/**
 * Supabase Storage REST API 完整客户端
 * 无需 SDK，纯 JavaScript/TypeScript 实现
 * 
 * 使用示例:
 * 
 * const client = new SupabaseStorageClient(
 *   'https://amiap.hzau.edu.cn/supa',
 *   'your-service-role-key'
 * );
 * 
 * // 创建 bucket
 * await client.createBucket('my-bucket');
 * 
 * // 上传文件
 * await client.uploadFile('my-bucket', fileObject, 'uploads/photo.jpg');
 * 
 * // 生成临时下载链接
 * const url = await client.createSignedUrl('my-bucket', 'uploads/photo.jpg', 3600);
 */

class SupabaseStorageClient {
    /**
     * 初始化客户端
     * @param {string} baseUrl - Supabase Base URL
     * @param {string} apiKey - SERVICE_ROLE_KEY 或 ANON_KEY
     */
    constructor(baseUrl, apiKey) {
        this.baseUrl = baseUrl.replace(/\/$/, '');
        this.headers = {
            'apikey': apiKey,
            'Authorization': `Bearer ${apiKey}`
        };
    }

    // ==================== Bucket 管理 ====================

    /**
     * 列出所有 buckets
     * @returns {Promise<Array>}
     */
    async listBuckets() {
        const response = await fetch(`${this.baseUrl}/storage/v1/bucket`, {
            headers: this.headers
        });
        return response.ok ? await response.json() : null;
    }

    /**
     * 创建 bucket
     * @param {string} name - bucket 名称
     * @param {boolean} isPublic - 是否公开
     * @param {number} fileSizeLimit - 文件大小限制（字节）
     * @returns {Promise<boolean>}
     */
    async createBucket(name, isPublic = false, fileSizeLimit = 52428800) {
        const response = await fetch(`${this.baseUrl}/storage/v1/bucket`, {
            method: 'POST',
            headers: {
                ...this.headers,
                'Content-Type': 'application/json'
            },
            body: JSON.stringify({
                name,
                public: isPublic,
                file_size_limit: fileSizeLimit
            })
        });
        return response.ok || response.status === 409;
    }

    /**
     * 删除 bucket
     * @param {string} name - bucket 名称
     * @returns {Promise<boolean>}
     */
    async deleteBucket(name) {
        const response = await fetch(`${this.baseUrl}/storage/v1/bucket/${name}`, {
            method: 'DELETE',
            headers: this.headers
        });
        return response.ok;
    }

    /**
     * 清空 bucket
     * @param {string} name - bucket 名称
     * @returns {Promise<boolean>}
     */
    async emptyBucket(name) {
        const response = await fetch(`${this.baseUrl}/storage/v1/bucket/${name}/empty`, {
            method: 'POST',
            headers: this.headers
        });
        return response.ok;
    }

    // ==================== 文件上传 ====================

    /**
     * 上传文件
     * @param {string} bucket - bucket 名称
     * @param {File} file - 文件对象
     * @param {string} storagePath - 云端存储路径
     * @returns {Promise<Object|null>}
     */
    async uploadFile(bucket, file, storagePath) {
        const formData = new FormData();
        formData.append('file', file);

        const response = await fetch(
            `${this.baseUrl}/storage/v1/object/${bucket}/${storagePath}`,
            {
                method: 'POST',
                headers: this.headers,
                body: formData
            }
        );
        return response.ok ? await response.json() : null;
    }

    /**
     * 上传字节数据
     * @param {string} bucket - bucket 名称
     * @param {Blob|ArrayBuffer} data - 数据
     * @param {string} storagePath - 云端存储路径
     * @param {string} contentType - MIME 类型
     * @returns {Promise<Object|null>}
     */
    async uploadBytes(bucket, data, storagePath, contentType = 'application/octet-stream') {
        const response = await fetch(
            `${this.baseUrl}/storage/v1/object/${bucket}/${storagePath}`,
            {
                method: 'POST',
                headers: {
                    ...this.headers,
                    'Content-Type': contentType
                },
                body: data
            }
        );
        return response.ok ? await response.json() : null;
    }

    /**
     * 更新文件
     * @param {string} bucket - bucket 名称
     * @param {File} file - 文件对象
     * @param {string} storagePath - 云端存储路径
     * @returns {Promise<Object|null>}
     */
    async updateFile(bucket, file, storagePath) {
        const formData = new FormData();
        formData.append('file', file);

        const response = await fetch(
            `${this.baseUrl}/storage/v1/object/${bucket}/${storagePath}`,
            {
                method: 'PUT',
                headers: this.headers,
                body: formData
            }
        );
        return response.ok ? await response.json() : null;
    }

