local-api.js

'use strict'
const Permissions = require('./permissions')
const u = require('./util')

module.exports = function createLocalCall (api, manifest, perms) {
  perms = Permissions(perms)

  function has (type, name) {
    return type === u.get(manifest, name)
  }

  function localCall (type, name, args) {
    if (name === 'emit') throw new Error('emit has been removed')

    // is there a way to know whether it's sync or async?
    if (type === 'async') {
      if (has('sync', name)) {
        const cb = args.pop()
        let value
        try {
          value = u.get(api, name).apply(this, args)
        } catch (err) {
          return cb(err)
        }
        return cb(null, value)
      }
    }

    if (!has(type, name)) {
      throw new Error(`no ${type}:${name}`)
    }

    return u.get(api, name).apply(this, args)
  }

  return function localCallWithPerms (type, name, args) {
    const err = perms.pre(name, args)
    if (err) throw err
    return localCall.call(this, type, name, args)
  }
}