WunderlistJsonIteratee.sc

import java.util.Date

import net.fortuna.ical4j.model.component.VEvent
import net.fortuna.ical4j.model.property.Summary
import play.api.libs.iteratee._
import play.api.libs.json.JsString
import play.extras.iteratees.{CharString, Combinators, Encoding}
import play.extras.iteratees.JsonIteratees._
import play.extras.iteratees.JsonEnumeratees._
import scala.concurrent.Await
import scala.concurrent.duration._
import scala.concurrent.ExecutionContext.Implicits.global
import net.fortuna.ical4j.model._
val json = """
             |{
             |  "id": 1051180611,
             |  "created_at": "2015-03-18T17:38:35.583Z",
             |  "recurrence_type": "day",
             |  "recurrence_count": 1,
             |  "due_date": "2015-03-19",
             |  "completed": false,
             |  "starred": false,
             |  "list_id": 121063920,
             |  "revision": 1,
             |  "title": "Заправить диван",
             |  "type": "task"
             |}
             |""".stripMargin
val json2 = """
              |{
              |  "id": 1051180611,
              |  "created_at": "2015-03-18T17:38:35.583Z",
              |  "title": "Жепь",
              |  "type": "task"
              |}
              |""".stripMargin
val json3 = s"[$json,$json2,$json]"

val timeFormat = new java.text.SimpleDateFormat("yyyy-MM-dd")
val ignoreObject = new property.Tel()

val taskSchema = jsObject { field:String =>
  field match {
    case "id" =>
      jsNumber map { idjs =>
        new property.Uid(s"wunderlist-task-${idjs.value.toString()}")
      }
    case "due_date" =>
      jsNullOr(jsString) map {
        case None => ignoreObject
        case Some(str) =>
          val javaDate = timeFormat.parse(str.value)
          val calDate = new net.fortuna.ical4j.model.Date(javaDate)
          new property.DtStart(calDate)
      }
    case "title" =>
      jsNullOr(jsString) map { topt =>
        new property.Summary(topt.getOrElse(JsString("")).value)
      }
    case _ => jsValue.map(_ => ignoreObject)
  }
}

val ignore = Enumeratee.filterNot[Property](_ == ignoreObject)
val buildEvent = Iteratee.fold[Property, Option[VEvent]](None) {
  (maybeEvent, prop) =>
    val event = maybeEvent.getOrElse(new VEvent())
    event.getProperties.add(prop)
    Some(event)
}.map(_.getOrElse(new VEvent()))

val task = taskSchema ><> ignore &>> buildEvent

val ignoreNoDate = Enumeratee.filterNot[VEvent](_.getStartDate == null)

val buildCalendar = Iteratee.fold[VEvent, Option[Calendar]](None) {
  (maybeCal, event) =>
    val cal = maybeCal.getOrElse(new Calendar())
    cal.getComponents.add(event)
    Some(cal)
}.map(_.getOrElse(new Calendar()))

val taskList = jsArray(_ => task) ><> ignoreNoDate &>> buildCalendar
// Encoding.decode() ><> Combinators.errorReporter ><>
Await.result(
  Enumerator(CharString.fromString(json3)) |>>> taskList,
  1 second
)

Output is:

BEGIN:VCALENDAR
BEGIN:VEVENT
DTSTAMP:20150319T125117Z
UID:wunderlist-task-1051180611
DTSTART;VALUE=DATE:20150318
SUMMARY:Заправить диван
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20150319T125117Z
UID:wunderlist-task-1051180611
DTSTART;VALUE=DATE:20150318
SUMMARY:Заправить диван
END:VEVENT
END:VCALENDAR