<?php
/**
 * App Store API
 * 版本: 2.0
 * 支持的端点:
 * - /api.php?t=getallapps - 获取所有APP列表
 * - /api.php?t=getappinfo&id={appid} - 获取APP信息
 * - /api.php?t=getalltags - 获取所有标签
 * - /api.php?t=gettagapp&id={tagid} - 获取某标签里的APP列表
 * - /api.php?t=getdeveloperapp&id={developerid} - 获取某开发者的APP列表
 * - /api.php?t=getdeveloperinfo&id={developerid} - 获取开发者信息
 * - /api.php?t=getalldevelopers - 获取所有开发者列表
 * - /api.php?t=getacc - 获取所有公告
 * - /api.php?t=getcount - 获取计数信息
 * - /api.php?t=getappversions&id={appid} - 获取某个应用的版本列表
 */

// 关闭错误显示（生产环境）
ini_set('display_errors', 0);
error_reporting(E_ALL);

// 包含配置文件
require_once 'config.php';

// 设置JSON响应头
header('Content-Type: application/json; charset=utf-8');
header('Access-Control-Allow-Origin: *');
header('Access-Control-Allow-Methods: GET, POST, OPTIONS');
header('Access-Control-Allow-Headers: Content-Type');

// 处理OPTIONS请求
if ($_SERVER['REQUEST_METHOD'] === 'OPTIONS') {
    http_response_code(200);
    exit;
}

// 检查数据库连接
if (!$conn) {
    sendErrorResponse('数据库连接失败', 500);
    exit;
}

// 获取API类型参数
$apiType = isset($_GET['t']) ? trim($_GET['t']) : '';

// 根据API类型调用对应处理函数
switch ($apiType) {
    case 'getallapps':
        getAllApps();
        break;
    case 'getappinfo':
        getAppInfo();
        break;
    case 'getalltags':
        getAllTags();
        break;
    case 'gettagapp':
        getTagApps();
        break;
    case 'getdeveloperapp':
        getDeveloperApps();
        break;
    case 'getdeveloperinfo':
        getDeveloperInfo();
        break;
    case 'getacc':
        getAllAnnouncements();
        break;
    case 'getcount':
        getCountInfo();
        break;
    case 'getappversions':
        getAppVersions();
        break;
    case 'getalldevelopers':
        getAllDevelopers();
        break;
    default:
        showApiEndpoints();
        break;
}

/**
 * 发送成功响应
 * @param mixed $data 要返回的数据
 */
function sendSuccessResponse($data) {
    $response = [
        'status' => 'success',
        'data' => $data
    ];
    echo json_encode($response, JSON_UNESCAPED_UNICODE);
    exit;
}

/**
 * 发送错误响应
 * @param string $message 错误消息
 * @param int $statusCode HTTP状态码
 */
function sendErrorResponse($message, $statusCode = 400) {
    http_response_code($statusCode);
    $response = [
        'status' => 'error',
        'message' => $message
    ];
    echo json_encode($response, JSON_UNESCAPED_UNICODE);
    exit;
}

/**
 * 显示所有API端点信息
 */
function showApiEndpoints() {
    $endpoints = [
        '/api.php?t=getallapps' => '获取所有APP列表',
        '/api.php?t=getappinfo&id={appid}' => '获取APP信息',
        '/api.php?t=getalltags' => '获取所有标签',
        '/api.php?t=gettagapp&id={tagid}' => '获取某标签里的APP列表',
        '/api.php?t=getdeveloperapp&id={developerid}' => '获取某开发者的APP列表',
        '/api.php?t=getdeveloperinfo&id={developerid}' => '获取开发者信息',
        '/api.php?t=getalldevelopers' => '获取所有开发者列表',
        '/api.php?t=getacc' => '获取所有公告',
        '/api.php?t=getcount' => '获取计数信息（如所有APP的数量、开发者的数量等）',
        '/api.php?t=getappversions&id={appid}' => '获取某个应用的版本列表'
    ];
    
