use std::{
    cell::RefCell,
    str::FromStr,
    sync::{Arc, Mutex},
};

use discord::create_discord_client;
use matrix::create_matrix_client;
use matrix_sdk::{
    ruma::{
        events::{room::message::MessageEventContent, AnyMessageEventContent},
        RoomId,
    },
    SyncSettings,
};
use serde::{Deserialize, Serialize};

mod discord;
mod matrix;
mod message_ast;

use message_ast::MessageContent;
use serenity::model::id::ChannelId;
use tokio::sync::mpsc;

#[derive(Serialize, Deserialize)]
pub enum MessageReference {
    Discord(u64, u64),
    Matrix(String, String),
}

pub struct SentMessage {
    pub source: MessageReference,
    pub content: MessageContent,
}

struct Bridgers {
    discord: Mutex<RefCell<Option<discord::Context>>>,
    matrix: Mutex<RefCell<Option<matrix::Client>>>,
}

impl Bridgers {
    fn new() -> Self {
        Self {
            discord: Mutex::new(RefCell::new(None)),
            matrix: Mutex::new(RefCell::new(None)),
        }
    }

    async fn send_message(
        &self,
        source: MessageReference,
        content: MessageContent,
    ) -> Vec<MessageReference> {
        let mut created_messages = Vec::new();

        if let Some(discord) = self.discord.lock().unwrap().borrow().as_ref() {
            // We probably want a function that returns an Option<ChannelId> taking the source
            match &source {
                MessageReference::Matrix(_room_id, _event_id) => {
                    let channel_id = ChannelId(885690775193661463); // TODO: Look up linked channel
                    let discord_message = channel_id
                        .send_message(&discord.http, |m| {
                            m.content(message_ast::format_discord(&content))
                        })
                        .await
                        .expect("Failed to send discord message");

                    created_messages.push(MessageReference::from(&discord_message));
                }
                _ => {}
            };
        }

        if let Some(matrix) = self.matrix.lock().unwrap().borrow().as_ref() {
            match &source {
                MessageReference::Discord(_, _) => {
                    let room_id = RoomId::from_str("asdfghj").unwrap(); // TODO: Get a room id
                    if let Some(room) = matrix.get_joined_room(&room_id) {
                        let event = room
                            .send(
                                AnyMessageEventContent::RoomMessage(
                                    MessageEventContent::text_plain(message_ast::format_discord(
                                        &content, // TODO: Format as HTML
                                    )),
                                ),
                                None,
                            )
                            .await
                            .unwrap();

                        created_messages.push(MessageReference::from((&room_id, &event.event_id)));
                    }
                }
                _ => {}
            }
        }

        created_messages
    }
}

async fn setup_discord(
    token: String,
    bridgers: Arc<Bridgers>,
    discord_tx: mpsc::UnboundedSender<SentMessage>,
) {
    let (discord_ctx_tx, mut discord_ctx_rx) = mpsc::unbounded_channel::<discord::Context>();
    tokio::spawn(async move {
        let mut discord = create_discord_client(discord_ctx_tx, discord_tx, &token).await;
        discord.start().await.unwrap();
    });

    // Hack to grab the Context object when discord is ready
    tokio::spawn(async move {
        while let Some(discord) = discord_ctx_rx.recv().await {
            bridgers.discord.lock().unwrap().replace(Some(discord));
        }
    });
}

async fn setup_matrix(
    homeserver_url: String,
    username: String,
    password: String,
    bridgers: Arc<Bridgers>,
    message_tx: mpsc::UnboundedSender<SentMessage>,
) {
    let client = create_matrix_client(homeserver_url, username, password, message_tx).await;
    let settings = SyncSettings::default().token(client.sync_token().await.unwrap());

    bridgers
        .matrix
        .lock()
        .unwrap()
        .replace(Some(client.clone()));

    tokio::spawn(async move {
        client.sync(settings).await;
    });
}

#[tokio::main]
async fn main() {
    let bridgers = Arc::new(Bridgers::new());

    let (message_tx, mut message_rx) = tokio::sync::mpsc::unbounded_channel::<SentMessage>();

    setup_discord(
        "token".to_string(),
        Arc::clone(&bridgers),
        message_tx.clone(),
    )
    .await;

    setup_matrix(
        "https://matrix.org".to_string(),
        "username".to_string(),
        "password".to_string(),
        Arc::clone(&bridgers),
        message_tx.clone(),
    )
    .await;

    while let Some(message) = message_rx.recv().await {
        let _ = bridgers.send_message(message.source, message.content).await;
    }
}