mod data;

use std::{fmt::Debug, mem, sync::Arc};

use bytes::BytesMut;
use conduit::{debug_error, err, trace, utils::string_from_bytes, warn, Err, PduEvent, Result};
use ipaddress::IPAddress;
use ruma::{
	api::{
		client::push::{set_pusher, Pusher, PusherKind},
		push_gateway::send_event_notification::{
			self,
			v1::{Device, Notification, NotificationCounts, NotificationPriority},
		},
		IncomingResponse, MatrixVersion, OutgoingRequest, SendAccessToken,
	},
	events::{
		room::power_levels::RoomPowerLevelsEventContent, AnySyncTimelineEvent, StateEventType, TimelineEventType,
	},
	push::{Action, PushConditionPowerLevelsCtx, PushConditionRoomCtx, PushFormat, Ruleset, Tweak},
	serde::Raw,
	uint, RoomId, UInt, UserId,
};

use self::data::Data;
use crate::{client, globals, rooms, users, Dep};

pub struct Service {
	services: Services,
	db: Data,
}

struct Services {
	globals: Dep<globals::Service>,
	client: Dep<client::Service>,
	state_accessor: Dep<rooms::state_accessor::Service>,
	state_cache: Dep<rooms::state_cache::Service>,
	users: Dep<users::Service>,
}

impl crate::Service for Service {
	fn build(args: crate::Args<'_>) -> Result<Arc<Self>> {
		Ok(Arc::new(Self {
			services: Services {
				globals: args.depend::<globals::Service>("globals"),
				client: args.depend::<client::Service>("client"),
				state_accessor: args.depend::<rooms::state_accessor::Service>("rooms::state_accessor"),
				state_cache: args.depend::<rooms::state_cache::Service>("rooms::state_cache"),
				users: args.depend::<users::Service>("users"),
			},
			db: Data::new(args.db),
		}))
	}

	fn name(&self) -> &str { crate::service::make_name(std::module_path!()) }
}

impl Service {
	pub fn set_pusher(&self, sender: &UserId, pusher: &set_pusher::v3::PusherAction) -> Result<()> {
		self.db.set_pusher(sender, pusher)
	}

	pub fn get_pusher(&self, sender: &UserId, pushkey: &str) -> Result<Option<Pusher>> {
		self.db.get_pusher(sender, pushkey)
	}

	pub fn get_pushers(&self, sender: &UserId) -> Result<Vec<Pusher>> { self.db.get_pushers(sender) }

	#[must_use]
	pub fn get_pushkeys(&self, sender: &UserId) -> Box<dyn Iterator<Item = Result<String>> + '_> {
		self.db.get_pushkeys(sender)
	}

	#[tracing::instrument(skip(self, dest, request))]
	pub async fn send_request<T>(&self, dest: &str, request: T) -> Result<T::IncomingResponse>
	where
		T: OutgoingRequest + Debug + Send,
	{
		const VERSIONS: [MatrixVersion; 1] = [MatrixVersion::V1_0];

		let dest = dest.replace(self.services.globals.notification_push_path(), "");
		trace!("Push gateway destination: {dest}");

		let http_request = request
			.try_into_http_request::<BytesMut>(&dest, SendAccessToken::IfRequired(""), &VERSIONS)
			.map_err(|e| {
				err!(BadServerResponse(warn!(
					"Failed to find destination {dest} for push gateway: {e}"
				)))
			})?
			.map(BytesMut::freeze);

		let reqwest_request = reqwest::Request::try_from(http_request)?;

		if let Some(url_host) = reqwest_request.url().host_str() {
			trace!("Checking request URL for IP");
			if let Ok(ip) = IPAddress::parse(url_host) {
				if !self.services.globals.valid_cidr_range(&ip) {
					return Err!(BadServerResponse("Not allowed to send requests to this IP"));
				}
			}
		}

		let response = self.services.client.pusher.execute(reqwest_request).await;

		match response {
			Ok(mut response) => {
				// reqwest::Response -> http::Response conversion

				trace!("Checking response destination's IP");
				if let Some(remote_addr) = response.remote_addr() {
					if let Ok(ip) = IPAddress::parse(remote_addr.ip().to_string()) {
						if !self.services.globals.valid_cidr_range(&ip) {
							return Err!(BadServerResponse("Not allowed to send requests to this IP"));
						}
					}
				}

				let status = response.status();
				let mut http_response_builder = http::Response::builder()
					.status(status)
					.version(response.version());
				mem::swap(
					response.headers_mut(),
					http_response_builder
						.headers_mut()
						.expect("http::response::Builder is usable"),
				);

				let body = response.bytes().await?; // TODO: handle timeout

				if !status.is_success() {
					debug_error!("Push gateway response body: {:?}", string_from_bytes(&body));
					return Err!(BadServerResponse(error!(
						"Push gateway {dest} returned unsuccessful HTTP response: {status}"
					)));
				}

				let response = T::IncomingResponse::try_from_http_response(
					http_response_builder
						.body(body)
						.expect("reqwest body is valid http body"),
				);
				response
					.map_err(|e| err!(BadServerResponse(error!("Push gateway {dest} returned invalid response: {e}"))))
			},
			Err(e) => {
				debug_error!("Could not send request to pusher {dest}: {e}");
				Err(e.into())
			},
		}
	}

