'use strict'

const log = require('debug')('interactor:pm2:interface')
const path = require('path')
const async = require('async')
const fs = require('fs')
const cst = require('../constants')

module.exports = class PM2Interface {
  constructor (rpc) {
    log('PM2Interface instantiate')
    this.rpc = rpc
  }

  getProcessByName (name, cb) {
    var foundProc = []

    this.rpc.getMonitorData({}, (err, list) => {
      if (err) {
        log('Error retrieving process list: ' + err)
        return cb(err)
      }

      list.forEach((proc) => {
        if (proc.pm2_env.name === name || proc.pm2_env.pm_exec_path === path.resolve(name.toString())) {
          foundProc.push(proc)
        }
      })

      return cb(null, foundProc)
    })
  }

  /**
   * Scale up/down a process
   * @method scale
   */
  scale (opts, cb) {
    const self = this
    const appName = opts.name
    let number = opts.number

    function addProcs (proc, value, cb) {
      (function ex (proc, number) {
        if (number-- === 0) return cb()
        log('Scaling up application')
        self.rpc.duplicateProcessId(proc.pm2_env.pm_id, ex.bind(this, proc, number))
      })(proc, number)
    }

    function rmProcs (procs, value, cb) {
      let i = 0;

      (function ex (procs, number) {
        if (number++ === 0) return cb()
        self.rpc.deleteProcessId(procs[i++].pm2_env.pm_id, ex.bind(this, procs, number))
      })(procs, number)
    }

    let end = () => {
      return cb ? cb(null, {success: true}) : log('Successfuly scale')
    }

    this.getProcessByName(appName, (err, procs) => {
      if (err) {
        return cb ? cb(err) : log(err)
      }

      if (!procs || procs.length === 0) {
        log('Application %s not found', appName)
        return cb ? cb(new Error('App not found')) : log('App not found')
      }

      let procNumber = procs.length

      if (typeof (number) === 'string' && number.indexOf('+') >= 0) {
        number = parseInt(number, 10)
        return addProcs(procs[0], number, end)
      } else if (typeof (number) === 'string' && number.indexOf('-') >= 0) {
        number = parseInt(number, 10)
        return rmProcs(procs, number, end)
      } else {
        number = parseInt(number, 10)
        number = number - procNumber

        if (number < 0) {
          return rmProcs(procs, number, end)
        } else if (number > 0) {
          return addProcs(procs[0], number, end)
        } else {
          log('Nothing to do')
          return cb ? cb(new Error('Same process number')) : log('Same process number')
        }
      }
    })
  }

  /**
   * Dump current processes managed by pm2 into DUMP_FILE_PATH file
   * @method dump
   * @param {} cb
   * @return
   */
  dump (cb) {
    var envArr = []

    this.rpc.getMonitorData({}, (err, list) => {
      if (err) {
        return typeof cb === 'function' ? cb(err) : false
      }

      /**
       * Description
       * @method end
       * @param {} err
       * @return
       */
      const end = () => {
        // Overwrite dump file, delete if broken and exit
        try {
          fs.writeFileSync(cst.DUMP_FILE_PATH, JSON.stringify(envArr, '', 2))
        } catch (e) {
          log('Dump error', e.stack || e)
          return cb(e)
        }
        return (cb) ? cb(null, {success: true}) : true
      }

      async.each(list, (app, done) => {
        delete app.pm2_env.instances
        delete app.pm2_env.pm_id
        if (!app.pm2_env.pmx_module) {
          envArr.push(app.pm2_env)
        }
        done()
      }, end)
    })
  }

  _callWithProcessId (fn, params, cb) {
    if (params.id === undefined) {
      this.getProcessByName(params.name, (err, processes) => {
        if (err) return cb(err)

        // in case we don't find the process ourselves
        // we believe pm2 will find it
        if (processes.length === 0) {
          return fn(Object.assign({ id: params.name }, params), cb)
        }

        async.eachOf(processes, (process, _key, localCb) => {
          params.id = process.pm_id
          fn(params, localCb)
        }, cb)
      })
    } else {
      fn(params, cb)
    }
  }

  restart (params, cb) {
    this._callWithProcessId(this.rpc.restartProcessId, params, cb)
  }

  reload (params, cb) {
    this._callWithProcessId(this.rpc.reloadProcessId, params, cb)
  }

  reset (params, cb) {
    this._callWithProcessId(
      (newParams, cb) => this.rpc.resetMetaProcessId(newParams.id, cb),
      params,
      cb
    )
  }

  ping (params, cb) {
    this._callWithProcessId(this.rpc.ping, params, cb)
  }
}