package com.weEat.services

import play.api.Configuration
import org.mongodb.scala.{MongoClient,MongoDatabase,MongoCollection}
import org.mongodb.scala.bson.codecs.Macros._
import org.bson.{BsonReader,BsonWriter}
import org.bson.codecs.{Codec,DecoderContext,EncoderContext}
import org.bson.codecs.configuration.{CodecProvider,CodecRegistry}
import org.bson.codecs.configuration.CodecRegistries.{fromRegistries,fromProviders}
import com.weEat.models._
import com.weEat.shared.models.{USDANode,RecipeNode,FoodNode,UnitType}
import javax.inject.{Inject,Singleton}
import scala.reflect.ClassTag
import com.weEat.migrations.{Migration,Metadata}
import scala.concurrent.ExecutionContext
import scala.util.{Try,Success,Failure}
import gov.usda.nal.fdc.models.Nutrient

@Singleton
class MongoDBService @Inject()(config: Configuration) {

  implicit val ec = scala.concurrent.ExecutionContext.global

  private val prefix = "mongo"

  val url = config.getOptional[String](s"$prefix.url").getOrElse("localhost")
  val name = config.getOptional[String](s"$prefix.name").getOrElse("recipes")
  val user = config.getOptional[String](s"$prefix.user").getOrElse("application")
  val ssl = config.getOptional[Boolean](s"$prefix.ssl").getOrElse(true)
  val port = config.getOptional[Int](s"$prefix.port").getOrElse(27017)

  val codecRegistry = fromRegistries(
    fromProviders(classOf[Metadata]),
    fromProviders(classOf[FoodNode]),
    fromProviders(classOf[User]),
    fromProviders(classOf[Authorization]),
    fromProviders(classOf[Nutrient]),
    //fromProviders(classOf[UnitType.Value]),
    fromProviders(UnitTypeEnumCodecProvider),
    MongoClient.DEFAULT_CODEC_REGISTRY
  )

  val con = {
    import org.mongodb.scala._
    import org.mongodb.scala.connection.{SslSettings,ClusterSettings}
    import scala.jdk.CollectionConverters._

    implicit val ec: ExecutionContext = ExecutionContext.global
    
    val password = Option(config.get[String](s"$prefix.password"))
      .getOrElse("").toCharArray()
    val credential = MongoCredential.createCredential(user, name, password)

    val db = MongoClient(
      MongoClientSettings.builder()
        .applyToSslSettings((builder: SslSettings.Builder) =>
          builder.enabled(ssl)
        ).applyToClusterSettings((builder: ClusterSettings.Builder) =>
          builder.hosts(List(new ServerAddress(url, port)).asJava)
        ).credential(credential)
        .build()
    ).getDatabase(name)
      .withCodecRegistry(codecRegistry)
    Migration.updateToLatest(db).map(_ => db)
  }

  def apply[T](coll: Collectable[T])(implicit ct: ClassTag[T]) =
    con.map(_.getCollection[T](coll.collectionName))

  def withCollection[T, U](coll: Collectable[U])(fn: (MongoCollection[U] => T))
    (implicit ct: ClassTag[U]) =
    apply(coll).transform({
      case Success(collection) => Success(fn(collection))
      case Failure(e) => Failure(e)
    })
}

object UnitTypeEnumCodecProvider extends CodecProvider {

  def isCaseObjectEnum[T](clazz: Class[T]): Boolean =
    clazz.isInstance(UnitType.MASS) ||
    clazz.isInstance(UnitType.VOLUME) ||
    clazz.isInstance(UnitType.NUMBER)

  override def get[T](clazz: Class[T], registry: CodecRegistry): Codec[T] =
    if (isCaseObjectEnum(clazz)) UnitTypeEnumCodec.asInstanceOf[Codec[T]]
    else null

  object UnitTypeEnumCodec extends Codec[UnitType.UnitType] {
    override def decode(
      reader: BsonReader,
      decoderContext: DecoderContext
    ): UnitType.UnitType = UnitType.withName(reader.readString())

    override def encode(
      writer: BsonWriter,
      value: UnitType.UnitType,
      encoderContext: EncoderContext
    ): Unit = writer.writeString(value.name)

    override def getEncoderClass: Class[UnitType.UnitType] =
      UnitType.getClass.asInstanceOf[Class[UnitType.UnitType]]
  }
}