From 8ac69976e3945da5554c441f0d3a133344683eca Mon Sep 17 00:00:00 2001
From: johannes karoff <johannes@karoff.net>
Date: Sat, 22 Jun 2024 21:55:35 +0200
Subject: [PATCH] add Observable#bufferTimed

---
 .../src/main/scala/colibri/Observable.scala   | 41 ++++++++++++++++---
 .../test/scala/colibri/ObservableSpec.scala   | 39 ++++++++++++++++++
 2 files changed, 75 insertions(+), 5 deletions(-)

diff --git a/colibri/src/main/scala/colibri/Observable.scala b/colibri/src/main/scala/colibri/Observable.scala
index 43b12495..7b6e97d3 100644
--- a/colibri/src/main/scala/colibri/Observable.scala
+++ b/colibri/src/main/scala/colibri/Observable.scala
@@ -498,12 +498,12 @@ object Observable    {
 
     def parMapFuture[B](f: A => Future[B]): Observable[B] = parMapEffect(a => IO.fromFuture(IO(f(a))))
 
-    def discard: Observable[Nothing]                             = Observable.empty.subscribing(source)
-    def void: Observable[Unit]                                   = map(_ => ())
-    def as[B](value: B): Observable[B]                           = map(_ => value)
-    def asEval[B](value: => B): Observable[B]                    = map(_ => value)
+    def discard: Observable[Nothing]                                = Observable.empty.subscribing(source)
+    def void: Observable[Unit]                                      = map(_ => ())
+    def as[B](value: B): Observable[B]                              = map(_ => value)
+    def asEval[B](value: => B): Observable[B]                       = map(_ => value)
     def asEffect[F[_]: RunEffect, B](value: => F[B]): Observable[B] = mapEffect(_ => value)
-    def asFuture[B](value: => Future[B]): Observable[B]          = mapFuture(_ => value)
+    def asFuture[B](value: => Future[B]): Observable[B]             = mapFuture(_ => value)
 
     def mapFilter[B](f: A => Option[B]): Observable[B] = new Observable[B] {
       def unsafeSubscribe(sink: Observer[B]): Cancelable = source.unsafeSubscribe(sink.contramapFilter(f))
@@ -1316,6 +1316,37 @@ object Observable    {
       }
     }
 
+    @inline def bufferTimed[Col[_]](duration: FiniteDuration)(implicit factory: Factory[A, Col[A]]): Observable[Col[A]] = bufferTimedMillis(
+      duration.toMillis.toInt,
+    )
+
+    def bufferTimedMillis[Col[_]](duration: Int)(implicit factory: Factory[A, Col[A]]): Observable[Col[A]] = new Observable[Col[A]] {
+      def unsafeSubscribe(sink: Observer[Col[A]]): Cancelable = {
+        var isCancel = false
+        var builder  = factory.newBuilder
+
+        def send(): Unit = {
+          sink.unsafeOnNext(builder.result())
+          builder = factory.newBuilder
+        }
+
+        val intervalId = timers.setInterval(duration.toDouble) { if (!isCancel) send() }
+
+        Cancelable.composite(
+          Cancelable { () =>
+            isCancel = true
+            timers.clearInterval(intervalId)
+          },
+          source.unsafeSubscribe(
+            Observer.createUnrecovered(
+              value => builder += value,
+              sink.unsafeOnError,
+            ),
+          ),
+        )
+      }
+    }
+
     def evalOn(ec: ExecutionContext): Observable[A] = new Observable[A] {
       def unsafeSubscribe(sink: Observer[A]): Cancelable = {
         var isCancel = false
diff --git a/colibri/src/test/scala/colibri/ObservableSpec.scala b/colibri/src/test/scala/colibri/ObservableSpec.scala
index 65ce27ec..5d120785 100644
--- a/colibri/src/test/scala/colibri/ObservableSpec.scala
+++ b/colibri/src/test/scala/colibri/ObservableSpec.scala
@@ -1931,4 +1931,43 @@ class ObservableSpec extends AsyncFlatSpec with Matchers {
 
     test.unsafeToFuture()
   }
+
+  it should "bufferTimed" in {
+    var received = List.empty[Int]
+    var errors   = 0
+    val subject  = Subject.behavior[Int](0)
+    val stream   = subject.bufferTimedMillis[Vector](100)
+
+    import scala.concurrent.duration._
+
+    val cancelable = stream.unsafeSubscribe(
+      Observer.create[Vector[Int]](
+        received ++= _,
+        _ => errors += 1,
+      ),
+    )
+    cancelable.isEmpty() shouldBe false
+    received shouldBe List()
+
+    val test = for {
+      _ <- subject.onNextIO(1)
+      _  = received shouldBe List()
+      _ <- IO.sleep(50.millis)
+      _ <- subject.onNextIO(2)
+      _  = received shouldBe List()
+      _ <- IO.sleep(50.millis)
+      _ <- subject.onNextIO(3)
+      _  = received shouldBe List(0, 1, 2)
+      _ <- subject.onNextIO(4)
+      _  = received shouldBe List(0, 1, 2)
+      _ <- IO.sleep(200.millis)
+      _ <- subject.onNextIO(5)
+      _  = received shouldBe List(0, 1, 2, 3, 4)
+      _ <- IO.sleep(100.millis)
+      _  = received shouldBe List(0, 1, 2, 3, 4, 5)
+      _  = errors shouldBe 0
+    } yield succeed
+
+    test.unsafeToFuture()
+  }
 }