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

use sled::Db;

use crate::{
    channels::ChannelReference,
    discord::{self, delete_on_discord, edit_on_discord, forward_to_discord},
    matrix::{self, delete_on_matrix, edit_on_matrix, forward_to_matrix},
    messages::{DeletedMessage, EditedMessage, MessageReference, SentMessage},
};

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

impl Bridgers {
    pub fn new() -> Self {
        let db = sled::open("data/phoebe.sled").expect("Failed to open database");

        Self {
            db,
            discord: Mutex::new(RefCell::new(None)),
            matrix: Mutex::new(RefCell::new(None)),
        }
    }

    fn get_linked_discord_channel(&self, source: &MessageReference) -> Option<discord::ChannelId> {
        let discord_channels = self
            .db
            .open_tree("discord_channels")
            .expect("Failed to open discord channels tree");

        match source {
            MessageReference::Matrix(room_id, _) => {
                let channel_ref = ChannelReference::Matrix(room_id.to_string());
                let channel_ref = bincode::serialize(&channel_ref).unwrap();

                discord_channels
                    .get(channel_ref)
                    .unwrap()
                    .map(|bytes| bincode::deserialize::<u64>(&bytes).unwrap())
                    .map(discord::ChannelId)
            }
            _ => None,
        }
    }

    fn get_linked_matrix_room(&self, source: &MessageReference) -> Option<matrix::RoomId> {
        let matrix_channels = self
            .db
            .open_tree("matrix_channels")
            .expect("Failed to open matrix channels tree");

        match source {
            MessageReference::Discord(channel_id, _) => {
                let channel_ref = ChannelReference::Discord(*channel_id);
                let channel_ref = bincode::serialize(&channel_ref).unwrap();

                matrix_channels
                    .get(channel_ref)
                    .unwrap()
                    .map(|bytes| bincode::deserialize::<String>(&bytes).unwrap())
                    .as_deref()
                    .map(matrix::RoomId::from_str)
                    .map(Result::unwrap)
            }
            _ => None,
        }
    }

    fn get_related_messages(&self, source: &MessageReference) -> Option<Vec<MessageReference>> {
        let message_relations = self
            .db
            .open_tree("message_relations")
            .expect("Failed to open relations tree");

        let key = bincode::serialize(source).expect("Failed to serialize message reference");
        message_relations
            .get(key)
            .expect("Failed to retrieve message references")
            .map(|r| {
                bincode::deserialize::<Vec<MessageReference>>(&r)
                    .expect("Failed to deserialize message references")
            })
    }

    fn get_related_discord_message(&self, source: &MessageReference) -> Option<(u64, u64)> {
        if let MessageReference::Discord(channel_id, message_id) = source {
            return Some((*channel_id, *message_id));
        }

        if let Some(relations) = self.get_related_messages(source) {
            for relation in relations {
                if let MessageReference::Discord(channel_id, message_id) = relation {
                    return Some((channel_id, message_id));
                }
            }
        }

        None
    }

    fn get_related_matrix_message(&self, source: &MessageReference) -> Option<matrix::EventId> {
        if let MessageReference::Matrix(_, event_id) = source {
            return Some(matrix::EventId::from_str(event_id).unwrap());
        }

        if let Some(relations) = self.get_related_messages(source) {
            for relation in relations {
                if let MessageReference::Matrix(_, event_id) = relation {
                    return Some(matrix::EventId::from_str(&event_id).unwrap());
                }
            }
        }

        None
    }

    pub fn link_channels(&self, channels: &[ChannelReference]) {
        let discord_channels = self
            .db
            .open_tree("discord_channels")
            .expect("Failed to open discord channels tree");

        let matrix_channels = self
            .db
            .open_tree("matrix_channels")
            .expect("Failed to open matrix channels tree");

        for channel in channels.iter() {
            let other_channels = channels
                .iter()
                .filter(|r| r != &channel)
                .collect::<Vec<_>>();

            match channel {
                ChannelReference::Discord(channel_id) => {
                    for other_channel in other_channels {
                        let key = bincode::serialize(other_channel).unwrap();
                        let value = bincode::serialize(channel_id).unwrap();
                        discord_channels.insert(key, value).unwrap();
                    }
                }
                ChannelReference::Matrix(room_id) => {
                    for other_channel in other_channels {
                        let key = bincode::serialize(other_channel).unwrap();
                        let value = bincode::serialize(room_id.as_str()).unwrap();
                        matrix_channels.insert(key, value).unwrap();
                    }
                }
            }
        }
    }

