DEV: Move discourse-chat to the core repo. (#18776)

As part of this move, we are also renaming `discourse-chat` to `chat`.

plugins/chat/assets/javascripts/discourse/adapters/chat-message.js

@@ -0,0 +1,22 @@
+import RESTAdapter from "discourse/adapters/rest";
+
+export default class ChatMessage extends RESTAdapter {
+  pathFor(store, type, findArgs) {
+    if (findArgs.targetMessageId) {
+      return `/chat/lookup/${findArgs.targetMessageId}.json?chat_channel_id=${findArgs.channelId}`;
+    }
+
+    let path = `/chat/${findArgs.channelId}/messages.json?page_size=${findArgs.pageSize}`;
+    if (findArgs.messageId) {
+      path += `&message_id=${findArgs.messageId}`;
+    }
+    if (findArgs.direction) {
+      path += `&direction=${findArgs.direction}`;
+    }
+    return path;
+  }
+
+  apiNameFor() {
+    return "chat-message";
+  }
+}