use std::{mem::size_of, sync::Arc};

use conduit::{
	result::LogErr,
	utils::{stream::TryIgnore, u64_from_u8, ReadyExt},
	PduCount, PduEvent,
};
use database::Map;
use futures::{Stream, StreamExt};
use ruma::{api::Direction, EventId, RoomId, UserId};

use crate::{
	rooms,
	rooms::{
		short::{ShortEventId, ShortRoomId},
		timeline::{PduId, RawPduId},
	},
	Dep,
};

pub(super) struct Data {
	tofrom_relation: Arc<Map>,
	referencedevents: Arc<Map>,
	softfailedeventids: Arc<Map>,
	services: Services,
}

struct Services {
	timeline: Dep<rooms::timeline::Service>,
}

pub(super) type PdusIterItem = (PduCount, PduEvent);

impl Data {
	pub(super) fn new(args: &crate::Args<'_>) -> Self {
		let db = &args.db;
		Self {
			tofrom_relation: db["tofrom_relation"].clone(),
			referencedevents: db["referencedevents"].clone(),
			softfailedeventids: db["softfailedeventids"].clone(),
			services: Services {
				timeline: args.depend::<rooms::timeline::Service>("rooms::timeline"),
			},
		}
	}

	pub(super) fn add_relation(&self, from: u64, to: u64) {
		const BUFSIZE: usize = size_of::<u64>() * 2;

		let key: &[u64] = &[to, from];
		self.tofrom_relation.aput_raw::<BUFSIZE, _, _>(key, []);
	}

	pub(super) fn get_relations<'a>(
		&'a self, user_id: &'a UserId, shortroomid: ShortRoomId, target: ShortEventId, from: PduCount, dir: Direction,
	) -> impl Stream<Item = PdusIterItem> + Send + '_ {
		let current: RawPduId = PduId {
			shortroomid,
			shorteventid: from,
		}
		.into();

		match dir {
			Direction::Forward => self.tofrom_relation.raw_keys_from(&current).boxed(),
			Direction::Backward => self.tofrom_relation.rev_raw_keys_from(&current).boxed(),
		}
		.ignore_err()
		.ready_take_while(move |key| key.starts_with(&target.to_be_bytes()))
		.map(|to_from| u64_from_u8(&to_from[8..16]))
		.map(PduCount::from_unsigned)
		.filter_map(move |shorteventid| async move {
			let pdu_id: RawPduId = PduId {
				shortroomid,
				shorteventid,
			}
			.into();

			let mut pdu = self.services.timeline.get_pdu_from_id(&pdu_id).await.ok()?;

			if pdu.sender != user_id {
				pdu.remove_transaction_id().log_err().ok();
			}

			Some((shorteventid, pdu))
		})
	}

	pub(super) fn mark_as_referenced(&self, room_id: &RoomId, event_ids: &[Arc<EventId>]) {
		for prev in event_ids {
			let key = (room_id, prev);
			self.referencedevents.put_raw(key, []);
		}
	}

	pub(super) async fn is_event_referenced(&self, room_id: &RoomId, event_id: &EventId) -> bool {
		let key = (room_id, event_id);
		self.referencedevents.qry(&key).await.is_ok()
	}

	pub(super) fn mark_event_soft_failed(&self, event_id: &EventId) { self.softfailedeventids.insert(event_id, []); }

	pub(super) async fn is_event_soft_failed(&self, event_id: &EventId) -> bool {
		self.softfailedeventids.get(event_id).await.is_ok()
	}
}