collections::{
		HashMap,
		HashSet,
	},
	io::Error,
};






use async_std::{
	sync::Arc,
	task,
};
use mailin_embedded::{
	Response,
	response::{
		INTERNAL_ERROR,
		INVALID_CREDENTIALS,
		NO_MAILBOX,
		OK
	},
};
use regex::{
	Regex,
	escape,
};
use stacked_errors::{
	Result,
	StackableErr,
	bail,
};
use tgbot::types::ChatPeerId;

/// `SomeHeaders` object to store data through SMTP session
#[derive(Clone, Debug)]
struct SomeHeaders {
	from: String,

			.context("[smtp2tg.toml] missing \"default\" recipient.\n")?;

		let tg = Arc::new(TelegramTransport::new(api_key, recipients, default)?);
		let fields = HashSet::<String>::from_iter(settings.get_array("fields")
			.expect("[smtp2tg.toml] \"fields\" should be an array")
			.iter().map(|x| x.clone().into_string().expect("should be strings")));
		let mut domains: HashSet<String> = HashSet::new();
		let extra_domains = settings.get_array("domains").stack()?;
		for domain in extra_domains {
			let domain = domain.to_string().to_lowercase();
			if RE_DOMAIN.is_match(&domain) {
				domains.insert(domain);
			} else {
				panic!("[smtp2tg.toml] can't check of domains in \"domains\": {domain}");
			}
		}
		let domains = domains.into_iter().map(|s| escape(&s))
			.collect::<Vec<String>>().join("|");
		let address = Regex::new(&format!("^(?P<user>[a-z0-9][-a-z0-9])(@({domains}))$")).stack()?;
		let relay = match settings.get_string("unknown")
			.context("[smtp2tg.toml] can't get \"unknown\" policy.\n")?.as_str()
		{
			"relay" => true,
			"deny" => false,
			_ => {
				bail!("[smtp2tg.toml] \"unknown\" should be either \"relay\" or \"deny\".\n");

			let mut text_num = 0;
			let mut file_num = 0;
			// let's display first html or text part as body
			let mut body: Cow<'_, str> = "".into();
			/*
			 * actually I don't wanna parse that html stuff
			if html_parts > 0 {
				let text = mail.body_html(0).stack()?;
				if text.len() < 4096 - header_size {
					body = text;
					html_num = 1;
				}
			};
			*/
			if body.is_empty() && text_parts > 0 {

			reply.push("```".into());

			// and let's collect all other attachment parts
			let mut files_to_send = vec![];
			/*
			 * let's just skip html parts for now, they just duplicate text?
			while html_num < html_parts {
				files_to_send.push(mail.html_part(html_num).stack()?);
				html_num += 1;
			}
			*/
			while text_num < text_parts {
				files_to_send.push(mail.text_part(text_num.try_into().stack()?)
					.context("Failed to get text part from message.")?);
				text_num += 1;
			}
			while file_num < attachments {
				files_to_send.push(mail.attachment(file_num.try_into().stack()?)
					.context("Failed to get file part from message.")?);
				file_num += 1;
			}

			let msg = reply.join("\n");
			for chat in rcpt {
				if !files_to_send.is_empty() {

			from: from.to_string(),
			to: to.to_vec(),
		});
		OK
	}

	/// Save chunk(?) of data
	fn data (&mut self, buf: &[u8]) -> std::result::Result<(), Error> {
		self.data.append(buf.to_vec().as_mut());
		Ok(())
	}

	/// Attempt to send email, return temporary error if that fails
	fn data_end (&mut self) -> Response {
		let mut result = OK;