// Copyright 2016 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.

//! Utilities to check the status of all the outputs we have stored in
//! the wallet storage and update them.

use api;
use core::core::Output;
use secp::{self, pedersen};
use util;

use extkey::ExtendedKey;
use types::{WalletConfig, OutputStatus, WalletData};

/// Goes through the list of outputs that haven't been spent yet and check
/// with a node whether their status has changed.
pub fn refresh_outputs(config: &WalletConfig, ext_key: &ExtendedKey) {
	let secp = secp::Secp256k1::with_caps(secp::ContextFlag::Commit);

	// operate within a lock on wallet data
	WalletData::with_wallet(&config.data_file_dir, |wallet_data| {

		// check each output that's not spent
		for out in &mut wallet_data.outputs {
			if out.status != OutputStatus::Spent {
				// figure out the commitment
				let key = ext_key.derive(&secp, out.n_child).unwrap();
				let commitment = secp.commit(out.value, key.key).unwrap();

				// TODO check the pool for unconfirmed

				let out_res = get_output_by_commitment(config, commitment);
		
				if out_res.is_ok() {
					// output is known, it's a new utxo
					out.status = OutputStatus::Unspent;

				} else if out.status == OutputStatus::Unspent {
					// a UTXO we can't find anymore has been spent
					if let Err(api::Error::NotFound) = out_res {
						out.status = OutputStatus::Spent;
					}
				} else {
					//TODO find error with connection and return
					//error!("Error contacting server node at {}. Is it running?", config.check_node_api_http_addr);
				}
			}
		}
	});
}

// queries a reachable node for a given output, checking whether it's been
// confirmed
fn get_output_by_commitment(config: &WalletConfig,
                            commit: pedersen::Commitment)
                            -> Result<Output, api::Error> {
	let url = format!("{}/v1/chain/utxo/{}",
	                  config.check_node_api_http_addr,
	                  util::to_hex(commit.as_ref().to_vec()));
	api::client::get::<Output>(url.as_str())
}