    $response = [
        'status' => 'success',
        'message' => 'App Store API v2.0',
        'endpoints' => $endpoints,
        'example' => '/api.php?t=getallapps'
    ];
    
    echo json_encode($response, JSON_UNESCAPED_UNICODE);
    exit;
}

/**
 * 获取所有APP列表
 */
function getAllApps() {
    global $conn;
    
    // 获取分页参数
    $page = isset($_GET['page']) ? max(1, intval($_GET['page'])) : 1;
    $limit = isset($_GET['limit']) ? min(100, max(1, intval($_GET['limit']))) : 20;
    $offset = ($page - 1) * $limit;
    
    // 获取总数量
    $countSql = "SELECT COUNT(*) as total FROM apps WHERE status = 'approved' AND is_approved = 1";
    $countResult = $conn->query($countSql);
    $total = $countResult->fetch_assoc()['total'] ?? 0;
    $totalPages = ceil($total / $limit);
    
    // 获取应用列表
    $sql = "SELECT apps.id, apps.name, apps.description, apps.age_rating, apps.version, 
           AVG(reviews.rating) as avg_rating, SUM(app_versions.download_count) as total_downloads 
           FROM apps 
           LEFT JOIN reviews ON apps.id = reviews.app_id 
           LEFT JOIN app_versions ON apps.id = app_versions.app_id 
           WHERE apps.status = 'approved' AND apps.is_approved = 1 
           GROUP BY apps.id, apps.name, apps.description, apps.age_rating, apps.version 
           ORDER BY apps.created_at DESC 
           LIMIT ?, ?";
    
    $stmt = $conn->prepare($sql);
    $stmt->bind_param("ii", $offset, $limit);
    $stmt->execute();
    $result = $stmt->get_result();
    
    $apps = [];
    while ($row = $result->fetch_assoc()) {
        // 格式化JSON字段
        if (isset($row['platforms']) && !empty($row['platforms'])) {
            $row['platforms'] = json_decode($row['platforms'], true);
        }
        $apps[] = $row;
    }
    
    $response = [
        'apps' => $apps,
        'pagination' => [
            'total' => $total,
            'page' => $page,
            'limit' => $limit,
            'totalPages' => $totalPages
        ]
    ];
    
    sendSuccessResponse($response);
}

/**
 * 获取指定APP的详细信息
 */
function getAppInfo() {
    global $conn;
    
    // 检查是否提供了app_id参数
    if (!isset($_GET['id']) || !is_numeric($_GET['id'])) {
        sendErrorResponse('请提供有效的应用ID', 400);
    }
    
    $appId = intval($_GET['id']);
    
    // 获取应用基本信息
    $sqlApp = "SELECT apps.*, AVG(reviews.rating) as avg_rating, SUM(app_versions.download_count) as total_downloads 
               FROM apps 
               LEFT JOIN reviews ON apps.id = reviews.app_id 
               LEFT JOIN app_versions ON apps.id = app_versions.app_id 
               WHERE apps.id = ? AND apps.status = 'approved' AND apps.is_approved = 1 
               GROUP BY apps.id";
    
    $stmtApp = $conn->prepare($sqlApp);
    $stmtApp->bind_param("i", $appId);
    $stmtApp->execute();
    $resultApp = $stmtApp->get_result();
    
    if ($resultApp->num_rows === 0) {
        sendErrorResponse('未找到该应用', 404);
    }
    
    $app = $resultApp->fetch_assoc();
    
    // 格式化JSON字段
    if (isset($app['platforms']) && !empty($app['platforms'])) {
        $app['platforms'] = json_decode($app['platforms'], true);
    }
    
    // 获取版本信息
    $sqlVersions = "SELECT id, version, changelog, file_path, download_count, created_at 
                    FROM app_versions 
                    WHERE app_id = ? 
                    ORDER BY created_at DESC";
    $stmtVersions = $conn->prepare($sqlVersions);
    $stmtVersions->bind_param("i", $appId);
    $stmtVersions->execute();
    $resultVersions = $stmtVersions->get_result();
    
