<?php

namespace App\Services\Partners\Platforms;

use Exception;
use Illuminate\Support\Facades\Cache;
use Illuminate\Support\Facades\Http;

class Rakuten
{
    public function __construct(protected array $partnerConfig)
    {
    }

    /**
     * Generates an affiliate link for a given partner and URL.
     *
     * @param  string  $partnerName  The name of the partner.
     * @param  string  $originalUrl  The original URL to be converted into an affiliate link.
     * @return string|null The generated affiliate link or null in case of failure.
     */
    public function getAffiliateLink(string $partnerName, string $originalUrl): ?string
    {
        // Creating a unique cache key based on partner name and original URL
        $cacheKey = sprintf('rakuten_%s_%s', $partnerName, base64_encode($originalUrl));

        // Attempting to retrieve the affiliate link from cache to avoid unnecessary API calls
        if (Cache::has($cacheKey)) {
            return Cache::get($cacheKey);
        }

        // Getting access token for the API
        $accessToken = $this->getAccessToken();
        if (empty($accessToken)) {
            // Return null if we cannot obtain an access token
            return null;
        }

        try {
            // Making a POST request to the Rakuten API to generate the affiliate link
            $response = Http::throw()
                ->withHeaders([
                    'Authorization' => sprintf('Bearer %s', $accessToken),
                ])
                ->post('https://api.linksynergy.com/v1/links/deep_links', [
                    'url'           => $originalUrl,
                    'advertiser_id' => $this->partnerConfig['advertiser_id'],
                ]);
        } catch (Exception $ex) {
            // Logging the exception for debugging purposes
            report($ex);

            return null;
        }

        // Verifying the API response and extracting the affiliate link
        if (!$response->ok() || empty($response->json()['advertiser']['deep_link']['deep_link_url'])) {
            return null;
        }

        $url = $response->json()['advertiser']['deep_link']['deep_link_url'];

        // Storing the generated affiliate link in cache for 24 hours to improve performance
        Cache::put($cacheKey, $url, 60 * 60 * 24);

        return $url;
    }

    /**
     * Retrieves the access token required for API calls, with caching to optimize the process.
     *
     * @return string|null The access token or null if retrieval fails.
     */
    private function getAccessToken(): ?string
    {
        $cacheKey = 'rakuten.access_token';
        $token    = Cache::get($cacheKey);

        // Return cached token if available
        if (!empty($token)) {
            return $token;
        }

        try {
            // Requesting a new access token from the Rakuten API
            $response = Http::throw()
                ->asForm()
                ->withHeaders([
                    'Authorization' => sprintf('Bearer %s', config('services.rakuten.token_key')),
                ])
                ->post('https://api.linksynergy.com/token', [
                    'scope' => config('services.rakuten.sid'),
                ]);
        } catch (Exception $ex) {
            // Logging the exception for debugging purposes
            report($ex);

            return null;
        }

        // Verifying the API response and extracting the access token and its expiration time
        if (!$response->ok() || empty($response->json()['access_token']) || empty($response->json()['expires_in'])) {
            return null;
        }

        $accessToken = $response->json()['access_token'];
        $expire      = $response->json()['expires_in'];

        // Caching the access token for the duration of its validity to reduce API calls
        Cache::put($cacheKey, $accessToken, $expire);

        return $accessToken;
    }
}