpenApiApp $app
     * @param array $data
     * @return OpenApiWebhook
     */
    public function createWebhook(OpenApiApp $app, array $data): OpenApiWebhook
    {
        $data['app_id'] = $app->app_id;
        $data['status'] = $data['status'] ?? 'ACTIVE';
        $data['secret'] = $data['secret'] ?? $this->generateWebhookSecret();

        return OpenApiWebhook::create($data);
    }

    /**
     * 发送Webhook通知
     *
     * @param string $appId
     * @param string $event
     * @param array $payload
     * @param bool $async 是否异步发送
     * @return bool
     */
    public function sendWebhook(string $appId, string $event, array $payload, bool $async = true): bool
    {
        $webhooks = $this->getActiveWebhooks($appId, $event);

        if (empty($webhooks)) {
            return true; // 没有配置Webhook，视为成功
        }

        foreach ($webhooks as $webhook) {
            if ($async) {
                // 异步发送
                Queue::push(function () use ($webhook, $event, $payload) {
                    $this->deliverWebhook($webhook, $event, $payload);
                });
            } else {
                // 同步发送
                $this->deliverWebhook($webhook, $event, $payload);
            }
        }

        return true;
    }

    /**
     * 投递Webhook
     *
     * @param OpenApiWebhook $webhook
     * @param string $event
     * @param array $payload
     * @return bool
     */
    protected function deliverWebhook(OpenApiWebhook $webhook, string $event, array $payload): bool
    {
        $deliveryId = uniqid('webhook_');
        $timestamp = time();

        // 构建请求数据
        $requestData = [
            'id' => $deliveryId,
            'event' => $event,
            'timestamp' => $timestamp,
            'data' => $payload,
        ];

        // 生成签名
        $signature = $this->generateSignature($requestData, $webhook->secret);

        // 构建请求头
        $headers = [
            'Content-Type' => 'application/json',
            'User-Agent' => 'OpenAPI-Webhook/1.0',
            'X-Webhook-Event' => $event,
            'X-Webhook-Delivery' => $deliveryId,
            'X-Webhook-Timestamp' => $timestamp,
            'X-Webhook-Signature' => $signature,
        ];

        $startTime = microtime(true);
        $success = false;
        $responseStatus = 0;
        $responseBody = '';
        $errorMessage = '';

        try {
            // 发送HTTP请求
            $response = Http::timeout($webhook->timeout ?? 30)
                ->withHeaders($headers)
                ->post($webhook->url, $requestData);

            $responseStatus = $response->status();
            $responseBody = $response->body();
            $success = $response->successful();

            if (!$success) {
                $errorMessage = "HTTP {$responseStatus}: {$responseBody}";
            }

        } catch (\Exception $e) {
            $errorMessage = $e->getMessage();
            Log::error('Webhook delivery failed', [
                'webhook_id' => $webhook->id,
                'url' => $webhook->url,
                'event' => $event,
                'error' => $errorMessage,
            ]);
        }

        $responseTime = (microtime(true) - $startTime) * 1000; // 毫秒

        // 记录投递日志
        $this->logWebhookDelivery($webhook, $event, $requestData, [
            'delivery_id' => $deliveryId,
            'success' => $success,
            'response_status' => $responseStatus,
            'response_body' => $responseBody,
            'response_time' => $responseTime,
            'error_message' => $errorMessage,
        ]);

        // 更新Webhook统计
        $this->updateWebhookStats($webhook, $success);

        // 如果失败且配置了重试，安排重试
        if (!$success && $webhook->retry_count > 0) {
            $this->scheduleRetry($webhook, $event, $payload, $deliveryId);
        }

        return $success;
    }

    /**
     * 获取活跃的Webhook配置
     *
     * @param string $appId
     * @param string $event
     * @return array
     */
    protected function getActiveWebhooks(string $appId, string $event): array
    {
        return OpenApiWebhook::where('app_id', $appId)
            ->where('status', 'ACTIVE')
            ->where(function ($query) use ($event) {
                $query->whereJsonContains('events', $event)
                      ->orWhereJsonContains('events', '*');
            })
            ->get()
            ->toArray();
    }

    /**
     * 生成Webhook签名
     *
     * @param array $data
     * @param string $secret
     * @return string
     */
    protected function generateSignature(array $data, string $secret): string
    {
        $payload = json_encode($data, JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE);
        return 'sha256=' . hash_hmac('sha256', $payload, $secret);
    }