    $versions = [];
    while ($version = $resultVersions->fetch_assoc()) {
        $versions[] = $version;
    }
    $app['versions'] = $versions;
    
    // 获取图片信息
    $sqlImages = "SELECT id, image_path FROM app_images WHERE app_id = ?";
    $stmtImages = $conn->prepare($sqlImages);
    $stmtImages->bind_param("i", $appId);
    $stmtImages->execute();
    $resultImages = $stmtImages->get_result();
    
    $images = [];
    while ($image = $resultImages->fetch_assoc()) {
        $images[] = $image;
    }
    $app['images'] = $images;
    
    // 获取标签信息
    $sqlTags = "SELECT tags.id, tags.name FROM app_tags 
                JOIN tags ON app_tags.tag_id = tags.id 
                WHERE app_tags.app_id = ?";
    $stmtTags = $conn->prepare($sqlTags);
    $stmtTags->bind_param("i", $appId);
    $stmtTags->execute();
    $resultTags = $stmtTags->get_result();
    
    $tags = [];
    while ($tag = $resultTags->fetch_assoc()) {
        $tags[] = $tag;
    }
    $app['tags'] = $tags;
    
    sendSuccessResponse($app);
}

/**
 * 获取所有标签
 */
function getAllTags() {
    global $conn;
    
    $sql = "SELECT id, name FROM tags ORDER BY name ASC";
    $result = $conn->query($sql);
    
    $tags = [];
    while ($row = $result->fetch_assoc()) {
        $tags[] = $row;
    }
    
    sendSuccessResponse($tags);
}

/**
 * 获取指定标签下的应用列表
 */
function getTagApps() {
    global $conn;
    
    // 检查是否提供了tag_id参数
    if (!isset($_GET['id']) || !is_numeric($_GET['id'])) {
        sendErrorResponse('请提供有效的标签ID', 400);
    }
    
    $tagId = intval($_GET['id']);
    
    // 获取分页参数
    $page = isset($_GET['page']) ? max(1, intval($_GET['page'])) : 1;
    $limit = isset($_GET['limit']) ? min(100, max(1, intval($_GET['limit']))) : 20;
    $offset = ($page - 1) * $limit;
    
    // 获取标签信息
    $sqlTag = "SELECT name FROM tags WHERE id = ?";
    $stmtTag = $conn->prepare($sqlTag);
    $stmtTag->bind_param("i", $tagId);
    $stmtTag->execute();
    $resultTag = $stmtTag->get_result();
    
    if ($resultTag->num_rows === 0) {
        sendErrorResponse('未找到该标签', 404);
    }
    
    $tagInfo = $resultTag->fetch_assoc();
    
    // 获取总数量
    $countSql = "SELECT COUNT(DISTINCT apps.id) as total 
                 FROM apps 
                 JOIN app_tags ON apps.id = app_tags.app_id 
                 WHERE app_tags.tag_id = ? AND apps.status = 'approved' AND apps.is_approved = 1";
    $countStmt = $conn->prepare($countSql);
    $countStmt->bind_param("i", $tagId);
    $countStmt->execute();
    $countResult = $countStmt->get_result();
    $total = $countResult->fetch_assoc()['total'] ?? 0;
    $totalPages = ceil($total / $limit);
    
    // 获取应用列表
    $sql = "SELECT apps.id, apps.name, apps.description, apps.age_rating, apps.version, 
           AVG(reviews.rating) as avg_rating 
           FROM apps 
           JOIN app_tags ON apps.id = app_tags.app_id 
           LEFT JOIN reviews ON apps.id = reviews.app_id 
           WHERE app_tags.tag_id = ? AND apps.status = 'approved' AND apps.is_approved = 1 
           GROUP BY apps.id, apps.name, apps.description, apps.age_rating, apps.version 
           ORDER BY apps.created_at DESC 
           LIMIT ?, ?";
    
