<?php
/**
 * 🚀 API响应格式处理
 * 
 * 支持多种响应格式，提高App读取效率
 * - JSON: 通用格式，兼容性好
 * - MessagePack: 二进制格式，体积小30-50%，解析更快
 * - Gzip: 压缩JSON，减少传输大小
 * - CBOR: 二进制JSON，RFC 8949标准
 * 
 * @file      response.php
 * @author    AI Assistant
 * @date      2026-04-12
 * @version   2.1.0
 * @desc      API响应格式处理，包含评分格式化工具
 * @lastUpdate 2026-04-12 新增评分格式化函数，处理边缘情况
 */

class ApiResponse {
    
    private static $supportedFormats = array('json', 'msgpack', 'gzip', 'cbor');
    
    public static function getFormat() {
        $format = strtolower(trim($_GET['_format'] ?? 'json'));
        
        if (!in_array($format, self::$supportedFormats)) {
            $format = 'json';
        }
        
        if ($format === 'msgpack' && !function_exists('msgpack_pack')) {
            $format = 'json';
        }
        
        if ($format === 'cbor' && !class_exists('CBOR\CBOREncoder')) {
            $format = 'json';
        }
        
        return $format;
    }
    
    public static function output($data, $format = null) {
        if ($format === null) {
            $format = self::getFormat();
        }
        
        $startTime = microtime(true);
        
        switch ($format) {
            case 'msgpack':
                self::outputMsgpack($data);
                break;
            case 'gzip':
                self::outputGzip($data);
                break;
            case 'cbor':
                self::outputCbor($data);
                break;
            case 'json':
            default:
                self::outputJson($data);
                break;
        }
    }
    
    private static function outputJson($data) {
        header('Content-Type: application/json; charset=utf-8');
        
        $json = json_encode($data, JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES);
        
        if (isset($_GET['_pretty']) && $_GET['_pretty'] === '1') {
            $json = json_encode($data, JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES | JSON_PRETTY_PRINT);
        }
        
        $size = strlen($json);
        header('X-Response-Size: ' . $size);
        header('X-Response-Format: json');
        
        echo $json;
    }
    
    private static function outputMsgpack($data) {
        if (!function_exists('msgpack_pack')) {
            self::outputJson($data);
            return;
        }
        
        header('Content-Type: application/msgpack');
        
        $packed = msgpack_pack($data);
        $size = strlen($packed);
        
        $jsonData = json_encode($data, JSON_UNESCAPED_UNICODE);
        $jsonSize = strlen($jsonData);
        $saved = round((1 - $size / $jsonSize) * 100, 1);
        
        header('X-Response-Size: ' . $size);
        header('X-Json-Size: ' . $jsonSize);
        header('X-Size-Saved: ' . $saved . '%');
        header('X-Response-Format: msgpack');
        
        echo $packed;
    }
    
    private static function outputGzip($data) {
        if (!function_exists('gzencode')) {
            self::outputJson($data);
            return;
        }
        
        header('Content-Type: application/json');
        header('Content-Encoding: gzip');
        
        $json = json_encode($data, JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES);
        $gzip = gzencode($json, 6);
        
        $size = strlen($gzip);
        $jsonSize = strlen($json);
        $saved = round((1 - $size / $jsonSize) * 100, 1);
        
        header('X-Response-Size: ' . $size);
        header('X-Json-Size: ' . $jsonSize);
        header('X-Size-Saved: ' . $saved . '%');
        header('X-Response-Format: gzip');
        
        echo $gzip;
    }
    
    private static function outputCbor($data) {
        if (!class_exists('CBOR\CBOREncoder')) {
            self::outputJson($data);
            return;
        }
        
        header('Content-Type: application/cbor');
        
        try {
            $cbor = CBOR\CBOREncoder::encode($data);
            $size = strlen($cbor);
            
            $jsonData = json_encode($data, JSON_UNESCAPED_UNICODE);
            $jsonSize = strlen($jsonData);
            $saved = round((1 - $size / $jsonSize) * 100, 1);
            
            header('X-Response-Size: ' . $size);
            header('X-Json-Size: ' . $jsonSize);
            header('X-Size-Saved: ' . $saved . '%');
            header('X-Response-Format: cbor');
            
            echo $cbor;
        } catch (Exception $e) {
            self::outputJson($data);
        }
    }
    
    public static function getAcceptFormat() {
        $accept = isset($_SERVER['HTTP_ACCEPT']) ? $_SERVER['HTTP_ACCEPT'] : '';
        
        if (strpos($accept, 'application/msgpack') !== false) {
            return 'msgpack';
        }
        if (strpos($accept, 'application/cbor') !== false) {
            return 'cbor';
        }
        if (strpos($accept, 'application/json') !== false) {
            return 'json';
        }
        if (isset($_SERVER['HTTP_ACCEPT_ENCODING']) && strpos($_SERVER['HTTP_ACCEPT_ENCODING'], 'gzip') !== false) {
            return 'gzip';
        }
        
        return 'json';
    }
    
    public static function getStats($data) {
        $json = json_encode($data, JSON_UNESCAPED_UNICODE);
        $jsonSize = strlen($json);
        
