amazing recursion with futures on EventSignatures handler.

build.sbt

@@ -1,5 +1,4 @@
 enablePlugins(ScalaJSPlugin)
-// enablePlugins(ScalaJSBundlerPlugin)
 
 name := "app"
 scalaVersion := "2.13.7"
@@ -9,3 +8,7 @@ scalaJSUseMainModuleInitializer := true
 libraryDependencies += "org.scala-js" %%% "scalajs-dom" % "2.1.0"
 libraryDependencies += "me.shadaj" %%% "slinky-core" % "0.7.0"
 libraryDependencies += "me.shadaj" %%% "slinky-web" % "0.7.0"
+libraryDependencies ++= Seq(
+  "io.circe" %%% "circe-core",
+  "io.circe" %%% "circe-parser"
+).map(_ % "0.14.1")

src/main/scala/app/Base.scala

@@ -6,10 +6,10 @@ import slinky.core.FunctionalComponent
 import slinky.web.html._
 import slinky.core.facade.Hooks._
 
-import app.handlers.{Handler, Nothing, KeyHandling}
+import app.handlers.{Handler, Nothing, KeyHandling, EventSignatures}
 
 object Base {
-  val handlers: List[Handler] = List(KeyHandling, Nothing)
+  val handlers: List[Handler] = List(KeyHandling, EventSignatures, Nothing)
 
   val component = FunctionalComponent[Unit] { props =>
     val (typedValue, setTypedValue) = useState("")

src/main/scala/app/handlers/EventSignatures.scala

@@ -1,21 +1,200 @@
 package app.handlers
 
+import scala.annotation.{nowarn, tailrec}
+import scala.concurrent.ExecutionContext.Implicits.global
+import scala.concurrent.Future
 import scala.scalajs.js
 import slinky.core.FunctionalComponent
 import slinky.web.html._
 import slinky.core.facade.Hooks._
 import slinky.core.facade.Fragment
-import io.circe._
-import io.circe.parser._
+import io.circe.{Json, HCursor}
+import io.circe.parser.{parse}
 
+import app.modules.Nostr
 import app.handlers.{Handler}
+import app.components.{Item}
 
 object EventSignatures extends Handler {
-  override def handles(value: String): Boolean = false
+  val keymatcher = "^[a-f0-9]{64}$".r
 
