import { createReadStream, createWriteStream } from 'fs';
import es from 'event-stream';
import { basename, extname, join } from 'path';
import { obj2csvRow } from '../utils/csv';
import {
  HandleLogRowOptions, handleLogRow,
} from '../utils/log';
import { print, printSuccess, PrintTime } from '../utils/print';
import { checkConf, getProgressBarInstance, promiseQueue } from '../utils/common';
import { getFileRowsNumber } from '../utils/shell';

export interface HandleLog {
  inputFilePath: string,
  outputFilePath: string,
  options: HandleLogRowOptions,
}

export interface HandleLogs {
  inputDirPath: string,
  outputDirPath: string,
  files: string[],
  options: HandleLogRowOptions,
}

export async function handleLog({
  inputFilePath,
  outputFilePath,
  options,
}: HandleLog): Promise<void> {
  const parseTimeStr = `[${basename(inputFilePath)}] 解析耗时`;
  PrintTime.start(parseTimeStr);
  let isFirst = true;
  let i = 0;

  const total = await getFileRowsNumber(inputFilePath);
  const readStream = createReadStream(inputFilePath, { encoding: 'utf-8' });
  const writeStream = createWriteStream(outputFilePath);
  const bar = getProgressBarInstance(`${basename(inputFilePath)}: `, total);

  const handleComplete = () => {
    print('');
    print('-----------------------------------------------------');
    printSuccess(`[${basename(inputFilePath)}] 解析完成，共计 [${i}] 行`);
    PrintTime.end(parseTimeStr);
    print(`正确数据已经输出到 [${outputFilePath}]`);
    print('-----------------------------------------------------');
    print('');
  };

  async function handleLine(line: string, cb: (unknown: unknown, line: string) => void) {
    const obj = handleLogRow(line, options);

    if (line === '') {
      cb(null, '');
      return;
    }

    const { keys } = options;
    let rowStr = await obj2csvRow(keys, obj);

    if (isFirst) {
      isFirst = false;
      rowStr = `${keys.join(',')}\n${rowStr}`;
    }

    cb(null, rowStr);
    i += 1;
    bar.tick();
  }

  return new Promise((resolve) => {
    readStream
      .pipe(es.split())
      .pipe(es.map((handleLine)))
      .pipe(es.wait(() => {
        handleComplete();
        resolve();
      }))
      .pipe(writeStream);
  });
}

export function handleLogs(conf:HandleLogs): void {
  checkConf(conf);

  const {
    inputDirPath,
    outputDirPath,
    files,
    options,
  } = conf;
  promiseQueue(files.map((fileName) => {
    const ext = extname(fileName);
    const plainFileName = fileName.replace(ext, '');

    return () => handleLog({
      inputFilePath: join(inputDirPath, fileName),
      outputFilePath: join(outputDirPath, `${plainFileName}.csv`),
      options,
    });
  }));
}