    /**
     * 验证Webhook签名
     *
     * @param string $payload
     * @param string $signature
     * @param string $secret
     * @return bool
     */
    public function verifySignature(string $payload, string $signature, string $secret): bool
    {
        $expectedSignature = 'sha256=' . hash_hmac('sha256', $payload, $secret);
        return hash_equals($expectedSignature, $signature);
    }

    /**
     * 生成Webhook密钥
     *
     * @return string
     */
    protected function generateWebhookSecret(): string
    {
        return bin2hex(random_bytes(32));
    }

    /**
     * 记录Webhook投递日志
     *
     * @param OpenApiWebhook $webhook
     * @param string $event
     * @param array $requestData
     * @param array $responseData
     * @return void
     */
    protected function logWebhookDelivery(OpenApiWebhook $webhook, string $event, array $requestData, array $responseData): void
    {
        Log::info('Webhook delivered', [
            'webhook_id' => $webhook->id,
            'app_id' => $webhook->app_id,
            'url' => $webhook->url,
            'event' => $event,
            'delivery_id' => $responseData['delivery_id'],
            'success' => $responseData['success'],
            'response_status' => $responseData['response_status'],
            'response_time' => $responseData['response_time'],
            'error_message' => $responseData['error_message'] ?? null,
        ]);
    }

    /**
     * 更新Webhook统计
     *
     * @param OpenApiWebhook $webhook
     * @param bool $success
     * @return void
     */
    protected function updateWebhookStats(OpenApiWebhook $webhook, bool $success): void
    {
        $webhook->increment('total_deliveries');
        
        if ($success) {
            $webhook->increment('successful_deliveries');
            $webhook->update(['last_success_at' => now()]);
        } else {
            $webhook->increment('failed_deliveries');
            $webhook->update(['last_failure_at' => now()]);
        }
    }

    /**
     * 安排重试
     *
     * @param OpenApiWebhook $webhook
     * @param string $event
     * @param array $payload
     * @param string $originalDeliveryId
     * @return void
     */
    protected function scheduleRetry(OpenApiWebhook $webhook, string $event, array $payload, string $originalDeliveryId): void
    {
        // 计算重试延迟（指数退避）
        $retryAttempt = $webhook->current_retry_count ?? 0;
        $delay = min(300, pow(2, $retryAttempt) * 10); // 最大5分钟

        Queue::later($delay, function () use ($webhook, $event, $payload, $originalDeliveryId, $retryAttempt) {
            if ($retryAttempt < $webhook->retry_count) {
                $webhook->increment('current_retry_count');
                $this->deliverWebhook($webhook, $event, $payload);
            }
        });

        Log::info('Webhook retry scheduled', [
            'webhook_id' => $webhook->id,
            'original_delivery_id' => $originalDeliveryId,
            'retry_attempt' => $retryAttempt + 1,
            'delay_seconds' => $delay,
        ]);
    }

    /**
     * 测试Webhook配置
     *
     * @param OpenApiWebhook $webhook
     * @return array
     */
    public function testWebhook(OpenApiWebhook $webhook): array
    {
        $testPayload = [
            'test' => true,
            'message' => 'This is a test webhook delivery',
            'timestamp' => now()->toISOString(),
        ];

        $success = $this->deliverWebhook($webhook, 'test', $testPayload);

        return [
            'success' => $success,
            'webhook_id' => $webhook->id,
            'url' => $webhook->url,
            'test_payload' => $testPayload,
        ];
    }

    /**
     * 获取Webhook投递统计
     *
     * @param string $appId
     * @param string $period
     * @return array
     */
    public function getWebhookStats(string $appId, string $period = 'day'): array
    {
        $webhooks = OpenApiWebhook::where('app_id', $appId)->get();

        $stats = [
            'total_webhooks' => $webhooks->count(),
            'active_webhooks' => $webhooks->where('status', 'ACTIVE')->count(),
            'total_deliveries' => $webhooks->sum('total_deliveries'),
            'successful_deliveries' => $webhooks->sum('successful_deliveries'),
            'failed_deliveries' => $webhooks->sum('failed_deliveries'),
        ];

        $stats['success_rate'] = $stats['total_deliveries'] > 0 
            ? round(($stats['successful_deliveries'] / $stats['total_deliveries']) * 100, 2)
            : 0;

        return $stats;
    }
}