// Copyright 2019-2021 Parity Technologies (UK) Ltd.
// This file is part of Parity Bridges Common.

// Parity Bridges Common is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// Parity Bridges Common is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with Parity Bridges Common.  If not, see <http://www.gnu.org/licenses/>.

//! Deal with CLI args of substrate-to-substrate relay.

use async_std::prelude::*;
use codec::{Decode, Encode};
use futures::{select, FutureExt};
use rbtag::BuildInfo;
use signal_hook::consts::*;
use signal_hook_async_std::Signals;
use structopt::{clap::arg_enum, StructOpt};
use strum::{EnumString, VariantNames};

use bp_messages::LaneId;
use relay_substrate_client::SimpleRuntimeVersion;

pub(crate) mod bridge;

mod chain_schema;
mod detect_equivocations;
mod init_bridge;
mod relay_headers;
mod relay_headers_and_messages;
mod relay_messages;
mod relay_parachains;

/// The target that will be used when publishing logs related to this pallet.
pub const LOG_TARGET: &str = "bridge";

/// Parse relay CLI args.
pub fn parse_args() -> Command {
	Command::from_args()
}

/// Substrate-to-Substrate bridge utilities.
#[derive(StructOpt)]
#[structopt(about = "Substrate-to-Substrate relay")]
pub enum Command {
	/// Start headers relay between two chains.
	///
	/// The on-chain bridge component should have been already initialized with
	/// `init-bridge` sub-command.
	RelayHeaders(relay_headers::RelayHeaders),
	/// Start messages relay between two chains.
	///
	/// Ties up to `Messages` pallets on both chains and starts relaying messages.
	/// Requires the header relay to be already running.
	RelayMessages(relay_messages::RelayMessages),
	/// Start headers and messages relay between two Substrate chains.
	///
	/// This high-level relay internally starts four low-level relays: two `RelayHeaders`
	/// and two `RelayMessages` relays. Headers are only relayed when they are required by
	/// the message relays - i.e. when there are messages or confirmations that needs to be
	/// relayed between chains.
	RelayHeadersAndMessages(Box<relay_headers_and_messages::RelayHeadersAndMessages>),
	/// Initialize on-chain bridge pallet with current header data.
	///
	/// Sends initialization transaction to bootstrap the bridge with current finalized block data.
	InitBridge(init_bridge::InitBridge),
	/// Relay parachain heads.
	RelayParachains(relay_parachains::RelayParachains),
	/// Detect and report equivocations.
	///
	/// Parses the source chain headers that were synchronized with the target chain looking for
	/// equivocations. If any equivocation is found, it is reported to the source chain.
	DetectEquivocations(detect_equivocations::DetectEquivocations),
}

impl Command {
	// Initialize logger depending on the command.
	fn init_logger(&self) {
		use relay_utils::initialize::{initialize_logger, initialize_relay};

		match self {
			Self::RelayHeaders(_) |
			Self::RelayMessages(_) |
			Self::RelayHeadersAndMessages(_) |
			Self::InitBridge(_) => {
				initialize_relay();
			},
			_ => {
				initialize_logger(false);
			},
		}
	}

	/// Run the command.
	async fn do_run(self) -> anyhow::Result<()> {
		match self {
			Self::RelayHeaders(arg) => arg.run().await?,
			Self::RelayMessages(arg) => arg.run().await?,
			Self::RelayHeadersAndMessages(arg) => arg.run().await?,
			Self::InitBridge(arg) => arg.run().await?,
			Self::RelayParachains(arg) => arg.run().await?,
			Self::DetectEquivocations(arg) => arg.run().await?,
		}
		Ok(())
	}

	/// Run the command.
	pub async fn run(self) {
		self.init_logger();

		let exit_signals = match Signals::new([SIGINT, SIGTERM]) {
			Ok(signals) => signals,
			Err(e) => {
				log::error!(target: LOG_TARGET, "Could not register exit signals: {}", e);
				return
			},
		};
		let run = self.do_run().fuse();
		futures::pin_mut!(exit_signals, run);

		select! {
			signal = exit_signals.next().fuse() => {
				log::info!(target: LOG_TARGET, "Received exit signal {:?}", signal);
			},
			result = run => {
				if let Err(e) = result {
					log::error!(target: LOG_TARGET, "substrate-relay: {}", e);
				}
			},
		}
	}
}

arg_enum! {
	#[derive(Debug)]
	/// The origin to use when dispatching the message on the target chain.
	///
	/// - `Target` uses account existing on the target chain (requires target private key).
	/// - `Origin` uses account derived from the source-chain account.
	pub enum Origins {
		Target,
		Source,
	}
}

/// Bridge-supported network definition.
///
/// Used to abstract away CLI commands.
pub trait CliChain: relay_substrate_client::Chain {
	/// Current version of the chain runtime, known to relay.
	///
	/// can be `None` if relay is not going to submit transactions to that chain.
	const RUNTIME_VERSION: Option<SimpleRuntimeVersion>;
}

