// This file is part of Substrate.

// Copyright (C) 2017-2020 Parity Technologies (UK) Ltd.
// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0

// This program 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.

// This program 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 this program. If not, see <https://www.gnu.org/licenses/>.

//! Authoring RPC module errors.

use crate::errors;
use jsonrpc_core as rpc;

/// Author RPC Result type.
pub type Result<T> = std::result::Result<T, Error>;

/// Author RPC future Result type.
pub type FutureResult<T> = Box<dyn rpc::futures::Future<Item = T, Error = Error> + Send>;

/// Author RPC errors.
#[derive(Debug, derive_more::Display, derive_more::From)]
pub enum Error {
	/// Client error.
	#[display(fmt="Client error: {}", _0)]
	#[from(ignore)]
	Client(Box<dyn std::error::Error + Send>),
	/// Transaction pool error,
	#[display(fmt="Transaction pool error: {}", _0)]
	Pool(sp_transaction_pool::error::Error),
	/// Verification error
	#[display(fmt="Extrinsic verification error: {}", _0)]
	#[from(ignore)]
	Verification(Box<dyn std::error::Error + Send>),
	/// Incorrect extrinsic format.
	#[display(fmt="Invalid extrinsic format: {}", _0)]
	BadFormat(codec::Error),
	/// Incorrect seed phrase.
	#[display(fmt="Invalid seed phrase/SURI")]
	BadSeedPhrase,
	/// Key type ID has an unknown format.
	#[display(fmt="Invalid key type ID format (should be of length four)")]
	BadKeyType,
	/// Key type ID has some unsupported crypto.
	#[display(fmt="The crypto of key type ID is unknown")]
	UnsupportedKeyType,
	/// Some random issue with the key store. Shouldn't happen.
	#[display(fmt="The key store is unavailable")]
	KeyStoreUnavailable,
	/// Invalid session keys encoding.
	#[display(fmt="Session keys are not encoded correctly")]
	InvalidSessionKeys,
	/// Call to an unsafe RPC was denied.
	UnsafeRpcCalled(crate::policy::UnsafeRpcError),
}

impl std::error::Error for Error {
	fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
		match self {
			Error::Client(ref err) => Some(&**err),
			Error::Pool(ref err) => Some(err),
			Error::Verification(ref err) => Some(&**err),
			Error::UnsafeRpcCalled(ref err) => Some(err),
			_ => None,
		}
	}
}

/// Base code for all authorship errors.
const BASE_ERROR: i64 = 1000;
/// Extrinsic has an invalid format.
const BAD_FORMAT: i64 = BASE_ERROR + 1;
/// Error during transaction verification in runtime.
const VERIFICATION_ERROR: i64 = BASE_ERROR + 2;

/// Pool rejected the transaction as invalid
const POOL_INVALID_TX: i64 = BASE_ERROR + 10;
/// Cannot determine transaction validity.
const POOL_UNKNOWN_VALIDITY: i64 = POOL_INVALID_TX + 1;
/// The transaction is temporarily banned.
const POOL_TEMPORARILY_BANNED: i64 = POOL_INVALID_TX + 2;
/// The transaction is already in the pool
const POOL_ALREADY_IMPORTED: i64 = POOL_INVALID_TX + 3;
/// Transaction has too low priority to replace existing one in the pool.
const POOL_TOO_LOW_PRIORITY: i64 = POOL_INVALID_TX + 4;
/// Including this transaction would cause a dependency cycle.
const POOL_CYCLE_DETECTED: i64 = POOL_INVALID_TX + 5;
/// The transaction was not included to the pool because of the limits.
const POOL_IMMEDIATELY_DROPPED: i64 = POOL_INVALID_TX + 6;
/// The key type crypto is not known.
const UNSUPPORTED_KEY_TYPE: i64 = POOL_INVALID_TX + 7;

impl From<Error> for rpc::Error {
	fn from(e: Error) -> Self {
		use sp_transaction_pool::error::{Error as PoolError};

		match e {
			Error::BadFormat(e) => rpc::Error {
				code: rpc::ErrorCode::ServerError(BAD_FORMAT),
				message: format!("Extrinsic has invalid format: {}", e).into(),
				data: None,
			},
			Error::Verification(e) => rpc::Error {
				code: rpc::ErrorCode::ServerError(VERIFICATION_ERROR),
				message: format!("Verification Error: {}", e).into(),
				data: Some(format!("{:?}", e).into()),
			},
			Error::Pool(PoolError::InvalidTransaction(e)) => rpc::Error {
				code: rpc::ErrorCode::ServerError(POOL_INVALID_TX),
				message: "Invalid Transaction".into(),
				data: serde_json::to_value(e).ok(),
			},
			Error::Pool(PoolError::UnknownTransaction(e)) => rpc::Error {
				code: rpc::ErrorCode::ServerError(POOL_UNKNOWN_VALIDITY),
				message: "Unknown Transaction Validity".into(),
				data: serde_json::to_value(e).ok(),
			},
			Error::Pool(PoolError::TemporarilyBanned) => rpc::Error {
				code: rpc::ErrorCode::ServerError(POOL_TEMPORARILY_BANNED),
				message: "Transaction is temporarily banned".into(),
				data: None,
			},
			Error::Pool(PoolError::AlreadyImported(hash)) => rpc::Error {
				code: rpc::ErrorCode::ServerError(POOL_ALREADY_IMPORTED),
				message: "Transaction Already Imported".into(),
				data: Some(format!("{:?}", hash).into()),
			},
			Error::Pool(PoolError::TooLowPriority { old, new }) => rpc::Error {
				code: rpc::ErrorCode::ServerError(POOL_TOO_LOW_PRIORITY),
				message: format!("Priority is too low: ({} vs {})", old, new),
				data: Some("The transaction has too low priority to replace another transaction already in the pool.".into()),
			},
			Error::Pool(PoolError::CycleDetected) => rpc::Error {
				code: rpc::ErrorCode::ServerError(POOL_CYCLE_DETECTED),
				message: "Cycle Detected".into(),
				data: None,
			},
			Error::Pool(PoolError::ImmediatelyDropped) => rpc::Error {
				code: rpc::ErrorCode::ServerError(POOL_IMMEDIATELY_DROPPED),
				message: "Immediately Dropped".into(),
				data: Some("The transaction couldn't enter the pool because of the limit".into()),
			},
			Error::UnsupportedKeyType => rpc::Error {
				code: rpc::ErrorCode::ServerError(UNSUPPORTED_KEY_TYPE),
				message: "Unknown key type crypto" .into(),
				data: Some(
					"The crypto for the given key type is unknown, please add the public key to the \
					request to insert the key successfully.".into()
				),
			},
			Error::UnsafeRpcCalled(e) => e.into(),
			e => errors::internal(e),
		}
	}
}