        $stats = array(
            'json' => array(
                'size' => $jsonSize,
                'size_readable' => self::formatBytes($jsonSize)
            )
        );
        
        if (function_exists('gzencode')) {
            $gzip = gzencode($json, 6);
            $gzipSize = strlen($gzip);
            $stats['gzip'] = array(
                'size' => $gzipSize,
                'size_readable' => self::formatBytes($gzipSize),
                'saved' => round((1 - $gzipSize / $jsonSize) * 100, 1) . '%'
            );
        }
        
        if (function_exists('msgpack_pack')) {
            $msgpack = msgpack_pack($data);
            $msgpackSize = strlen($msgpack);
            $stats['msgpack'] = array(
                'size' => $msgpackSize,
                'size_readable' => self::formatBytes($msgpackSize),
                'saved' => round((1 - $msgpackSize / $jsonSize) * 100, 1) . '%'
            );
        }
        
        return $stats;
    }
    
    private static function formatBytes($bytes) {
        if ($bytes >= 1048576) {
            return number_format($bytes / 1048576, 2) . ' MB';
        } elseif ($bytes >= 1024) {
            return number_format($bytes / 1024, 2) . ' KB';
        } else {
            return $bytes . ' B';
        }
    }
    
    /**
     * 格式化评分显示
     * 处理边缘情况：暂无评分、评分数量少、评分异常
     * 
     * @param float $score 平均评分
     * @param int $nums 评分次数
     * @return array 格式化后的评分信息
     */
    public static function formatRating($score, $nums) {
        $result = array(
            'score' => 0.00,
            'nums' => 0,
            'display' => '暂无评分',
            'status' => 'none',
            'level' => '',
            'star' => 0
        );
        
        if ($nums <= 0) {
            return $result;
        }
        
        $score = (float) $score;
        $nums = (int) $nums;
        
        if ($score < 0 || $score > 5) {
            $result['status'] = 'abnormal';
            $result['display'] = '评分异常';
            return $result;
        }
        
        $result['score'] = round($score, 2);
        $result['nums'] = $nums;
        $result['star'] = round($score);
        
        if ($nums < 3) {
            $result['status'] = 'few';
            $result['display'] = sprintf('%.1f分 (%d人评分，样本较少)', $score, $nums);
        } elseif ($nums < 10) {
            $result['status'] = 'normal';
            $result['display'] = sprintf('%.1f分 (%d人评分)', $score, $nums);
        } else {
            $result['status'] = 'sufficient';
            $result['display'] = sprintf('%.1f分 (%d人评分)', $score, $nums);
        }
        
        if ($score >= 4.5) {
            $result['level'] = '优秀';
        } elseif ($score >= 4.0) {
            $result['level'] = '推荐';
        } elseif ($score >= 3.0) {
            $result['level'] = '一般';
        } elseif ($score >= 2.0) {
            $result['level'] = '较差';
        } else {
            $result['level'] = '不推荐';
        }
        
        return $result;
    }
    
    /**
     * 获取评分统计信息（用于列表显示）
     * 
     * @param float $score 平均评分
     * @param int $nums 评分次数
     * @return array 简化的评分信息
     */
    public static function getRatingSummary($score, $nums) {
        if ($nums <= 0) {
            return array(
                'score' => 0.00,
                'nums' => 0,
                'display' => '暂无评分',
                'star' => 0
            );
        }
        
        $score = (float) $score;
        
        if ($score < 0 || $score > 5) {
            return array(
                'score' => 0.00,
                'nums' => $nums,
                'display' => '评分异常',
                'star' => 0
            );
        }
        
        return array(
            'score' => round($score, 2),
            'nums' => (int) $nums,
            'display' => sprintf('%.1f分', $score),
            'star' => (int) round($score)
        );
    }
}

if (php_sapi_name() === 'cli' && isset($argv[0]) && basename($argv[0]) === 'response.php') {
    header('Content-Type: text/plain');
    
    echo "支持的响应格式:\n";
    echo "- json: JSON格式（默认）\n";
    echo "- gzip: Gzip压缩JSON\n";
    
    if (function_exists('msgpack_pack')) {
        echo "- msgpack: MessagePack二进制格式 ✅\n";
    } else {
        echo "- msgpack: MessagePack二进制格式 ❌ (需要安装msgpack扩展)\n";
    }
    
    if (class_exists('CBOR\CBOREncoder')) {
        echo "- cbor: CBOR二进制格式 ✅\n";
    } else {
        echo "- cbor: CBOR二进制格式 ❌ (需要安装cbor库)\n";
    }
    
    echo "\n使用方式:\n";
    echo "  api.php?act=list&_format=json     # JSON格式\n";
    echo "  api.php?act=list&_format=gzip     # Gzip压缩\n";
    echo "  api.php?act=list&_format=msgpack  # MessagePack格式\n";
    echo "  api.php?act=list&_format=cbor     # CBOR格式\n";
    echo "  api.php?act=list&_pretty=1        # 格式化JSON（调试用）\n";
}