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/* -------------------------------------------------------- *\
 *                                                          *
 *      ███╗░░░███╗░█████╗░░██████╗██╗░░██╗██╗███╗░░██╗     *
 *      ████╗░████║██╔══██╗██╔════╝██║░░██║██║████╗░██║     *
 *      ██╔████╔██║███████║╚█████╗░███████║██║██╔██╗██║     *
 *      ██║╚██╔╝██║██╔══██║░╚═══██╗██╔══██║██║██║╚████║     *
 *      ██║░╚═╝░██║██║░░██║██████╔╝██║░░██║██║██║░╚███║     *
 *      ╚═╝░░░░░╚═╝╚═╝░░╚═╝╚═════╝░╚═╝░░╚═╝╚═╝╚═╝░░╚══╝     *
 *                                         by Nutshimit     *
 * -------------------------------------------------------- *
 *                                                          *
 *   This file is dual-licensed as Apache-2.0 or GPL-3.0.   *
 *   see LICENSE for license details.                       *
 *                                                          *
\* ---------------------------------------------------------*/

use std::{
	any::{type_name, Any, TypeId},
	collections::BTreeMap,
};

#[derive(Debug, Default)]
pub struct ProviderState
where
	Self: Send + Sync,
{
	data: BTreeMap<TypeId, Box<dyn Any + Send + Sync>>,
}

impl ProviderState {
	/// Puts a value into the `State` storage. One value of each type is retained.
	/// Successive calls to `put` will overwrite the existing value of the same
	/// type.
	pub fn put<T: 'static + Send + Sync>(&mut self, t: T) {
		let type_id = TypeId::of::<T>();
		//trace!(" inserting record to state for type_id `{:?}`", type_id);
		self.data.insert(type_id, Box::new(t));
	}

	/// Determines if the current value exists in `State` storage.
	pub fn has<T: 'static>(&self) -> bool {
		let type_id = TypeId::of::<T>();
		self.data.get(&type_id).is_some()
	}

	/// Tries to borrow a value from the `State` storage.
	#[allow(clippy::should_implement_trait)]
	pub fn try_borrow<T: 'static>(&self) -> Option<&T> {
		let type_id = TypeId::of::<T>();
		//trace!(" borrowing state data for type_id `{:?}`", type_id);
		self.data.get(&type_id).and_then(|b| b.downcast_ref())
	}

	/// Borrows a value from the `State` storage.
	#[allow(clippy::should_implement_trait)]
	pub fn borrow<T: 'static>(&self) -> &T {
		self.try_borrow().unwrap_or_else(|| missing::<T>())
	}

	/// Tries to mutably borrow a value from the `State` storage.
	#[allow(clippy::should_implement_trait)]
	pub fn try_borrow_mut<T: 'static>(&mut self) -> Option<&mut T> {
		let type_id = TypeId::of::<T>();
		//trace!(" mutably borrowing state data for type_id `{:?}`", type_id);
		self.data.get_mut(&type_id).and_then(|b| b.downcast_mut())
	}

	/// Mutably borrows a value from the `State` storage.
	#[allow(clippy::should_implement_trait)]
	pub fn borrow_mut<T: 'static>(&mut self) -> &mut T {
		self.try_borrow_mut().unwrap_or_else(|| missing::<T>())
	}

	/// Tries to move a value out of the `State` storage and return ownership.
	pub fn try_take<T: 'static>(&mut self) -> Option<T> {
		let type_id = TypeId::of::<T>();
		//trace!(
		//    " taking ownership from state data for type_id `{:?}`",
		//    type_id
		//);
		self.data.remove(&type_id).and_then(|b| b.downcast().ok()).map(|b| *b)
	}

	/// Moves a value out of the `State` storage and returns ownership.
	///
	/// # Panics
	///
	/// If a value of type `T` is not present in `State`.
	pub fn take<T: 'static>(&mut self) -> T {
		self.try_take().unwrap_or_else(|| missing::<T>())
	}
}

fn missing<T: 'static>() -> ! {
	panic!("required type {} is not present in State container", type_name::<T>());
}