use axum::extract::State;
use axum_client_ip::InsecureClientIp;
use conduit::{info, warn, Err, Error, Result};
use futures::{StreamExt, TryFutureExt};
use ruma::{
	api::{
		client::{
			directory::{get_public_rooms, get_public_rooms_filtered, get_room_visibility, set_room_visibility},
			error::ErrorKind,
			room,
		},
		federation,
	},
	directory::{Filter, PublicRoomJoinRule, PublicRoomsChunk, RoomNetwork},
	events::{
		room::{
			join_rules::{JoinRule, RoomJoinRulesEventContent},
			power_levels::{RoomPowerLevels, RoomPowerLevelsEventContent},
		},
		StateEventType,
	},
	uint, OwnedRoomId, RoomId, ServerName, UInt, UserId,
};
use service::Services;

use crate::Ruma;

/// # `POST /_matrix/client/v3/publicRooms`
///
/// Lists the public rooms on this server.
///
/// - Rooms are ordered by the number of joined members
#[tracing::instrument(skip_all, fields(%client), name = "publicrooms")]
pub(crate) async fn get_public_rooms_filtered_route(
	State(services): State<crate::State>, InsecureClientIp(client): InsecureClientIp,
	body: Ruma<get_public_rooms_filtered::v3::Request>,
) -> Result<get_public_rooms_filtered::v3::Response> {
	if let Some(server) = &body.server {
		if services
			.globals
			.forbidden_remote_room_directory_server_names()
			.contains(server)
		{
			return Err(Error::BadRequest(
				ErrorKind::forbidden(),
				"Server is banned on this homeserver.",
			));
		}
	}

	let response = get_public_rooms_filtered_helper(
		&services,
		body.server.as_deref(),
		body.limit,
		body.since.as_deref(),
		&body.filter,
		&body.room_network,
	)
	.await
	.map_err(|e| {
		warn!(?body.server, "Failed to return /publicRooms: {e}");
		Error::BadRequest(ErrorKind::Unknown, "Failed to return the requested server's public room list.")
	})?;

	Ok(response)
}

/// # `GET /_matrix/client/v3/publicRooms`
///
/// Lists the public rooms on this server.
///
/// - Rooms are ordered by the number of joined members
#[tracing::instrument(skip_all, fields(%client), name = "publicrooms")]
pub(crate) async fn get_public_rooms_route(
	State(services): State<crate::State>, InsecureClientIp(client): InsecureClientIp,
	body: Ruma<get_public_rooms::v3::Request>,
) -> Result<get_public_rooms::v3::Response> {
	if let Some(server) = &body.server {
		if services
			.globals
			.forbidden_remote_room_directory_server_names()
			.contains(server)
		{
			return Err(Error::BadRequest(
				ErrorKind::forbidden(),
				"Server is banned on this homeserver.",
			));
		}
	}

	let response = get_public_rooms_filtered_helper(
		&services,
		body.server.as_deref(),
		body.limit,
		body.since.as_deref(),
		&Filter::default(),
		&RoomNetwork::Matrix,
	)
	.await
	.map_err(|e| {
		warn!(?body.server, "Failed to return /publicRooms: {e}");
		Error::BadRequest(ErrorKind::Unknown, "Failed to return the requested server's public room list.")
	})?;

	Ok(get_public_rooms::v3::Response {
		chunk: response.chunk,
		prev_batch: response.prev_batch,
		next_batch: response.next_batch,
		total_room_count_estimate: response.total_room_count_estimate,
	})
}

/// # `PUT /_matrix/client/r0/directory/list/room/{roomId}`
///
/// Sets the visibility of a given room in the room directory.
#[tracing::instrument(skip_all, fields(%client), name = "room_directory")]
pub(crate) async fn set_room_visibility_route(
	State(services): State<crate::State>, InsecureClientIp(client): InsecureClientIp,
	body: Ruma<set_room_visibility::v3::Request>,
) -> Result<set_room_visibility::v3::Response> {
	let sender_user = body.sender_user.as_ref().expect("user is authenticated");

	if !services.rooms.metadata.exists(&body.room_id).await {
		// Return 404 if the room doesn't exist
		return Err(Error::BadRequest(ErrorKind::NotFound, "Room not found"));
	}

	if services
		.users
		.is_deactivated(sender_user)
		.await
		.unwrap_or(false)
		&& body.appservice_info.is_none()
	{
		return Err!(Request(Forbidden("Guests cannot publish to room directories")));
	}