	#[tracing::instrument(skip(self, user, unread, pusher, ruleset, pdu))]
	pub async fn send_push_notice(
		&self, user: &UserId, unread: UInt, pusher: &Pusher, ruleset: Ruleset, pdu: &PduEvent,
	) -> Result<()> {
		let mut notify = None;
		let mut tweaks = Vec::new();

		let power_levels: RoomPowerLevelsEventContent = self
			.services
			.state_accessor
			.room_state_get(&pdu.room_id, &StateEventType::RoomPowerLevels, "")?
			.map(|ev| {
				serde_json::from_str(ev.content.get())
					.map_err(|e| err!(Database("invalid m.room.power_levels event: {e:?}")))
			})
			.transpose()?
			.unwrap_or_default();

		for action in self.get_actions(user, &ruleset, &power_levels, &pdu.to_sync_room_event(), &pdu.room_id)? {
			let n = match action {
				Action::Notify => true,
				Action::SetTweak(tweak) => {
					tweaks.push(tweak.clone());
					continue;
				},
				_ => false,
			};

			if notify.is_some() {
				return Err!(Database(
					r#"Malformed pushrule contains more than one of these actions: ["dont_notify", "notify", "coalesce"]"#
				));
			}

			notify = Some(n);
		}

		if notify == Some(true) {
			self.send_notice(unread, pusher, tweaks, pdu).await?;
		}
		// Else the event triggered no actions

		Ok(())
	}

	#[tracing::instrument(skip(self, user, ruleset, pdu), level = "debug")]
	pub fn get_actions<'a>(
		&self, user: &UserId, ruleset: &'a Ruleset, power_levels: &RoomPowerLevelsEventContent,
		pdu: &Raw<AnySyncTimelineEvent>, room_id: &RoomId,
	) -> Result<&'a [Action]> {
		let power_levels = PushConditionPowerLevelsCtx {
			users: power_levels.users.clone(),
			users_default: power_levels.users_default,
			notifications: power_levels.notifications.clone(),
		};

		let ctx = PushConditionRoomCtx {
			room_id: room_id.to_owned(),
			member_count: UInt::try_from(
				self.services
					.state_cache
					.room_joined_count(room_id)?
					.unwrap_or(1),
			)
			.unwrap_or_else(|_| uint!(0)),
			user_id: user.to_owned(),
			user_display_name: self
				.services
				.users
				.displayname(user)?
				.unwrap_or_else(|| user.localpart().to_owned()),
			power_levels: Some(power_levels),
		};

		Ok(ruleset.get_actions(pdu, &ctx))
	}

	#[tracing::instrument(skip(self, unread, pusher, tweaks, event))]
	async fn send_notice(&self, unread: UInt, pusher: &Pusher, tweaks: Vec<Tweak>, event: &PduEvent) -> Result<()> {
		// TODO: email
		match &pusher.kind {
			PusherKind::Http(http) => {
				// TODO:
				// Two problems with this
				// 1. if "event_id_only" is the only format kind it seems we should never add
				//    more info
				// 2. can pusher/devices have conflicting formats
				let event_id_only = http.format == Some(PushFormat::EventIdOnly);

				let mut device = Device::new(pusher.ids.app_id.clone(), pusher.ids.pushkey.clone());
				device.data.default_payload = http.default_payload.clone();
				device.data.format.clone_from(&http.format);

				// Tweaks are only added if the format is NOT event_id_only
				if !event_id_only {
					device.tweaks.clone_from(&tweaks);
				}

				let d = vec![device];
				let mut notifi = Notification::new(d);

				notifi.prio = NotificationPriority::Low;
				notifi.event_id = Some((*event.event_id).to_owned());
				notifi.room_id = Some((*event.room_id).to_owned());
				// TODO: missed calls
				notifi.counts = NotificationCounts::new(unread, uint!(0));

				if event.kind == TimelineEventType::RoomEncrypted
					|| tweaks
						.iter()
						.any(|t| matches!(t, Tweak::Highlight(true) | Tweak::Sound(_)))
				{
					notifi.prio = NotificationPriority::High;
				}

				if event_id_only {
					self.send_request(&http.url, send_event_notification::v1::Request::new(notifi))
						.await?;
				} else {
					notifi.sender = Some(event.sender.clone());
					notifi.event_type = Some(event.kind.clone());
					notifi.content = serde_json::value::to_raw_value(&event.content).ok();

					if event.kind == TimelineEventType::RoomMember {
						notifi.user_is_target = event.state_key.as_deref() == Some(event.sender.as_str());
					}

					notifi.sender_display_name = self.services.users.displayname(&event.sender)?;

					notifi.room_name = self.services.state_accessor.get_name(&event.room_id)?;

					self.send_request(&http.url, send_event_notification::v1::Request::new(notifi))
						.await?;
				}

				Ok(())
			},
			// TODO: Handle email
			//PusherKind::Email(_) => Ok(()),
			_ => Ok(()),
		}
	}
}