procedure.js

var cadence = require('cadence')

var Procession = require('procession')
var coalesce = require('extant')

var Operation = require('operation/variadic')

function Procedure () {
    var vargs = Array.prototype.slice.call(arguments)
    this._operation = new Operation(vargs)

    this.write = new Procession
    this.read = new Procession

    this.write.shifter().pump(this, '_enqueue')
}

Procedure.prototype._enqueue = cadence(function (async, envelope) {
    if (
        envelope != null &&
        envelope.module == 'conduit/caller' &&
        envelope.method == 'invoke'
    ) {
        async(function () {
            this._operation.call(null, envelope.body, async())
        }, function (response) {
            this.read.enqueue({
                module: 'conduit/procedure',
                method: 'invocation',
                cookie: envelope.cookie,
                body: coalesce(response)
            }, async())
        })
    }
})

module.exports = Procedure