	if !user_can_publish_room(&services, sender_user, &body.room_id).await? {
		return Err(Error::BadRequest(
			ErrorKind::forbidden(),
			"User is not allowed to publish this room",
		));
	}

	match &body.visibility {
		room::Visibility::Public => {
			if services.globals.config.lockdown_public_room_directory
				&& !services.users.is_admin(sender_user).await
				&& body.appservice_info.is_none()
			{
				info!(
					"Non-admin user {sender_user} tried to publish {0} to the room directory while \
					 \"lockdown_public_room_directory\" is enabled",
					body.room_id
				);

				if services.globals.config.admin_room_notices {
					services
						.admin
						.send_text(&format!(
							"Non-admin user {sender_user} tried to publish {0} to the room directory while \
							 \"lockdown_public_room_directory\" is enabled",
							body.room_id
						))
						.await;
				}

				return Err(Error::BadRequest(
					ErrorKind::forbidden(),
					"Publishing rooms to the room directory is not allowed",
				));
			}

			services.rooms.directory.set_public(&body.room_id);

			if services.globals.config.admin_room_notices {
				services
					.admin
					.send_text(&format!("{sender_user} made {} public to the room directory", body.room_id))
					.await;
			}
			info!("{sender_user} made {0} public to the room directory", body.room_id);
		},
		room::Visibility::Private => services.rooms.directory.set_not_public(&body.room_id),
		_ => {
			return Err(Error::BadRequest(
				ErrorKind::InvalidParam,
				"Room visibility type is not supported.",
			));
		},
	}

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

/// # `GET /_matrix/client/r0/directory/list/room/{roomId}`
///
/// Gets the visibility of a given room in the room directory.
pub(crate) async fn get_room_visibility_route(
	State(services): State<crate::State>, body: Ruma<get_room_visibility::v3::Request>,
) -> Result<get_room_visibility::v3::Response> {
	if !services.rooms.metadata.exists(&body.room_id).await {
		// Return 404 if the room doesn't exist
		return Err(Error::BadRequest(ErrorKind::NotFound, "Room not found"));
	}

	Ok(get_room_visibility::v3::Response {
		visibility: if services.rooms.directory.is_public_room(&body.room_id).await {
			room::Visibility::Public
		} else {
			room::Visibility::Private
		},
	})
}

pub(crate) async fn get_public_rooms_filtered_helper(
	services: &Services, server: Option<&ServerName>, limit: Option<UInt>, since: Option<&str>, filter: &Filter,
	_network: &RoomNetwork,
) -> Result<get_public_rooms_filtered::v3::Response> {
	if let Some(other_server) = server.filter(|server_name| !services.globals.server_is_ours(server_name)) {
		let response = services
			.sending
			.send_federation_request(
				other_server,
				federation::directory::get_public_rooms_filtered::v1::Request {
					limit,
					since: since.map(ToOwned::to_owned),
					filter: Filter {
						generic_search_term: filter.generic_search_term.clone(),
						room_types: filter.room_types.clone(),
					},
					room_network: RoomNetwork::Matrix,
				},
			)
			.await?;

		return Ok(get_public_rooms_filtered::v3::Response {
			chunk: response.chunk,
			prev_batch: response.prev_batch,
			next_batch: response.next_batch,
			total_room_count_estimate: response.total_room_count_estimate,
		});
	}

	// Use limit or else 10, with maximum 100
	let limit = limit.map_or(10, u64::from);
	let mut num_since: u64 = 0;

	if let Some(s) = &since {
		let mut characters = s.chars();
		let backwards = match characters.next() {
			Some('n') => false,
			Some('p') => true,
			_ => return Err(Error::BadRequest(ErrorKind::InvalidParam, "Invalid `since` token")),
		};

		num_since = characters
			.collect::<String>()
			.parse()
			.map_err(|_| Error::BadRequest(ErrorKind::InvalidParam, "Invalid `since` token."))?;

		if backwards {
			num_since = num_since.saturating_sub(limit);
		}
	}

	let mut all_rooms: Vec<PublicRoomsChunk> = services
		.rooms
		.directory
		.public_rooms()
		.map(ToOwned::to_owned)
		.then(|room_id| public_rooms_chunk(services, room_id))
		.filter_map(|chunk| async move {
			if let Some(query) = filter.generic_search_term.as_ref().map(|q| q.to_lowercase()) {
				if let Some(name) = &chunk.name {
					if name.as_str().to_lowercase().contains(&query) {
						return Some(chunk);
					}
				}

