"use strict";

const fs = require("fs");
const util = require("util");
const {sj, res204, err400, err500} = require("./utils");

const rd = util.promisify(fs.readdir);
const rf = util.promisify(fs.readFile);
const wf = util.promisify(fs.writeFile);

const {R_OK,W_OK} = fs.constants;
const exists = s => new Promise(r => fs.access(s, R_OK|W_OK, e => r(!e)));

const NOTE_DIR = "./users";

function genNoteID() {
  const now = new Date().toISOString();
  return now.replace(/[^0-9]/g,"").slice(0,16);
}

async function newNote(req, res) {
  let noteID, noteFile;

  do {
    noteID = genNoteID();
    noteFile = `${NOTE_DIR}/${req.uid}/${noteID}.md`;
  } while (await exists(noteFile)) // TODO increment

  console.log(Date.now()+` Creating note ${req.uid}:${noteID}`);

  await wf(noteFile, "");

  sj(res, {id:noteID, content:""});
}

async function getNote(req, res, match) {
  console.log(Date.now()+` Getting note ${req.uid}:${match.noteID}`);
  const noteFile = `${NOTE_DIR}/${req.uid}/${match.noteID}.md`;
  const content = await rf(noteFile, "UTF-8"); // TODO exists
  sj(res, {id:match.noteID, content});
}

async function setNote(req, res, match, data) {
  console.log(Date.now()+` Setting note ${req.uid}:${match.noteID}`);
  if (match.noteID !== data.id) return err400(res);
  const noteFile = `${NOTE_DIR}/${req.uid}/${match.noteID}.md`;
  await wf(noteFile, data.content, "UTF-8");
  sj(res, {});
}

async function listNotes(req, res) {
  console.log(Date.now()+` Getting notes for ${req.uid}`);
  const files = await rd(`${NOTE_DIR}/${req.uid}`);
  const notes = files.map(fn => fn.slice(0,-3));
  sj(res, notes);
}

// TODO list in order of recent updates w/ timestamps
// TODO pagination?

module.exports.attach = (app, {authed}) => {
  app.get("/list", authed(listNotes));
  app.post("/new", authed(newNote));
  app.get("/(?<noteID>[0-9]{16})", authed(getNote));
  app.jpost("/(?<noteID>[0-9]{16})", authed(setNote));
};