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

// Open 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.

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

//! Lazily-decoded owning views of RLP-encoded blockchain objects.
//! These views are meant to contain _trusted_ data -- without encoding
//! errors or inconsistencies.
//!
//! In general these views are useful when only a few fields of an object
//! are relevant. In these cases it's more efficient to decode the object piecemeal.
//! When the entirety of the object is needed, it's better to upgrade it to a fully
//! decoded object where parts like the hash can be saved.

use ethereum_types::{H256, Bloom, U256, Address};
use hash::keccak;
use parity_util_mem::MallocSizeOf;
use rlp::{self, Rlp, RlpStream};
use crate::{
	block::Block as FullBlock,
	header::Header as FullHeader,
	transaction::UnverifiedTransaction,
	views::{self, BlockView, HeaderView, BodyView},
	BlockNumber
};

/// Owning header view.
#[derive(Debug, Clone, PartialEq, Eq, MallocSizeOf)]
pub struct Header(Vec<u8>);

impl Header {
	/// Create a new owning header view.
	/// Expects the data to be an RLP-encoded header -- any other case will likely lead to
	/// panics further down the line.
	pub fn new(encoded: Vec<u8>) -> Self { Header(encoded) }

	/// Upgrade this encoded view to a fully owned `Header` object.
	pub fn decode(&self) -> Result<FullHeader, rlp::DecoderError> {
		rlp::decode(&self.0)
	}

	/// Get a borrowed header view onto the data.
	#[inline]
	pub fn view(&self) -> HeaderView { view!(HeaderView, &self.0) }

	/// Get the rlp of the header.
	#[inline]
	pub fn rlp(&self) -> Rlp { Rlp::new(&self.0) }

	/// Consume the view and return the raw bytes.
	pub fn into_inner(self) -> Vec<u8> { self.0 }
}

impl std::fmt::LowerHex for Header {
	fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
		for byte in &self.0 {
			write!(f, "{:02x}", byte)?;
		}
		Ok(())
	}
}

// forwarders to borrowed view.
impl Header {
	/// Returns the header hash.
	pub fn hash(&self) -> H256 { keccak(&self.0) }

	/// Returns the parent hash.
	pub fn parent_hash(&self) -> H256 { self.view().parent_hash() }

	/// Returns the uncles hash.
	pub fn uncles_hash(&self) -> H256 { self.view().uncles_hash() }

	/// Returns the author.
	pub fn author(&self) -> Address { self.view().author() }

	/// Returns the state root.
	pub fn state_root(&self) -> H256 { self.view().state_root() }

	/// Returns the transaction trie root.
	pub fn transactions_root(&self) -> H256 { self.view().transactions_root() }

	/// Returns the receipts trie root
	pub fn receipts_root(&self) -> H256 { self.view().receipts_root() }

	/// Returns the block log bloom
	pub fn log_bloom(&self) -> Bloom { self.view().log_bloom() }

	/// Difficulty of this block
	pub fn difficulty(&self) -> U256 { self.view().difficulty() }

	/// Number of this block.
	pub fn number(&self) -> BlockNumber { self.view().number() }

	/// Time this block was produced.
	pub fn timestamp(&self) -> u64 { self.view().timestamp() }

	/// Gas limit of this block.
	pub fn gas_limit(&self) -> U256 { self.view().gas_limit() }

	/// Total gas used in this block.
	pub fn gas_used(&self) -> U256 { self.view().gas_used() }

	/// Block extra data.
	pub fn extra_data(&self) -> Vec<u8> { self.view().extra_data() }

	/// Engine-specific seal fields.
	pub fn seal(&self) -> Vec<Vec<u8>> { self.view().seal() }
}

/// Owning block body view.
#[derive(Debug, Clone, PartialEq, Eq, MallocSizeOf)]
pub struct Body(Vec<u8>);

impl Body {
	/// Create a new owning block body view. The raw bytes passed in must be an rlp-encoded block
	/// body.
	pub fn new(raw: Vec<u8>) -> Self { Body(raw) }

	/// Get a borrowed view of the data within.
	#[inline]
	pub fn view(&self) -> BodyView { view!(BodyView, &self.0) }

	/// Fully decode this block body.
	pub fn decode(&self) -> (Vec<UnverifiedTransaction>, Vec<FullHeader>) {
		(self.view().transactions(), self.view().uncles())
	}

	/// Get the RLP of this block body.
	#[inline]
	pub fn rlp(&self) -> Rlp {
		Rlp::new(&self.0)
	}

	/// Consume the view and return the raw bytes.
	pub fn into_inner(self) -> Vec<u8> { self.0 }
}

// forwarders to borrowed view.
impl Body {
	/// Get raw rlp of transactions
	pub fn transactions_rlp(&self) -> Rlp { self.view().transactions_rlp().rlp }

	/// Get a vector of all transactions.
	pub fn transactions(&self) -> Vec<UnverifiedTransaction> { self.view().transactions() }

	/// Number of transactions in the block.
	pub fn transactions_count(&self) -> usize { self.view().transactions_count() }

	/// A view over each transaction in the block.
	pub fn transaction_views(&self) -> Vec<views::TransactionView> { self.view().transaction_views() }

	/// The hash of each transaction in the block.
	pub fn transaction_hashes(&self) -> Vec<H256> { self.view().transaction_hashes() }

