<?php
// Timezone: the eternal struggle between server time and human sanity
date_default_timezone_set('UTC'); // Adjust to your server's actual timezone

header('Content-Type: application/json');

// Paranoid? Maybe. Secure? Definitely.
// Nginx filters IPs, but we're not taking chances with your data
$allowedIPs = ['127.0.0.1', '::1'];
$clientIP = $_SERVER['REMOTE_ADDR'] ?? '';

// Math! It's what separates us from the script kiddies
function ipInRange($ip, $range) {
    list($subnet, $mask) = explode('/', $range);
    $ipLong = ip2long($ip);
    $subnetLong = ip2long($subnet);
    $maskLong = -1 << (32 - (int)$mask);
    return ($ipLong & $maskLong) === ($subnetLong & $maskLong);
}

$isLocal = in_array($clientIP, $allowedIPs) || 
           (filter_var($clientIP, FILTER_VALIDATE_IP, FILTER_FLAG_NO_PRIV_RANGE | FILTER_FLAG_NO_RES_RANGE) === false) ||
           ipInRange($clientIP, '10.0.0.0/8') ||
           ipInRange($clientIP, '172.16.0.0/12') ||
           ipInRange($clientIP, '192.168.0.0/16');

if (!$isLocal) {
    http_response_code(403);
    echo json_encode(['error' => 'Access denied']);  // No peeking, strangers
    exit;
}

$date = isset($_GET['date']) ? $_GET['date'] : date('Y-m-d');
$endDate = isset($_GET['endDate']) ? $_GET['endDate'] : null;
$dataDir = __DIR__ . '/../data/analytics';
$reactionsDir = __DIR__ . '/../data/reactions';

// Date range wizard - conjures dates out of thin air
function getDatesInRange($startDate, $endDate) {
    $dates = [];
    $current = strtotime($startDate);
    $end = strtotime($endDate);
    while ($current <= $end) {
        $dates[] = date('Y-m-d', $current);
        $current = strtotime('+1 day', $current);
    }
    return $dates;
}

// Load summary data - aggregate if date range is provided
$data = [
    'total' => 0,
    'new' => 0,
    'returning' => 0,
    'byHour' => array_fill(0, 24, 0),
    'shares' => ['mastodon' => 0, 'bluesky' => 0, 'copy' => 0],
    'rss' => 0
];

if ($endDate && $endDate >= $date) {
    // Date range mode - aggregate data from multiple days
    $dates = getDatesInRange($date, $endDate);
    $allVisits = [];
    
    foreach ($dates as $dayDate) {
        $filename = $dataDir . '/summary_' . $dayDate . '.json';
        if (file_exists($filename)) {
            $dayData = json_decode(file_get_contents($filename), true);
            if ($dayData) {
                // Aggregate totals
                $data['total'] += $dayData['total'] ?? 0;
                $data['new'] += $dayData['new'] ?? 0;
                $data['returning'] += $dayData['returning'] ?? 0;
                
                // Aggregate shares
                if (isset($dayData['shares'])) {
                    $data['shares']['mastodon'] += $dayData['shares']['mastodon'] ?? 0;
                    $data['shares']['bluesky'] += $dayData['shares']['bluesky'] ?? 0;
                    $data['shares']['copy'] += $dayData['shares']['copy'] ?? 0;
                }
                
                // Aggregate hourly data
                if (isset($dayData['byHour']) && is_array($dayData['byHour'])) {
                    for ($i = 0; $i < 24; $i++) {
                        $data['byHour'][$i] += $dayData['byHour'][$i] ?? 0;
                    }
                }
                
                // Collect visits for recent visitors
                $visitsFile = $dataDir . '/visits_' . $dayDate . '.json';
                if (file_exists($visitsFile)) {
                    $dayVisits = json_decode(file_get_contents($visitsFile), true) ?: [];
                    $allVisits = array_merge($allVisits, $dayVisits);
                }
            }
        } else {
            // Load visits even if summary doesn't exist
            $visitsFile = $dataDir . '/visits_' . $dayDate . '.json';
            if (file_exists($visitsFile)) {
                $dayVisits = json_decode(file_get_contents($visitsFile), true) ?: [];
                $allVisits = array_merge($allVisits, $dayVisits);
            }
        }
    }
    