    // ==================== 文件下载 ====================

    /**
     * 下载文件为 Blob
     * @param {string} bucket - bucket 名称
     * @param {string} storagePath - 云端文件路径
     * @returns {Promise<Blob|null>}
     */
    async downloadFile(bucket, storagePath) {
        const response = await fetch(
            `${this.baseUrl}/storage/v1/object/${bucket}/${storagePath}`,
            { headers: this.headers }
        );
        return response.ok ? await response.blob() : null;
    }

    /**
     * 下载文件为 ArrayBuffer
     * @param {string} bucket - bucket 名称
     * @param {string} storagePath - 云端文件路径
     * @returns {Promise<ArrayBuffer|null>}
     */
    async downloadBytes(bucket, storagePath) {
        const response = await fetch(
            `${this.baseUrl}/storage/v1/object/${bucket}/${storagePath}`,
            { headers: this.headers }
        );
        return response.ok ? await response.arrayBuffer() : null;
    }

    /**
     * 下载文件为文本
     * @param {string} bucket - bucket 名称
     * @param {string} storagePath - 云端文件路径
     * @returns {Promise<string|null>}
     */
    async downloadText(bucket, storagePath) {
        const response = await fetch(
            `${this.baseUrl}/storage/v1/object/${bucket}/${storagePath}`,
            { headers: this.headers }
        );
        return response.ok ? await response.text() : null;
    }

    // ==================== 文件列表 ====================

    /**
     * 列出文件
     * @param {string} bucket - bucket 名称
     * @param {string} folder - 文件夹路径
     * @param {number} limit - 返回数量限制
     * @param {number} offset - 偏移量
     * @returns {Promise<Array|null>}
     */
    async listFiles(bucket, folder = '', limit = 100, offset = 0) {
        const response = await fetch(
            `${this.baseUrl}/storage/v1/object/list/${bucket}`,
            {
                method: 'POST',
                headers: {
                    ...this.headers,
                    'Content-Type': 'application/json'
                },
                body: JSON.stringify({
                    prefix: folder,
                    limit,
                    offset,
                    sortBy: { column: 'name', order: 'asc' }
                })
            }
        );
        return response.ok ? await response.json() : null;
    }

    /**
     * 搜索文件
     * @param {string} bucket - bucket 名称
     * @param {string} searchText - 搜索关键词
     * @param {number} limit - 返回数量限制
     * @returns {Promise<Array|null>}
     */
    async searchFiles(bucket, searchText, limit = 100) {
        const response = await fetch(
            `${this.baseUrl}/storage/v1/object/list/${bucket}`,
            {
                method: 'POST',
                headers: {
                    ...this.headers,
                    'Content-Type': 'application/json'
                },
                body: JSON.stringify({ search: searchText, limit })
            }
        );
        return response.ok ? await response.json() : null;
    }

    // ==================== 文件操作 ====================

    /**
     * 移动文件
     * @param {string} bucket - bucket 名称
     * @param {string} fromPath - 源路径
     * @param {string} toPath - 目标路径
     * @returns {Promise<boolean>}
     */
    async moveFile(bucket, fromPath, toPath) {
        const response = await fetch(
            `${this.baseUrl}/storage/v1/object/move`,
            {
                method: 'POST',
                headers: {
                    ...this.headers,
                    'Content-Type': 'application/json'
                },
                body: JSON.stringify({
                    bucketId: bucket,
                    sourceKey: fromPath,
                    destinationKey: toPath
                })
            }
        );
        return response.ok;
    }

    /**
     * 复制文件
     * @param {string} bucket - bucket 名称
     * @param {string} fromPath - 源路径
     * @param {string} toPath - 目标路径
     * @returns {Promise<Object|null>}
     */
    async copyFile(bucket, fromPath, toPath) {
        const response = await fetch(
            `${this.baseUrl}/storage/v1/object/copy`,
            {
                method: 'POST',
                headers: {
                    ...this.headers,
                    'Content-Type': 'application/json'
                },
                body: JSON.stringify({
                    bucketId: bucket,
                    sourceKey: fromPath,
                    destinationKey: toPath
                })
            }
        );
        return response.ok ? await response.json() : null;
    }