	/// Get raw rlp of uncle headers
	pub fn uncles_rlp(&self) -> Rlp { self.view().uncles_rlp().rlp }

	/// Decode uncle headers.
	pub fn uncles(&self) -> Vec<FullHeader> { self.view().uncles() }

	/// Number of uncles.
	pub fn uncles_count(&self) -> usize { self.view().uncles_count() }

	/// Borrowed view over each uncle.
	pub fn uncle_views(&self) -> Vec<views::HeaderView> { self.view().uncle_views() }

	/// Hash of each uncle.
	pub fn uncle_hashes(&self) -> Vec<H256> { self.view().uncle_hashes() }
}

/// Owning block view.
#[derive(Debug, Clone, PartialEq, Eq, MallocSizeOf)]
pub struct Block(Vec<u8>);

impl Block {
	/// Create a new owning block view. The raw bytes passed in must be an rlp-encoded block.
	pub fn new(raw: Vec<u8>) -> Self { Block(raw) }

	/// Create a new owning block view by concatenating the encoded header and body
	pub fn new_from_header_and_body(header: &views::HeaderView, body: &views::BodyView) -> Self {
		let mut stream = RlpStream::new_list(3);
		stream.append_raw(header.rlp().as_raw(), 1);
		stream.append_raw(body.transactions_rlp().as_raw(), 1);
		stream.append_raw(body.uncles_rlp().as_raw(), 1);
		Block::new(stream.out())
	}

	/// Get a borrowed view of the whole block.
	#[inline]
	pub fn view(&self) -> BlockView { view!(BlockView, &self.0) }

	/// Get a borrowed view of the block header.
	#[inline]
	pub fn header_view(&self) -> HeaderView { self.view().header_view() }

	/// Decode to a full block.
	pub fn decode(&self) -> Result<FullBlock, rlp::DecoderError> { rlp::decode(&self.0) }

	/// Decode the header.
	pub fn decode_header(&self) -> FullHeader { self.view().rlp().val_at(0) }

	/// Clone the encoded header.
	pub fn header(&self) -> Header { Header(self.view().rlp().at(0).as_raw().to_vec()) }

	/// Get the rlp of this block.
	#[inline]
	pub fn rlp(&self) -> Rlp {
		Rlp::new(&self.0)
	}

	/// Consume the view and return the raw bytes.
	pub fn into_inner(self) -> Vec<u8> { self.0 }

	/// Returns the reference to slice of bytes
	pub fn raw(&self) -> &[u8] {
		&self.0
	}
}

// forwarders to borrowed header view.
impl Block {
	/// Returns the header hash.
	pub fn hash(&self) -> H256 { self.header_view().hash() }

	/// Returns the parent hash.
	pub fn parent_hash(&self) -> H256 { self.header_view().parent_hash() }

	/// Returns the uncles hash.
	pub fn uncles_hash(&self) -> H256 { self.header_view().uncles_hash() }

	/// Returns the author.
	pub fn author(&self) -> Address { self.header_view().author() }

	/// Returns the state root.
	pub fn state_root(&self) -> H256 { self.header_view().state_root() }

	/// Returns the transaction trie root.
	pub fn transactions_root(&self) -> H256 { self.header_view().transactions_root() }

	/// Returns the receipts trie root
	pub fn receipts_root(&self) -> H256 { self.header_view().receipts_root() }

	/// Returns the block log bloom
	pub fn log_bloom(&self) -> Bloom { self.header_view().log_bloom() }

	/// Difficulty of this block
	pub fn difficulty(&self) -> U256 { self.header_view().difficulty() }

	/// Number of this block.
	pub fn number(&self) -> BlockNumber { self.header_view().number() }

	/// Time this block was produced.
	pub fn timestamp(&self) -> u64 { self.header_view().timestamp() }

	/// Gas limit of this block.
	pub fn gas_limit(&self) -> U256 { self.header_view().gas_limit() }

	/// Total gas used in this block.
	pub fn gas_used(&self) -> U256 { self.header_view().gas_used() }

	/// Block extra data.
	pub fn extra_data(&self) -> Vec<u8> { self.header_view().extra_data() }

	/// Engine-specific seal fields.
	pub fn seal(&self) -> Vec<Vec<u8>> { self.header_view().seal() }
}

// forwarders to body view.
impl Block {
	/// Get a vector of all transactions.
	pub fn transactions(&self) -> Vec<UnverifiedTransaction> { self.view().transactions() }

	/// Number of transactions in the block.
	pub fn transactions_count(&self) -> usize { self.view().transactions_count() }

	/// A view over each transaction in the block.
	pub fn transaction_views(&self) -> Vec<views::TransactionView> { self.view().transaction_views() }

	/// The hash of each transaction in the block.
	pub fn transaction_hashes(&self) -> Vec<H256> { self.view().transaction_hashes() }

	/// Decode uncle headers.
	pub fn uncles(&self) -> Vec<FullHeader> { self.view().uncles() }

	/// Number of uncles.
	pub fn uncles_count(&self) -> usize { self.view().uncles_count() }

	/// Borrowed view over each uncle.
	pub fn uncle_views(&self) -> Vec<views::HeaderView> { self.view().uncle_views() }

	/// Hash of each uncle.
	pub fn uncle_hashes(&self) -> Vec<H256> { self.view().uncle_hashes() }
}
