<?php
/**
 * Récupération des statistiques de followers pour chaque plateforme sociale.
 * Toutes les fonctions retournent null en cas d'échec — l'affichage reste optionnel.
 * Cache 24h pour limiter les appels externes.
 */

function formatFollowerCount(int $n): string {
    if ($n >= 1_000_000) return number_format($n / 1_000_000, 1, '.', '') . 'M';
    if ($n >= 1_000)     return number_format($n / 1_000, 1, '.', '') . 'K';
    return (string) $n;
}

function _statsCurlFetch(string $url, array $headers = []): ?string {
    $ch = curl_init();
    curl_setopt_array($ch, [
        CURLOPT_URL            => $url,
        CURLOPT_RETURNTRANSFER => true,
        CURLOPT_TIMEOUT        => 8,
        CURLOPT_CONNECTTIMEOUT => 5,
        CURLOPT_FOLLOWLOCATION => false,
        CURLOPT_SSL_VERIFYPEER => true,
        CURLOPT_SSL_VERIFYHOST => 2,
        CURLOPT_USERAGENT      => 'Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 Chrome/124.0 Safari/537.36',
        CURLOPT_HTTPHEADER     => $headers,
    ]);
    $body     = curl_exec($ch);
    $httpCode = curl_getinfo($ch, CURLINFO_HTTP_CODE);
    curl_close($ch);
    return ($body && $httpCode === 200) ? $body : null;
}

function getYouTubeSubscriberCount(): ?int {
    // Priority 1: YouTube Data API v3 (exact count)
    if (defined('YOUTUBE_API_KEY') && !empty(YOUTUBE_API_KEY)) {
        $channelId = getYouTubeChannelId();
        if ($channelId) {
            $cacheKey = 'stat_yt_' . $channelId;
            $cached   = $GLOBALS['simple_api_cache']->get($cacheKey, []);
            if ($cached !== null) return (int) $cached ?: null;

            $data  = callYouTubeApi('channels', ['part' => 'statistics', 'id' => $channelId]);
            $count = isset($data['items'][0]['statistics']['subscriberCount'])
                     ? (int) $data['items'][0]['statistics']['subscriberCount']
                     : null;

            if ($count !== null) {
                $GLOBALS['simple_api_cache']->set($cacheKey, [], $count, 86400);
                return $count;
            }
        }
    }

    // Priority 2: parse ytInitialData from public channel page
    $handle = '';
    if (defined('YOUTUBE_HANDLE') && !empty(YOUTUBE_HANDLE)) {
        $handle = ltrim(YOUTUBE_HANDLE, '@');
    } elseif (defined('YOUTUBE_CHANNEL_HANDLE') && !empty(YOUTUBE_CHANNEL_HANDLE)) {
        $handle = ltrim(YOUTUBE_CHANNEL_HANDLE, '@');
    }

    $pageUrl  = $handle
        ? 'https://www.youtube.com/@' . urlencode($handle)
        : (defined('YOUTUBE_CHANNEL_ID') && YOUTUBE_CHANNEL_ID
            ? 'https://www.youtube.com/channel/' . urlencode(YOUTUBE_CHANNEL_ID)
            : null);

    if (!$pageUrl) return null;

    $cacheKey = 'stat_yt_page_' . preg_replace('/[^a-z0-9]/i', '_', $handle ?: YOUTUBE_CHANNEL_ID);
    $cached   = $GLOBALS['simple_api_cache']->get($cacheKey, []);
    if ($cached !== null) return (int) $cached ?: null;

    $body = _statsCurlFetch($pageUrl, ['Accept-Language: fr-FR,fr;q=0.9,en;q=0.8']);
    if (!$body) return null;

    // ytInitialData embeds exact subscriberCount as a quoted integer string
    if (preg_match('/"subscriberCount"\s*:\s*"(\d+)"/', $body, $m)) {
        $count = (int) $m[1];
        $GLOBALS['simple_api_cache']->set($cacheKey, [], $count, 86400);
        return $count;
    }

    return null;
}

function getInstagramFollowers(): ?int {
    if (!defined('INSTAGRAM_HANDLE') || empty(INSTAGRAM_HANDLE)) return null;

    $handle   = ltrim(INSTAGRAM_HANDLE, '@');
    $cacheKey = 'stat_ig_' . $handle;
    $cached   = $GLOBALS['simple_api_cache']->get($cacheKey, []);
    if ($cached !== null) return (int) $cached ?: null;

    $body = _statsCurlFetch(
        'https://www.instagram.com/api/v1/users/web_profile_info/?username=' . urlencode($handle),
        ['X-IG-App-ID: 936619743392459', 'Accept: application/json']
    );
    if (!$body) return null;

    $data  = json_decode($body, true);
    $count = $data['data']['user']['edge_followed_by']['count'] ?? null;

    if ($count !== null) {
        $count = (int) $count;
        $GLOBALS['simple_api_cache']->set($cacheKey, [], $count, 86400);
    }
    return $count;
}

function getTikTokFollowers(): ?int {
    if (!defined('TIKTOK_HANDLE') || empty(TIKTOK_HANDLE)) return null;

    $handle   = ltrim(TIKTOK_HANDLE, '@');
    $cacheKey = 'stat_tt_' . $handle;
    $cached   = $GLOBALS['simple_api_cache']->get($cacheKey, []);
    if ($cached !== null) return (int) $cached ?: null;

    $body = _statsCurlFetch('https://www.tiktok.com/embed/@' . urlencode($handle));
    if (!$body) return null;

    preg_match('/"followerCount"\s*:\s*(\d+)/', $body, $m);
    $count = isset($m[1]) ? (int) $m[1] : null;

    if ($count !== null) {
        $GLOBALS['simple_api_cache']->set($cacheKey, [], $count, 86400);
    }
    return $count;
}