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 {
  handlePostUpload,
  imageLinkForFile,
  removeImageLink,
  removeUploadedFile,
} = require("../../middleware/post_upload");

async function editPost(req, res) {
  const id = req.query.id;
  const { title, text, remove_image: removeImageValue } = req.body;
  const removeImage = removeImageValue === "true";

  if (removeImageValue !== undefined && !["true", "false"].includes(removeImageValue)) {
    await removeUploadedFile(req.file);
    return res.status(400).send("remove_image must be true or false");
  }
  if (req.file && removeImage) {
    await removeUploadedFile(req.file);
    return res.status(400).send("Choose either an image or remove_image=true");
  }
  if (title === "" || text === "") {
    await removeUploadedFile(req.file);
    return res.status(400).send("title and text cannot be empty");
  }
  if (title === undefined && text === undefined && !req.file && !removeImage) {
    return res.status(400).send("At least one post field must be changed");
  }

  try {
    const existing = await pool.query(
      "SELECT id, image_link FROM posts WHERE id = $1 AND author_id = $2",
      [id, req.user.id],
    );
    if (existing.rowCount === 0) {
      await removeUploadedFile(req.file);
      return res.status(404).send("Post not found or does not belong to you");
    }

    const oldImageLink = existing.rows[0].image_link;
    const fields = [];
    const values = [];
    const addField = (field, value) => {
      fields.push(`${field} = $${values.length + 1}`);
      values.push(value);
    };

    if (title !== undefined) addField("title", title);
    if (text !== undefined) addField("text", text);
    if (req.file) addField("image_link", imageLinkForFile(req.file));
    if (removeImage) addField("image_link", null);
    values.push(id, req.user.id);

    let updated;
    try {
      updated = await pool.query(
        `UPDATE posts SET ${fields.join(", ")} WHERE id = $${values.length - 1} AND author_id = $${values.length} RETURNING id, title, text, author_id, image_link`,
        values,
      );
    } catch (err) {
      await removeUploadedFile(req.file);
      throw err;
    }

    if (req.file || removeImage) {
      await removeImageLink(oldImageLink).catch((err) => {
        console.error("old post image could not be removed", { message: err.message });
      });
    }
    return res.status(200).json(updated.rows[0]);
  } catch (err) {
    await removeUploadedFile(req.file);
    console.error("database query failed", {
      message: err.message,
      code: err.code,
      detail: err.detail,
      hint: err.hint,
      stack: err.stack,
    });
    return res.status(500).send("Post was not updated, request failed");
  }
}

router.put(
  "/",
  authenticateToken,
  handlePostUpload,
  strictInput({
    query: ["id"],
    body: ["title", "text", "remove_image"],
    cleanupUploadedFile: true,
  }),
  editPost,
);

module.exports = router;