index.js

const Model = require('scuttlebutt/model')

const Module = require('@microverse-network/core/module')

const Collection = require('./collection')

module.exports = class Database extends Module {
  constructor(options = {}) {
    super(options)
    this.collections = {}
    this.map = new Model().on('update', (...args) => {
      this.handleMapUpdate(...args)
    })
  }

  createStreams(mux) {
    super.createStreams()
    this.bindMapStream(mux.createStream('map'))
  }

  bindStreamHandlers() {
    super.bindStreamHandlers()
    this.on('stream.map', stream => this.bindMapStream(stream))
  }

  bindMapStream(stream) {
    this.debug('binding stream %s %s', stream.meta, stream.id)
    stream.pipe(this.map.createStream()).pipe(stream)
  }

  get(name, options = {}) {
    if (this.collections[name]) {
      return this.collections[name]
    }

    options.id = name
    options.db = this

    const collection = new Collection(options)

    this.collections[name] = collection
    this.map.set(name, true)
    return collection
  }

  list() {
    const list = []
    Object.keys(this.collections).forEach(name => {
      return list.push(this.collections[name])
    })
    return list
  }

  handleMapUpdate([name, exists], update, source) {
    if (source === this.map.id) return
    if (exists && this.collections[name]) return

    this.debug('database map update %s %o', name, exists)
    if (exists) {
      this.get(name)
    }
  }
}