    fn store_related_messages(&self, related_messages: &[MessageReference]) {
        let tree = self
            .db
            .open_tree("message_relations")
            .expect("Failed to open relations tree");

        for source in related_messages {
            let relations = related_messages
                .iter()
                .filter(|r| r != &source)
                .collect::<Vec<_>>();

            let key = bincode::serialize(source).expect("Failed to serialize message reference");
            let value =
                bincode::serialize(&relations).expect("Failed to serialize message relations");

            tree.insert(key, value)
                .expect("Failed to store message relations");
        }
    }

    pub async fn send_message(&self, message: SentMessage) {
        let mut related_messages = vec![message.source.clone()];

        if let Some(discord) = self.discord.lock().unwrap().borrow().as_ref() {
            if let Some(channel) = self.get_linked_discord_channel(&message.source) {
                let reply = message
                    .replies_to
                    .as_ref()
                    .and_then(|r| self.get_related_discord_message(r));

                if let Some(m) = forward_to_discord(discord, channel, &message, reply).await {
                    related_messages.push(m);
                }
            }
        }

        if let Some(matrix) = self.matrix.lock().unwrap().borrow().as_ref() {
            if let Some(room_id) = self.get_linked_matrix_room(&message.source) {
                let reply = message
                    .replies_to
                    .as_ref()
                    .and_then(|r| self.get_related_matrix_message(r));

                if let Some(m) = forward_to_matrix(matrix, room_id, &message, reply).await {
                    related_messages.push(m);
                }
            }
        }

        self.store_related_messages(&related_messages);
    }

    pub async fn edit_message(&self, message: EditedMessage) {
        if let Some(related_messages) = self.get_related_messages(&message.replacing) {
            let mut new_related_messages = HashSet::new();
            related_messages.iter().for_each(|r| {
                new_related_messages.insert(r.clone());
            });

            for related_message in related_messages.iter() {
                match related_message {
                    MessageReference::Discord(channel_id, message_id) => {
                        if let Some(discord) = self.discord.lock().unwrap().borrow().as_ref() {
                            let channel_id = discord::ChannelId(*channel_id);
                            let message_id = discord::MessageId(*message_id);

                            if let Some(m) =
                                edit_on_discord(discord, channel_id, message_id, &message).await
                            {
                                new_related_messages.insert(m);
                            }
                        }
                    }
                    MessageReference::Matrix(room_id, event_id) => {
                        if let Some(matrix) = self.matrix.lock().unwrap().borrow().as_ref() {
                            let room_id = matrix::RoomId::from_str(room_id).unwrap();
                            let event_id = matrix::EventId::from_str(event_id).unwrap();

                            if let Some(m) =
                                edit_on_matrix(matrix, room_id, event_id, &message).await
                            {
                                new_related_messages.insert(m);
                            }
                        }
                    }
                }
            }

            self.store_related_messages(&new_related_messages.into_iter().collect::<Vec<_>>())
        }
    }

    pub async fn delete_message(&self, message: DeletedMessage) {
        if let Some(related_messages) = self.get_related_messages(&message.reference) {
            for related_message in related_messages.iter() {
                // TODO: What do we want to do with the success / failure ???

                match related_message {
                    MessageReference::Discord(channel_id, message_id) => {
                        if let Some(discord) = self.discord.lock().unwrap().borrow().as_ref() {
                            let channel_id = discord::ChannelId(*channel_id);
                            let message_id = discord::MessageId(*message_id);

                            let _success =
                                delete_on_discord(discord, channel_id, message_id, &message).await;
                        }
                    }
                    MessageReference::Matrix(room_id, event_id) => {
                        if let Some(matrix) = self.matrix.lock().unwrap().borrow().as_ref() {
                            let room_id = matrix::RoomId::from_str(room_id).unwrap();
                            let event_id = matrix::EventId::from_str(event_id).unwrap();

                            let _success =
                                delete_on_matrix(matrix, room_id, event_id, &message).await;
                        }
                    }
                }
            }
        }
    }
}