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

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

//! Blockhain info type definition

use std::fmt;

use ethereum_types::{U256, H256};
use security_level::SecurityLevel;
use BlockNumber;

/// Information about the blockchain gathered together.
#[derive(Clone, Debug)]
pub struct BlockChainInfo {
	/// Blockchain difficulty.
	pub total_difficulty: U256,
	/// Block queue difficulty.
	pub pending_total_difficulty: U256,
	/// Genesis block hash.
	pub genesis_hash: H256,
	/// Best blockchain block hash.
	pub best_block_hash: H256,
	/// Best blockchain block number.
	pub best_block_number: BlockNumber,
	/// Best blockchain block timestamp.
	pub best_block_timestamp: u64,
	/// Best ancient block hash.
	pub ancient_block_hash: Option<H256>,
	/// Best ancient block number.
	pub ancient_block_number: Option<BlockNumber>,
	/// First block on the best sequence.
	pub first_block_hash: Option<H256>,
	/// Number of the first block on the best sequence.
	pub first_block_number: Option<BlockNumber>,
}

impl BlockChainInfo {
	/// Determine the security model for the current state.
	pub fn security_level(&self) -> SecurityLevel {
		// TODO: Detect SecurityLevel::FullState : https://github.com/paritytech/parity-ethereum/issues/3834
		if self.ancient_block_number.is_none() || self.first_block_number.is_none() {
			SecurityLevel::FullProofOfWork
		} else {
			SecurityLevel::PartialProofOfWork(self.best_block_number - self.first_block_number.expect("Guard condition means this is not none"))
		}
	}
}

impl fmt::Display for BlockChainInfo {
	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
		write!(f, "#{}.{}", self.best_block_number, self.best_block_hash)
	}
}
