import assert from "assert";
import { OakUploadException } from '../../types/Exception';
// 辅助方法：将文件切片
export async function sliceFile(file, chunkSize, partCount) {
    if (process.env.OAK_PLATFORM === 'wechatMp') {
        // 微信小程序环境下，file 可能是临时文件路径字符串
        if (typeof file === 'string') {
            return sliceFileForMp(file, chunkSize, partCount);
        }
        else {
            assert(false, '小程序环境下得到不为string的文件');
        }
    }
    assert(file instanceof File, '分片上传仅支持 File 类型的文件');
    const chunks = [];
    for (let i = 0; i < partCount; i++) {
        const start = i * chunkSize;
        const end = Math.min(start + chunkSize, file.size);
        chunks.push(file.slice(start, end));
    }
    return chunks;
}
// 小程序环境下的文件分片
export async function sliceFileForMp(filePath, chunkSize, partCount) {
    const fs = wx.getFileSystemManager();
    const tempDir = `${wx.env.USER_DATA_PATH}/oak_upload_temp`;
    assert(chunkSize <= 10 * 1024 * 1024, '小程序下，单个分片大小不能超过 10MB'); // 微信小程序限制单个文件不能超过10MB
    // 确保临时目录存在
    try {
        fs.accessSync(tempDir);
    }
    catch (e) {
        fs.mkdirSync(tempDir, false);
    }
    const chunks = [];
    // 读取文件信息
    const fileStat = fs.statSync(filePath);
    assert(!Array.isArray(fileStat), '无法获取文件信息');
    const fileSize = fileStat.size;
    // 读取每个分片并写入临时文件
    for (let i = 0; i < partCount; i++) {
        const start = i * chunkSize;
        const length = Math.min(chunkSize, fileSize - start);
        try {
            // 读取分片数据
            const data = await new Promise((resolve, reject) => {
                fs.readFile({
                    filePath: filePath,
                    encoding: 'binary',
                    position: start,
                    length: length,
                    success: (res) => resolve(res.data),
                    fail: reject
                });
            });
            // 写入临时文件
            const tempFilePath = `${tempDir}/chunk_${Date.now()}_${i}.temp`;
            await new Promise((resolve, reject) => {
                fs.writeFile({
                    filePath: tempFilePath,
                    encoding: 'binary',
                    data: data,
                    success: () => resolve(),
                    fail: reject
                });
            });
            chunks.push(tempFilePath);
        }
        catch (err) {
            console.error('分片读取失败:', err);
            // 清理已创建的临时文件
            await cleanTempFiles(chunks);
            throw new OakUploadException(`分片 ${i + 1} 读取失败: ${err}`);
        }
    }
    return chunks;
}
// 清理临时文件
export async function cleanTempFiles(tempFiles) {
    if (process.env.OAK_PLATFORM !== 'wechatMp') {
        return;
    }
    const fs = wx.getFileSystemManager();
    for (const filePath of tempFiles) {
        try {
            fs.unlinkSync(filePath);
        }
        catch (err) {
            console.warn(`清理临时文件失败: ${filePath}`, err);
        }
    }
}