Improve slash command API and add support for components

buildSrc/build.gradle.kts

@@ -14,4 +14,4 @@ dependencies {
     implementation(kotlin("gradle-plugin-api", version = "1.5.0"))
     implementation(gradleApi())
     implementation(localGroovy())
-}
+}

common/src/main/kotlin/entity/DiscordComponent.kt

@@ -0,0 +1,140 @@
+package dev.kord.common.entity
+
+import dev.kord.common.annotation.KordPreview
+import dev.kord.common.entity.optional.Optional
+import dev.kord.common.entity.optional.OptionalBoolean
+import kotlinx.serialization.KSerializer
+import kotlinx.serialization.SerialName
+import kotlinx.serialization.Serializable
+import kotlinx.serialization.descriptors.PrimitiveKind
+import kotlinx.serialization.descriptors.PrimitiveSerialDescriptor
+import kotlinx.serialization.descriptors.SerialDescriptor
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
+
+/**
+ * Represent a [intractable component within a message sent in Discord](https://discord.com/developers/docs/interactions/message-components#what-are-components).
+ *
+ * @property type the [ComponentType] of the component
+ * @property style the [ButtonStyle] of the component (if it is a button)
+ * @property style the text that appears on the button (if the component is a button)
+ * @property emoji an [DiscordPartialEmoji] that appears on the button (if the component is a button)
+ * @property customId a developer-defined identifier for the button, max 100 characters
+ * @property url a url for link-style buttons
+ * @property disabled whether the button is disabled, default `false`
+ * @property components a list of child components (for action rows)
+ */
+@KordPreview
+@Serializable
+data class DiscordComponent(
+    val type: ComponentType,
+    val style: Optional<ButtonStyle> = Optional.Missing(),
+    val label: Optional<String> = Optional.Missing(),
+    val emoji: Optional<DiscordPartialEmoji> = Optional.Missing(),
+    @SerialName("custom_id")
+    val customId: Optional<String> = Optional.Missing(),
+    val url: Optional<String> = Optional.Missing(),
+    val disabled: OptionalBoolean = OptionalBoolean.Missing,
+    val components: Optional<List<DiscordComponent>> = Optional.Missing()
+)
+
+/**
+ * Representation of different [DiscordComponent] types.
+ *
+ * @property value the raw type value used by the Discord API
+ */
+@KordPreview
+@Serializable(with = ComponentType.Serializer::class)
+sealed class ComponentType(val value: Int) {
+
+    /**
+     * Fallback type used for types that haven't been added to Kord yet.
+     */
+    class Unknown(value: Int) : ComponentType(value)
+
+    /**
+     * A container for other components.
+     */
+    object ActionRow : ComponentType(1)
+
+    /**
+     * A clickable button.
+     */
+    object Button : ComponentType(2)
+
+    companion object Serializer : KSerializer<ComponentType> {
+        override val descriptor: SerialDescriptor = PrimitiveSerialDescriptor("ComponentType", PrimitiveKind.INT)
+
+        override fun deserialize(decoder: Decoder): ComponentType =
+            when (val value = decoder.decodeInt()) {
+                1 -> ActionRow
+                2 -> Button
+                else -> Unknown(value)
+            }
+
+        override fun serialize(encoder: Encoder, value: ComponentType) = encoder.encodeInt(value.value)
+    }
+}
+
+/**
+ * Representation of different ButtonStyles.
+ *
+ * A cheat sheet on how the styles look like can be found [here](https://discord.com/assets/7bb017ce52cfd6575e21c058feb3883b.png)
+ *
+ * @see ComponentType.Button
+ */
+@KordPreview
+@Serializable(with = ButtonStyle.Serializer::class)
+sealed class ButtonStyle(val value: Int) {
+
+    /**
+     * A fallback style used for styles that haven't been added to Kord yet.
+     */
+    class Unknown(value: Int) : ButtonStyle(value)
+
+    /**
+     * Blurple.
+     * Requires: [DiscordComponent.customId]
+     */
+    object Primary : ButtonStyle(1)
+
+    /**
+     * Grey.
+     * Requires: [DiscordComponent.customId]
+     */
+    object Secondary : ButtonStyle(2)
+
+    /**
+     * Green
+     * Requires: [DiscordComponent.customId]
+     */
+    object Success : ButtonStyle(3)
+
+    /**
+     * Red.
+     * Requires: [DiscordComponent.customId]
+     */
+    object Danger : ButtonStyle(4)
+
+    /**
+     * Grey, navigates to an URL.
+     * Requires: [DiscordComponent.url]
+     */
+    object Link : ButtonStyle(5)
+
+    companion object Serializer : KSerializer<ButtonStyle> {
+        override val descriptor: SerialDescriptor = PrimitiveSerialDescriptor("ButtonStyle", PrimitiveKind.INT)
+
+        override fun deserialize(decoder: Decoder): ButtonStyle =
+            when (val value = decoder.decodeInt()) {
+                1 -> Primary
+                2 -> Secondary
+                3 -> Success
+                4 -> Danger
+                5 -> Link
+                else -> Unknown(value)
+            }
+
+        override fun serialize(encoder: Encoder, value: ButtonStyle) = encoder.encodeInt(value.value)
+    }
+}

common/src/main/kotlin/entity/DiscordEmoji.kt

@@ -47,7 +47,7 @@ data class DiscordUpdatedEmojis(
  */
 @Serializable
 data class DiscordPartialEmoji(
-    val id: Snowflake?,
-    val name: String?,
+    val id: Snowflake? = null,
+    val name: String? = null,
     val animated: OptionalBoolean = OptionalBoolean.Missing,
 )

common/src/main/kotlin/entity/DiscordMessage.kt

@@ -63,6 +63,7 @@ import kotlin.contracts.contract
  * @param stickers The stickers sent with the message (bots currently can only receive messages with stickers, not send).
  * @param referencedMessage the message associated with [messageReference].
  * @param applicationId if the message is a response to an [Interaction][DiscordInteraction], this is the id of the interaction's application
+ * @param components a list of [components][DiscordComponent] which have been added to this message
  */
 @Serializable
 data class DiscordMessage(
@@ -103,6 +104,11 @@ data class DiscordMessage(
     val stickers: Optional<List<DiscordMessageSticker>> = Optional.Missing(),
     @SerialName("referenced_message")
     val referencedMessage: Optional<DiscordMessage?> = Optional.Missing(),
+    /*
+     * don't trust the docs:
+     * This is a list even though the docs say it's a component
+     */
+    val components: Optional<List<DiscordComponent>> = Optional.Missing(),
     val interaction: Optional<DiscordMessageInteraction> = Optional.Missing()
 )