import { Target } from '../types/target';
import { exporterFactory } from '../services/exporter.factory';
import { EXPORTED_PATH } from '../config';

import { Task, TaskTableRowConfig } from '../types';

import * as express from 'express';

import * as path from 'path';
import * as fs from 'fs';

type TRequest = {
  body: {
    from: string,
    to: string,
    username: string,
    tasks: Task[],
    url: string,
  },
};

async function getTasks(req, res) {
  const resp: TaskTableRowConfig[] = [];
  fs.readdir(EXPORTED_PATH, (err, items) => {
    if(err) {
      console.error(err);
      res.status(500).send('Something went wrong');
    } else {
      for(let item of items) {
        let file = path.parse(item);
        if(file.ext !== '.json') {
          continue;
        }
        // TODO: read async
        let data = fs.readFileSync(path.join(EXPORTED_PATH, item), 'utf8');
        let status = JSON.parse(data);

        let requestedUrl = `http://${req.headers.host}`;
        let downloadLink = '';
        let deleteLink = '';
        if(status.status === 'finished') {
          downloadLink = `<a class="download-csv" href="${requestedUrl}/static/${file.name}.csv" target="_blank"><i class="fa fa-download"></i></a>`;
        }
        resp.push({
          timestamp: status.time,
          user: status.user,
          datasourceRef: status.datasourceRef,
          rowsCount: status.exportedRows,
          progress: status.progress,
          status: status.status,
          downloadLink,
        });
      }

      res.status(200).send(resp);
    }
  });
}

async function addTask(req: TRequest, res) {

  const body = req.body;

  const clientUrl = body.url;
  const from = parseInt(body.from);
  const to = parseInt(body.to);
  const username = body.username;
  const tasks = body.tasks;

  const datasourceUrl = `${new URL(clientUrl).origin}/api/ds/query`;

  if(isNaN(from) || isNaN(to)) {
    res.status(400).send('Range error: please fill both "from" and "to" fields');
  } else if(from >= to) {
    res.status(400).send('Range error: "from" should be less than "to"');
  } else {
    const names = tasks.map(item => item.datasource.name).join(', ');
    res.status(200).send(`Exporting ${names} data from ${new Date(from).toLocaleString()} to ${new Date(to).toLocaleString()}`);

    const targets = tasks.map((task: Task) => new Target(
      task.panel,
      task.datasource,
    ));
    const exporter = exporterFactory.getExporter();
    exporter.export(targets, datasourceUrl, username, from, to);
  }
}

async function deleteTask(req, res) {
  let filename = req.query.filename;
  let csvFilePath = path.join(EXPORTED_PATH, `${filename}.csv`);
  let jsonFilePath = path.join(EXPORTED_PATH, `${filename}.json`);

  if(fs.existsSync(csvFilePath)) {
    fs.unlink(csvFilePath, err => console.error(err));
  }
  if(fs.existsSync(jsonFilePath)) {
    fs.unlink(jsonFilePath, err => console.error(err));
  }

  res.status(200).send({ status: 'OK' });
}

export const router = express.Router();

router.get('/', getTasks);
router.post('/', addTask);
router.delete('/', deleteTask);