    /**
     * 删除文件
     * @param {string} bucket - bucket 名称
     * @param {string} storagePath - 文件路径
     * @returns {Promise<boolean>}
     */
    async deleteFile(bucket, storagePath) {
        const response = await fetch(
            `${this.baseUrl}/storage/v1/object/${bucket}/${storagePath}`,
            {
                method: 'DELETE',
                headers: this.headers
            }
        );
        return response.ok;
    }

    /**
     * 批量删除文件
     * @param {string} bucket - bucket 名称
     * @param {Array<string>} filePaths - 文件路径数组
     * @returns {Promise<boolean>}
     */
    async deleteFiles(bucket, filePaths) {
        const response = await fetch(
            `${this.baseUrl}/storage/v1/object/${bucket}`,
            {
                method: 'DELETE',
                headers: {
                    ...this.headers,
                    'Content-Type': 'application/json'
                },
                body: JSON.stringify({ prefixes: filePaths })
            }
        );
        return response.ok;
    }

    // ==================== URL 生成 ====================

    /**
     * 生成签名 URL（临时下载链接）
     * @param {string} bucket - bucket 名称
     * @param {string} storagePath - 文件路径
     * @param {number} expiresIn - 过期时间（秒），默认 1 小时
     * @returns {Promise<string|null>}
     */
    async createSignedUrl(bucket, storagePath, expiresIn = 3600) {
        const response = await fetch(
            `${this.baseUrl}/storage/v1/object/sign/${bucket}/${storagePath}`,
            {
                method: 'POST',
                headers: {
                    ...this.headers,
                    'Content-Type': 'application/json'
                },
                body: JSON.stringify({ expiresIn })
            }
        );

        if (response.ok) {
            const data = await response.json();
            // 签名 URL 需要加上 /storage/v1 前缀
            return this.baseUrl + '/storage/v1' + data.signedURL;
        }
        return null;
    }

    /**
     * 生成上传签名 URL（允许前端直接上传）
     * @param {string} bucket - bucket 名称
     * @param {string} storagePath - 文件路径
     * @returns {Promise<Object|null>} {url, token}
     */
    async createUploadSignedUrl(bucket, storagePath) {
        const response = await fetch(
            `${this.baseUrl}/storage/v1/object/upload/sign/${bucket}/${storagePath}`,
            {
                method: 'POST',
                headers: this.headers
            }
        );

        if (response.ok) {
            const data = await response.json();
            return {
                url: this.baseUrl + '/storage/v1' + data.url,
                token: data.token
            };
        }
        return null;
    }

    /**
     * 获取公开 URL（仅适用于 public bucket）
     * @param {string} bucket - bucket 名称
     * @param {string} storagePath - 文件路径
     * @returns {string}
     */
    getPublicUrl(bucket, storagePath) {
        return `${this.baseUrl}/storage/v1/object/public/${bucket}/${storagePath}`;
    }
}

// ==================== 使用示例 ====================

// 在浏览器中使用
if (typeof window !== 'undefined') {
    window.SupabaseStorageClient = SupabaseStorageClient;
}

// 在 Node.js 中使用
if (typeof module !== 'undefined' && module.exports) {
    module.exports = SupabaseStorageClient;
}

// 示例代码
/*
// 初始化客户端
const client = new SupabaseStorageClient(
    'https://amiap.hzau.edu.cn/supa',
    'your-service-role-key'
);

// 上传文件（HTML5 File API）
const fileInput = document.querySelector('input[type="file"]');
fileInput.addEventListener('change', async (e) => {
    const file = e.target.files[0];
    const result = await client.uploadFile('my-bucket', file, `uploads/${file.name}`);
    console.log('上传成功:', result);
    
    // 生成临时下载链接
    const url = await client.createSignedUrl('my-bucket', `uploads/${file.name}`, 3600);
    console.log('下载链接:', url);
});

// 列出文件
const files = await client.listFiles('my-bucket', 'uploads/');
console.log('文件列表:', files);

// 下载文件
const blob = await client.downloadFile('my-bucket', 'uploads/photo.jpg');
const url = URL.createObjectURL(blob);
// 创建下载链接
const a = document.createElement('a');
a.href = url;
a.download = 'photo.jpg';
a.click();

查看 OPERATIONS_GUIDE.md 了解更多用法
*/