/**
 * The chat history route.
 *
 * @module
 */

import { Router } from "@oak/oak";
import type { APIResponse } from "../../shared/api.ts";
import type { ChatMessage } from "../../shared/chat.ts";
import { authMiddleware } from "../middleware/auth.ts";
import {
  getChatMessagesAfter,
  getRecentChatMessages,
} from "../services/chat-service.ts";

/**
 * The chat history route; messages are posted and edited over the socket (see
 * routes/ws.ts):
 *
 * - `GET /api/chat?limit=&before=&beforeId=&after=&afterId=` — signed in.
 *   Answers messages in ascending order: the most recent by default; with
 *   `before`, the page of older messages preceding that cursor ("load older");
 *   with `after`, the messages following it (resync after a reconnect). A
 *   cursor is an ISO `created_at` plus the message id to break ties; without
 *   `afterId` the `after` timestamp itself is included.
 */
const router: Router = new Router({ prefix: "/api/chat" });

router.get("/", authMiddleware, (ctx) => {
  const params = ctx.request.url.searchParams;
  const limitParam = params.get("limit");
  const limit = limitParam ? Number(limitParam) : NaN;
  const cappedLimit = Number.isFinite(limit) ? limit : undefined;
  const before = params.get("before");
  const after = params.get("after");
  const messages = after
    ? getChatMessagesAfter(
      { createdAt: after, id: params.get("afterId") ?? undefined },
      cappedLimit,
    )
    : getRecentChatMessages(
      cappedLimit,
      before
        ? { createdAt: before, id: params.get("beforeId") ?? undefined }
        : undefined,
    );
  const responseBody: APIResponse<ChatMessage[]> = {
    success: true,
    data: messages,
  };
  ctx.response.body = responseBody;
});

export default router;