<?php
/**
 * 🚀 API缓存系统
 * 
 * 支持文件缓存，自动清理过期缓存
 * 优化多人多次请求性能
 */

class ApiCache {
    private static $cacheDir = null;
    private static $defaultTTL = 300;
    
    private static $ttlConfig = array(
        'list' => 300,
        'detail' => 600,
        'full' => 600,
        'ingredients' => 600,
        'ingredient_detail' => 1200,
        'search' => 180,
        'categories' => 1800,
        'tags' => 1800,
        'stats' => 120,
        'stats_full' => 120,
        'hot' => 300,
        'query' => 180,
        'filter' => 180,
        'like' => 0,
        'recommend' => 0,
        'view' => 0
    );
    
    public static function init() {
        if (self::$cacheDir === null) {
            self::$cacheDir = dirname(__FILE__) . '/cache/';
            if (!is_dir(self::$cacheDir)) {
                @mkdir(self::$cacheDir, 0755, true);
            }
        }
    }
    
    public static function getTTL($act) {
        return isset(self::$ttlConfig[$act]) ? self::$ttlConfig[$act] : self::$defaultTTL;
    }
    
    public static function getCacheKey($act, $params = array()) {
        ksort($params);
        $paramStr = http_build_query($params);
        return md5($act . '_' . $paramStr);
    }
    
    public static function get($act, $params = array()) {
        self::init();
        
        $ttl = isset(self::$ttlConfig[$act]) ? self::$ttlConfig[$act] : self::$defaultTTL;
        if ($ttl <= 0) {
            return null;
        }
        
        $key = self::getCacheKey($act, $params);
        $file = self::$cacheDir . $key . '.json';
        
        if (!file_exists($file)) {
            return null;
        }
        
        $content = file_get_contents($file);
        $data = json_decode($content, true);
        
        if (!$data || !isset($data['expire']) || !isset($data['data'])) {
            @unlink($file);
            return null;
        }
        
        if (time() > $data['expire']) {
            @unlink($file);
            return null;
        }
        
        return $data['data'];
    }
    
    public static function getStale($act, $params = array()) {
        self::init();
        
        $key = self::getCacheKey($act, $params);
        $file = self::$cacheDir . $key . '.json';
        
        if (!file_exists($file)) {
            return null;
        }
        
        $content = @file_get_contents($file);
        if ($content === false) {
            return null;
        }
        
        $data = json_decode($content, true);
        
        if (!$data || !isset($data['data'])) {
            return null;
        }
        
        return $data['data'];
    }
    
    public static function isExpired($act, $params = array()) {
        self::init();
        
        $key = self::getCacheKey($act, $params);
        $file = self::$cacheDir . $key . '.json';
        
        if (!file_exists($file)) {
            return true;
        }
        
        $content = @file_get_contents($file);
        if ($content === false) {
            return true;
        }
        
        $data = json_decode($content, true);
        
        if (!$data || !isset($data['expire'])) {
            return true;
        }
        
        return time() > $data['expire'];
    }
    
    public static function getCacheAge($act, $params = array()) {
        self::init();
        
        $key = self::getCacheKey($act, $params);
        $file = self::$cacheDir . $key . '.json';
        
        if (!file_exists($file)) {
            return -1;
        }
        
        $content = @file_get_contents($file);
        if ($content === false) {
            return -1;
        }
        
        $data = json_decode($content, true);
        
        if (!$data || !isset($data['created'])) {
            return -1;
        }
        
        return time() - $data['created'];
    }
    
    public static function set($act, $params, $data) {
        self::init();
        
        $ttl = isset(self::$ttlConfig[$act]) ? self::$ttlConfig[$act] : self::$defaultTTL;
        if ($ttl <= 0) {
            return false;
        }
        
        $key = self::getCacheKey($act, $params);
        $file = self::$cacheDir . $key . '.json';
        
        $cacheData = array(
            'act' => $act,
            'params' => $params,
            'data' => $data,
            'expire' => time() + $ttl,
            'created' => time()
        );
        
        return file_put_contents($file, json_encode($cacheData, JSON_UNESCAPED_UNICODE)) !== false;
    }
    
    public static function clear($act = null, $params = array()) {
        self::init();
        
        if ($act === null) {
            $files = glob(self::$cacheDir . '*.json');
            foreach ($files as $file) {
                @unlink($file);
            }
            return true;
        }
        
        $key = self::getCacheKey($act, $params);
        $file = self::$cacheDir . $key . '.json';
        
        if (file_exists($file)) {
            @unlink($file);
        }
        
        return true;
    }
    
    public static function clearByAct($act) {
        self::init();
        
        $files = glob(self::$cacheDir . '*.json');
        $count = 0;
        
        foreach ($files as $file) {
            $content = file_get_contents($file);
            $data = json_decode($content, true);
            if ($data && isset($data['act']) && $data['act'] === $act) {
                @unlink($file);
                $count++;
            }
        }
        
        return $count;
    }
    
    public static function cleanExpired() {
        self::init();
        
        $files = glob(self::$cacheDir . '*.json');
        $count = 0;
        $now = time();
        
        foreach ($files as $file) {
            $content = @file_get_contents($file);
            if ($content === false) {
                @unlink($file);
                $count++;
                continue;
            }
            
            $data = json_decode($content, true);
            if (!$data || !isset($data['expire']) || $now > $data['expire']) {
                @unlink($file);
                $count++;
            }
        }
        
        return $count;
    }
    
    public static function getStats() {
        self::init();
        
        $files = glob(self::$cacheDir . '*.json');
        $totalSize = 0;
        $count = 0;
        $oldest = time();
        $newest = 0;
        
        foreach ($files as $file) {
            $count++;
            $totalSize += filesize($file);
            $content = file_get_contents($file);
            $data = json_decode($content, true);
            if ($data && isset($data['created'])) {
                $oldest = min($oldest, $data['created']);
                $newest = max($newest, $data['created']);
            }
        }
        
        return array(
            'count' => $count,
            'total_size' => $totalSize,
            'total_size_readable' => self::formatBytes($totalSize),
            'oldest' => $oldest > 0 ? date('Y-m-d H:i:s', $oldest) : '-',
            'newest' => $newest > 0 ? date('Y-m-d H:i:s', $newest) : '-'
        );
    }
    
    private static function formatBytes($bytes) {
        if ($bytes >= 1073741824) {
            return number_format($bytes / 1073741824, 2) . ' GB';
        } elseif ($bytes >= 1048576) {
            return number_format($bytes / 1048576, 2) . ' MB';
        } elseif ($bytes >= 1024) {
            return number_format($bytes / 1024, 2) . ' KB';
        } else {
            return $bytes . ' bytes';
        }
    }
}

if (php_sapi_name() === 'cli' && isset($argv[0]) && basename($argv[0]) === 'cache.php') {
    $action = $argv[1] ?? 'stats';
    
    switch ($action) {
        case 'clean':
            $count = ApiCache::cleanExpired();
            echo "Cleaned {$count} expired cache files.\n";
            break;
        case 'clear':
            ApiCache::clear();
            echo "All cache cleared.\n";
            break;
        case 'stats':
        default:
            $stats = ApiCache::getStats();
            echo "Cache Statistics:\n";
            echo "  Files: {$stats['count']}\n";
            echo "  Size: {$stats['total_size_readable']}\n";
            echo "  Oldest: {$stats['oldest']}\n";
            echo "  Newest: {$stats['newest']}\n";
            break;
    }
}