				if let Some(topic) = &chunk.topic {
					if topic.to_lowercase().contains(&query) {
						return Some(chunk);
					}
				}

				if let Some(canonical_alias) = &chunk.canonical_alias {
					if canonical_alias.as_str().to_lowercase().contains(&query) {
						return Some(chunk);
					}
				}

				return None;
			}

			// No search term
			Some(chunk)
		})
		// We need to collect all, so we can sort by member count
		.collect()
		.await;

	all_rooms.sort_by(|l, r| r.num_joined_members.cmp(&l.num_joined_members));

	let total_room_count_estimate = UInt::try_from(all_rooms.len()).unwrap_or_else(|_| uint!(0));

	let chunk: Vec<_> = all_rooms
		.into_iter()
		.skip(
			num_since
				.try_into()
				.expect("num_since should not be this high"),
		)
		.take(limit.try_into().expect("limit should not be this high"))
		.collect();

	let prev_batch = if num_since == 0 {
		None
	} else {
		Some(format!("p{num_since}"))
	};

	let next_batch = if chunk.len() < limit.try_into().unwrap() {
		None
	} else {
		Some(format!(
			"n{}",
			num_since
				.checked_add(limit)
				.expect("num_since and limit should not be that large")
		))
	};

	Ok(get_public_rooms_filtered::v3::Response {
		chunk,
		prev_batch,
		next_batch,
		total_room_count_estimate: Some(total_room_count_estimate),
	})
}

/// Check whether the user can publish to the room directory via power levels of
/// room history visibility event or room creator
async fn user_can_publish_room(services: &Services, user_id: &UserId, room_id: &RoomId) -> Result<bool> {
	if let Ok(event) = services
		.rooms
		.state_accessor
		.room_state_get(room_id, &StateEventType::RoomPowerLevels, "")
		.await
	{
		serde_json::from_str(event.content.get())
			.map_err(|_| Error::bad_database("Invalid event content for m.room.power_levels"))
			.map(|content: RoomPowerLevelsEventContent| {
				RoomPowerLevels::from(content).user_can_send_state(user_id, StateEventType::RoomHistoryVisibility)
			})
	} else if let Ok(event) = services
		.rooms
		.state_accessor
		.room_state_get(room_id, &StateEventType::RoomCreate, "")
		.await
	{
		Ok(event.sender == user_id)
	} else {
		return Err(Error::BadRequest(
			ErrorKind::forbidden(),
			"User is not allowed to publish this room",
		));
	}
}

async fn public_rooms_chunk(services: &Services, room_id: OwnedRoomId) -> PublicRoomsChunk {
	PublicRoomsChunk {
		canonical_alias: services
			.rooms
			.state_accessor
			.get_canonical_alias(&room_id)
			.await
			.ok(),
		name: services.rooms.state_accessor.get_name(&room_id).await.ok(),
		num_joined_members: services
			.rooms
			.state_cache
			.room_joined_count(&room_id)
			.await
			.unwrap_or(0)
			.try_into()
			.expect("joined count overflows ruma UInt"),
		topic: services
			.rooms
			.state_accessor
			.get_room_topic(&room_id)
			.await
			.ok(),
		world_readable: services
			.rooms
			.state_accessor
			.is_world_readable(&room_id)
			.await,
		guest_can_join: services.rooms.state_accessor.guest_can_join(&room_id).await,
		avatar_url: services
			.rooms
			.state_accessor
			.get_avatar(&room_id)
			.await
			.into_option()
			.unwrap_or_default()
			.url,
		join_rule: services
			.rooms
			.state_accessor
			.room_state_get_content(&room_id, &StateEventType::RoomJoinRules, "")
			.map_ok(|c: RoomJoinRulesEventContent| match c.join_rule {
				JoinRule::Public => PublicRoomJoinRule::Public,
				JoinRule::Knock => PublicRoomJoinRule::Knock,
				_ => "invite".into(),
			})
			.await
			.unwrap_or_default(),
		room_type: services
			.rooms
			.state_accessor
			.get_room_type(&room_id)
			.await
			.ok(),
		room_id,
	}
}