    $stmt = $conn->prepare($sql);
    $stmt->bind_param("iii", $tagId, $offset, $limit);
    $stmt->execute();
    $result = $stmt->get_result();
    
    $apps = [];
    while ($row = $result->fetch_assoc()) {
        $apps[] = $row;
    }
    
    $response = [
        'tag' => $tagInfo,
        'apps' => $apps,
        'pagination' => [
            'total' => $total,
            'page' => $page,
            'limit' => $limit,
            'totalPages' => $totalPages
        ]
    ];
    
    sendSuccessResponse($response);
}

/**
 * 获取指定开发者的应用列表
 */
function getDeveloperApps() {
    global $conn;
    
    // 检查是否提供了developer_id参数
    if (!isset($_GET['id']) || !is_numeric($_GET['id'])) {
        sendErrorResponse('请提供有效的开发者ID', 400);
    }
    
    $developerId = intval($_GET['id']);
    
    // 获取分页参数
    $page = isset($_GET['page']) ? max(1, intval($_GET['page'])) : 1;
    $limit = isset($_GET['limit']) ? min(100, max(1, intval($_GET['limit']))) : 20;
    $offset = ($page - 1) * $limit;
    
    // 获取开发者信息
    $sqlDeveloper = "SELECT username FROM developers WHERE id = ?";
    $stmtDeveloper = $conn->prepare($sqlDeveloper);
    $stmtDeveloper->bind_param("i", $developerId);
    $stmtDeveloper->execute();
    $resultDeveloper = $stmtDeveloper->get_result();
    
    if ($resultDeveloper->num_rows === 0) {
        sendErrorResponse('未找到该开发者', 404);
    }
    
    $developerInfo = $resultDeveloper->fetch_assoc();
    
    // 获取总数量
    $countSql = "SELECT COUNT(*) as total FROM apps WHERE developer_id = ? AND status = 'approved' AND is_approved = 1";
    $countStmt = $conn->prepare($countSql);
    $countStmt->bind_param("i", $developerId);
    $countStmt->execute();
    $countResult = $countStmt->get_result();
    $total = $countResult->fetch_assoc()['total'] ?? 0;
    $totalPages = ceil($total / $limit);
    
    // 获取应用列表
    $sql = "SELECT id, name, description, age_rating, version, created_at 
           FROM apps 
           WHERE developer_id = ? AND status = 'approved' AND is_approved = 1 
           ORDER BY created_at DESC 
           LIMIT ?, ?";
    
    $stmt = $conn->prepare($sql);
    $stmt->bind_param("iii", $developerId, $offset, $limit);
    $stmt->execute();
    $result = $stmt->get_result();
    
    $apps = [];
    while ($row = $result->fetch_assoc()) {
        $apps[] = $row;
    }
    
    $response = [
        'developer' => $developerInfo,
        'apps' => $apps,
        'pagination' => [
            'total' => $total,
            'page' => $page,
            'limit' => $limit,
            'totalPages' => $totalPages
        ]
    ];
    
    sendSuccessResponse($response);
}

/**
 * 获取开发者信息
 */
function getDeveloperInfo() {
    global $conn;
    
    // 检查是否提供了developer_id参数
    if (!isset($_GET['id']) || !is_numeric($_GET['id'])) {
        sendErrorResponse('请提供有效的开发者ID', 400);
    }
    
    $developerId = intval($_GET['id']);
    
    // 获取开发者基本信息
    $sqlDeveloper = "SELECT id, username, email, created_at FROM developers WHERE id = ?";
    $stmtDeveloper = $conn->prepare($sqlDeveloper);
    $stmtDeveloper->bind_param("i", $developerId);
    $stmtDeveloper->execute();
    $resultDeveloper = $stmtDeveloper->get_result();
    
    if ($resultDeveloper->num_rows === 0) {
        sendErrorResponse('未找到该开发者', 404);
    }
    
    $developer = $resultDeveloper->fetch_assoc();
    