/// Lane id.
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct HexLaneId(pub [u8; 4]);

impl From<HexLaneId> for LaneId {
	fn from(lane_id: HexLaneId) -> LaneId {
		LaneId(lane_id.0)
	}
}

impl std::str::FromStr for HexLaneId {
	type Err = hex::FromHexError;

	fn from_str(s: &str) -> Result<Self, Self::Err> {
		let mut lane_id = [0u8; 4];
		hex::decode_to_slice(s, &mut lane_id)?;
		Ok(HexLaneId(lane_id))
	}
}

/// Nicer formatting for raw bytes vectors.
#[derive(Default, Encode, Decode, PartialEq, Eq)]
pub struct HexBytes(pub Vec<u8>);

impl std::str::FromStr for HexBytes {
	type Err = hex::FromHexError;

	fn from_str(s: &str) -> Result<Self, Self::Err> {
		Ok(Self(hex::decode(s)?))
	}
}

impl std::fmt::Debug for HexBytes {
	fn fmt(&self, fmt: &mut std::fmt::Formatter) -> std::fmt::Result {
		write!(fmt, "0x{self}")
	}
}

impl std::fmt::Display for HexBytes {
	fn fmt(&self, fmt: &mut std::fmt::Formatter) -> std::fmt::Result {
		write!(fmt, "{}", hex::encode(&self.0))
	}
}

/// Prometheus metrics params.
#[derive(Clone, Debug, PartialEq, StructOpt)]
pub struct PrometheusParams {
	/// Do not expose a Prometheus metric endpoint.
	#[structopt(long)]
	pub no_prometheus: bool,
	/// Expose Prometheus endpoint at given interface.
	#[structopt(long, default_value = "127.0.0.1")]
	pub prometheus_host: String,
	/// Expose Prometheus endpoint at given port.
	#[structopt(long, default_value = "9616")]
	pub prometheus_port: u16,
}

/// Struct to get git commit info and build time.
#[derive(BuildInfo)]
struct SubstrateRelayBuildInfo;

impl SubstrateRelayBuildInfo {
	/// Get git commit in form `<short-sha-(clean|dirty)>`.
	pub fn get_git_commit() -> String {
		// on gitlab we use images without git installed, so we can't use `rbtag` there
		// locally we don't have `CI_*` env variables, so we can't rely on them
		// => we are using `CI_*` env variables or else `rbtag`
		let maybe_sha_from_ci = option_env!("CI_COMMIT_SHORT_SHA");
		maybe_sha_from_ci
			.map(|short_sha| {
				// we assume that on CI the copy is always clean
				format!("{short_sha}-clean")
			})
			.unwrap_or_else(|| SubstrateRelayBuildInfo.get_build_commit().into())
	}
}

impl PrometheusParams {
	/// Tries to convert CLI metrics params into metrics params, used by the relay.
	pub fn into_metrics_params(self) -> anyhow::Result<relay_utils::metrics::MetricsParams> {
		let metrics_address = if !self.no_prometheus {
			Some(relay_utils::metrics::MetricsAddress {
				host: self.prometheus_host,
				port: self.prometheus_port,
			})
		} else {
			None
		};

		let relay_version = option_env!("CARGO_PKG_VERSION").unwrap_or("unknown");
		let relay_commit = SubstrateRelayBuildInfo::get_git_commit();
		relay_utils::metrics::MetricsParams::new(
			metrics_address,
			relay_version.into(),
			relay_commit,
		)
		.map_err(|e| anyhow::format_err!("{:?}", e))
	}
}

/// Either explicit or maximal allowed value.
#[derive(Debug, Clone, PartialEq, Eq)]
pub enum ExplicitOrMaximal<V> {
	/// User has explicitly specified argument value.
	Explicit(V),
	/// Maximal allowed value for this argument.
	Maximal,
}

impl<V: std::str::FromStr> std::str::FromStr for ExplicitOrMaximal<V>
where
	V::Err: std::fmt::Debug,
{
	type Err = String;

	fn from_str(s: &str) -> Result<Self, Self::Err> {
		if s.to_lowercase() == "max" {
			return Ok(ExplicitOrMaximal::Maximal)
		}

		V::from_str(s)
			.map(ExplicitOrMaximal::Explicit)
			.map_err(|e| format!("Failed to parse '{e:?}'. Expected 'max' or explicit value"))
	}
}

#[doc = "Runtime version params."]
#[derive(StructOpt, Debug, PartialEq, Eq, Clone, Copy, EnumString, VariantNames)]
pub enum RuntimeVersionType {
	/// Auto query version from chain
	Auto,
	/// Custom `spec_version` and `transaction_version`
	Custom,
	/// Read version from bundle dependencies directly.
	Bundle,
}

#[cfg(test)]
mod tests {
	use super::*;

	#[test]
	fn hex_bytes_display_matches_from_str_for_clap() {
		// given
		let hex = HexBytes(vec![1, 2, 3, 4]);
		let display = format!("{hex}");

		// when
		let hex2: HexBytes = display.parse().unwrap();

		// then
		assert_eq!(hex.0, hex2.0);
	}
}