<?php

namespace App\Services\Video;

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

class TrendingKeywordService
{
    private const CACHE_KEY = 'google_trends_kr';

    private const CACHE_TTL = 1800; // 30분

    private const RSS_URL = 'https://trends.google.co.kr/trending/rss?geo=KR';

    /**
     * Google Trends RSS에서 한국 실시간 급상승 키워드 수집
     */
    public function fetchTrendingKeywords(int $limit = 10): array
    {
        return Cache::remember(self::CACHE_KEY, self::CACHE_TTL, function () use ($limit) {
            try {
                $response = Http::timeout(10)
                    ->withHeaders(['Accept' => 'application/xml'])
                    ->get(self::RSS_URL);

                if (! $response->successful()) {
                    Log::warning('TrendingKeywordService: RSS 호출 실패', [
                        'status' => $response->status(),
                    ]);

                    return [];
                }

                $keywords = $this->parseGoogleTrendsRss($response->body());

                return array_slice($keywords, 0, $limit);
            } catch (\Exception $e) {
                Log::error('TrendingKeywordService: 예외 발생', [
                    'error' => $e->getMessage(),
                ]);

                return [];
            }
        });
    }

    /**
     * RSS XML 파싱
     */
    private function parseGoogleTrendsRss(string $xml): array
    {
        $keywords = [];

        try {
            // XML namespace 처리를 위해 ht: 접두사 등록
            $doc = new \SimpleXMLElement($xml);
            $namespaces = $doc->getNamespaces(true);

            $items = $doc->channel->item ?? [];

            foreach ($items as $item) {
                $keyword = (string) $item->title;

                if (empty($keyword)) {
                    continue;
                }

                $traffic = '';
                $newsTitle = '';

                if (isset($namespaces['ht'])) {
                    $htData = $item->children($namespaces['ht']);
                    $traffic = (string) ($htData->approx_traffic ?? '');

                    if (isset($htData->news_item)) {
                        $newsTitle = (string) ($htData->news_item->news_item_title ?? '');
                    }
                }

                $pubDate = (string) ($item->pubDate ?? '');

                $keywords[] = [
                    'keyword' => $keyword,
                    'traffic' => $traffic,
                    'news_title' => $newsTitle,
                    'pub_date' => $pubDate ? date('c', strtotime($pubDate)) : null,
                ];
            }
        } catch (\Exception $e) {
            Log::error('TrendingKeywordService: XML 파싱 실패', [
                'error' => $e->getMessage(),
            ]);
        }

        return $keywords;
    }
}