import TelegramBot from "node-telegram-bot-api";
import {
  readerTaskEither as rte,
  readonlyArray,
  semigroup,
  string,
} from "fp-ts";
import { flow, pipe } from "fp-ts/lib/function.js";
import { describeArticle } from "./api.mjs";
import config from "./config.mjs";

const bot = new TelegramBot(config.telegramBotToken, {
  polling: true,
});

console.log("The telegram bot listens for updates");

bot.on("channel_post", async (msg) => {
  const link = extractMessageLink(msg);
  if (!link) {
    console.log("cannot find link in msg:", msg);
    return;
  }

  pipe(
    describeArticle(link),
    rte.map(
      flow(
        readonlyArray.foldMap({
          ...string.Monoid,
          ...pipe(string.Semigroup, semigroup.intercalate("\n")),
        })((row) => `- ${row}`),
        string.trimLeft,
      ),
    ),
    rte.match(
      (err) => console.log({ err }),
      (res) =>
        bot.editMessageText(msg.text + "\n\nYandexGPT:\n\n" + res, {
          chat_id: msg.chat.id,
          message_id: msg.message_id,
        }),
    ),
  )(config)();
});

// TODO: use option instead
function extractMessageLink(msg) {
  return getTextLink(msg) || getMessageUrl(msg);
}

const RE_URL =
  /(http|https):\/\/([\w_-]+(?:(?:\.[\w_-]+)+))([\w.,@?^=%&:\/~+#-]*[\w@?^=%&\/~+#-])/;

function getMessageUrl(msg) {
  return RE_URL.exec(msg.text)[0];
}

function getTextLink(msg) {
  const textLinks = (msg.entities ?? []).filter(isTextLink);
  return textLinks.length ? textLinks[0].url : null;
}

function isTextLink(msgEntity) {
  return msgEntity.type === "text_link";
}