const express = require("express");
const router = express.Router();
const pool = require("../../db");
const { strictInput } = require("../../middleware/strict_input");
const { authenticateToken } = require("../../middleware/authenticate_token");
const { areFriends } = require("../relations/friend_graph");
const { likePost, unlikePost } = require("./post_graph");

async function getVisiblePostId(req) {
  const postId = Number(req.query.id);
  if (!Number.isInteger(postId) || postId <= 0) {
    return { error: 400 };
  }
  const { rows } = await pool.query(
    `SELECT p.id, p.author_id, people.private AS author_private
     FROM posts p
     LEFT JOIN people ON people.id = p.author_id
     WHERE p.id = $1 AND p.active = true`,
    [postId],
  );
  if (rows.length === 0) {
    return { error: 404 };
  }
  const post = rows[0];
  if (
    post.author_private &&
    Number(post.author_id) !== req.user.id &&
    !(await areFriends(req.user.id, post.author_id))
  ) {
    return { error: 404 };
  }
  return { postId: Number(post.id) };
}

async function handleLike(req, res, like) {
  try {
    const { postId, error } = await getVisiblePostId(req);
    if (error === 400) return res.status(400).send("Invalid post id");
    if (error === 404) return res.status(404).send("Post not found");

    if (like) {
      await likePost(req.user.id, postId);
      return res.status(200).json({ message: "Post liked" });
    }
    await unlikePost(req.user.id, postId);
    return res.status(200).json({ message: "Post unliked" });
  } catch (err) {
    console.error(like ? "like failed" : "unlike failed", {
      message: err.message,
      code: err.code,
      detail: err.detail,
      hint: err.hint,
    });
    return res.status(500).send("Request could not be completed");
  }
}

router.post(
  "/",
  authenticateToken,
  strictInput({ query: ["id"] }),
  (req, res) => handleLike(req, res, true),
);

router.delete(
  "/",
  authenticateToken,
  strictInput({ query: ["id"] }),
  (req, res) => handleLike(req, res, false),
);

module.exports = router;