/**
 * Serves what the caller follows, and follows or stops following for them.
 * The dumps of what they follow, the index's "follow" tab, are
 * `GET /api/dumps?follow=`'s (`routes/dumps.ts`), and what another user
 * follows is `routes/users.ts`'s.
 *
 * - `GET /api/me/follow` — signed in. Answers the ids of the users and
 *   playlists they follow.
 * - `PUT /api/me/follow/users/:userId` — signed in. Follows a user.
 * - `DELETE /api/me/follow/users/:userId` — signed in. Stops following a user.
 * - `PUT /api/me/follow/playlists/:playlistId` — signed in. Follows a public
 *   playlist.
 * - `DELETE /api/me/follow/playlists/:playlistId` — signed in. Stops following
 *   a playlist.
 *
 * @module
 */

import { Router } from "@oak/oak";
import { authMiddleware } from "../middleware/auth.ts";
import type { APIResponse } from "../../shared/api.ts";
import type { FollowStatus } from "../../shared/follow.ts";
import {
  followPlaylist,
  followUser,
  getFollowStatus,
  unfollowPlaylist,
  unfollowUser,
} from "../services/follow-service.ts";

/**
 * Mounted by `api/main.ts` behind the error, Open Graph and CORS middleware.
 * An `APIException` thrown by a handler becomes the JSON error response there.
 */
const router: Router = new Router({ prefix: "/api/me" });

router.get("/follow", authMiddleware, (ctx) => {
  const status = getFollowStatus(ctx.state.user.userId);
  const body: APIResponse<FollowStatus> = { success: true, data: status };
  ctx.response.body = body;
});

router.put("/follow/users/:userId", authMiddleware, (ctx) => {
  followUser(ctx.state.user.userId, ctx.params.userId);
  ctx.response.status = 204;
});

router.delete("/follow/users/:userId", authMiddleware, (ctx) => {
  unfollowUser(ctx.state.user.userId, ctx.params.userId);
  ctx.response.status = 204;
});

router.put("/follow/playlists/:playlistId", authMiddleware, (ctx) => {
  followPlaylist(ctx.state.user.userId, ctx.params.playlistId);
  ctx.response.status = 204;
});

router.delete("/follow/playlists/:playlistId", authMiddleware, (ctx) => {
  unfollowPlaylist(ctx.state.user.userId, ctx.params.playlistId);
  ctx.response.status = 204;
});

export default router;