tg,
			fields,
			address,
		})
	}

	/// Returns id for provided email address
	fn get_id (&self, name: &str) -> Result<&ChatPeerId> {
	fn get_id (&self, name_str: &str) -> Result<&ChatPeerId> {
		// here we need to store String locally to borrow it after
		let mut link = name;
		let mut link = name_str;
		let name: String;
		if let Some(caps) = self.address.captures(link) {
			name = caps["name"].to_string();
			link = &name;
		}
		match self.tg.get(link) {
			Ok(addr) => Ok(addr),

//! Simple SMTP-to-Telegram gateway. Can parse email and send them as telegram
//! messages to specified chats, generally you specify which email address is
//! available in configuration, everything else is sent to default address.

mod mail;
mod telegram;
mod utils;

#[cfg(test)]
mod tests;

use crate::mail::MailServer;

use async_compat::Compat;
use just_getopt::{
	OptFlags,
	OptSpecs,
	OptValue,
};
use smol::{
	fs::metadata,
};
use stacked_errors::{
use stacked_errors:: Result;
	Result,
	StackableErr,
	bail,
};

use std::{
	io::Cursor,
	os::unix::fs::PermissionsExt,
	path::Path,
};

// main function stub that executes main code from lib
fn main () -> Result<()> {
	smol::block_on(Compat::new(async {
		async_main().await.unwrap()
		smtp2tg::async_main().await.unwrap()
	}));

	Ok(())
}

/// Actual main function running async with Error propagation support
async fn async_main () -> Result<()> {
	let specs = OptSpecs::new()
		.option("help", "h", OptValue::None)
		.option("help", "help", OptValue::None)
		.option("config", "c", OptValue::Required)
		.option("config", "config", OptValue::Required)
		.flag(OptFlags::OptionsEverywhere);
	let mut args = std::env::args();
	args.next();
	let parsed = specs.getopt(args);
	for u in &parsed.unknown {
		println!("Unknown option: {u}");
	}
	if !(parsed.unknown.is_empty()) || parsed.options_first("help").is_some() {
		println!("SMTP2TG v{}, (C) 2024 - 2026\n\n\
			\t-h|--help\tDisplay this help\n\
			\t-c|--config …\tSet configuration file location.",
			env!("CARGO_PKG_VERSION"));
		return Ok(());
	};
	let config_file = Path::new(if let Some(path) = parsed.options_value_last("config") {
		&path[..]
	} else {
		"smtp2tg.toml"
	});
	if !config_file.exists() {
		bail!("can't read configuration from {config_file:?}");
	};
	{
		let meta = metadata(config_file).await.stack()?;
		if (!0o100600 & meta.permissions().mode()) > 0 {
			bail!("other users can read or write config file {config_file:?}\n\
				File permissions: {:o}", meta.permissions().mode());
		}
	}
	let settings: config::Config = config::Config::builder()
		.set_default("api_gateway", "https://api.telegram.org").stack()?
		.set_default("fields", vec!["date", "from", "subject"]).stack()?
		.set_default("hostname", "smtp.2.tg").stack()?
		.set_default("listen_on", "0.0.0.0:1025").stack()?
		.set_default("unknown", "relay").stack()?
		.set_default("domains", vec!["localhost", hostname::get().stack()?.to_str().expect("Failed to get current hostname")]).stack()?
		.add_source(config::File::from(config_file))
		.build()
		.with_context(|| format!("[{config_file:?}] there was an error reading config\n\
			\tplease consult \"smtp2tg.toml.example\" for details"))?;

	let listen_on = settings.get_string("listen_on").stack()?;
	let server_name = settings.get_string("hostname").stack()?;
	let core = MailServer::new(settings)?;
	let mut server = mailin_embedded::Server::new(core);

	server.with_name(server_name)
		.with_ssl(mailin_embedded::SslConfig::None).unwrap()
		.with_addr(listen_on).unwrap();
	server.serve().unwrap();

	Ok(())
}

use crate::Cursor;

use std::borrow::Cow;

use html_escape::encode_text;
use lazy_static::lazy_static;
use regex::Regex;
use stacked_errors::{
	bail,
	Result,
};

lazy_static! {
	pub static ref RE_DOMAIN: Regex = Regex::new(r"^[a-z0-9]([-a-z0-9]*[a-z0-9])?(\.[a-z0-9]([-a-z0-9]*[a-z0-9])?)*$").unwrap();
	pub static ref RE_CLOSING: Regex = Regex::new(r"</[ \t]*(pre|code)[ \t]*>").unwrap();
	pub static ref RE_DOMAIN: Regex = Regex::new(r"^[a-z0-9]([-a-z0-9]*[a-z0-9])?(\.[a-z0-9]([-a-z0-9]*[a-z0-9])?)*$").expect("Invalid domain regex");
	pub static ref RE_CLOSING: Regex = Regex::new(r"</[ \t]*(pre|code)[ \t]*>").expect("Invalid cloding tag regex");
}

/// `Attachment` object to store number attachment data and corresponding file name
/// Stores binary attachment data and metadata for Telegram messages.
/// The data is wrapped in a `Cursor<Vec<u8>>` for efficient streaming,
/// while `name` holds the filename or display name of the attachment.
#[derive(Debug)]
pub struct Attachment {
	pub data: Cursor<Vec<u8>>,
	pub name: String,
}

/// Pass any text here to be validated as not breaking from Telegram preformatted blocks
/// escape all HTML chars afterwards
pub fn validate (text: &str) -> Result<Cow<'_, str>> {
pub fn validate <'a>(text: &'a str) -> Result<Cow<'a, str>> {
	if RE_CLOSING.is_match(text) {
		bail!("Telegram closing tag found.");
	} else {
		Ok(encode_text(text))
	}
}