use lapin::{

    message::Delivery, options::*, types::FieldTable, BasicProperties, Connection,

    ConnectionProperties,

};

use tokio_amqp::*;

use futures::prelude::*;

use irc::client::prelude::*;

use anyhow::{bail, Result as AHResult};

use url::Url;

use rand::distributions::Alphanumeric;

use rand::{thread_rng, Rng};

fn url2irc_config(url: &str) -> AHResult<Config> {

    let url = Url::parse(url)?;

    if url.scheme() != "irc" {

        bail!("Expected 'irc' scheme")

    }

    Ok(Config {

        nickname: Some(url.username().to_owned()),

        nick_password: url.password().map(|s| s.to_owned()),

        server: url.host_str().map(|s| s.to_owned()),

        port: url.port(),

        channels: vec![format!("#{}", &url.path()[1..])],

        //use_mock_connection: true,

        ..Config::default()

    })

}

fn random_string(size: usize) -> String {

    thread_rng()

        .sample_iter(&Alphanumeric)

        .take(size)

        .map(char::from)

        .collect()

}

async fn handle_irc(pub_channel: &lapin::Channel, irc_message: &Message) -> AHResult<()> {

    if let Command::PRIVMSG(msgtarget, message) = &irc_message.command {

        let target = irc_message

            .response_target()

            .expect("Really expected PRIVMSG would have a source");

        let target = if target.starts_with('#') {

            &target[1..]

        } else {

            &target

        };

        if message.starts_with("!") {

            if let Some((cmd, param)) = message.split_once(' ') {

                pub_channel

                    .basic_publish(

                        "irc",

                        &format!("cmd.{}.{}", &cmd[1..], target),

                        BasicPublishOptions::default(),

                        BasicProperties::default(),

                    )

                    .await?;

            } else {

                pub_channel

                    .basic_publish(

                        "irc",

                        &format!("cmd.{}.{}", &message[1..], target),

                        BasicPublishOptions::default(),

                        BasicProperties::default(),

                    )

                    .await?;

            }

        } else {

            pub_channel

                .basic_publish(

                    "irc",

                    &format!("msg.{}", target),

                    BasicPublishOptions::default(),

                    BasicProperties::default(),

                )

                .await?;

        }

    }

    Ok(())

}

async fn handle_amqp(

    irc_client: &mut Client,

    irc_channel: &str,

    delivery: Delivery,

) -> AHResult<()> {

    let message = String::from_utf8(delivery.data)?;

    Ok(irc_client.send_privmsg(irc_channel, message)?)

}

#[tokio::main]

async fn main() -> AHResult<()> {

    let amqp_url = std::env::var("AMQP_URL").expect("expected AMQP_URL env variabe");

    let irc_url = std::env::var("IRC_URL").expect("expected IRC_URL env variabe");

    let conn = Connection::connect(&amqp_url, ConnectionProperties::default().with_tokio()).await?;

    let pub_channel = conn.create_channel().await?;

    let sub_channel = conn.create_channel().await?;

    let irc_config = url2irc_config(&irc_url)?;

    let irc_channel = irc_config.channels[0].to_owned();

    let mut irc_client = Client::from_config(irc_config).await?;

    let mut irc_stream = irc_client.stream()?;

    irc_client.identify()?;

    let queue = sub_channel

        .queue_declare(

            &random_string(32),

            QueueDeclareOptions {

                exclusive: true,

                auto_delete: true,

                ..QueueDeclareOptions::default()

            },

            FieldTable::default(),

        )

        .await?;

    sub_channel

        .queue_bind(

            queue.name().as_str(),

            "irc",

            &format!("say.{}", &irc_channel[1..]),

            QueueBindOptions::default(),

            FieldTable::default(),

        )

        .await?;

    let mut subscriber = sub_channel

        .basic_consume(

            queue.name().as_str(),

            &random_string(32),

            BasicConsumeOptions::default(),

            FieldTable::default(),

        )

        .await?;

    loop {

        tokio::select! {

            Some(irc_message) = irc_stream.next() => handle_irc(&pub_channel, &irc_message?).await?,

            Some(amqp_message) = subscriber.next() => {

                let (_, delivery) = amqp_message.expect("error in consumer");

                delivery

                    .ack(BasicAckOptions::default())

                    .await?;

                    handle_amqp(&mut irc_client, &irc_channel, delivery).await?

            }

        }

    }

}