// 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.

//! Client functions, implementations of the WalletClient trait
//! specific to the FileWallet

use failure::ResultExt;
use futures::{stream, Stream};

use libwallet::types::*;
use std::collections::HashMap;
use tokio::runtime::Runtime;

use api;
use error::{Error, ErrorKind};
use libtx::slate::Slate;
use libwallet;
use util::secp::pedersen;
use util::{self, LOGGER};

#[derive(Clone)]
pub struct HTTPWalletClient {
	node_url: String,
}

impl HTTPWalletClient {
	/// Create a new client that will communicate with the given grin node
	pub fn new(node_url: &str) -> HTTPWalletClient {
		HTTPWalletClient {
			node_url: node_url.to_owned(),
		}
	}
}

impl WalletClient for HTTPWalletClient {
	fn node_url(&self) -> &str {
		&self.node_url
	}

	/// Call the wallet API to create a coinbase output for the given
	/// block_fees. Will retry based on default "retry forever with backoff"
	/// behavior.
	fn create_coinbase(
		&self,
		dest: &str,
		block_fees: &BlockFees,
	) -> Result<CbData, libwallet::Error> {
		let url = format!("{}/v1/wallet/foreign/build_coinbase", dest);
		match single_create_coinbase(&url, &block_fees) {
			Err(e) => {
				error!(
					LOGGER,
					"Failed to get coinbase from {}. Run grin wallet listen?", url
				);
				error!(LOGGER, "Underlying Error: {}", e.cause().unwrap());
				error!(LOGGER, "Backtrace: {}", e.backtrace().unwrap());
				Err(libwallet::ErrorKind::ClientCallback(
					"Failed to get coinbase",
				))?
			}
			Ok(res) => Ok(res),
		}
	}

	/// Send the slate to a listening wallet instance
	fn send_tx_slate(&self, dest: &str, slate: &Slate) -> Result<Slate, libwallet::Error> {
		if &dest[..4] != "http" {
			let err_str = format!(
				"dest formatted as {} but send -d expected stdout or http://IP:port",
				dest
			);
			error!(LOGGER, "{}", err_str,);
			Err(libwallet::ErrorKind::Uri)?
		}
		let url = format!("{}/v1/wallet/foreign/receive_tx", dest);
		debug!(LOGGER, "Posting transaction slate to {}", url);

		let res = api::client::post(url.as_str(), slate).context(
			libwallet::ErrorKind::ClientCallback("Posting transaction slate"),
		)?;
		Ok(res)
	}

	/// Posts a transaction to a grin node
	fn post_tx(&self, tx: &TxWrapper, fluff: bool) -> Result<(), libwallet::Error> {
		let url;
		let dest = self.node_url();
		if fluff {
			url = format!("{}/v1/pool/push?fluff", dest);
		} else {
			url = format!("{}/v1/pool/push", dest);
		}
		api::client::post_no_ret(url.as_str(), tx).context(libwallet::ErrorKind::ClientCallback(
			"Posting transaction to node",
		))?;
		Ok(())
	}

	/// Return the chain tip from a given node
	fn get_chain_height(&self) -> Result<u64, libwallet::Error> {
		let addr = self.node_url();
		let url = format!("{}/v1/chain", addr);
		let res = api::client::get::<api::Tip>(url.as_str()).context(
			libwallet::ErrorKind::ClientCallback("Getting chain height from node"),
		)?;
		Ok(res.height)
	}

	/// Retrieve outputs from node
	fn get_outputs_from_node(
		&self,
		wallet_outputs: Vec<pedersen::Commitment>,
	) -> Result<HashMap<pedersen::Commitment, (String, u64)>, libwallet::Error> {
		let addr = self.node_url();
		// build the necessary query params -
		// ?id=xxx&id=yyy&id=zzz
		let query_params: Vec<String> = wallet_outputs
			.iter()
			.map(|commit| format!("id={}", util::to_hex(commit.as_ref().to_vec())))
			.collect();

		// build a map of api outputs by commit so we can look them up efficiently
		let mut api_outputs: HashMap<pedersen::Commitment, (String, u64)> = HashMap::new();
		let mut tasks = Vec::new();

		for query_chunk in query_params.chunks(500) {
			let url = format!("{}/v1/chain/outputs/byids?{}", addr, query_chunk.join("&"),);
			tasks.push(api::client::get_async::<Vec<api::Output>>(url.as_str()));
		}

		let task = stream::futures_unordered(tasks).collect();

		let mut rt = Runtime::new().unwrap();
		let results = match rt.block_on(task) {
			Ok(outputs) => outputs,
			Err(e) => {
				error!(LOGGER, "Outputs by id failed: {}", e);
				return Err(libwallet::ErrorKind::ClientCallback("Error from server"))?;
			}
		};

		for res in results {
			for out in res {
				api_outputs.insert(
					out.commit.commit(),
					(util::to_hex(out.commit.to_vec()), out.height),
				);
			}
		}
		Ok(api_outputs)
	}

	fn get_outputs_by_pmmr_index(
		&self,
		start_height: u64,
		max_outputs: u64,
	) -> Result<
		(
			u64,
			u64,
			Vec<(pedersen::Commitment, pedersen::RangeProof, bool, u64)>,
		),
		libwallet::Error,
	> {
		let addr = self.node_url();
		let query_param = format!("start_index={}&max={}", start_height, max_outputs);

		let url = format!("{}/v1/txhashset/outputs?{}", addr, query_param,);

		let mut api_outputs: Vec<(pedersen::Commitment, pedersen::RangeProof, bool, u64)> =
			Vec::new();

		match api::client::get::<api::OutputListing>(url.as_str()) {
			Ok(o) => {
				for out in o.outputs {
					let is_coinbase = match out.output_type {
						api::OutputType::Coinbase => true,
						api::OutputType::Transaction => false,
					};
					api_outputs.push((
						out.commit,
						out.range_proof().unwrap(),
						is_coinbase,
						out.block_height.unwrap(),
					));
				}

				Ok((o.highest_index, o.last_retrieved_index, api_outputs))
			}
			Err(e) => {
				// if we got anything other than 200 back from server, bye
				error!(
					LOGGER,
					"get_outputs_by_pmmr_index: unable to contact API {}. Error: {}", addr, e
				);
				Err(libwallet::ErrorKind::ClientCallback(
					"unable to contact api",
				))?
			}
		}
	}
}
/// Call the wallet API to create a coinbase output for the given block_fees.
/// Will retry based on default "retry forever with backoff" behavior.
pub fn create_coinbase(dest: &str, block_fees: &BlockFees) -> Result<CbData, Error> {
	let url = format!("{}/v1/wallet/foreign/build_coinbase", dest);
	match single_create_coinbase(&url, &block_fees) {
		Err(e) => {
			error!(
				LOGGER,
				"Failed to get coinbase from {}. Run grin wallet listen?", url
			);
			error!(LOGGER, "Underlying Error: {}", e.cause().unwrap());
			error!(LOGGER, "Backtrace: {}", e.backtrace().unwrap());
			Err(e)?
		}
		Ok(res) => Ok(res),
	}
}

/// Makes a single request to the wallet API to create a new coinbase output.
fn single_create_coinbase(url: &str, block_fees: &BlockFees) -> Result<CbData, Error> {
	let res = api::client::post(url, block_fees).context(ErrorKind::GenericError(
		"Posting create coinbase".to_string(),
	))?;
	Ok(res)
}