/*
	This file is part of cpp-ethereum.

	cpp-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.

	cpp-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 cpp-ethereum.  If not, see <http://www.gnu.org/licenses/>.
*/
/** @file State.h
 * @author Gav Wood <i@gavwood.com>
 * @date 2014
 */

#pragma once

#include <array>
#include <unordered_map>
#include <libdevcore/Common.h>
#include <libdevcore/RLP.h>
#include <libdevcore/TrieDB.h>
#include <libdevcrypto/OverlayDB.h>
#include <libethcore/Exceptions.h>
#include <libethcore/BlockInfo.h>
#include <libethcore/Miner.h>
#include <libevm/ExtVMFace.h>
#include "Account.h"
#include "Transaction.h"
#include "TransactionReceipt.h"
#include "AccountDiff.h"
#include "GasPricer.h"

namespace dev
{

namespace test { class ImportTest; class StateLoader; }

namespace eth
{

// Import-specific errinfos
using errinfo_uncleIndex = boost::error_info<struct tag_uncleIndex, unsigned>;
using errinfo_currentNumber = boost::error_info<struct tag_currentNumber, u256>;
using errinfo_uncleNumber = boost::error_info<struct tag_uncleNumber, u256>;
using errinfo_unclesExcluded = boost::error_info<struct tag_unclesExcluded, h256Hash>;
using errinfo_block = boost::error_info<struct tag_block, bytes>;
using errinfo_now = boost::error_info<struct tag_now, unsigned>;

using errinfo_transactionIndex = boost::error_info<struct tag_transactionIndex, unsigned>;

using errinfo_vmtrace = boost::error_info<struct tag_vmtrace, std::string>;
using errinfo_receipts = boost::error_info<struct tag_receipts, std::vector<bytes>>;
using errinfo_transaction = boost::error_info<struct tag_transaction, bytes>;
using errinfo_phase = boost::error_info<struct tag_phase, unsigned>;
using errinfo_required_LogBloom = boost::error_info<struct tag_required_LogBloom, LogBloom>;
using errinfo_got_LogBloom = boost::error_info<struct tag_get_LogBloom, LogBloom>;
using LogBloomRequirementError = boost::tuple<errinfo_required_LogBloom, errinfo_got_LogBloom>;

class BlockChain;
class State;
class TransactionQueue;
struct VerifiedBlockRef;

struct StateChat: public LogChannel { static const char* name(); static const int verbosity = 4; };
struct StateTrace: public LogChannel { static const char* name(); static const int verbosity = 5; };
struct StateDetail: public LogChannel { static const char* name(); static const int verbosity = 14; };
struct StateSafeExceptions: public LogChannel { static const char* name(); static const int verbosity = 21; };

enum class BaseState
{
	PreExisting,
	Empty
};

enum class Permanence
{
	Reverted,
	Committed
};

/**
 * @brief Model of an Ethereum state, essentially a facade for the trie.
 * Allows you to query the state of accounts, and has built-in caching for various aspects of the
 * state.
 */
class State
{
	friend class ExtVM;
	friend class dev::test::ImportTest;
	friend class dev::test::StateLoader;
	friend class Executive;
	friend class BlockChain;

public:
	/// Default constructor; creates with a blank database prepopulated with the genesis block.
	State(): State(OverlayDB(), BaseState::Empty) {}

	/// Basic state object from database.
	/// Use the default when you already have a database and you just want to make a State object
	/// which uses it. If you have no preexisting database then set BaseState to something other
	/// than BaseState::PreExisting in order to prepopulate the Trie.
	/// You can also set the coinbase address.
	explicit State(OverlayDB const& _db, BaseState _bs = BaseState::PreExisting);

	/// Copy state object.
	State(State const& _s);

	/// Copy state object.
	State& operator=(State const& _s);

	/// Open a DB - useful for passing into the constructor & keeping for other states that are necessary.
	static OverlayDB openDB(std::string const& _path, h256 const& _genesisHash, WithExisting _we = WithExisting::Trust);
	static OverlayDB openDB(h256 const& _genesisHash, WithExisting _we = WithExisting::Trust) { return openDB(std::string(), _genesisHash, _we); }
	OverlayDB const& db() const { return m_db; }
	OverlayDB& db() { return m_db; }

	/// Populate the state from the given AccountMap. Just uses dev::eth::commit().
	void populateFrom(AccountMap const& _map);

	/// @returns the set containing all addresses currently in use in Ethereum.
	/// @warning This is slowslowslow. Don't use it unless you want to lock the object for seconds or minutes at a time.
	/// @throws InterfaceNotSupported if compiled without ETH_FATDB.
	std::unordered_map<Address, u256> addresses() const;

	/// Execute a given transaction.
	/// This will change the state accordingly.
	std::pair<ExecutionResult, TransactionReceipt> execute(EnvInfo const& _envInfo, Transaction const& _t, Permanence _p = Permanence::Committed, OnOpFunc const& _onOp = OnOpFunc());

	/// Check if the address is in use.
	bool addressInUse(Address const& _address) const;

	/// Check if the address contains executable code.
	bool addressHasCode(Address const& _address) const;

	/// Get an account's balance.
	/// @returns 0 if the address has never been used.
	u256 balance(Address const& _id) const;

