package org.scalatra.util

import scala.collection.generic.CanBuildFrom
import scala.collection.immutable.{HashMap, Map, MapLike}
import scala.collection.mutable.{Builder, MapBuilder}

class MultiMap
  extends HashMap[String, Seq[String]]
  with MapLike[String, Seq[String], MultiMap]
  with MapWithIndifferentAccess[Seq[String]]
{
  override def get(key: String): Option[Seq[String]] =
    (super.get(key) orElse super.get(key + "[]"))

  override def default(key: String): Seq[String] = Seq.empty

  override def empty: MultiMap = MultiMap.empty
}

object MultiMap {
  def apply(elems: (String, Seq[String])*): MultiMap = (newBuilder ++= elems).result
  def apply(map: scala.collection.Map[String, Seq[String]]): MultiMap =
    apply(map.toSeq:_*)

  def newBuilder: Builder[(String, Seq[String]), MultiMap] =
    new MapBuilder[String, Seq[String], MultiMap](empty)

  implicit def canBuildFrom: CanBuildFrom[Map[String, Seq[String]], (String, Seq[String]), MultiMap] = {
    new CanBuildFrom[Map[String, Seq[String]], (String, Seq[String]), MultiMap] {
      def apply(from: Map[String, Seq[String]]) = newBuilder

      def apply() = newBuilder
    }
  }
  def empty = new MultiMap
}