use std::sync::Arc;

use database::KvTree;
use ruma::api::appservice::Registration;

use crate::{utils, Error, KeyValueDatabase, Result};

pub struct Data {
	id_appserviceregistrations: Arc<dyn KvTree>,
}

impl Data {
	pub(super) fn new(db: &Arc<KeyValueDatabase>) -> Self {
		Self {
			id_appserviceregistrations: db.id_appserviceregistrations.clone(),
		}
	}

	/// Registers an appservice and returns the ID to the caller
	pub(super) fn register_appservice(&self, yaml: Registration) -> Result<String> {
		let id = yaml.id.as_str();
		self.id_appserviceregistrations
			.insert(id.as_bytes(), serde_yaml::to_string(&yaml).unwrap().as_bytes())?;

		Ok(id.to_owned())
	}

	/// Remove an appservice registration
	///
	/// # Arguments
	///
	/// * `service_name` - the name you send to register the service previously
	pub(super) fn unregister_appservice(&self, service_name: &str) -> Result<()> {
		self.id_appserviceregistrations
			.remove(service_name.as_bytes())?;
		Ok(())
	}

	pub fn get_registration(&self, id: &str) -> Result<Option<Registration>> {
		self.id_appserviceregistrations
			.get(id.as_bytes())?
			.map(|bytes| {
				serde_yaml::from_slice(&bytes)
					.map_err(|_| Error::bad_database("Invalid registration bytes in id_appserviceregistrations."))
			})
			.transpose()
	}

	pub(super) fn iter_ids<'a>(&'a self) -> Result<Box<dyn Iterator<Item = Result<String>> + 'a>> {
		Ok(Box::new(self.id_appserviceregistrations.iter().map(|(id, _)| {
			utils::string_from_bytes(&id)
				.map_err(|_| Error::bad_database("Invalid id bytes in id_appserviceregistrations."))
		})))
	}

	pub fn all(&self) -> Result<Vec<(String, Registration)>> {
		self.iter_ids()?
			.filter_map(Result::ok)
			.map(move |id| {
				Ok((
					id.clone(),
					self.get_registration(&id)?
						.expect("iter_ids only returns appservices that exist"),
				))
			})
			.collect()
	}
}