import sangria.macros.derive._
import sangria.schema._

import graphql.OutputTypes._


trait Execution {
  this: CatalogRepo =>

  // ... other entities

  def course(id: Int):Option[Course] = course(id) // call to backend

  def courses(ids: Option[Seq[Int]], limit: Option[Int], offset: Option[Int], search: Option[String]): List[Course] = courses(ids, limit, offset, search) // call to backend

  def teachingCenter(id: Int):Option[TeachingCenter] = teachingCenter(id) // call to backend

  def teachingCenters(ids: Option[Seq[Int]], limit: Option[Int], offset: Option[Int], search: Option[String]): List[TeachingCenter] = teachingCenters(ids, limit, offset, search) // call to backend
}

object SchemaDefinition {

val QueryType = ObjectType("Query", fields[Ctx, Unit](

  // ... other entities

  Field("course", OptionType(CourseType),
    description = Some("Returns a Course with specific `id`."),
    arguments = Id :: Nil,
    resolve = c ⇒ c.ctx.execution.course(c arg Id) ),

  Field("courses", ListType(CourseType),
    description = Some("Returns a list of all available Courses."),
    arguments = Limit :: Offset :: Search :: Nil,
    resolve = c ⇒ c.ctx.execution.courses(None, c arg Limit, c arg Offset, c arg Search) )

,		Field("teachingCenter", OptionType(TeachingCenterType),
    description = Some("Returns a TeachingCenter with specific `id`."),
    arguments = Id :: Nil,
    resolve = c ⇒ c.ctx.execution.teachingCenter(c arg Id) ),

  Field("teachingCenters", ListType(TeachingCenterType),
    description = Some("Returns a list of all available TeachingCenters."),
    arguments = Limit :: Offset :: Search :: Nil,
    resolve = c ⇒ c.ctx.execution.teachingCenters(None, c arg Limit, c arg Offset, c arg Search)
))

  // Ctx is defined in OutputTypes.scala
  val ExecutionType = deriveContextObjectType[Ctx, Execution, Unit](_.execution)

  val schema = Schema(QueryType, Some(ExecutionType), Some(SubscriptionType))
}