use std::collections::BTreeMap;

use ruma::{
	api::client::{error::ErrorKind, read_marker::set_read_marker, receipt::create_receipt},
	events::{
		receipt::{ReceiptThread, ReceiptType},
		RoomAccountDataEventType,
	},
	MilliSecondsSinceUnixEpoch,
};

use crate::{service::rooms::timeline::PduCount, services, Error, Result, Ruma};

/// # `POST /_matrix/client/r0/rooms/{roomId}/read_markers`
///
/// Sets different types of read markers.
///
/// - Updates fully-read account data event to `fully_read`
/// - If `read_receipt` is set: Update private marker and public read receipt
///   EDU
pub(crate) async fn set_read_marker_route(
	body: Ruma<set_read_marker::v3::Request>,
) -> Result<set_read_marker::v3::Response> {
	let sender_user = body.sender_user.as_ref().expect("user is authenticated");

	if let Some(fully_read) = &body.fully_read {
		let fully_read_event = ruma::events::fully_read::FullyReadEvent {
			content: ruma::events::fully_read::FullyReadEventContent {
				event_id: fully_read.clone(),
			},
		};
		services().account_data.update(
			Some(&body.room_id),
			sender_user,
			RoomAccountDataEventType::FullyRead,
			&serde_json::to_value(fully_read_event).expect("to json value always works"),
		)?;
	}

	if body.private_read_receipt.is_some() || body.read_receipt.is_some() {
		services()
			.rooms
			.user
			.reset_notification_counts(sender_user, &body.room_id)?;
	}

	if let Some(event) = &body.private_read_receipt {
		let count = services()
			.rooms
			.timeline
			.get_pdu_count(event)?
			.ok_or(Error::BadRequest(ErrorKind::InvalidParam, "Event does not exist."))?;
		let count = match count {
			PduCount::Backfilled(_) => {
				return Err(Error::BadRequest(
					ErrorKind::InvalidParam,
					"Read receipt is in backfilled timeline",
				))
			},
			PduCount::Normal(c) => c,
		};
		services()
			.rooms
			.read_receipt
			.private_read_set(&body.room_id, sender_user, count)?;
	}

	if let Some(event) = &body.read_receipt {
		let mut user_receipts = BTreeMap::new();
		user_receipts.insert(
			sender_user.clone(),
			ruma::events::receipt::Receipt {
				ts: Some(MilliSecondsSinceUnixEpoch::now()),
				thread: ReceiptThread::Unthreaded,
			},
		);

		let mut receipts = BTreeMap::new();
		receipts.insert(ReceiptType::Read, user_receipts);

		let mut receipt_content = BTreeMap::new();
		receipt_content.insert(event.to_owned(), receipts);

		services().rooms.read_receipt.readreceipt_update(
			sender_user,
			&body.room_id,
			ruma::events::receipt::ReceiptEvent {
				content: ruma::events::receipt::ReceiptEventContent(receipt_content),
				room_id: body.room_id.clone(),
			},
		)?;
	}

	Ok(set_read_marker::v3::Response {})
}

/// # `POST /_matrix/client/r0/rooms/{roomId}/receipt/{receiptType}/{eventId}`
///
/// Sets private read marker and public read receipt EDU.
pub(crate) async fn create_receipt_route(
	body: Ruma<create_receipt::v3::Request>,
) -> Result<create_receipt::v3::Response> {
	let sender_user = body.sender_user.as_ref().expect("user is authenticated");

	if matches!(
		&body.receipt_type,
		create_receipt::v3::ReceiptType::Read | create_receipt::v3::ReceiptType::ReadPrivate
	) {
		services()
			.rooms
			.user
			.reset_notification_counts(sender_user, &body.room_id)?;
	}

	match body.receipt_type {
		create_receipt::v3::ReceiptType::FullyRead => {
			let fully_read_event = ruma::events::fully_read::FullyReadEvent {
				content: ruma::events::fully_read::FullyReadEventContent {
					event_id: body.event_id.clone(),
				},
			};
			services().account_data.update(
				Some(&body.room_id),
				sender_user,
				RoomAccountDataEventType::FullyRead,
				&serde_json::to_value(fully_read_event).expect("to json value always works"),
			)?;
		},
		create_receipt::v3::ReceiptType::Read => {
			let mut user_receipts = BTreeMap::new();
			user_receipts.insert(
				sender_user.clone(),
				ruma::events::receipt::Receipt {
					ts: Some(MilliSecondsSinceUnixEpoch::now()),
					thread: ReceiptThread::Unthreaded,
				},
			);
			let mut receipts = BTreeMap::new();
			receipts.insert(ReceiptType::Read, user_receipts);

			let mut receipt_content = BTreeMap::new();
			receipt_content.insert(body.event_id.clone(), receipts);

			services().rooms.read_receipt.readreceipt_update(
				sender_user,
				&body.room_id,
				ruma::events::receipt::ReceiptEvent {
					content: ruma::events::receipt::ReceiptEventContent(receipt_content),
					room_id: body.room_id.clone(),
				},
			)?;
		},
		create_receipt::v3::ReceiptType::ReadPrivate => {
			let count = services()
				.rooms
				.timeline
				.get_pdu_count(&body.event_id)?
				.ok_or(Error::BadRequest(ErrorKind::InvalidParam, "Event does not exist."))?;
			let count = match count {
				PduCount::Backfilled(_) => {
					return Err(Error::BadRequest(
						ErrorKind::InvalidParam,
						"Read receipt is in backfilled timeline",
					))
				},
				PduCount::Normal(c) => c,
			};
			services()
				.rooms
				.read_receipt
				.private_read_set(&body.room_id, sender_user, count)?;
		},
		_ => return Err(Error::bad_database("Unsupported receipt type")),
	}

	Ok(create_receipt::v3::Response {})
}