    // Recalculate byHour from actual timestamps for the range
    $recalculatedByHour = array_fill(0, 24, 0);
    foreach ($allVisits as $visit) {
        if (isset($visit['type']) && $visit['type'] === 'pageview' && isset($visit['timestamp'])) {
            $hour = (int)date('H', $visit['timestamp']);
            if ($hour >= 0 && $hour < 24) {
                $recalculatedByHour[$hour]++;
            }
        }
    }
    $data['byHour'] = $recalculatedByHour;
    
    // Use all visits for recent visitors
    $visits = $allVisits;
} else {
    // Single date mode
    $filename = $dataDir . '/summary_' . $date . '.json';
    if (file_exists($filename)) {
        $data = json_decode(file_get_contents($filename), true);
    }
    
    // Load visits file for this date
    $visitsFile = $dataDir . '/visits_' . $date . '.json';
    $visits = [];
    if (file_exists($visitsFile)) {
        $visits = json_decode(file_get_contents($visitsFile), true) ?: [];
    }
    
    // Recalculate byHour from actual timestamps
    $recalculatedByHour = array_fill(0, 24, 0);
    foreach ($visits as $visit) {
        if (isset($visit['type']) && $visit['type'] === 'pageview' && isset($visit['timestamp'])) {
            $hour = (int)date('H', $visit['timestamp']);
            if ($hour >= 0 && $hour < 24) {
                $recalculatedByHour[$hour]++;
            }
        }
    }
    $data['byHour'] = $recalculatedByHour;
}

// Ensure RSS tracking exists
if (!isset($data['rss'])) {
    $data['rss'] = 0;
}

// Calculate active RSS subscribers (readers who fetched in last 7 days)
$readersFile = $dataDir . '/rss_readers.json';
$activeRssSubscribers = 0;
if (file_exists($readersFile)) {
    $readers = json_decode(file_get_contents($readersFile), true) ?: [];
    $sevenDaysAgo = time() - (7 * 24 * 60 * 60);
    foreach ($readers as $reader) {
        if (isset($reader['lastFetch']) && $reader['lastFetch'] >= $sevenDaysAgo) {
            $activeRssSubscribers++;
        }
    }
}
$data['activeRssSubscribers'] = $activeRssSubscribers;

// Get 10 most recent unique IP addresses with geolocation
function getGeolocation($ip) {
    // Skip private/local IPs
    if (filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_NO_PRIV_RANGE | FILTER_FLAG_NO_RES_RANGE) === false) {
        return ['country' => 'Local', 'city' => 'Private Network', 'isp' => ''];
    }
    
    // Use ip-api.com (free, no API key needed, 45 requests/minute limit)
    $url = "http://ip-api.com/json/{$ip}?fields=status,country,countryCode,city,region,isp,query";
    
    // Use file_get_contents with stream context
    $context = stream_context_create([
        'http' => [
            'timeout' => 2,
            'method' => 'GET',
            'header' => 'User-Agent: Analytics/1.0'
        ]
    ]);
    
    $response = @file_get_contents($url, false, $context);
    
    if ($response) {
        $geo = json_decode($response, true);
        if ($geo && isset($geo['status']) && $geo['status'] === 'success') {
            return [
                'country' => $geo['country'] ?? 'Unknown',
                'countryCode' => $geo['countryCode'] ?? '',
                'city' => $geo['city'] ?? 'Unknown',
                'region' => $geo['region'] ?? '',
                'isp' => $geo['isp'] ?? 'Unknown',
                'ip' => $geo['query'] ?? $ip
            ];
        }
    }
    
    return ['country' => 'Unknown', 'city' => 'Unknown', 'isp' => 'Unknown', 'ip' => $ip];
}

// Get unique IPs with their most recent visit timestamp
$ipVisits = [];
foreach ($visits as $visit) {
    $ip = $visit['ip'] ?? '';
    if ($ip && !isset($ipVisits[$ip])) {
        $ipVisits[$ip] = [
            'ip' => $ip,
            'timestamp' => $visit['timestamp'] ?? 0,
            'page' => $visit['page'] ?? '',
            'userAgent' => $visit['userAgent'] ?? ''
        ];
    } elseif ($ip && isset($ipVisits[$ip])) {
        // Keep the most recent timestamp
        if (($visit['timestamp'] ?? 0) > $ipVisits[$ip]['timestamp']) {
            $ipVisits[$ip]['timestamp'] = $visit['timestamp'] ?? 0;
            $ipVisits[$ip]['page'] = $visit['page'] ?? '';
        }
    }
}