	/// Add some amount to balance.
	/// Will initialise the address if it has never been used.
	void addBalance(Address const& _id, u256 const& _amount);

	/** Subtract some amount from balance.
	 * @throws NotEnoughCash if balance of @a _id is less than @a _value (or has never been used).
	 * @note We use bigint here as we don't want any accidental problems with negative numbers.
	 */
	void subBalance(Address const& _id, bigint const& _value);

	/**
	 * @brief Transfers "the balance @a _value between two accounts.
	 * @param _from Account from which @a _value will be deducted.
	 * @param _to Account to which @a _value will be added.
	 * @param _value Amount to be transferred.
	 */
	void transferBalance(Address const& _from, Address const& _to, u256 const& _value) { subBalance(_from, _value); addBalance(_to, _value); }

	/// Get the root of the storage of an account.
	h256 storageRoot(Address const& _contract) const;

	/// Get the value of a storage position of an account.
	/// @returns 0 if no account exists at that address.
	u256 storage(Address const& _contract, u256 const& _memory) const;

	/// Set the value of a storage position of an account.
	void setStorage(Address const& _contract, u256 const& _location, u256 const& _value) { m_cache[_contract].setStorage(_location, _value); }

	/// Create a new contract.
	Address newContract(u256 const& _balance, bytes const& _code);

	/// Get the storage of an account.
	/// @note This is expensive. Don't use it unless you need to.
	/// @returns std::unordered_map<u256, u256> if no account exists at that address.
	std::unordered_map<u256, u256> storage(Address const& _contract) const;

	/// Get the code of an account.
	/// @returns bytes() if no account exists at that address.
	bytes const& code(Address const& _contract) const;

	/// Get the code hash of an account.
	/// @returns EmptySHA3 if no account exists at that address or if there is no code associated with the address.
	h256 codeHash(Address const& _contract) const;

	/// Note that the given address is sending a transaction and thus increment the associated ticker.
	void noteSending(Address const& _id);

	/// Get the number of transactions a particular address has sent (used for the transaction nonce).
	/// @returns 0 if the address has never been used.
	u256 transactionsFrom(Address const& _address) const;

	/// The hash of the root of our state tree.
	h256 rootHash() const { return m_state.root(); }

	/// @return the difference between this state (origin) and @a _c (destination).
	/// @param _quick if true doesn't check all addresses possible (/very/ slow for a full chain)
	/// but rather only those touched by the transactions in creating the two States.
	StateDiff diff(State const& _c, bool _quick = false) const;

	/// Commit all changes waiting in the address cache to the DB.
	void commit();

	/// Resets any uncommitted changes to the cache.
	void setRoot(h256 const& _root);

private:
	/// Retrieve all information about a given address into the cache.
	/// If _requireMemory is true, grab the full memory should it be a contract item.
	/// If _forceCreate is true, then insert a default item into the cache, in the case it doesn't
	/// exist in the DB.
	void ensureCached(Address const& _a, bool _requireCode, bool _forceCreate) const;

	/// Retrieve all information about a given address into a cache.
	void ensureCached(std::unordered_map<Address, Account>& _cache, Address const& _a, bool _requireCode, bool _forceCreate) const;

	/// Debugging only. Good for checking the Trie is in shape.
	bool isTrieGood(bool _enforceRefs, bool _requireNoLeftOvers) const;

	/// Debugging only. Good for checking the Trie is in shape.
	void paranoia(std::string const& _when, bool _enforceRefs = false) const;

	OverlayDB m_db;								///< Our overlay for the state tree.
	SecureTrieDB<Address, OverlayDB> m_state;	///< Our state tree, as an OverlayDB DB.
	mutable std::unordered_map<Address, Account> m_cache;	///< Our address cache. This stores the states of each address that has (or at least might have) been changed.
	AddressHash m_touched;						///< Tracks all addresses touched so far.

	static std::string c_defaultPath;

	friend std::ostream& operator<<(std::ostream& _out, State const& _s);
};

std::ostream& operator<<(std::ostream& _out, State const& _s);

template <class DB>
AddressHash commit(AccountMap const& _cache, SecureTrieDB<Address, DB>& _state)
{
	AddressHash ret;
	for (auto const& i: _cache)
		if (i.second.isDirty())
		{
			if (!i.second.isAlive())
				_state.remove(i.first);
			else
			{
				RLPStream s(4);
				s << i.second.nonce() << i.second.balance();

				if (i.second.storageOverlay().empty())
				{
					assert(i.second.baseRoot());
					s.append(i.second.baseRoot());
				}
				else
				{
					SecureTrieDB<h256, DB> storageDB(_state.db(), i.second.baseRoot());
					for (auto const& j: i.second.storageOverlay())
						if (j.second)
							storageDB.insert(j.first, rlp(j.second));
						else
							storageDB.remove(j.first);
					assert(storageDB.root());
					s.append(storageDB.root());
				}

				if (i.second.isFreshCode())
				{
					h256 ch = sha3(i.second.code());
					_state.db()->insert(ch, &i.second.code());
					s << ch;
				}
				else
					s << i.second.codeHash();

				_state.insert(i.first, &s.out());
			}
			ret.insert(i.first);
		}
	return ret;
}

}
}