import { EventEmitter } from 'events'
import fs from 'fs/promises'

export default class Application extends EventEmitter {
  constructor(util, db, provider, name, opts = {}) {
    super()
    this.util = util
    this.db = db
    this.config = db.config[name] || { }
    this.provider = provider
    this.name = name
    this.updating = false

    Object.assign(this, {
      setInterval: opts.setInterval || setInterval,
      fs: opts.fs || fs,
    })

    this.db.addApplication(name)
  }

  startAutoupdater() {
    if (this.provider.static) return

    let timer = this.setInterval(() => {
      this.update().then(
        () => {
          this.db.data.core[this.name].updater += 'Automatic update finished successfully. '
        },
        (err) => {
          this.db.data.core[this.name].updater += 'Error while running automatic update: ' + err.message + '. '
        }
      )
    }, (this.config.updateEvery || 180) * 60 * 1000)
    timer.unref()
  }

  updateLog(message) {
    this.db.data.core[this.name].updater += message
    this.db.log.info(message)
    return message
  }

  async update() {
    if (this.updating) return

    if (this.provider.static) {
      this.updateLog('Provider in question is static and so no update required, nothing to do.')
      return
    }

    this.updating = true
    this.db.data.core[this.name].updater = ''
    let cleanup = true
    let folder = ''
    let log = ''
    let latest = null

    try {
      log += this.updateLog(`Checking for latest version at ${new Date().toISOString().replace('T', ' ').split('.')[0]}. `) + '\n'

      latest = await this.provider.getLatestVersion()

      log += this.updateLog(`Found ${latest.version}. `) + '\n'

      if (this.db.data.core[this.name].latestInstalled === latest.version) {
        this.updateLog('Already up to date, nothing to do. ')
        this.updating = false
        return
      }
      
      latest.id = latest.version
      var found = this.db.get(this.db.data.core[this.name].versions, latest.id)
      if (found) {
        Object.keys(latest).forEach(function(key) {
          found[key] = latest[key]
        })
        latest = found
        log = latest.log + log
      } else {
        this.db.upsert(this.db.data.core[this.name].versions, latest)
      }

      if (latest.failtodownload && latest.failtodownload > 3) {
        this.updateLog('Version failed to download too many times, skipping this version. ')
        this.updating = false
        return
      }
      if (latest.failtoinstall && latest.failtoinstall > 3) {
        this.updateLog('Version failed to install too many times, skipping this version. ')
        this.updating = false
        return
      }

      let target = this.util.getPathFromRoot(`./${this.name}/${latest.version}/file${this.util.getExtension(latest.filename)}`)
      folder = this.util.getPathFromRoot(`./${this.name}/${latest.version}`)

      await this.fs.mkdir(folder, { recursive: true })

      log += this.updateLog(`Downloading ${latest.link} to ${target}. `) + '\n'
      await this.provider.downloadVersion(latest, target)
        .catch(function(err) {
          latest.failtodownload = (latest.failtodownload || 0) + 1
          return Promise.reject(err)
        })

      log += '\n' + this.updateLog(`Extracting ${target}. `) + '\n'
      await this.util.extractFile(target, function(msg) {
        log += msg
      }).catch(function(err) {
        latest.failtodownload = (latest.failtodownload || 0) + 1
        return Promise.reject(err)
      })

      await this.fs.rm(target, { force: true }).catch(function() {})

      if (!log.endsWith('\n')) {
        log += '\n'
      }
      if (!log.endsWith('\n\n')) {
        log += '\n'
      }

      await this.fs.stat(this.util.getPathFromRoot(`./${this.name}/${latest.version}/index.mjs`))
        .catch((err) => {
          latest.failtodownload = (latest.failtodownload || 0) + 1
          log += this.updateLog('Version did not include or was missing index.mjs. ') + '\n'
          return Promise.reject(err)
        })

      cleanup = false

      let packageStat = await this.fs.stat(this.util.getPathFromRoot(`./${this.name}/${latest.version}/package.json`))
        .catch(function() { return null })

      if (packageStat) {
        log += this.updateLog(`running npm install --production. `) + '\n'
        await this.util.runCommand(
          'npm.cmd',
          ['install', '--production', '--no-optional', '--no-package-lock', '--no-audit', '--loglevel=notice'],
          folder,
          function(msg) {
            log += msg
          }
        ).catch(function(err) {
          latest.failtoinstall = (latest.failtoinstall || 0) + 1
          return Promise.reject(err)
        })
    
        if (!log.endsWith('\n')) {
          log += '\n'
        }
        if (!log.endsWith('\n\n')) {
          log += '\n'
        }

      } else {
        log += this.updateLog('Release did not contain package.json, skipping npm install. ') + '\n'
      }
    } catch (err) {
      this.updating = false
      log += this.updateLog(`Error: ${err.message}. `) + '\n'
      if (folder && cleanup) {
        await this.fs.rm(folder, { force: true, recursive: true }).catch((err) => {
          this.updateLog(`Error while cleaning up: ${err.message}. `)
        })
      }
      if (latest) {
        latest.log = log
      }
      return Promise.reject(err)
    }

    log += this.updateLog(`Finished updating ${this.name} to version ${latest.version}.`) + '\n'
    this.db.data.core[this.name].latestInstalled = latest.version
    latest.log = log
    this.updating = false
  }
}