<?php

namespace App\Services;

use Illuminate\Support\Facades\Log;

/**
 * خدمة إشعارات Firebase (FCM Service)
 * 
 * الغرض من الملف:
 * إرسال التنبيهات (Push Notifications) للهواتف الذكية عبر خدمة Google Firebase.
 * 
 * كيفية العمل:
 * 1. يتصل بخوادم Google باستخدام مفاتيح الوصول (API Keys).
 * 2. يرسل التنبيه للراكب أو السائق بناءً على الرمز (Token) الخاص بجهازه.
 * 3. يدير إرسال البيانات الإضافية (مثل معرف الرحلة) داخل التنبيه لتسهيل التفاعل معه داخل التطبيق.
 */
class FcmService
{
    private ?string $accessToken = null;
    private string $credentialsPath;
    private string $cachePath;

    public function __construct()
    {
        $this->credentialsPath = config('intaleq.fcm_credentials_path');
        $this->cachePath = config('intaleq.fcm_cache_path');
    }

    /**
     * Send localized FCM notification using translation keys (Best for multi-language support)
     */
    /**
     * Send FCM notification to a specific device token (Raw Text)
     */
    public function sendToDevice(string $token, string $title, string $body, array $data = [], string $category = ''): array
    {
        if (empty($token)) {
            return ['status' => 'error', 'message' => 'Empty token'];
        }

        if ($category) {
            $data['category'] = $category;
        }

        $stringData = [];
        foreach ($data as $key => $value) {
            $stringData[$key] = is_array($value) ? json_encode($value) : (string) $value;
        }

        $payload = [
            'message' => [
                'token' => $token,
                'notification' => [
                    'title' => $title,
                    'body' => $body,
                ],
                'data' => $stringData,
                'android' => [
                    'priority' => 'high',
                ],
                'apns' => [
                    'payload' => [
                        'aps' => [
                            'sound' => 'default',
                            'badge' => 1,
                        ],
                    ],
                ],
            ],
        ];

        return $this->sendRequest($payload);
    }

    /**
     * Send localized FCM notification using translation keys (Best for multi-language support)
     */
    public function sendLocalizedToDevice(string $token, string $titleKey, string $bodyKey, array $data = [], string $category = ''): array
    {
        if (empty($token)) {
            return ['status' => 'error', 'message' => 'Empty token'];
        }

        if ($category) {
            $data['category'] = $category;
        }

        $stringData = [];
        foreach ($data as $key => $value) {
            $stringData[$key] = is_array($value) ? json_encode($value) : (string) $value;
        }

        $payload = [
            'message' => [
                'token' => $token,
                'data' => $stringData,
                'android' => [
                    'priority' => 'high',
                    'notification' => [
                        'title_loc_key' => $titleKey,
                        'body_loc_key' => $bodyKey,
                    ],
                ],
                'apns' => [
                    'payload' => [
                        'aps' => [
                            'sound' => 'default',
                            'badge' => 1,
                            'alert' => [
                                'title-loc-key' => $titleKey,
                                'loc-key' => $bodyKey,
                            ],
                        ],
                    ],
                ],
            ],
        ];

        return $this->sendRequest($payload);
    }

    /**
     * Send to FCM topic
     */
    public function sendToTopic(string $topic, string $title, string $body, array $data = []): array
    {
        $payload = [
            'message' => [
                'topic' => $topic,
                'notification' => [
                    'title' => $title,
                    'body' => $body,
                ],
                'data' => array_map('strval', $data),
            ],
        ];

        return $this->sendRequest($payload);
    }

    private function sendRequest(array $payload): array
    {
        $accessToken = $this->getAccessToken();
        if (!$accessToken) {
            return ['status' => 'error', 'message' => 'Failed to get access token'];
        }

        $credentials = json_decode(file_get_contents($this->credentialsPath), true);
        $projectId = $credentials['project_id'] ?? '';
        $url = "https://fcm.googleapis.com/v1/projects/{$projectId}/messages:send";

        $ch = curl_init($url);
        curl_setopt_array($ch, [
            CURLOPT_POST => true,
            CURLOPT_HTTPHEADER => [
                "Authorization: Bearer {$accessToken}",
                'Content-Type: application/json',
            ],
            CURLOPT_POSTFIELDS => json_encode($payload),
            CURLOPT_RETURNTRANSFER => true,
            CURLOPT_TIMEOUT => 10,
        ]);

        $result = curl_exec($ch);
        $httpCode = curl_getinfo($ch, CURLINFO_HTTP_CODE);
        curl_close($ch);

        if ($httpCode === 200) {
            return ['status' => 'success', 'response' => json_decode($result, true)];
        }

        Log::error("[FCM] Error {$httpCode}: {$result}");
        return ['status' => 'error', 'code' => $httpCode, 'response' => $result];
    }

    private function getAccessToken(): ?string
    {
        // Check cache
        if (file_exists($this->cachePath)) {
            $cached = json_decode(file_get_contents($this->cachePath), true);
            if ($cached && ($cached['expires_at'] ?? 0) > time() + 60) {
                return $cached['token'];
            }
        }

        if (!file_exists($this->credentialsPath)) return null;

        $credentials = json_decode(file_get_contents($this->credentialsPath), true);
        $clientEmail = $credentials['client_email'];
        $privateKey = $credentials['private_key'];

        $now = time();
        $header = rtrim(strtr(base64_encode(json_encode(['alg' => 'RS256', 'typ' => 'JWT'])), '+/', '-_'), '=');
        $claim = rtrim(strtr(base64_encode(json_encode([
            'iss' => $clientEmail,
            'scope' => 'https://www.googleapis.com/auth/firebase.messaging',
            'aud' => 'https://oauth2.googleapis.com/token',
            'exp' => $now + 3600,
            'iat' => $now,
        ])), '+/', '-_'), '=');

        $signature = '';
        openssl_sign("{$header}.{$claim}", $signature, $privateKey, 'SHA256');
        $jwt = "{$header}.{$claim}." . rtrim(strtr(base64_encode($signature), '+/', '-_'), '=');

        $ch = curl_init('https://oauth2.googleapis.com/token');
        curl_setopt_array($ch, [
            CURLOPT_POST => true,
            CURLOPT_POSTFIELDS => http_build_query([
                'grant_type' => 'urn:ietf:params:oauth:grant-type:jwt-bearer',
                'assertion' => $jwt,
            ]),
            CURLOPT_RETURNTRANSFER => true,
        ]);
        $res = curl_exec($ch);
        curl_close($ch);

        $token = json_decode($res, true)['access_token'] ?? null;

        if ($token) {
            file_put_contents($this->cachePath, json_encode([
                'token' => $token,
                'expires_at' => time() + 3500,
            ]));
        }

        return $token;
    }
}