// Copyright 2015-2018 Parity Technologies (UK) Ltd.
// This file is part of Parity.

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

//! General error types for use in ethcore.

use std::{fmt, error};
use std::time::SystemTime;

use ethereum_types::{H256, U256, Address, Bloom};
use ethkey::Error as EthkeyError;
use ethtrie::TrieError;
use rlp;
use snappy::InvalidInput;
use snapshot::Error as SnapshotError;
use types::transaction::Error as TransactionError;
use types::BlockNumber;
use unexpected::{Mismatch, OutOfBounds};

use account_provider::SignError as AccountsError;
use engines::EngineError;

pub use executed::{ExecutionError, CallError};

#[derive(Debug, PartialEq, Clone, Copy, Eq)]
/// Errors concerning block processing.
pub enum BlockError {
	/// Block has too many uncles.
	TooManyUncles(OutOfBounds<usize>),
	/// Extra data is of an invalid length.
	ExtraDataOutOfBounds(OutOfBounds<usize>),
	/// Seal is incorrect format.
	InvalidSealArity(Mismatch<usize>),
	/// Block has too much gas used.
	TooMuchGasUsed(OutOfBounds<U256>),
	/// Uncles hash in header is invalid.
	InvalidUnclesHash(Mismatch<H256>),
	/// An uncle is from a generation too old.
	UncleTooOld(OutOfBounds<BlockNumber>),
	/// An uncle is from the same generation as the block.
	UncleIsBrother(OutOfBounds<BlockNumber>),
	/// An uncle is already in the chain.
	UncleInChain(H256),
	/// An uncle is included twice.
	DuplicateUncle(H256),
	/// An uncle has a parent not in the chain.
	UncleParentNotInChain(H256),
	/// State root header field is invalid.
	InvalidStateRoot(Mismatch<H256>),
	/// Gas used header field is invalid.
	InvalidGasUsed(Mismatch<U256>),
	/// Transactions root header field is invalid.
	InvalidTransactionsRoot(Mismatch<H256>),
	/// Difficulty is out of range; this can be used as an looser error prior to getting a definitive
	/// value for difficulty. This error needs only provide bounds of which it is out.
	DifficultyOutOfBounds(OutOfBounds<U256>),
	/// Difficulty header field is invalid; this is a strong error used after getting a definitive
	/// value for difficulty (which is provided).
	InvalidDifficulty(Mismatch<U256>),
	/// Seal element of type H256 (max_hash for Ethash, but could be something else for
	/// other seal engines) is out of bounds.
	MismatchedH256SealElement(Mismatch<H256>),
	/// Proof-of-work aspect of seal, which we assume is a 256-bit value, is invalid.
	InvalidProofOfWork(OutOfBounds<U256>),
	/// Some low-level aspect of the seal is incorrect.
	InvalidSeal,
	/// Gas limit header field is invalid.
	InvalidGasLimit(OutOfBounds<U256>),
	/// Receipts trie root header field is invalid.
	InvalidReceiptsRoot(Mismatch<H256>),
	/// Timestamp header field is invalid.
	InvalidTimestamp(OutOfBounds<SystemTime>),
	/// Timestamp header field is too far in future.
	TemporarilyInvalid(OutOfBounds<SystemTime>),
	/// Log bloom header field is invalid.
	InvalidLogBloom(Mismatch<Bloom>),
	/// Number field of header is invalid.
	InvalidNumber(Mismatch<BlockNumber>),
	/// Block number isn't sensible.
	RidiculousNumber(OutOfBounds<BlockNumber>),
	/// Too many transactions from a particular address.
	TooManyTransactions(Address),
	/// Parent given is unknown.
	UnknownParent(H256),
	/// Uncle parent given is unknown.
	UnknownUncleParent(H256),
	/// No transition to epoch number.
	UnknownEpochTransition(u64),
}

impl fmt::Display for BlockError {
	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
		use self::BlockError::*;

		let msg = match *self {
			TooManyUncles(ref oob) => format!("Block has too many uncles. {}", oob),
			ExtraDataOutOfBounds(ref oob) => format!("Extra block data too long. {}", oob),
			InvalidSealArity(ref mis) => format!("Block seal in incorrect format: {}", mis),
			TooMuchGasUsed(ref oob) => format!("Block has too much gas used. {}", oob),
			InvalidUnclesHash(ref mis) => format!("Block has invalid uncles hash: {}", mis),
			UncleTooOld(ref oob) => format!("Uncle block is too old. {}", oob),
			UncleIsBrother(ref oob) => format!("Uncle from same generation as block. {}", oob),
			UncleInChain(ref hash) => format!("Uncle {} already in chain", hash),
			DuplicateUncle(ref hash) => format!("Uncle {} already in the header", hash),
			UncleParentNotInChain(ref hash) => format!("Uncle {} has a parent not in the chain", hash),
			InvalidStateRoot(ref mis) => format!("Invalid state root in header: {}", mis),
			InvalidGasUsed(ref mis) => format!("Invalid gas used in header: {}", mis),
			InvalidTransactionsRoot(ref mis) => format!("Invalid transactions root in header: {}", mis),
			DifficultyOutOfBounds(ref oob) => format!("Invalid block difficulty: {}", oob),
			InvalidDifficulty(ref mis) => format!("Invalid block difficulty: {}", mis),
			MismatchedH256SealElement(ref mis) => format!("Seal element out of bounds: {}", mis),
			InvalidProofOfWork(ref oob) => format!("Block has invalid PoW: {}", oob),
			InvalidSeal => "Block has invalid seal.".into(),
			InvalidGasLimit(ref oob) => format!("Invalid gas limit: {}", oob),
			InvalidReceiptsRoot(ref mis) => format!("Invalid receipts trie root in header: {}", mis),
			InvalidTimestamp(ref oob) => {
				let oob = oob.map(|st| st.elapsed().unwrap_or_default().as_secs());
				format!("Invalid timestamp in header: {}", oob)
			},
			TemporarilyInvalid(ref oob) => {
				let oob = oob.map(|st| st.elapsed().unwrap_or_default().as_secs());
				format!("Future timestamp in header: {}", oob)
			},
			InvalidLogBloom(ref oob) => format!("Invalid log bloom in header: {}", oob),
			InvalidNumber(ref mis) => format!("Invalid number in header: {}", mis),
			RidiculousNumber(ref oob) => format!("Implausible block number. {}", oob),
			UnknownParent(ref hash) => format!("Unknown parent: {}", hash),
			UnknownUncleParent(ref hash) => format!("Unknown uncle parent: {}", hash),
			UnknownEpochTransition(ref num) => format!("Unknown transition to epoch number: {}", num),
			TooManyTransactions(ref address) => format!("Too many transactions from: {}", address),
		};

