use std::collections::BTreeMap;

use axum::extract::State;
use conduit::{err, Err};
use ruma::{api::client::message::send_message_event, events::MessageLikeEventType};
use serde_json::from_str;

use crate::{service::pdu::PduBuilder, utils, Result, Ruma};

/// # `PUT /_matrix/client/v3/rooms/{roomId}/send/{eventType}/{txnId}`
///
/// Send a message event into the room.
///
/// - Is a NOOP if the txn id was already used before and returns the same event
///   id again
/// - The only requirement for the content is that it has to be valid json
/// - Tries to send the event into the room, auth rules will determine if it is
///   allowed
pub(crate) async fn send_message_event_route(
	State(services): State<crate::State>, body: Ruma<send_message_event::v3::Request>,
) -> Result<send_message_event::v3::Response> {
	let sender_user = body.sender_user();
	let sender_device = body.sender_device.as_deref();
	let appservice_info = body.appservice_info.as_ref();

	// Forbid m.room.encrypted if encryption is disabled
	if MessageLikeEventType::RoomEncrypted == body.event_type && !services.globals.allow_encryption() {
		return Err!(Request(Forbidden("Encryption has been disabled")));
	}

	let state_lock = services.rooms.state.mutex.lock(&body.room_id).await;

	if body.event_type == MessageLikeEventType::CallInvite
		&& services.rooms.directory.is_public_room(&body.room_id).await
	{
		return Err!(Request(Forbidden("Room call invites are not allowed in public rooms")));
	}

	// Check if this is a new transaction id
	if let Ok(response) = services
		.transaction_ids
		.existing_txnid(sender_user, sender_device, &body.txn_id)
		.await
	{
		// The client might have sent a txnid of the /sendToDevice endpoint
		// This txnid has no response associated with it
		if response.is_empty() {
			return Err!(Request(InvalidParam(
				"Tried to use txn id already used for an incompatible endpoint."
			)));
		}

		return Ok(send_message_event::v3::Response {
			event_id: utils::string_from_bytes(&response)
				.map(TryInto::try_into)
				.map_err(|e| err!(Database("Invalid event_id in txnid data: {e:?}")))??,
		});
	}

	let mut unsigned = BTreeMap::new();
	unsigned.insert("transaction_id".to_owned(), body.txn_id.to_string().into());

	let content =
		from_str(body.body.body.json().get()).map_err(|e| err!(Request(BadJson("Invalid JSON body: {e}"))))?;

	let event_id = services
		.rooms
		.timeline
		.build_and_append_pdu(
			PduBuilder {
				event_type: body.event_type.clone().into(),
				content,
				unsigned: Some(unsigned),
				timestamp: appservice_info.and(body.timestamp),
				..Default::default()
			},
			sender_user,
			&body.room_id,
			&state_lock,
		)
		.await?;

	services
		.transaction_ids
		.add_txnid(sender_user, sender_device, &body.txn_id, event_id.as_bytes());

	drop(state_lock);

	Ok(send_message_event::v3::Response {
		event_id: event_id.into(),
	})
}