// 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.

//! Provides the JSON/HTTP API for wallets to receive payments. Because
//! receiving money in MimbleWimble requires an interactive exchange, a
//! wallet server that's running at all time is required in many cases.

use bodyparser;
use iron::Handler;
use iron::prelude::*;
use iron::status;
use serde_json;
use std::sync::{Arc, RwLock};

use api;
use core::consensus::reward;
use core::core::{Output, TxKernel};
use core::global;
use failure::Fail;
use grinwallet::{keys, selection};
use keychain::Keychain;
use libwallet::{aggsig, reward, transaction};
use types::*;
use util::LOGGER;

/// Dummy wrapper for the hex-encoded serialized transaction.
#[derive(Serialize, Deserialize)]
pub struct TxWrapper {
	pub tx_hex: String,
}

lazy_static! {
	/// Static reference to aggsig context (temporary while wallet is being refactored)
	pub static ref AGGSIG_CONTEXT_MANAGER:Arc<RwLock<aggsig::ContextManager>>
		= Arc::new(RwLock::new(aggsig::ContextManager::new()));
}

fn handle_send(
	config: &WalletConfig,
	keychain: &Keychain,
	context_manager: &mut aggsig::ContextManager,
	slate: &mut transaction::Slate,
) -> Result<(), Error> {
	// create an output using the amount in the slate
	let (_, receiver_create_fn) =
		selection::build_recipient_output_with_slate(config, keychain, context_manager, slate)
			.unwrap();

	// fill public keys
	let _ = slate.fill_round_1(&keychain, context_manager, 1)?;

	// perform partial sig
	let _ = slate.fill_round_2(&keychain, context_manager, 1)?;

	// Save output in wallet
	let _ = receiver_create_fn();

	Ok(())
}

/// Component used to receive coins, implements all the receiving end of the
/// wallet REST API as well as some of the command-line operations.
#[derive(Clone)]
pub struct WalletReceiver {
	pub keychain: Keychain,
	pub config: WalletConfig,
}

impl Handler for WalletReceiver {
	fn handle(&self, req: &mut Request) -> IronResult<Response> {
		let struct_body = req.get::<bodyparser::Struct<transaction::Slate>>();

		if let Ok(Some(mut slate)) = struct_body {
			let mut acm = AGGSIG_CONTEXT_MANAGER.write().unwrap();
			let _ = handle_send(&self.config, &self.keychain, &mut acm, &mut slate)
				.map_err(|e| {
					error!(
						LOGGER,
						"Handling send -> Problematic slate, looks like this: {:?}", slate
					);
					e.context(api::ErrorKind::Internal(
						"Error processing partial transaction".to_owned(),
					))
				})
				.unwrap();
			let json = serde_json::to_string(&slate).unwrap();
			Ok(Response::with((status::Ok, json)))
		} else {
			Ok(Response::with((status::BadRequest, "")))
		}
	}
}

//TODO: Split up the output creation and the wallet insertion
/// Build a coinbase output and the corresponding kernel
pub fn receive_coinbase(
	config: &WalletConfig,
	keychain: &Keychain,
	block_fees: &BlockFees,
) -> Result<(Output, TxKernel, BlockFees), Error> {
	let root_key_id = keychain.root_key_id();

	let height = block_fees.height;
	let lock_height = height + global::coinbase_maturity();

	// Now acquire the wallet lock and write the new output.
	let (key_id, derivation) = WalletData::with_wallet(&config.data_file_dir, |wallet_data| {
		let key_id = block_fees.key_id();
		let (key_id, derivation) = match key_id {
			Some(key_id) => keys::retrieve_existing_key(&wallet_data, key_id),
			None => keys::next_available_key(&wallet_data, keychain),
		};

		// track the new output and return the stuff needed for reward
		wallet_data.add_output(OutputData {
			root_key_id: root_key_id.clone(),
			key_id: key_id.clone(),
			n_child: derivation,
			value: reward(block_fees.fees),
			status: OutputStatus::Unconfirmed,
			height: height,
			lock_height: lock_height,
			is_coinbase: true,
			block: None,
			merkle_proof: None,
		});

		(key_id, derivation)
	})?;

	debug!(
		LOGGER,
		"receive_coinbase: built candidate output - {:?}, {}",
		key_id.clone(),
		derivation,
	);

	let mut block_fees = block_fees.clone();
	block_fees.key_id = Some(key_id.clone());

	debug!(LOGGER, "receive_coinbase: {:?}", block_fees);

	let (out, kern) =
		reward::output(&keychain, &key_id, block_fees.fees, block_fees.height).unwrap();
	/* .context(ErrorKind::Keychain)?; */
	Ok((out, kern, block_fees))
}