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

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

error_chain! {
	types {
		QueueError, QueueErrorKind, QueueErrorResultExt, QueueErrorResult;
	}

	errors {
		#[doc = "Queue is full"]
		Full(limit: usize) {
			description("Queue is full")
			display("The queue is full ({})", limit)
		}
	}

	foreign_links {
		Channel(::io::IoError) #[doc = "Io channel error"];
	}
}

error_chain! {
	types {
		ImportError, ImportErrorKind, ImportErrorResultExt, ImportErrorResult;
	}

	errors {
		#[doc = "Already in the block chain."]
		AlreadyInChain {
			description("Block already in chain")
			display("Block already in chain")
		}

		#[doc = "Already in the block queue"]
		AlreadyQueued {
			description("block already in the block queue")
			display("block already in the block queue")
		}

		#[doc = "Already marked as bad from a previous import (could mean parent is bad)."]
		KnownBad {
			description("block known to be bad")
			display("block known to be bad")
		}
	}
}

/// Api-level error for transaction import
#[derive(Debug, Clone)]
pub enum TransactionImportError {
	/// Transaction error
	Transaction(TransactionError),
	/// Other error
	Other(String),
}

impl From<Error> for TransactionImportError {
	fn from(e: Error) -> Self {
		match e {
			Error(ErrorKind::Transaction(transaction_error), _) => TransactionImportError::Transaction(transaction_error),
			_ => TransactionImportError::Other(format!("other block import error: {:?}", e)),
		}
	}
}

error_chain! {
	types {
		Error, ErrorKind, ErrorResultExt, EthcoreResult;
	}

	links {
		Import(ImportError, ImportErrorKind) #[doc = "Error concerning block import." ];
		Queue(QueueError, QueueErrorKind) #[doc = "Io channel queue error"];
	}

	foreign_links {
		Io(::io::IoError) #[doc = "Io create error"];
		StdIo(::std::io::Error) #[doc = "Error concerning the Rust standard library's IO subsystem."];
		Trie(TrieError) #[doc = "Error concerning TrieDBs."];
		Execution(ExecutionError) #[doc = "Error concerning EVM code execution."];
		Block(BlockError) #[doc = "Error concerning block processing."];
		Transaction(TransactionError) #[doc = "Error concerning transaction processing."];
		Snappy(InvalidInput) #[doc = "Snappy error."];
		Engine(EngineError) #[doc = "Consensus vote error."];
		Ethkey(EthkeyError) #[doc = "Ethkey error."];
		Decoder(rlp::DecoderError) #[doc = "RLP decoding errors"];
	}

	errors {
		#[doc = "Snapshot error."]
		Snapshot(err: SnapshotError) {
			description("Snapshot error.")
			display("Snapshot error {}", err)
		}

		#[doc = "Account Provider error"]
		AccountProvider(err: AccountsError) {
			description("Accounts Provider error")
			display("Accounts Provider error {}", err)
		}

		#[doc = "PoW hash is invalid or out of date."]
		PowHashInvalid {
			description("PoW hash is invalid or out of date.")
			display("PoW hash is invalid or out of date.")
		}

		#[doc = "The value of the nonce or mishash is invalid."]
		PowInvalid {
			description("The value of the nonce or mishash is invalid.")
			display("The value of the nonce or mishash is invalid.")
		}

		#[doc = "Unknown engine given"]
		UnknownEngineName(name: String) {
			description("Unknown engine name")
			display("Unknown engine name ({})", name)
		}
	}
}

impl From<AccountsError> for Error {
	fn from(err: AccountsError) -> Error {
		ErrorKind::AccountProvider(err).into()
	}
}

impl From<SnapshotError> for Error {
	fn from(err: SnapshotError) -> Error {
		match err {
			SnapshotError::Io(err) => ErrorKind::StdIo(err).into(),
			SnapshotError::Trie(err) => ErrorKind::Trie(err).into(),
			SnapshotError::Decoder(err) => err.into(),
			other => ErrorKind::Snapshot(other).into(),
		}
	}
}

impl<E> From<Box<E>> for Error where Error: From<E> {
	fn from(err: Box<E>) -> Error {
		Error::from(*err)
	}
}