const chunk = require('chunk')

const MAX_DATA_BYTES = 65533

module.exports = class CreationService {
  constructor (opts) {
    this.hypervisor = opts.hypervisor
    this.scheduler = this.hypervisor.scheduler
  }

  queue (port, message) {
    if (message.data.type) {
      let id
      if (message.fromId) {
        const creator = this.scheduler.getInstance(message.fromId)
        id = creator.generateNextId()
      }
      return this.createInstance(message, id)
    }
  }

  getPort () {
    return {
      messages: [],
      destId: 0
    }
  }

  // send (port, message) {
  //   message._hops++
  //   message._fromTicks = this.ticks
  //   message.fromId = this.id

  //   return this.hypervisor.send(port, message)
  // }

  /**
   * creates an new container instances and save it in the state
   * @returns {Promise}
   */
  async createInstance (message, id = {nonce: 0, parent: null}) {
    const idHash = await this._getHashFromObj(id)
    const state = {
      nonce: [0],
      ports: {},
      type: message.data.type
    }

    if (message.data.code && message.data.code.length) {
      state.code = message.data.code
    }

    // create the container instance
    const instance = await this.hypervisor._loadInstance(idHash, state)

    // send the intialization message
    await instance.create(message)

    if (state.code && state.code.length > MAX_DATA_BYTES) {
      state.code = chunk(state.code, MAX_DATA_BYTES).map(chk => {
        return {
          '/': chk
        }
      })
    }
    // save the container in the state
    await this.hypervisor.tree.set(idHash, state)

    if (!Object.keys(instance.ports.ports).length) {
      this.hypervisor.addNodeToCheck(instance.id)
    }

    return instance
  }

  // get a hash from a POJO
  _getHashFromObj (obj) {
    return this.hypervisor.graph.flush(obj).then(obj => obj['/'])
  }
}