git ssb

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const Message = require('primea-message')
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const BN = require('bn.js')
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const PortManager = require('./portManager.js')
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const DeleteMessage = require('./deleteMessage')
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module.exports = class Kernel {
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  /**
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   * the Kernel manages the varous message passing functions and provides
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   * an interface for the containers to use
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   * @param {Object} opts
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   * @param {Object} opts.id - the UUID of the Kernel
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   * @param {Object} opts.state - the state of the container
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   * @param {Object} opts.hypervisor
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   * @param {Object} opts.container - the container constuctor and argments
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   */
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  constructor (opts) {
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    this.state = opts.state
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    this.hypervisor = opts.hypervisor
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    this.id = opts.id
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    this.container = new opts.container.Constructor(this, opts.container.args)
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    this.ticks = 0
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    this.containerState = 'idle'
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    // create the port manager
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    this.ports = new PortManager(Object.assign({
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      kernel: this
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    }, opts))
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  }
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  /**
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   * adds a message to this containers message queue
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   * @param {string} portName
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   * @param {object} message
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   */
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  queue (portName, message) {
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    this.ports.queue(portName, message)
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    if (this.containerState !== 'running') {
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      this.containerState = 'running'
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      this._runNextMessage()
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    }
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  }
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  initialize (message) {
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    this.containerState = 'running'
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    this.run(message, 'initialize')
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  }
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  // waits for the next message
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  async _runNextMessage () {
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    // check if the ports are saturated, if so we don't have to wait on the
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    // scheduler
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    const message = await this.ports.getNextMessage()
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    if (!message) {
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      // if no more messages then shut down
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      this.hypervisor.scheduler.done(this.id)
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    } else {
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      message.fromPort.messages.shift()
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      // if the message we recived had more ticks then we currently have the
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      // update it
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      if (message._fromTicks > this.ticks) {
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        this.ticks = message._fromTicks
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      }
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      this.hypervisor.scheduler.update(this)
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      // run the next message
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      this.run(message)
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    }
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  }
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  /**
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   * run the kernels code with a given enviroment
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   * @param {object} message - the message to run
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   * @param {boolean} init - whether or not to run the intialization routine
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   * @returns {Promise}
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   */
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  async run (message, method = 'run') {
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    let result
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    const responsePort = message.responsePort
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    delete message.responsePort
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    message.ports.forEach(port => this.ports._unboundPorts.add(port))
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    message._hops++
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    if (message.constructor === DeleteMessage) {
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      this.ports._delete(message.fromName)
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    } else {
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      try {
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        result = await this.container[method](message) || {}
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      } catch (e) {
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        result = {
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          exception: true,
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          exceptionError: e
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        }
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      }
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    }
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    if (responsePort) {
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      this.send(responsePort, new Message({
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        data: result
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      }))
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      this.ports._unboundPorts.add(responsePort)
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    }
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    this.ports.clearUnboundedPorts()
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    this._runNextMessage()
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    return result
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  }
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  getResponsePort (message) {
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    if (message.responsePort) {
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      return message.responsePort.destPort
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    } else {
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      const [portRef1, portRef2] = this.ports.createChannel()
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      message.responsePort = portRef2
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      this.ports._unboundPorts.delete(portRef2)
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      return portRef1
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    }
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  }
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  /**
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   * updates the number of ticks that the container has run
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   * @param {Number} count - the number of ticks to add
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   */
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  incrementTicks (count) {
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    this.ticks += count
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    this.hypervisor.scheduler.update(this)
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  }
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  /**
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   * creates a new message
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   * @param {*} data
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   */
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  createMessage (opts) {
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    const message = new Message(opts)
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    for (const port of message.ports) {
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      if (this.ports.isBound(port)) {
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        throw new Error('message must not contain bound ports')
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      }
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    }
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    return message
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  }
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  /**
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   * creates a new container. Returning a port to it.
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   * @param {String} type
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   * @param {*} data - the data to populate the initail state with
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   * @returns {Object}
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   */
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  createInstance (type, message) {
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    let nonce = this.state.nonce
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    const id = {
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      nonce: nonce,
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      parent: this.id
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    }
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    // incerment the nonce
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    nonce = new BN(nonce)
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    nonce.iaddn(1)
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    this.state.nonce = nonce.toArray()
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    this.ports.removeSentPorts(message)
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    this.hypervisor.createInstance(type, message, id)
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  }
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  /**
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   * sends a message to a given port
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   * @param {Object} portRef - the port
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   * @param {Message} message - the message
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   */
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  async send (port, message) {
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    // set the port that the message came from
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    message._fromTicks = this.ticks
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    this.ports.removeSentPorts(message)
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    // if (this.currentMessage !== message && !message.responsePort) {
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    //   this.currentMessage._addSubMessage(message)
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    // }
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    if (port.destId) {
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      const id = port.destId
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      const instance = await this.hypervisor.getInstance(id)
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      instance.queue(port.destName, message)
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    } else {
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      // port is unbound
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      port.destPort.messages.push(message)
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    }
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  }
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}
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