import { mkdir, writeFile } from 'fs'
import { spawn } from 'child_process'
import { v1 as uuidv1 } from 'uuid'

import { getDirPath, getDocPath, getTexCmd } from './utils'

function copyToTemp(id: string, texDocument: string): Promise<string> {
  return new Promise((resolve, reject) => {
    const dirPath = getDirPath(id)

    mkdir(dirPath, (err) => {
      if (err) {
        reject(err)
        return
      }

      const docPath = getDocPath(id)
      writeFile(docPath, texDocument, (err) => {
        if (err) {
          reject(err)
        }
        resolve(id)
      })
    })
  })
}

function generateDoc(id: string) {
  return new Promise((resolve, reject): void => {
    const pdflatex = spawn(...getTexCmd(id))
    pdflatex.stderr?.on('data', (data: string) => {
      console.error('error: ', data)
      reject()
    })
    pdflatex.on('error', (error) => {
      console.error('error', error)
      reject()
    })

    pdflatex.on('close', (code) => {
      if (code !== null && code > 0) {
        reject(`pdflatex returned with code ${code}`)
        return
      }
      console.log(`PDF ${id} generated`)
      resolve(id)
    })
  })
}

export default async function (texDocument: string) {
  const id = uuidv1()
  const id_2 = await copyToTemp(id, texDocument)
  return generateDoc(id_2)
}