// Sort by timestamp (most recent first) and get top 10
usort($ipVisits, function($a, $b) {
    return $b['timestamp'] - $a['timestamp'];
});
$recentIPs = array_slice($ipVisits, 0, 10);

// Get geolocation for each IP (with caching to avoid rate limits)
$geoCacheFile = $dataDir . '/geo_cache.json';
$geoCache = [];
if (file_exists($geoCacheFile)) {
    $geoCache = json_decode(file_get_contents($geoCacheFile), true) ?: [];
}

$recentVisitors = [];
foreach ($recentIPs as $ipVisit) {
    $ip = $ipVisit['ip'];
    
    // Check cache first (cache expires after 24 hours)
    $geo = null;
    if (isset($geoCache[$ip]) && (time() - $geoCache[$ip]['cached_at']) < 86400) {
        $geo = $geoCache[$ip]['data'];
    } else {
        $geo = getGeolocation($ip);
        $geoCache[$ip] = ['data' => $geo, 'cached_at' => time()];
        // Small delay to respect API rate limits
        usleep(200000); // 0.2 second delay
    }
    
    $recentVisitors[] = [
        'ip' => $ip,
        'timestamp' => $ipVisit['timestamp'],
        'time' => gmdate('Y-m-d\TH:i:s\Z', $ipVisit['timestamp']), // ISO 8601 UTC format for frontend conversion
        'page' => $ipVisit['page'],
        'country' => $geo['country'] ?? 'Unknown',
        'countryCode' => $geo['countryCode'] ?? '',
        'city' => $geo['city'] ?? 'Unknown',
        'region' => $geo['region'] ?? '',
        'isp' => $geo['isp'] ?? 'Unknown'
    ];
}

// Save updated cache
if (count($geoCache) > 0) {
    file_put_contents($geoCacheFile, json_encode($geoCache, JSON_PRETTY_PRINT));
}

$data['recentVisitors'] = $recentVisitors;

// Ensure shares structure exists and normalize old platform names
if (!isset($data['shares'])) {
    $data['shares'] = ['mastodon' => 0, 'bluesky' => 0, 'copy' => 0];
} else {
    // Normalize old platform names to new ones
    $normalizedShares = ['mastodon' => 0, 'bluesky' => 0, 'copy' => 0];
    foreach ($data['shares'] as $platform => $count) {
        if ($platform === 'twitter' || $platform === 'mastodon') {
            $normalizedShares['mastodon'] += $count;
        } else if ($platform === 'facebook' || $platform === 'bluesky') {
            $normalizedShares['bluesky'] += $count;
        } else if ($platform === 'copy') {
            $normalizedShares['copy'] += $count;
        }
    }
    $data['shares'] = $normalizedShares;
}

// Load blog posts and their stats
$postsFile = __DIR__ . '/../blog/data/posts.json';
$posts = [];
if (file_exists($postsFile)) {
    $posts = json_decode(file_get_contents($postsFile), true) ?: [];
}

// Get reactions and shares for each post
$blogStats = [];
foreach ($posts as $post) {
    $postId = $post['id'];
    $reactionFile = $reactionsDir . '/post_' . $postId . '.json';
    
    $reactions = ['like' => 0, 'love' => 0, 'helpful' => 0];
    if (file_exists($reactionFile)) {
        $reactionData = json_decode(file_get_contents($reactionFile), true);
        if (isset($reactionData['counts'])) {
            $reactions = $reactionData['counts'];
        }
    }
    
    // Get shares for this post from visits data (already loaded, includes date range)
    $postShares = ['mastodon' => 0, 'bluesky' => 0, 'copy' => 0];
    foreach ($visits as $visit) {
        if (isset($visit['type']) && $visit['type'] === 'share' && 
            isset($visit['page']) && strpos($visit['page'], '#post-' . $postId) !== false) {
            $platform = $visit['platform'] ?? 'copy';
            if (isset($postShares[$platform])) {
                $postShares[$platform]++;
            }
        }
    }
    
    $blogStats[] = [
        'id' => $postId,
        'title' => $post['title'],
        'reactions' => $reactions,
        'shares' => $postShares,
        'totalReactions' => array_sum($reactions),
        'totalShares' => array_sum($postShares)
    ];
}

$data['blogPosts'] = $blogStats;

echo json_encode(['success' => true, 'data' => $data]);
?>