From 48a1c62a172a29f279e6303f0547d41a88d7d7c2 Mon Sep 17 00:00:00 2001
From: Nabil Abdel-Hafeez <7283535+987Nabil@users.noreply.github.com>
Date: Tue, 24 Sep 2024 23:10:59 +0200
Subject: [PATCH] Special case encode optional for HttpCodec.Content (#3144)

---
 .../endpoint/openapi/OpenAPIGenSpec.scala     |  3 +-
 .../main/scala/zio/http/codec/HttpCodec.scala | 13 ++++++++
 .../zio/http/codec/HttpContentCodec.scala     | 30 +++++++++++++++++++
 .../http/endpoint/openapi/JsonSchema.scala    |  4 +--
 4 files changed, 46 insertions(+), 4 deletions(-)

diff --git a/zio-http/jvm/src/test/scala/zio/http/endpoint/openapi/OpenAPIGenSpec.scala b/zio-http/jvm/src/test/scala/zio/http/endpoint/openapi/OpenAPIGenSpec.scala
index 06e00af622..7f7a642e78 100644
--- a/zio-http/jvm/src/test/scala/zio/http/endpoint/openapi/OpenAPIGenSpec.scala
+++ b/zio-http/jvm/src/test/scala/zio/http/endpoint/openapi/OpenAPIGenSpec.scala
@@ -1379,8 +1379,7 @@ object OpenAPIGenSpec extends ZIOSpecDefault {
                          |                    "width",
                          |                    "height",
                          |                    "metadata"
-                         |                  ],
-                         |                  "description" : "Test doc\n\n"
+                         |                  ]
                          |                }
                          |              }
                          |            }
diff --git a/zio-http/shared/src/main/scala/zio/http/codec/HttpCodec.scala b/zio-http/shared/src/main/scala/zio/http/codec/HttpCodec.scala
index df546bd0da..8a2fe790a8 100644
--- a/zio-http/shared/src/main/scala/zio/http/codec/HttpCodec.scala
+++ b/zio-http/shared/src/main/scala/zio/http/codec/HttpCodec.scala
@@ -566,6 +566,19 @@ object HttpCodec extends ContentCodecs with HeaderCodecs with MethodCodecs with
     def tag: AtomTag = AtomTag.Content
 
     def index(index: Int): Content[A] = copy(index = index)
+
+    /**
+     * Returns a new codec, where the value produced by this one is optional.
+     */
+    override def optional: HttpCodec[HttpCodecType.Content, Option[A]] =
+      Annotated(
+        Content(
+          codec.optional,
+          name,
+          index,
+        ),
+        Metadata.Optional(),
+      )
   }
   private[http] final case class ContentStream[A](
     codec: HttpContentCodec[A],
diff --git a/zio-http/shared/src/main/scala/zio/http/codec/HttpContentCodec.scala b/zio-http/shared/src/main/scala/zio/http/codec/HttpContentCodec.scala
index c0223e4fe6..3f8a3f29a2 100644
--- a/zio-http/shared/src/main/scala/zio/http/codec/HttpContentCodec.scala
+++ b/zio-http/shared/src/main/scala/zio/http/codec/HttpContentCodec.scala
@@ -148,6 +148,36 @@ sealed trait HttpContentCodec[A] { self =>
     choices.headOption.map(_._2).getOrElse {
       throw new IllegalArgumentException(s"No codec defined")
     }
+
+  def optional: HttpContentCodec[Option[A]] =
+    self match {
+      case HttpContentCodec.Choices(choices)           =>
+        HttpContentCodec.Choices(
+          choices.map { case (mediaType, BinaryCodecWithSchema(fromConfig, schema)) =>
+            mediaType -> BinaryCodecWithSchema(fromConfig.andThen(optBinaryCodec), schema.optional)
+          },
+        )
+      case HttpContentCodec.Filtered(codec, mediaType) =>
+        HttpContentCodec.Filtered(codec.optional, mediaType)
+    }
+
+  private def optBinaryCodec(bc: BinaryCodec[A]): BinaryCodec[Option[A]] = new BinaryCodec[Option[A]] {
+    override def encode(value: Option[A]): Chunk[Byte] = value match {
+      case Some(a) => bc.encode(a)
+      case None    => Chunk.empty
+    }
+
+    override def decode(bytes: Chunk[Byte]): Either[DecodeError, Option[A]] =
+      if (bytes.isEmpty) Right(None)
+      else bc.decode(bytes).map(Some(_))
+
+    override def streamDecoder: ZPipeline[Any, DecodeError, Byte, Option[A]] =
+      ZPipeline.chunks[Byte].map(bc.decode).map(_.toOption)
+
+    override def streamEncoder: ZPipeline[Any, Nothing, Option[A], Byte] =
+      ZPipeline.identity[Option[A]].map(_.fold(Chunk.empty[Byte])(bc.encode)).flattenChunks
+  }
+
 }
 
 object HttpContentCodec {
diff --git a/zio-http/shared/src/main/scala/zio/http/endpoint/openapi/JsonSchema.scala b/zio-http/shared/src/main/scala/zio/http/endpoint/openapi/JsonSchema.scala
index 4163ace700..cdc38d22d2 100644
--- a/zio-http/shared/src/main/scala/zio/http/endpoint/openapi/JsonSchema.scala
+++ b/zio-http/shared/src/main/scala/zio/http/endpoint/openapi/JsonSchema.scala
@@ -117,8 +117,8 @@ private[openapi] object BoolOrSchema {
 private[openapi] sealed trait TypeOrTypes { self =>
   def add(value: String): TypeOrTypes =
     self match {
-      case TypeOrTypes.Type(string) => TypeOrTypes.Types(Chunk(string, value))
-      case TypeOrTypes.Types(chunk) => TypeOrTypes.Types(chunk :+ value)
+      case TypeOrTypes.Type(string) => TypeOrTypes.Types(Chunk(string, value).distinct)
+      case TypeOrTypes.Types(chunk) => TypeOrTypes.Types((chunk :+ value).distinct)
     }
 }