Add avro4s encoders and decoders

build.sbt

@@ -6,7 +6,7 @@ ThisBuild / organizationName := "mlopes"
 
 lazy val wen = project
   .in(file("."))
-  .aggregate(core, cats, circe)
+  .aggregate(core, cats, circe, avro4s)
   .settings(name := "Wen Root")
   .settings(
     publish := {},
@@ -42,6 +42,16 @@ lazy val circe = project
     defaultConfig
   )
 
+lazy val avro4s = project
+  .in(file("modules/avro4s"))
+  .dependsOn(core % "compile->compile;test->test", cats)
+  .settings(moduleName := "wen-avro4s", name := "Wen Avro4s", description := "Avro4s instances for Wen")
+  .settings(
+    libraryDependencies ++= avro4sDependencies,
+    libraryDependencies ++= testDependencies,
+    defaultConfig
+  )
+
 lazy val defaultConfig = Seq(
   scalacOptions := appScalacOptions,
   compile in Compile := (compile in Compile).dependsOn(dependencyUpdates).value,

modules/avro4s/src/main/scala/wen/avro4s/package.scala

@@ -0,0 +1,40 @@
+package wen
+
+import java.time.Instant
+
+import cats.implicits._
+import com.sksamuel.avro4s.{Encoder, SchemaFor}
+import com.sksamuel.avro4s.Encoder._
+import org.apache.avro.Schema
+import wen.datetime._
+import wen.instances.iso._
+import wen.types._
+
+package object avro4s {
+  implicit object DateTimeSchemaFor extends SchemaFor[DateTime] {
+    override def schema: Schema = Schema.create(Schema.Type.LONG)
+  }
+
+  implicit val DateTimeEncoder: Encoder[DateTime] = {
+    LongEncoder.comap[DateTime] { x =>
+      val dateTimeAsString: String = f"${x.show}.${x.time.millisecond.millisecond.value}%03dZ"
+      Instant.parse(dateTimeAsString).toEpochMilli
+    }
+  }
+
+  implicit object TimeSchemaFor extends SchemaFor[Time] {
+    override def schema: Schema = Schema.create(Schema.Type.INT)
+  }
+
+  implicit val TimeEncoder: Encoder[Time] = {
+    IntEncoder.comap[Time] { x =>
+      x match {
+        case Time(Hour(h), Minute(m), Second(s), Millisecond(ms)) =>
+          (h.value * 60 * 60 * 1000) +
+          (m.value * 60 * 1000) +
+          (s.value * 1000) +
+          ms.value
+      }
+    }
+  }
+}

modules/avro4s/src/test/scala/wen/avro4s/Avro4sSpec.scala

@@ -0,0 +1,36 @@
+package wen.avro4s
+
+import java.time.{Instant, LocalDateTime, LocalTime, ZoneOffset}
+
+import com.sksamuel.avro4s.{AvroSchema, Encoder, ImmutableRecord}
+import org.scalactic.TypeCheckedTripleEquals
+import org.scalatest.{Matchers, WordSpec}
+import org.scalatestplus.scalacheck.ScalaCheckDrivenPropertyChecks
+import wen.datetime.{DateTime, Time}
+import wen.test.Generators._
+
+class Avro4sSpec extends WordSpec  with Matchers with TypeCheckedTripleEquals with ScalaCheckDrivenPropertyChecks  {
+
+  "Avro4s Encoders" should {
+    "encode a Time" in forAll (timeOfDayInMilliseconds) { millisecondsOfDay: Int =>
+      case class Foo(s: Time)
+
+      val schema = AvroSchema[Foo]
+      val localTime = LocalTime.ofNanoOfDay(millisecondsOfDay * 1000000L)
+      val time = Time(localTime)
+
+      Encoder[Foo].encode(Foo(time), schema) shouldBe ImmutableRecord(schema, Vector(java.lang.Integer.valueOf(millisecondsOfDay)))
+    }
+
+    "encode a DateTime" in forAll (epochLong) { timestamp: Long =>
+      case class Foo(s: DateTime)
+
+      val schema = AvroSchema[Foo]
+      val localDateTime = LocalDateTime.ofInstant(Instant.ofEpochMilli(timestamp), ZoneOffset.UTC)
+      val dateTime = DateTime(localDateTime)
+
+      Encoder[Foo].encode(Foo(dateTime), schema) shouldBe ImmutableRecord(schema, Vector(java.lang.Long.valueOf(timestamp)))
+    }
+  }
+
+}

modules/core/src/test/scala/wen/test/Generators.scala

@@ -77,4 +77,10 @@ object Generators {
   val yearWithDefaultEpochGen: Gen[Year] =
     Gen.posNum[Int].map(i => Year(refineV[NumericYearConstraint].unsafeFrom(i)))
 
+  val epochLong: Gen[Long] =
+    Gen.choose(0, Long.MaxValue)
+
+  val timeOfDayInMilliseconds: Gen[Int] =
+    Gen.choose(0, 84239999)
+
 }

project/Dependencies.scala

@@ -7,6 +7,7 @@ object Dependencies {
   val refinedVersion = "0.9.5"
   val catsVersion = "1.6.0"
   val circeVersion = "0.11.1"
+  val avro4sVersion = "2.0.4"
 
 
   lazy val testDependencies = Seq(
@@ -20,6 +21,10 @@ object Dependencies {
     "org.typelevel" %% "cats-core" % catsVersion
   )
 
+  lazy val avro4sDependencies = Seq(
+    "com.sksamuel.avro4s" %% "avro4s-core" % avro4sVersion
+  )
+
   lazy val refinedDependencies = Seq(
     "eu.timepit" %% "refined" % refinedVersion
   )