// Copyright 2018 The Grin Developers
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

//! Wallet key management functions
use keychain::Identifier;
use libwallet::error::Error;
use libwallet::types::WalletBackend;

/// Get our next available key
pub fn new_output_key<T>(wallet: &mut T) -> Result<(Identifier, u32), Error>
where
	T: WalletBackend,
{
	wallet.with_wallet(|wallet_data| next_available_key(wallet_data))
}

/// Get next available key in the wallet
pub fn next_available_key<T>(wallet: &mut T) -> (Identifier, u32)
where
	T: WalletBackend,
{
	let root_key_id = wallet.keychain().root_key_id();
	let derivation = wallet.next_child(root_key_id.clone());
	let key_id = wallet.keychain().derive_key_id(derivation).unwrap();
	(key_id, derivation)
}

/// Retrieve an existing key from a wallet
pub fn retrieve_existing_key<T>(wallet: &T, key_id: Identifier) -> (Identifier, u32)
where
	T: WalletBackend,
{
	if let Some(existing) = wallet.get_output(&key_id) {
		let key_id = existing.key_id.clone();
		let derivation = existing.n_child;
		(key_id, derivation)
	} else {
		panic!("should never happen");
	}
}