import fs from 'fs/promises'
import fsSync from 'fs'
import path from 'path'
import { fileURLToPath } from 'url'

const __dirname = path.dirname(fileURLToPath(import.meta.url));

let structure = `
home/
  a/
    file1
    file2
  b/
    file1
    file2
  c/
  bb/
    file1
    file2
  d/
    file1
    file2
  e/
    file1
    file2
    sub/
  deep_node_modules/
    ma/
      file1
      file2
    mb/
      file1
      file2
    mc/
`

let code = structure
  .split('\n')
  .filter(line => line)
  .map(function(line) {
    return {
      indent: line.length - line.replace(/^\s+/,'').length,
      type: /\/$/.test(line) ? 'dir': 'file',
      text: line.replace(/^\s+|\s*\/\s*|\s+$/g, '')
    }
  })

function join(arr) {
  return arr.join('/')
}

function transform(arr) {
  let result = []
  let temp = []
  let indent = 0
  arr.forEach(function(line) {
    if (!line.text) {
      return
    }
    else if (!line.indent) {
      temp.push(line.text)
      result.push({type: line.type, text: join(temp) })
    }
    else if (indent < line.indent) {
      temp.push(line.text)
      result[result.length - 1].type = 'dir'
      result.push({type: line.type, text: join(temp) })
    }
    else if (indent === line.indent) {
      temp.pop()
      temp.push(line.text)
      result.push({type: line.type, text: join(temp) })
    }
    else if(indent > line.indent) {
      temp.pop()
      temp.pop()
      temp.push(line.text)
      result.push({type: line.type, text: join(temp) })
    }

    indent = line.indent
  })
  return result
}

function gracefully(promise) {
  return promise.catch(function(err) {
    console.log(err)
  })
}

function emptyFile(target) {
  let folder = target.slice(0, target.lastIndexOf('/'))

  /*return fs.mkdir(folder, { recursive: true, force: true })
    .then(() => fs.open(target, 'w').then(fd => fd.close()))*/

  return fs.stat(folder)
  .catch(() => fs.mkdir(folder, { recursive: true, force: true }))
  .then(() => {
    return fs.open(target, 'w').then(fd => fd.close())
  })
}

export function Builder() {
  this.root = path.join(__dirname, '__TREE__')
  this.transformed = transform(code)
}

Builder.prototype.init = async function() {
  await Promise.all(
    this.transformed.filter(line => line.type === 'dir').map(line => {
      let target = path.join(this.root, line.text)
      return gracefully(fs.mkdir(target, { recursive: true }))
    })
  )
  await Promise.all(
    this.transformed.filter(line => line.type !== 'dir').map(line => {
      let target = path.join(this.root, line.text)
      return gracefully(emptyFile(target))
    })
  )
}

Builder.prototype.getPath = function(fpath, sub) {
  return path.join(this.root, fpath, sub || '')
}

Builder.prototype.modify = function(fpath, delay) {
  if (delay) throw new Error('remove delay')
  let filePath = this.getPath(fpath)
  return fs.appendFile(filePath, 'hello')
}

Builder.prototype.remove = function(fpath) {
  let filePath = this.getPath(fpath)
  return fs.rm(filePath, { recursive: true, force: true })
}

Builder.prototype.removeSync = function(fpath) {
  let filePath = this.getPath(fpath)
  return fsSync.rmSync(filePath, { recursive: true, force: true })
}

Builder.prototype.newFile = function(fpath, delay) {
  if (delay) throw new Error('remove delay')
  let filePath = this.getPath(fpath)
  return emptyFile(filePath)
}

Builder.prototype.createDirectory = function(fpath) {
  let filePath = this.getPath(fpath)
  return fs.mkdir(filePath, { recursive: true })
}

Builder.prototype.randomName = function() {
  return Math.random().toString(36).substring(2, 14)
}

Builder.prototype.newRandomFiles = function(fpath, count) {
  return Promise.all(
    new Array(count).fill(0).map(() => {
      let name = this.randomName()
      let filePath = this.getPath(fpath, name)

      return emptyFile(filePath).then(() => name)
    })
  )
}

Builder.prototype.cleanup = function() {
  return fs.rmdir(this.root)
}

Builder.prototype.getAllDirectories = function() {
  function walk(dir) {
    let ret = []
    fsSync.readdirSync(dir).forEach(function(d) {
      let fpath = path.join(dir, d)
      if (fsSync.statSync(fpath).isDirectory()) {
        ret.push(fpath)
        ret = ret.concat(walk(fpath))
      }
    })
    return ret
  }
  return walk(this.root)
}

export function Counter(res, countTotal, waitForSignal = false) {
  this._res = res
  this.counter = 0
  this._countTotal = countTotal
  this._startCount = !waitForSignal
  this._gotSignal = false
  this._signal = null
}

Counter.prototype.waitForCount = function(promise) {
  if (!promise) {
    promise = Promise.resolve()
  }
  return new Promise(res => {
    promise.then(() => {
      this._signal = res
      this.hasSignal()
    })
  })
}

Counter.prototype.hasSignal = function() {
  if (this._gotSignal && this._signal) {
    this._gotSignal = false
    let temp = this._signal
    this._signal = null
    temp()
  }
}

Counter.prototype.startCounting = function() {
  this._startCount = true
}

Counter.prototype.count = function() {
  if (!this._startCount) return

  this._gotSignal = true
  this.counter++
  if (this.counter === this._countTotal && this._res) {
    this._res()
  }

  this.hasSignal()
}