/* 引入 interface.uts 文件中定义的变量 */
import { ChooseFileOptions, ChooseFileResult, ChooseFile, ChooseFileSync } from '../interface.uts';

/* 引入 unierror.uts 文件中定义的变量 */
import { ChooseFileFailImpl } from '../unierror.uts';

import picker from '@ohos.file.picker'
import { fileIo as fs } from '@kit.CoreFileKit';
import uri from '@ohos.uri'
import { common } from '@kit.AbilityKit';
import { BusinessError } from '@ohos.base'


export const chooseFileFromModule : ChooseFile = function (options : ChooseFileOptions) {
	const documentSelectOptions = new picker.DocumentSelectOptions();
	// 选择文档的最大数目 暂时只选一个。
	documentSelectOptions.maxSelectNumber = 1;
	let uris: Array<string> = [];
	let context = getContext() as common.Context; // 请确保 getContext(this) 返回结果为 UIAbilityContext
	// 创建文件选择器实例
	const documentViewPicker = new picker.DocumentViewPicker(context);
	documentViewPicker.select(documentSelectOptions).then((documentSelectResult: Array<string>) => {
	  //文件选择成功后，返回被选中文档的URI结果集。
	  uris = documentSelectResult;
	  let uri: string = '';
	  let filePath: string = '';
	  let totalSize = 0;
	  const BUFFER_SIZE = 4096; // 可调整的常量
	  if(uris.length > 0) {
		  uri = uris[0]
		  // 解码中文路径
		  filePath = decodeURIComponent(uri);
		  console.info('filePath are:' + filePath);
		  
		  // 获取描述符 这里需要注意接口权限参数是fs.OpenMode.READ_ONLY。
		  let file = fs.openSync(uri, fs.OpenMode.READ_ONLY);		  
		  // 获取文件大小 更完整的读取示例（循环读取直到文件结束）		  
		  let buffer = new ArrayBuffer(BUFFER_SIZE);		  
		  while (true) {
		    let readLen = fs.readSync(file.fd, buffer);
		    if (readLen <= 0) break; // 读取结束
		    totalSize += readLen;
		    // 处理buffer中的数据...
		  }
		  
		  fs.closeSync(file);
		  console.log(`文件总大小: ${totalSize}字节`);
	  }
	  console.info('documentViewPicker.select to file succeed and uris are:' + uris);	  
	  // 返回数据
	  const res : ChooseFileResult = {
	    size: totalSize,
	    path: filePath,
		name: ''
	  };
	  options.success?.(res);
	  options.complete?.(res);  
	}).catch((err: BusinessError) => {
	  console.error(`Invoke documentViewPicker.select failed, code is ${err.code}, message is ${err.message}`);
	})
	
}

async function getFileSize(filePath: string): Promise<number> {
    try {
        const stat = await fileio.stat(filePath)
        return stat.size  // 返回文件大小(字节)
    } catch (err) {
        console.error('获取文件大小失败:', err)
        return -1
    }
}