-  override val component = FunctionalComponent[String] { props =>
-    Fragment(
-      "nada"
+  def badProperties(c: HCursor): Seq[String] = Seq(
+    (
+      c.get[Double]("kind").getOrElse[Double](-1) >= 0 match {
+        case true  => None;
+        case false => Some("kind")
+      }
+    ),
+    (
+      keymatcher.matches(
+        c.get[String]("pubkey").getOrElse("").toLowerCase()
+      ) match {
+        case true  => None;
+        case false => Some("pubkey")
+      }
+    ),
+    (
+      c.get[String]("content").exists((_) => true) match {
+        case true  => None;
+        case false => Some("content")
+      }
+    ),
+    (
+      c
+        .get[List[List[String]]]("tags")
+        .exists((_) => true) match {
+        case true  => None;
+        case false => Some("tags")
+      }
+    )
+  )
+    .filter(res => res.isDefined)
+    .map(res => res.get)
+
+  override def handles(value: String): Boolean = parse(value) match {
+    case Left(_) => false
+    case Right(json) => {
+      badProperties(json.hcursor).length < 4
+    }
+  }
+
+  type MaybeItem = Future[
+    Either[slinky.core.TagMod[Nothing], slinky.core.TagMod[Nothing]]
+  ]
+
+  @nowarn("cat=other")
+  def itemWrongProperties(evtj: String): MaybeItem = Future {
+    val c = parse(evtj).toOption.get.hcursor
+    val bad = badProperties(c)
+
+    if (bad.length > 0) {
+      Left(
+        Item.component(
+          Item.props(
+            "event missing or wrong properties",
+            "",
+            bad.mkString(", ")
+          )
+        )
+      )
+    } else {
+      Right(div())
+    }
+  }
+
+  @nowarn("cat=other")
+  def itemSerializedEvent(evtj: String): MaybeItem = Future {
+    val event: js.Dynamic = js.JSON.parse(evtj)
+
+    Right(
+      Item.component(
+        Item.props(
+          "serialized event",
+          "according to nip-01 signature algorithm",
+          Nostr.serializeEvent(event)
+        )
+      )
     )
   }
+
+  @nowarn("cat=other")
+  def itemEventId(evtj: String): MaybeItem = Future {
+    val event: js.Dynamic = js.JSON.parse(evtj)
+
+    Right(
+      Item.component(
+        Item.props(
+          "event id",
+          "sha256 hash of serialized event",
+          Nostr.getEventHash(event)
+        )
+      )
+    )
+  }
+
+  @nowarn("cat=other")
+  def itemEventIdMatches(evtj: String): MaybeItem = Future {
+    val c = parse(evtj).toOption.get.hcursor
+    val event: js.Dynamic = js.JSON.parse(evtj)
+
+    def render(result: Boolean) = Item.component(
+      Item.props(
+        "does the implied event id match the given event id?",
+        "if not, that means you're hashing the event uncorrectly",
+        f"${result match {
+            case true => "yes"; case false => "no"
+          }}"
+      )
+    )
+
+    Nostr
+      .getEventHash(event) == (c.get[String]("id")).toOption.get match {
+      case true  => Right(render(true))
+      case false => Left(render(false))
+    }
+  }
+
+  @nowarn("cat=other")
+  def itemSignatureValid(evtj: String): MaybeItem = Future {
+    val event: js.Dynamic = js.JSON.parse(evtj)
+
+    def render(result: Boolean) = Item.component(
+      Item.props(
+        "is signature valid?",
+        "",
+        f"${result match {
+            case true => "yes"; case false => "no"
+          }}"
+      )
+    )
+
+    true match {
+      case true  => Right(render(true))
+      case false => Left(render(false))
+    }
+  }
+
+  val protoElements = List[(String) => MaybeItem](
+    itemWrongProperties,
+    itemSerializedEvent,
+    itemEventId,
+    itemEventIdMatches,
+    itemSignatureValid
+  )
+
+  @nowarn("cat=other")
+  override val component = FunctionalComponent[String] { props =>
+    val (elements, setElements) =
+      useState(Seq.empty[slinky.core.TagMod[Nothing]])
+
+    useEffect(
+      () => {
+        def runAndUnwrapUntilFirstLeft(
+            remaining: List[String => Future[
+              Either[slinky.core.TagMod[Nothing], slinky.core.TagMod[Nothing]]
+            ]],
+            acc: List[slinky.core.TagMod[Nothing]]
+        ): Future[List[slinky.core.TagMod[Nothing]]] = remaining match {
+          case fn :: tail => {
+            fn(props) flatMap { res =>
+              res match {
+                case Left(el)  => runAndUnwrapUntilFirstLeft(Nil, el :: acc)
+                case Right(el) => runAndUnwrapUntilFirstLeft(tail, el :: acc)
+              }
+            }
+          }
+          case Nil => Future { acc.reverse }
+        }
+
+        runAndUnwrapUntilFirstLeft(protoElements, List()) foreach { elements =>
+          setElements(elements)
+        }
+
+        () => {}
+      },
+      Seq(props)
+    )
+
+    Fragment(elements: _*)
+  }
 }

src/main/scala/app/modules/Nostr.scala

@@ -7,4 +7,8 @@ import scala.scalajs.js
 @JSGlobal
 object Nostr extends js.Object {
   def getPublicKey(text: String): String = js.native
+  def getEventHash(evt: js.Dynamic): String = js.native
+  def serializeEvent(evt: js.Dynamic): String = js.native
+  def verifySignature(evt: js.Dynamic): Boolean = js.native
+  def signEvent(evt: js.Dynamic, privateKey: String): String = js.native
 }