// once a minute (what's the point if it's out of date!)
// do days since last update (0 will be obvious then), should (please please please let this be true) only need three digits MAX
// until hs2 ends of course but let's not think about that now
// okay aaaa hs2 will end that will be sad and good i guess but
// not important right now

import { contentType } from "https://deno.land/std@0.202.0/media_types/mod.ts";
import {
  DOMParser,
  NodeType,
} from "https://deno.land/x/deno_dom@v0.1.38/deno-dom-wasm.ts";
import {
  Image,
  TextLayout,
} from "https://deno.land/x/imagescript@1.2.15/ImageScript.js";

// not sure how worthwhile this optimization is but
const dom_parser = new DOMParser();

async function get_last_update_date(): Promise<Date | string> {
  try {
    const res = await fetch("https://homestuck2.com/log");
    const body = await res.text();
    if (!body) return "couldn't get a string body";

    // could just regex for the date lol
    const doc = dom_parser.parseFromString(body, "text/html");
    if (!doc) return "couldn't parse the body into the DOM";

    const p = doc.querySelector("p");
    if (!p) return "couldn't get a p from the doc";

    // should really enable strict indexing
    const us_date_node = p.childNodes[0];
    if (!us_date_node || us_date_node.nodeType != NodeType.TEXT_NODE) {
      return "couldn't get a date node from the log entry";
    }

    const us_date = us_date_node.textContent.replace(" - ", "");
    // apparently doing new Date("10/8/2023") is implementation defined which is icky but it works with deno
    const date = new Date(us_date);
    if (Number.isNaN(date.valueOf())) {
      return `got an invalid date :(. the text_content was '${us_date}'`;
    }
    return date;
  } catch (e) {
    return `caught error: ${e}`;
  }
}

async function check_again() {
  last_checked = new Date();

  const new_date = await get_last_update_date();
  if (typeof new_date == "string") {
    console.log(`failed to get a date when checking 😬: '${new_date}'`);
    console.log(
      "^ ironically enough, this is more likely when there *is* an update",
    );
    console.log(
      "^ unironically, this is *most* likely the result of a bug",
    );
    return;
  }
  last_updated = new_date;
}

function days_since_update(): number {
  const millis = new Date().getTime() - last_updated.getTime();
  return millis / (24 * 60 * 60 * 1000);
}

// silly, i know
let last_updated: Date = new Date(0);
let last_checked: Date = new Date();
await check_again();

// *definitely* a worthwhile optimization
// (still inefficient to go over http...)
const font = await fetch("https://static.pyrope.net/courier-std-bold.otf")
  .then((r) => r.arrayBuffer())
  .then((b) => new Uint8Array(b));

function make_image(): Image {
  const days = Math.floor(days_since_update()).toString().padStart(3, "0");
  console.log(days_since_update());
  const image = new Image(106, 44);
  const text = Image.renderText(
    font,
    64,
    days,
    0x00_00_00_ff,
    new TextLayout({ verticalAlign: "center", horizontalAlign: "middle" }),
  );

  return image.composite(text, -5);
}

async function update_image() {
  image = await make_image().encode();
}

let image: Uint8Array = new Uint8Array();
await update_image();

Deno.serve({ port: 61264 }, async () => {
  if (new Date().getTime() - last_checked.getTime() >= 60 * 1000) {
    await check_again();
    await update_image();
  }

  return new Response(image, {
    headers: { "Content-Type": contentType("png") },
  });
});

await Deno.writeFile("/tmp/poop.png", image);