import { Bot, Context, session, BotError, GrammyError, HttpError } from "https://deno.land/x/grammy/mod.ts";
import { Ctx, defaultSessionData } from "./ctx.ts";
import { BotConfig } from "../cfg/config.ts"
import { ERR_CODES, Err } from "../utils/errors.ts";
import { I18n } from "https://deno.land/x/grammy_i18n@v1.1.0/mod.ts";

class BotUnknownOnStartErr extends Err {
  code: ERR_CODES = ERR_CODES.UnknownErr
}

export const runBot = async (cfg: BotConfig, initMode: (bot: Bot<Ctx>) => void) => {
  const bot = new Bot<Ctx>(cfg.bot_token)

  const i18n = new I18n<Ctx>({
    defaultLocale: "en",
    directory: cfg.locales_dir,
    localeNegotiator: (ctx) => 
      ctx.from?.language_code ?? "en"
  })
  console.log("Loaded locales: ", i18n.locales)
  bot.use(session({ initial: defaultSessionData }), i18n)

  bot.catch((err: BotError<Context>) => {
    const ctx = err.ctx;
    console.error(`Error while handling update ${ctx.update.update_id}:`);
    const e = err.error;
    if (e instanceof GrammyError) {
      if (e.error_code === 400 && e.method === "deleteMessage") return
      console.error("Error in request:", e.description);
    } else if (e instanceof HttpError) {
      console.error("Could not contact Telegram:", e);
    } else {
      throw new BotUnknownOnStartErr("Unknown error while starting the bot",
        { cause: err })
    }
  })

  initMode(bot)
  await bot.init()

  console.log(`starting bot ${bot.botInfo.username}`)
  await bot.start({
    allowed_updates: [
      "chat_member",
      "message",
      "inline_query"
    ]
  }).catch(err => console.log(err))
  await bot.stop();
}