import { promisify } from 'util'
import { readFile, writeFile } from 'fs'
const read = promisify(readFile)
const write = promisify(writeFile)
// alternative with new promise experimental fs
// import fs from 'fs'
// const read = fs.promises.readFile
import settle from 'p-settle'
import path from 'path'
import logger from '@uci/logger'
let log = logger({ name: 'remote-code', file:'src/read-lines.js'})

// A promise helper function to return a list of paths to ignore from .npmignore, .gitignore, .rcignore
function readLines (files=[],dir) {
  // console.log('additional files', files)
  let list = []
  if (!Array.isArray(files)) files=[files]

  // each set in an the array is new line delimited set of ignore patterns
  // settle returns array of error,value pairs
  return settle(files.map(file => {
    // console.log('directory',path.dirname(file))
    if (path.dirname(file)==='.') file = dir+'/'+file
    log.info({function:'readLines',file:file,msg:'reading a file of lines into array'})
    return read(file)
  }))
    .then((sets) => {
      sets.forEach( set =>  {
        if (set.isFulfilled) list.push(...set.value.toString().match(/.+/g))
        else log.warn({function:'readLines', error:set.reason, msg:' was unable to read file'})
      })
      return Promise.resolve(list)
    })
    .catch((err) => {
      // only returned when something horrible is wrong
      return Promise.reject(err)
    })
}

// an ignore list should not be huge so can serailize at once
function writeLines (filePath,list) {

  return write(filePath,list.join('\n'))
    .then(() => {
      log.info({function:'writeLines', file:filePath, msg:'wrote array to file of lines'})
    })
    .catch( err => {
      log.fatal({function:'writeLines', error:err, msg:'unable to write array to file of lines'})
    })
}

export default readLines
export { readLines, writeLines }