    // 获取开发者的应用数量
    $appCountSql = "SELECT COUNT(*) as count FROM apps WHERE developer_id = ? AND status = 'approved' AND is_approved = 1";
    $appCountStmt = $conn->prepare($appCountSql);
    $appCountStmt->bind_param("i", $developerId);
    $appCountStmt->execute();
    $appCountResult = $appCountStmt->get_result();
    $appCount = $appCountResult->fetch_assoc()['count'] ?? 0;
    $developer['app_count'] = $appCount;
    
    // 获取开发者的总下载量
    $downloadCountSql = "SELECT SUM(download_count) as count FROM app_versions 
                        JOIN apps ON app_versions.app_id = apps.id 
                        WHERE apps.developer_id = ?";
    $downloadCountStmt = $conn->prepare($downloadCountSql);
    $downloadCountStmt->bind_param("i", $developerId);
    $downloadCountStmt->execute();
    $downloadCountResult = $downloadCountStmt->get_result();
    $downloadCount = $downloadCountResult->fetch_assoc()['count'] ?? 0;
    $developer['total_downloads'] = $downloadCount;
    
    sendSuccessResponse($developer);
}

/**
 * 获取所有公告
 */
function getAllAnnouncements() {
    global $conn;
    
    $sql = "SELECT id, title, content, created_at FROM announcements ORDER BY created_at DESC";
    $result = $conn->query($sql);
    
    $announcements = [];
    while ($row = $result->fetch_assoc()) {
        $announcements[] = $row;
    }
    
    sendSuccessResponse($announcements);
}

/**
 * 获取计数信息
 */
function getCountInfo() {
    global $conn;
    
    // 总应用数
    $appCountSql = "SELECT COUNT(*) as count FROM apps WHERE status = 'approved' AND is_approved = 1";
    $appCountResult = $conn->query($appCountSql);
    $appCount = $appCountResult->fetch_assoc()['count'] ?? 0;
    
    // 总开发者数
    $developerCountSql = "SELECT COUNT(*) as count FROM developers";
    $developerCountResult = $conn->query($developerCountSql);
    $developerCount = $developerCountResult->fetch_assoc()['count'] ?? 0;
    
    // 总标签数
    $tagCountSql = "SELECT COUNT(*) as count FROM tags";
    $tagCountResult = $conn->query($tagCountSql);
    $tagCount = $tagCountResult->fetch_assoc()['count'] ?? 0;
    
    // 总公告数
    $announcementCountSql = "SELECT COUNT(*) as count FROM announcements";
    $announcementCountResult = $conn->query($announcementCountSql);
    $announcementCount = $announcementCountResult->fetch_assoc()['count'] ?? 0;
    
    // 总下载量
    $downloadCountSql = "SELECT SUM(download_count) as count FROM app_versions";
    $downloadCountResult = $conn->query($downloadCountSql);
    $downloadCount = $downloadCountResult->fetch_assoc()['count'] ?? 0;
    
    $counts = [
        'total_apps' => $appCount,
        'total_developers' => $developerCount,
        'total_tags' => $tagCount,
        'total_announcements' => $announcementCount,
        'total_downloads' => $downloadCount
    ];
    
    sendSuccessResponse($counts);
}

/**
 * 获取所有开发者列表
 */
function getAllDevelopers() {
    global $conn;
    
    // 获取分页参数
    $page = isset($_GET['page']) ? max(1, intval($_GET['page'])) : 1;
    $limit = isset($_GET['limit']) ? min(100, max(1, intval($_GET['limit']))) : 20;
    $offset = ($page - 1) * $limit;
    
    // 获取总数量
    $countSql = "SELECT COUNT(*) as total FROM developers";
    $countResult = $conn->query($countSql);
    $total = $countResult->fetch_assoc()['total'] ?? 0;
    $totalPages = ceil($total / $limit);
    
    // 获取开发者列表
    $sql = "SELECT id, username, email, created_at FROM developers ORDER BY created_at DESC LIMIT ?, ?";
    $stmt = $conn->prepare($sql);
    $stmt->bind_param("ii", $offset, $limit);
    $stmt->execute();
    $result = $stmt->get_result();
    
