// 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 NodeClient trait
//! specific to the FileWallet

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

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

use crate::api;
use crate::error::{Error, ErrorKind};
use crate::libwallet;
use crate::util;
use crate::util::secp::pedersen;

#[derive(Clone)]
pub struct HTTPNodeClient {
	node_url: String,
	node_api_secret: Option<String>,
}

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

impl NodeClient for HTTPNodeClient {
	fn node_url(&self) -> &str {
		&self.node_url
	}
	fn node_api_secret(&self) -> Option<String> {
		self.node_api_secret.clone()
	}

	fn set_node_url(&mut self, node_url: &str) {
		self.node_url = node_url.to_owned();
	}

	fn set_node_api_secret(&mut self, node_api_secret: Option<String>) {
		self.node_api_secret = node_api_secret;
	}

	/// 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(), self.node_api_secret(), 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(), self.node_api_secret()).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, 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, 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(),
				self.node_api_secret(),
			));
		}

		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!("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, out.mmr_index),
				);
			}
		}
		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, 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, u64)> =
			Vec::new();

		match api::client::get::<api::OutputListing>(url.as_str(), self.node_api_secret()) {
			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(),
						out.mmr_index,
					));
				}

				Ok((o.highest_index, o.last_retrieved_index, api_outputs))
			}
			Err(e) => {
				// if we got anything other than 200 back from server, bye
				error!(
					"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!(
				"Failed to get coinbase from {}. Run grin wallet listen?",
				url
			);
			error!("Underlying Error: {}", e.cause().unwrap());
			error!("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, None, block_fees).context(ErrorKind::GenericError(
		"Posting create coinbase".to_string(),
	))?;
	Ok(res)
}