// Copyright 2015-2020 Parity Technologies (UK) Ltd.
// This file is part of Tetsy Vapory.

// Tetsy Vapory 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.

// Tetsy Vapory 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 Tetsy Vapory.  If not, see <http://www.gnu.org/licenses/>.

use std::{fmt, error};

use vapory_types::U256;
use tetsy_crypto::publickey::{Error as VapPublicKeyCryptoError};
use tetsy_rlp;
use tetsy_unexpected::OutOfBounds;

use crate::errors::ExecutionError;

#[derive(Debug, PartialEq, Clone)]
/// Errors concerning transaction processing.
pub enum Error {
	/// Transaction is already imported to the queue
	AlreadyImported,
	/// Transaction is not valid anymore (state already has higher nonce)
	Old,
	/// Transaction was not imported to the queue because limit has been reached.
	LimitReached,
	/// Transaction's gas price is below threshold.
	InsufficientGasPrice {
		/// Minimal expected gas price
		minimal: U256,
		/// Transaction gas price
		got: U256,
	},
	/// Transaction has too low fee
	/// (there is already a transaction with the same sender-nonce but higher gas price)
	TooCheapToReplace {
		/// previous transaction's gas price
		prev: Option<U256>,
		/// new transaction's gas price
		new: Option<U256>,
	},
	/// Transaction's gas is below currently set minimal gas requirement.
	InsufficientGas {
		/// Minimal expected gas
		minimal: U256,
		/// Transaction gas
		got: U256,
	},
	/// Sender doesn't have enough funds to pay for this transaction
	InsufficientBalance {
		/// Senders balance
		balance: U256,
		/// Transaction cost
		cost: U256,
	},
	/// Transactions gas is higher then current gas limit
	GasLimitExceeded {
		/// Current gas limit
		limit: U256,
		/// Declared transaction gas
		got: U256,
	},
	/// Transaction's gas limit (aka gas) is invalid.
	InvalidGasLimit(OutOfBounds<U256>),
	/// Transaction sender is banned.
	SenderBanned,
	/// Transaction receipient is banned.
	RecipientBanned,
	/// Contract creation code is banned.
	CodeBanned,
	/// Invalid chain ID given.
	InvalidChainId,
	/// Not enough permissions given by permission contract.
	NotAllowed,
	/// Signature error
	InvalidSignature(String),
	/// Transaction too big
	TooBig,
	/// Invalid RLP encoding
	InvalidRlp(String),
}

impl From<VapPublicKeyCryptoError> for Error {
	fn from(err: VapPublicKeyCryptoError) -> Self {
		Error::InvalidSignature(format!("{}", err))
	}
}

impl From<tetsy_rlp::DecoderError> for Error {
	fn from(err: tetsy_rlp::DecoderError) -> Self {
		Error::InvalidRlp(format!("{}", err))
	}
}

impl fmt::Display for Error {
	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
		use self::Error::*;
		let msg = match *self {
			AlreadyImported => "Already imported".into(),
			Old => "No longer valid".into(),
			TooCheapToReplace { prev, new } =>
				format!("Gas price too low to replace, previous tx gas: {:?}, new tx gas: {:?}",
						prev, new
				),
			LimitReached => "Transaction limit reached".into(),
			InsufficientGasPrice { minimal, got } =>
				format!("Insufficient gas price. Min={}, Given={}", minimal, got),
			InsufficientGas { minimal, got } =>
				format!("Insufficient gas. Min={}, Given={}", minimal, got),
			InsufficientBalance { balance, cost } =>
				format!("Insufficient balance for transaction. Balance={}, Cost={}",
					balance, cost),
			GasLimitExceeded { limit, got } =>
				format!("Gas limit exceeded. Limit={}, Given={}", limit, got),
			InvalidGasLimit(ref err) => format!("Invalid gas limit. {}", err),
			SenderBanned => "Sender is temporarily banned.".into(),
			RecipientBanned => "Recipient is temporarily banned.".into(),
			CodeBanned => "Contract code is temporarily banned.".into(),
			InvalidChainId => "Transaction of this chain ID is not allowed on this chain.".into(),
			InvalidSignature(ref err) => format!("Transaction has invalid signature: {}.", err),
			NotAllowed => "Sender does not have permissions to execute this type of transaction".into(),
			TooBig => "Transaction too big".into(),
			InvalidRlp(ref err) => format!("Transaction has invalid RLP structure: {}.", err),
		};

		f.write_fmt(format_args!("Transaction error ({})", msg))
	}
}

impl error::Error for Error {
	fn description(&self) -> &str {
		"Transaction error"
	}
}

/// Result of executing the transaction.
#[derive(PartialEq, Debug, Clone)]
pub enum CallError {
	/// Couldn't find the transaction in the chain.
	TransactionNotFound,
	/// Couldn't find requested block's state in the chain.
	StatePruned,
	/// Couldn't find an amount of gas that didn't result in an exception.
	Exceptional(tetsy_vm::Error),
	/// Corrupt state.
	StateCorrupt,
	/// Error executing.
	Execution(ExecutionError),
}

impl From<ExecutionError> for CallError {
	fn from(error: ExecutionError) -> Self {
		CallError::Execution(error)
	}
}

impl fmt::Display for CallError {
	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
		use self::CallError::*;
		let msg = match *self {
			TransactionNotFound => "Transaction couldn't be found in the chain".into(),
			StatePruned => "Couldn't find the transaction block's state in the chain".into(),
			Exceptional(ref e) => format!("An exception ({}) happened in the execution", e),
			StateCorrupt => "Stored state found to be corrupted.".into(),
			Execution(ref e) => format!("{}", e),
		};

		f.write_fmt(format_args!("Transaction execution error ({}).", msg))
	}
}