    $developers = [];
    while ($row = $result->fetch_assoc()) {
        // 获取每个开发者的应用数量
        $appCountSql = "SELECT COUNT(*) as count FROM apps WHERE developer_id = ? AND status = 'approved' AND is_approved = 1";
        $appCountStmt = $conn->prepare($appCountSql);
        $appCountStmt->bind_param("i", $row['id']);
        $appCountStmt->execute();
        $appCountResult = $appCountStmt->get_result();
        $appCount = $appCountResult->fetch_assoc()['count'] ?? 0;
        $row['app_count'] = $appCount;
        
        // 获取每个开发者的总下载量
        $downloadCountSql = "SELECT SUM(download_count) as count FROM app_versions 
                            JOIN apps ON app_versions.app_id = apps.id 
                            WHERE apps.developer_id = ?";
        $downloadCountStmt = $conn->prepare($downloadCountSql);
        $downloadCountStmt->bind_param("i", $row['id']);
        $downloadCountStmt->execute();
        $downloadCountResult = $downloadCountStmt->get_result();
        $downloadCount = $downloadCountResult->fetch_assoc()['count'] ?? 0;
        $row['total_downloads'] = $downloadCount;
        
        $developers[] = $row;
    }
    
    $response = [
        'developers' => $developers,
        'pagination' => [
            'total' => $total,
            'page' => $page,
            'limit' => $limit,
            'totalPages' => $totalPages
        ]
    ];
    
    sendSuccessResponse($response);
}

/**
 * 获取指定应用的版本列表
 */
function getAppVersions() {
    global $conn;
    
    // 检查是否提供了app_id参数
    if (!isset($_GET['id']) || !is_numeric($_GET['id'])) {
        sendErrorResponse('请提供有效的应用ID', 400);
    }
    
    $appId = intval($_GET['id']);
    
    // 检查应用是否存在
    $appCheckSql = "SELECT id FROM apps WHERE id = ? AND status = 'approved' AND is_approved = 1";
    $appCheckStmt = $conn->prepare($appCheckSql);
    $appCheckStmt->bind_param("i", $appId);
    $appCheckStmt->execute();
    $appCheckResult = $appCheckStmt->get_result();
    
    if ($appCheckResult->num_rows === 0) {
        sendErrorResponse('未找到该应用', 404);
    }
    
    // 获取分页参数
    $page = isset($_GET['page']) ? max(1, intval($_GET['page'])) : 1;
    $limit = isset($_GET['limit']) ? min(100, max(1, intval($_GET['limit']))) : 20;
    $offset = ($page - 1) * $limit;
    
    // 获取总数量
    $countSql = "SELECT COUNT(*) as total FROM app_versions WHERE app_id = ?";
    $countStmt = $conn->prepare($countSql);
    $countStmt->bind_param("i", $appId);
    $countStmt->execute();
    $countResult = $countStmt->get_result();
    $total = $countResult->fetch_assoc()['total'] ?? 0;
    $totalPages = ceil($total / $limit);
    
    // 获取版本列表
    $sqlVersions = "SELECT id, version, changelog, file_path, download_count, created_at 
                    FROM app_versions 
                    WHERE app_id = ? 
                    ORDER BY created_at DESC 
                    LIMIT ?, ?";
    $stmtVersions = $conn->prepare($sqlVersions);
    $stmtVersions->bind_param("iii", $appId, $offset, $limit);
    $stmtVersions->execute();
    $resultVersions = $stmtVersions->get_result();
    
    $versions = [];
    while ($version = $resultVersions->fetch_assoc()) {
        $versions[] = $version;
    }
    
    // 构建响应数据
    $response = [
        'app_id' => $appId,
        'versions' => $versions,
        'pagination' => [
            'total' => $total,
            'page' => $page,
            'limit' => $limit,
            'totalPages' => $totalPages
        ]
    ];
    
    sendSuccessResponse($response);
}

// 关闭数据库连接
$conn->close();
?>