Feature/171 supabase chat messages

src/main/kotlin/chatserver/MessageResult.kt

@@ -1,15 +1,16 @@
 package chatserver
 
 import chatserver.ReadChatRepository.ReadResult
+import chatserver.messages.SupabaseMessageRepository.*
 
 data class MessageResult(
     override val isOk: Boolean,
-    override val item: List<String>,
+    override val item: List<Message>,
     override val error: Exception?,
 ) :
-    ReadResult<List<String>> {
+    ReadResult<List<Message>> {
     companion object {
-        fun ok(item: List<String>): MessageResult = MessageResult(true, item, null)
+        fun ok(item: List<Message>): MessageResult = MessageResult(true, item, null)
 
         fun fail(e: Exception? = null): MessageResult = MessageResult(false, emptyList(), e)
     }

src/main/kotlin/chatserver/messages/SupabaseMessageRepository.kt

@@ -0,0 +1,66 @@
+package chatserver.messages
+
+import chatserver.MessageResult
+import chatserver.ReadChatRepository
+import chatserver.SubscribeChatRepository
+import chatserver.WriteChatRepository
+import io.github.jan.supabase.SupabaseClient
+import io.github.jan.supabase.annotations.SupabaseExperimental
+import io.github.jan.supabase.auth.auth
+import io.github.jan.supabase.postgrest.from
+import io.github.jan.supabase.realtime.selectAsFlow
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.cancel
+import kotlinx.coroutines.flow.*
+import kotlinx.coroutines.launch
+import kotlinx.datetime.Clock
+import kotlinx.serialization.SerialName
+import kotlinx.serialization.Serializable
+import java.util.UUID
+
+class SupabaseMessageRepository(
+    private val client: SupabaseClient,
+    private val scope: CoroutineScope,
+) : ReadChatRepository<MessageResult>, WriteChatRepository<String>, SubscribeChatRepository {
+    private val messages: MutableStateFlow<MessageResult> = MutableStateFlow(MessageResult.ok(emptyList()))
+
+    override fun latest(): MessageResult = messages.value
+
+    override fun observe(): Flow<MessageResult> = messages.asStateFlow()
+
+    @OptIn(SupabaseExperimental::class)
+    override fun subscribe() {
+        client.from("messages")
+            .selectAsFlow(Message::id)
+            .map { MessageResult.ok(it) }
+            .onEach { messages.value = it }
+            .catch { println(it) }
+            .launchIn(scope)
+    }
+
+    override fun write(item: String) {
+        scope.launch {
+            client.from("messages").insert(item.toChatMessage())
+        }
+    }
+
+    private fun String.toChatMessage() =
+        Message(
+            id = UUID.randomUUID().toString(),
+            profileId = client.auth.currentUserOrNull()?.id.orEmpty(),
+            content = this,
+            createdAt = Clock.System.now().toString(),
+        )
+
+    override fun unsubscribe() {
+        scope.cancel()
+    }
+
+    @Serializable
+    data class Message(
+        @SerialName("id") val id: String,
+        @SerialName("profile_id") val profileId: String,
+        @SerialName("content") val content: String,
+        @SerialName("created_at") val createdAt: String,
+    )
+}